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Home My WebLink About; Hydromodification & Exemption Analysis for Select Carlsbad Watersheds; Hydromodification & Exemption Analysis for Select Carlsbad Watersheds; 2015-09-17HYDROMODIFICATION EXEMPTION ANALYSES FOR SELECT CARLSBAD WATERSHEDS September 17, 2015 Wayne W. Chang, MS, PE 46548 Chang Civil Engineering ◦ Hydrology ◦ Hydraulics ◦ Sedimentation P.O. Box 9496 Rancho Santa Fe, CA 92067 (858) 692-0760 TABLE OF CONTENTS Executive Summary ........................................................................................................................... i Introduction ........................................................................................................................................ I Outlet Conditions ............................................................................................................................... 3 Discharge to Lagoons ........................................................................................................................ 5 Hydrologic and Hydraulic Analyses .................................................................................................. 7 Cone I usion ......................................................................................................................................... 1 O Figures ................................................................................................................................................ 12 APPENDICES (on CD in map pocket) A. Dokken Engineering's HEC-RAS Analyses B. I 0-Year Rational Method Analyses MAP POCKET Study Area Exhibit HMP Exemption Exhibit CD Containing As-Built Plans City of Carlsbad Report accepted by: JasorvGeldert, City Engineer PE# 639 12 Exp 9/30/16 <;e,pTe t¥\ .6u 2 Z. 2 2-0 J .5 Date i EXECUTIVE SUMMARY In accordance with Order No. R9-2013-0001, issued by the California Regional Water Quality Control Board (Municipal Permit), projects that are subject to Priority Development Project requirements must incorporate: 1) Treatment control best management practices, and 2) Flow- control requirements to address potential hydromodification impacts to downstream natural (non- hardened) channels. However, certain improved/hardened drainage systems are not impacted by channel erosion. For these cases, the Municipal Permit includes provisions where a local agency may provide exemptions from hydromodification: Each Copermittee has the discretion to exempt a Priority Development Project from hydromodification management BMP performance requirements of Provisions E.3.c.(2) where the project discharges water runoff to: (i) Existing underground storm drains discharging directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. ii) Conveyance channels whose bed and bank are concrete lined all the way from the point of discharge to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean; Having development/redevelopment projects explore HMP exemption criteria could require an individual project proponent to undertake significant engineering analyses and evaluation of downstream drainage facilities and conditions within a watershed area. Consequently, the City of Carlsbad’s Land Development Engineering Division commissioned this hydromodification exemption study. This report focuses on certain watershed areas tributary to the Agua Hedionda Lagoon, Batiquitos Lagoon, and Buena Vista Lagoon. All three Lagoons are located within the Carlsbad Watershed area and are considered enclosed embayments per the Municipal Permit. The study limits focus on select areas draining to the lagoons that are highly-developed and are served by improved existing paved streets that collect and convey runoff via reinforced concrete pipes (hardened systems) that are not subject to erosion potential. For each storm drain network discharging to the lagoon, the discharge locations were evaluated to ensure they qualify as a ‘direct discharge’. To qualify as a direct discharge, field visits were performed at each outlet location to verify properly sized energy dissipation and, by a review of record drawings, that the discharge locations are below the 100-year flood elevation of the lagoon (consistent with Watershed Management Area Analysis (WMAA) for the San Diego River). Pictures of the outlet locations are at the end of this study. The HMP Exemption Exhibit in the map pocket at the back of this report includes the limits of the study areas. For those projects located within a hatched area, they are considered exempt from hydromodification requirements either under current conditions or with some future ii improvements. In accordance with the Municipal Permit, projects that are exempt from hydromodification must still satisfy all other applicable storm water standards (i.e.: site design, source control measures, treatment control best management practices, low impact development, etc.). Although several watershed areas were evaluated, not all drainage areas qualified for exemption from hydromodifcation requirements. These reasons why they did not qualify will be explained further in the study and are, therefore, not included as exempt areas in the HMP Exemption Exhibit. 1 INTRODUCTION In accordance with the Municipal Permit, development and redevelopment projects are subject to either: 1) Standard Stormwater or 2) Priority Development Project (PDP) requirements, which are more rigorous. The City’s “Storm Water Standards Questionnaire E-34” (see Figure 11) is used to determine whether a project must meet Standard Stormwater or PDP requirements. The questionnaire, using criteria from the Municipal Permit, provides specific thresholds under which these new development/redevelopment projects trigger PDP requirements. Among other things, projects subject to PDP requirements must include treatment control best management practices (BMPs) and are required to incorporate hydromodification BMPs. Hydromodification provides requirements to control post-development storm water runoff rates, velocities, and durations in order to maintain or reduce pre-development downstream erosion, sediment pollutant generation, and protect beneficial uses and stream habitat. For this study, a focus was made to look at the three lagoons within the city (Buena Vista, Agua Hedionda, and Batiquitos Lagoon) and explore applicable HMP exemptions. This study assesses the lagoons and seven (7) major drainage areas contributing to the lagoons to determine whether they meet hydromodification exemption criteria. The seven major drainage areas are tributary to one of the seven following storm drain outlets into Buena Vista, Agua Hedionda, or Batiquitos Lagoon (see the Study Area Exhibits and HMP Exemption Exhibit in the map pocket): Buena Vista Lagoon  48” and 66” outlets on the east side of Carlsbad Boulevard into the south side of the lagoon  48” outlet on the west side of Interstate 5 into the south side of the lagoon  66” outlet on the west side of Jefferson Street into the south side of the lagoon Agua Hedionda Lagoon  18” outlet on the west end of Date Avenue into the north side of the lagoon  84” outlet on the east side of the railroad tracks into the north side of the lagoon  60” outlet near the south end of Marina Drive into the north side of the lagoon Batiquitos Lagoon  84” outlet on the east side of Carlsbad Boulevard into the north side of the lagoon With the exception of one area, the studied tributary areas do not include natural (non-hardened) channels directly to a lagoon. Each of these major drainage areas is served by a network of improved (hardened) public drainage facilities that outlet into a lagoon. The majority of the public facilities are underground storm drain systems or paved streets. Some facilities are also lined (concrete, gunite, etc.) drainage ditches or swales. Provided runoff from the study area discharges into a non-erodible drainage network that is continuous with a direct discharge to a lagoon, it is potentially eligible for a hydromodification exemption. Based on record drawing research and field reconnaissance, the Study Area Exhibits identify the improved (hardened) drainage networks. The exhibits demonstrate that each major drainage area, except the 48” outlet 2 towards Buena Vista Lagoon on the west side of Interstate 5, contains a continuously improved non-erodible network that serves the drainage area; therefore MS4’s draining directly into the lagoons are not subject to potential impacts from hydromodification. The discharge points must be below the 100-year water surface elevations in the lagoon (consistent with Watershed Management Area Analysis (WMAA) for the San Diego River). Areas Draining to Buena Vista Lagoon Using rational method analyses from the 2003 County Hydrology Manual and as-built (record drawing) research, the existing storm drain network collecting run-off for all of the Buena Vista Lagoon drainage areas (Major Drainage Basins 100, 200, and 300 as shown on the Study Area Exhibits) analyzed in this report have been shown to be adequate to convey the Q10 runoff, which is the upper range for hydromodification as described the Municipal Permit. Each outlet structure was observed to ensure they include adequate energy dissipation to address erosion potential. For details of how these each of these criteria where satisfied, refer to the Appendices of this study. The select areas draining to the Buena Vista Lagoon from Major Drainage Basins 100 and 300, which are determined to be exempt from HMP are shown in the HMP Exemption Exhibit. Although Major Drainage Basin 200 includes an improved non-erosive (hardened) storm drain system, the existing 48” outlet is not directly adjacent to the waters edge of Buena Vista Lagoon; therefore, does not qualify as a direct discharge to an exempt water body. In order for Major Drainage Basin 200 to qualify for an exemption a non-erodible drainage facility capable of conveying at least the 10-year flow will need to be constructed from the existing 48” outlet to the 100-year floodplain in the receiving lagoon. Areas Draining to Agua Hedionda Lagoon and Batiquitos Lagoon Certain drainage areas that drain to these lagoons were selected (Major Drainage Basin 400, 500, 600, and 700 as shown on the Study Area Exhibits). The existing storm drain network for each drainage area was also evaluated against their ability to carry the Q10. As provided in the Technical Appendices, the storm drain system for each drainage areas has the capacity to carry the Q10. The outlet for each storm drain system was also observed to ensure they include adequate energy dissipation to address erosion potential. For details of how these each of these criteria where satisfied, refer to the Appendices of this study. Based on these findings, the select areas draining to Agua Hedionda Lagoon and Batiquitos Lagoon are shall be considered exempt from HMP. These exempt areas are shown in the HMP Exemption Exhibit. There are two isolated areas within Major Drainage Basin 600 that direct storm runoff over the natural ground surface west of the railroad tracks. Without further analysis using erosion potential (or equivalent), the naturally-lined swales are not considered exempt from hydromodification. Therefore, these areas were excluded from the exemption area in HMP Exemption Exhibit and from further analysis. 3 OUTLET CONDITIONS Since the storm drain networks considered in this report are continuously non-erodible to one of the three lagoons (except from Major Drainage Basin 200 and a portion of 600), the energy dissipation to be studied are at the lagoon outlets. As-built drawings were reviewed and a site visit was performed to determine the conditions at each outlet. The following describes the findings for each outlet. In addition, the Lagoon Assessment section contained next in this report confirms that each outlet is below the 100-year water surface elevation. This effort confirms the storm drain network (MS4’s) qualifies as a ‘direct discharge’ to an exempt water body. Buena Vista Lagoon 48” and 66” Outlets These are adjacent reinforced concrete pipe outlets that discharge into the south edge of Buena Vista Lagoon immediately east of the merge of State Street and Carlsbad Boulevard. During the site visit, the lagoon water level was at the invert of the 48” outlet and just above the invert of the 66” outlet (see Figure 1 after this report text). Riprap energy dissipation was not observed below the outlets nor was there evidence of erosion below the outlets (see Figure 2). Drawing No. 215-9 shows that the invert elevation of the 66” reinforced concrete pipe outlet is at 6.0 feet NGVD 29 (the reference drawings are included on the compact disc in the map pocket). The 48” outlet is shown on Drawing 153-9, but the plan does not identify the vertical datum. Based on the site visit, the 48” outlet invert is approximately 6 inches higher than the 66” outlet invert. Buena Vista Lagoon contains a weir structure near the Pacific Ocean that controls the water surface in the lagoon. A field survey by Algert Engineering revealed that the top of the weir structure is at 7.6 feet NAVD 88 or 5.5 feet NGVD 29. Therefore, the water level in the lagoon will be within at least 6 to 12 inches of the outlets. During most periods, the water level should be higher than 5.5 feet due to natural sand build-up above the weir crest caused by littoral processes as well as backwater in the lagoon. Since ponded water is an effective energy dissipater, the 48” and 66” outlets contain proper energy dissipation. This is further evidenced by the absence of erosion below the outlets even though they have been in place since at least the mid-1980’s. Buena Vista Lagoon 48” Outlet This 48” reinforced concrete pipe is a Caltrans facility whose outlet discharges towards, but not directly into, the south edge of Buena Vista Lagoon immediately west of Interstate 5. The as- built plans (Document No. 40002483) show that the outlet is at elevation 22.0 feet and was designed with “rock slope protection.” During the site visit, riprap was observed below the 48” outlet (see Figure 3). The typical riprap diameter was over 12 inches, which is consistent with the sizing proposed on the design plans. Tall grasses obscured some of the riprap, but the grass indicates that the energy dissipation is effective. However, since this outlet is not a ‘direct’ discharge to the lagoon (see Lagoon Assessment section), no further analysis is provided. Buena Vista Lagoon 66” Outlet This 66” reinforced concrete pipe discharges into the south edge of Buena Vista Lagoon immediately west of Jefferson Street. The as-built plans (Drawing No. 182-10) show that the outlet invert is at elevation 5.3 feet NGVD 29 and contains ¼-ton riprap. The outlet invert was just below the lagoon water level (see Figure 4) during the site visit, which is consistent with the 4 weir-controlled lagoon water level. Riprap was not observed at the outlet during the site visit due to the difficulty in accessing the outlet through the dense vegetation. However, the fact that the water level will be at or above the outlet invert indicates that this outlet has appropriate energy dissipation. Agua Hedionda Lagoon 18” Outlet This 18” corrugated metal pipe discharges onto a riprap-lined revetment protecting the northeast bank of Agua Hedionda Lagoon immediately west of the intersection of Date Avenue with Garfield Street (see Figure 5). Storm runoff flows a short distance down the revetment and into the lagoon. As-built plans (Drawing No. 133-3) show that the outlet invert is at elevation 5.36 feet and that energy dissipation has been designed below the outlet. In addition, the tributary drainage area covers approximately 5.2 acres, so the pipe flows will be relatively small. Agua Hedionda Lagoon 84” Outlet This 84” reinforced concrete pipe discharges into the north edge of Agua Hedionda Lagoon just east of the railroad tracks. The engineering plans (Drawing No. 360-5) were as-built in 2006, so this is a relatively recent system. The plans show that the storm drain system and its grouted riprap energy dissipater were designed for the 100-year storm flow in accordance with current engineering criteria. A site visit confirmed that the grouted riprap energy dissipater exists and is in substantial conformance with the plans (see Figure 6). Agua Hedionda Lagoon 60” Outlet This 60” reinforced concrete pipe discharges directly into the north edge of Agua Hedionda Lagoon just west of Marina Drive. The as-built plans (Drawing No. 152-3) show that the outlet invert elevation is -1.75 feet NGVD 29. This elevation is lower than mean sea level, so the lagoon water level will serve as appropriate energy dissipation for the outflow. A site visit confirmed that the invert is lower than the lagoon water level (see Figure 8). Batiquitos Lagoon 84” Outlet This 84” reinforced concrete pipe discharges into the north edge of Batiquitos Lagoon just east of Carlsbad Boulevard and west of the railroad tracks. The as-built drawings (Drawing No. 337- 9) show that the storm drain system and its energy dissipater (1-ton riprap and concrete sill) were designed for the 100-year storm flow in accordance with current engineering criteria. A site visit confirmed that the energy dissipater exists in substantial conformance with the plans (see Figure 9). Summary For those outlets that qualify as direct discharges, the above information confirms that proper energy dissipation currently exists at each of the storm drain outlet locations for the drainage areas. The dissipation is provided by either riprap or the water level in a lagoon. 5 DISCHARGE TO LAGOONS The October 3, 2014, San Diego River Watershed Management Area Analysis, states that “to qualify for the potential [hydromodification] exemption, the outlet elevation must be between the river bottom elevation and the 100-year floodplain elevation and properly designed energy dissipation must be provided.” Proper energy dissipation was verified in the prior section. This section discusses the 100-year floodplain elevations. Research was performed to determine the 100- year water surface elevations in each of the three lagoons. FEMA provides 100-year floodplain information for many waterbodies. FEMA defines a 100-year floodplain for the lagoons, but does not provide the necessary water surface elevations. However, Dokken Engineering (Dokken) performed detailed HEC-RAS hydraulic analyses of each lagoon as part of their December 2008, Interstate 5 North Coast Floodplain Studies, for Caltrans. Relevant excerpts from the Dokken studies are included in the Appendices. Table 1 summarizes the outlet elevations of each discharge point from the as-built drawings (discussed in the prior section) and the associated 100-year floodplain elevation from the Dokken studies. The as-built drawings are either identified as being on NGVD 29 datum or were prepared prior to 1988, so by default should be on NGVD 29. On the other hand, the Dokken studies are on NAVD 88 datum. Corpscon is provided by the US Army Corps of Engineers for coordinate conversions, and shows that 2.2 feet is added to the NGVD 29 elevations to convert to NAVD 88 elevations. Major Drainage Basin Description Outlet Elevation, feet1 Lagoon 100-Year Water Surface Elevation, feet2 100 Buena Vista Lagoon 48” and 66” Outlets 6.00 13.93 200 Buena Vista Lagoon 48” Outlet 22.00 13.89 300 Buena Vista Lagoon 66” Outlet 5.30 15.75 400 Agua Hedionda Lagoon 60” Outlet -1.75 12.33 500 Agua Hedionda Lagoon 18” Outlet 5.36 11.68 600 Agua Hedionda Lagoon 84” Outlet 7.95 12.21 700 Batiquitos Lagoon 84” Outlet 6.27 8.90 1Elevations are on NGVD 29 (add 2.2 feet to convert to NAVD 88) 2Elevations are on NAVD 88 Table 1. Summary of Storm Drain Outlet Elevations and Lagoon Elevations Table 1 shows that all of the storm drain outlets (with the conversion applied) except at Major Drainage Basin 200 are below the 100-year water surface elevation in the associated lagoon. Therefore, the hydromodification exemption requirement to have the outlet elevation below the 100-year floodplain elevation is met except at Major Drainage Basin 200. Summary The four drainage areas (Major Drainage Basins 400, 500, 600, 700) tributary to the Agua Hedionda Lagoon and Batiquitos Lagoon are served by an improved (non-erosive) street and underground storm drains system and have capacity to convey the 10-year rain event condition. The storm drain outlets for these drainage areas to the lagoon are considered direct discharges. Therefore, these areas are considered exempt from hydromodification. 6 The easterly and westerly drainage areas (Major Dainage Basins 100 and 300) tributary to and outletting directly into Buena Vista Lagoon are served by an improved (non-erosive) street and underground storm drains system and have capacity to convey the 10-year rain event condition. The storm drain outlets for these drainage areas to the lagoon are considered direct discharges. Therefore, these areas are also considered exempt from hydromodification. The westerly drainage areas (Major Drainage Basin 200) tributary to and outletting adjacent to the Buena Vista Lagoon west of Interstate 15 is served by an improved (non-erosive) street and underground storm drains system and have capacity to convey the 10-year rain event condition. However, this outlet is not considered a direct discharge. In order to create a direct discharge, drainage improvements will need to be constructed that are capable of conveying the 10-year flow to the lagoon. The new outlet must have proper energy dissipation and extend below the 100-year water surface elevation. If such improvements are constructed in the future, this area can be considered as exempt from hydromodification. 7 HYDROLOGIC AND HYDRAULIC ANALYSES As mentioned in the Introduction, hydromodification applies to flows up to the 10-year event. Consequently, the drainage network (storm drain pipes, streets, etc.) within each major drainage area are required to convey the 10-year flow in order to qualify for an exemption. All of the available as-built plans for the public storm drain systems in the seven major drainage areas were obtained and reviewed. Several of the more recent as-built plans list 10- or 100-year flow rates in the pipes and/or hydraulic grade lines on the storm drain profiles. These systems have been identified on the Study Area Exhibits and further analyses were not required since the systems have been designed to convey the 10-year or greater flow rates. Therefore, development within these areas is exempt from HMP. Hydrologic and hydraulic analyses have been performed for the remaining systems whose plans do not contain the flow or hydraulic grade line data. The hydrologic analyses were performed to determine the ultimate condition 10-year flow rates. The County of San Diego’s 2003 Hydrology Manual rational method procedure was used for the 10-year hydrologic analyses. The rational method input parameters are summarized below and the supporting data is included in Appendix B:  Precipitation: The 10-year, 6- and 24-hour precipitation values are 1.7 and 3.1 inches, respectively, for the drainage areas tributary to Buena Vista and Agua Hedionda Lagoon. The 10-year, 6- and 24-hour precipitation values are 1.7 and 2.9 inches, respectively, for the drainage areas tributary to Batiquitos Lagoon.  Drainage subbasin: The drainage subbasins were delineated from the City’s 2005 2-foot contour interval topographic mapping, the City’s GIS storm drain network, available as- built plans, and a site investigation. See the Study Area Exhibits in the map pocket for the major and subbasin boundaries, rational method node numbers, and subbasin areas.  Hydrologic soil groups: The hydrologic soil groups were determined from the San Diego County Soils Interpretation Study maps for Encinitas and Rancho Santa Fe. The soil group in the study area is primarily A with some pockets of C and D.  Runoff coefficients: The runoff coefficients were assigned based on the underlying land uses and soil groups. The land uses range from undisturbed areas to commercial/industrial development. The land uses were determined from a 2009 aerial photograph from the City and 2010 Google Earth aerials as well as a site investigation. For undeveloped areas that could be subject to development, a developed condition was assumed. Therefore, the hydrologic analyses essentially model a fully built-out condition. This approach is similar to what would be done for a storm water master plan.  Flow lengths and elevations: The flow lengths and elevations were obtained from the topographic mapping and engineering plans. 8 The 10-year rational method analyses were performed using CivilDesign’s San Diego County Rational Hydrology Program and the results are included in Appendix B. Separate analyses were performed for the major drainage areas and are labeled as follows: Buena Vista Lagoon  Major Basin 100 is tributary to the 48” and 66” outlet on the east side of Carlsbad Boulevard  Major Basin 200 is tributary to the 48” outlet on the west side of Interstate 5  Major Basin 300 is tributary to the 66” outlet on the west side of Jefferson Street Agua Hedionda Lagoon  Major Basin 400 is tributary to the 60” outlet at the south end of Marina Drive  Major Basin 500 is tributary to the 18” outlet at the west end of Date Avenue  Analyses were not performed for the 84” outlet on the east side of the railroad tracks because flow rates and hydraulic grade lines were provided on the majority of the as-built plans. Batiquitos Lagoon  Analyses were not performed for the 84” outlet on the east side of Carlsbad Boulevard because flow rates and hydraulic grade lines were provided on the majority of the as-built plans. The CivilDesign rational method analyses include pipeflow routines for modeling flow in circular pipes. The upstream and downstream invert elevations and pipe length are entered in the model for each storm drain segment. The program then determines the required normal depth pipe size based on the calculated 10-year flow rate, longitudinal slope, and roughness coefficient. The pipeflow routines were used to assess the adequacy of the existing pipes. Invert elevations were selected so that the longitudinal slope from the as-built plans was accurately modeled in the analyses. The longitudinal slope of each storm drain segment was determined from a review of all relevant as-built plans. Some storm drain segments contain varying or multiple slopes. In this case, the flattest slope was used because it will result in the most conservative sizing. A few segments were missing elevations on the as-built plans. For these segments, the average street slope was used. The pipe size from the hydraulic analyses were then compared to the size from the as-built plans to identify pipes with adequate capacity and those with deficiencies. Since the rational method program determines the minimum required pipe size to convey the 10- year flow in each specific segment, it is possible that program will show the required size increasing or decreasing in adjacent segments of the overall storm drain system. For instance, if the same flow rate is conveyed in two adjacent segments, but the downstream segment has a steeper longitudinal slope, the results can show that the downstream pipe is smaller. Engineering design criteria typically does not allow subsequent segments in a storm drain system to be smaller. However, since the rational method results are merely used as a comparison with the sizes from the as-built plans, any usual telescoping effects are not relevant. 9 The pipes have been categorized based on their capacity and identified on the Study Area Exhibits per their category. The first category represents pipes in which the as-built plans contain flow rate or hydraulic grade line information indicating that the pipes can convey the 10-year runoff. As mentioned above, analyses were not specifically performed for these systems since detailed information is contained on the as-built plans. The second category represents pipes in which the rational method analyses show that the existing size can convey the 10-year flow rate. The third category represents pipes in which the rational method analyses show that the existing pipes need to be upsized by at most one pipe size (6 inches) to convey the 10-year flow. The fourth category represents pipes in which the rational method analyses show that the existing pipes need to be upsized by more than one pipe size to convey the 10-year flow. The first and second categories represent no major deficiencies in capacity. The third category indicates that the existing pipe is slightly undersized. However, if pressure flow and street capacity are considered, these systems will be capable of conveying the 10-year flows since the additional flow associated with an at most 6 inch increase in pipe size can be conveyed under pressure or within the adjacent street. This was confirmed by comparing the 10-year flow rates with a street flow capacity chart. For a given pipe segment, the street flow capacity chart indicated that the associated street can convey the required flow. Therefore, the drainage systems within the first three categories have capacity for the 10-year flow. Existing pipes under the fourth category require additional review to determine whether the 10- year flow can be conveyed. Additional review resulted in the following assessment of the storm drain systems within the fourth category. Major Basin 100 There are four storm drain segments in Major Basin 100 that fall within the fourth category. The segments are between rational method nodes 105 to 109, 135 to 136, 137 to 138, and 138 to 141. The following assesses the pipe and street capacity of each of these four segments. The existing pipe from nodes 105 to 109 has an 18” diameter with a normal depth capacity of approximately 10 cubic feet per second (cfs). However, the rational method results show that the 10-year flow rate is 37 cfs, and the pipe size needed to convey 37 cfs varies from 30” to 33”. The corridor along the street between these nodes has capacity for the additional 27 cfs (37 – 10 = 27 cfs) needed beyond the pipe capacity. Therefore, the combined pipe and street in this area can convey the 10-year flow. A similar assessment is made for the other three segments. The existing pipe from nodes 135 to 136 is a 24” reinforced concrete pipe (RCP), while the analyses show that a 33” RCP is needed. The existing pipe from nodes 137 to 138 is a 36” RCP while the analyses show that a 45” RCP is needed. The existing pipe from nodes 138 to 141 is a 12” RCP while the analyses show that a 30” RCP is needed. For each of these deficient segments, the associated streets can handle the additional capacity needs. In addition, the adjacent upstream and downstream pipe segments are not deficient. Therefore, the overall drainage systems along these nodes can convey the 10-year flow. 10 Major Basin 300 There are two storm drain segments in Major Basin 300 that fall within the fourth category. The segments are between rational method nodes 309 to 316 and nodes 340 to 343. The existing pipes from nodes 309 to 316 are 24” RCPs, while the required pipe varies from 36” to 39”. The existing pipes from nodes 340 to 343 are 66” RCPs, while the required size varies from 78” to 81”. For both of these areas, the associated streets can handle the additional capacity needs, so these areas can convey the 10-year flow. Major Basin 400 There are two storm drain segments in Major Basin 400 that fall within the fourth category. The segments are between rational method nodes 408 to 409 and 418 to 420. The existing pipe between nodes 408 and 409 is an 18” RCP, while a 30” RCP is needed. This pipe crosses a sump in the street. The excess stormwater will pond in the street until it drains through the 18” RCP. Therefore, the 10-year flow will be detained in this area. In addition, there are no natural streams in the vicinity that would be subject to HMP requirements. The existing pipe between nodes 418 and 420 is a 60” RCP that outlets into Agua Hedionda Lagoon, while the analyses show that a 72” RCP is required. However, a 60” bypass structure near the upper end of this segment can divert a portion of the runoff to a second outlet that discharges to a cove connecting to Agua Hedionda Lagoon. The as-built plans (Drawing No. 152-3) show that the bypass is controlled by stop logs. If the bypass is open, then the pipe capacity below the bypass will be sufficient for the 10-year flow. The City of Carlsbad’s Utilities Operations staff has a “Weir Wall Removal Procedure,” so the stop logs will be removed during high flow events to ensure 10-year flow capacity. Therefore, this area conveys the 10-year runoff to Agua Hedionda Lagoon. CONCLUSION The City of Carlsbad’s final HMP outlines conditions under which a Priority Development Project can be exempt from hydromodification requirements. The purpose of this study is to explore HMP exemptions based on the January 2011 Carlsbad SUSMP and Order No. R9-2013- 0001 adopted by the Regional Water Quality Control Board. In particular, this study examines the criteria necessary for HMP exemptions for 1) enclosed embayments (lagoons) and 2) stabilized conveyances to exempt systems. These analyses have been performed for seven major drainage areas selected by the City of Carlsbad and are summarized below based on the two primary criteria that were investigated. Additional criteria must be met in addition to the primary criteria to achieve an exemption. The additional criteria is also summarized below. Stabilized Conveyances with Energy Dissipation The hydrologic and hydraulic analyses show that the 10-year flow is conveyed by the underground storm drain alone in most areas, and the combination of the underground storm drain and improved public streets in the remaining areas. In addition, each storm drain outlet into 11 a lagoon has proper energy dissipation. Therefore, each study area contains an underground storm drain or conveyance channel that discharges directly to an enclosed conveyance. Lagoon Floodplains A comparison of as-built drawings with a recent detailed HEC-RAS analysis of each lagoon confirmed that each outlet is below the 100-year floodplain except in Major Drainage Basin 200. Each outlet is also at or above the associated lagoon floor. Therefore, each outlet except in Major Drainage Basin 200 meets the floodplain criteria for a hydromodification exemption. Major Drainage Basin 200 can meet the criteria if its non-erodible drainage system is extended to the lagoon. Future Projects Based on the findings in this report, future projects within one of the studied drainage areas (except Major Drainage Basin 200) qualify for an exemption if their storm runoff is directed to a public drainage facility included in this report without being conveyed over a natural drainage course. However, future projects in certain locations within the study area will be required to perform additional analyses prior to receiving a hydromodification exemption. These exceptions are outlined below. The major drainage area tributary to the 84” outlet into Agua Hedionda Lagoon is bisected along its westerly side by the existing railroad tracks. Storm runoff from two areas west of the tracks will be directed to naturally-lined swales near the tracks. Since naturally-lined swales prevent a hydromodification exemption, development west of the tracks may need to replace a natural swale with a non-erodible conveyance. It will be the responsibility for a future development project west of the tracks to assess this situation in detail and propose a solution, as needed. The HMP Exemption Exhibit delineates the two non-exempt areas for reference. Hydrologic analyses have not been performed for these two areas. Figure 9. Outlet of 84" RCP into Batiquitos Lagoon Figure 10. Sand Flat below Outlet of 84" RCP into Batiquitos Lagoon 16 Figure 7. Open Water· Adjacent to Energy Dissipater at 84" RCP into Agua Hedionda Lagoon Figure 8. Outlet of 60" RCP into Agua Hedionda Lagoon 15 Figure 5. Outlet of 18" RCP into Agua Hedionda Lagoon Figm·e 6. Outlet of 84" RCP into Agua Hedionda Lagoon 14 Figure 4. 13 Figure 1. Outlet of 48" and 66" RCPs into Buena Vista Lagoon Figure 2. Downstream of 48" and 66" RCPs showing no Erosion 12 E-34 Page 1 of 3 REV 1/14/11 Development Services Land Development Engineering 1635 Faraday Avenue 760-602-2750 www.carlsbadca.gov STORM WATER STANDARDS QUESTIONNAIRE E-34 INSTRUCTIONS: To address post-development pollutants that may be generated from development projects, the City requires that new development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management Practices (BMP’s) into the project design per the City’s Standard Urban Stormwater Management Plan (SUSMP). To view the SUSMP, refer to the Engineering Standards (Volume 4, Chapter 2) at www.carlsbadca.gov/standards. Initially this questionnaire must be completed by the applicant in advance of submitting for a development application (subdivision, discretionary permits and/or construction permits). The results of the questionnaire determine the level of storm water standards that must be applied to a proposed development or redevelopment project. Depending on the outcome, your project will either be subject to ‘Standard Stormwater Requirements’ or be subject to additional criteria called ‘Priority Development Project Requirements’. Many aspects of project site design are dependent upon the storm water standards applied to a project. Your responses to the questionnaire represent an initial assessment of the proposed project conditions and impacts. City staff has responsibility for making the final assessment after submission of the development application. If staff determines that the questionnaire was incorrectly filled out and is subject to more stringent storm water standards than initially assessed by you, this will result in the return of the development application as incomplete. In this case, please make the changes to the questionnaire and resubmit to the City. If you are unsure about the meaning of a question or need help in determining how to respond to one or more of the questions, please seek assistance from Land Development Engineering staff. A separate completed and signed questionnaire must be submitted for each new development application submission. Only one completed and signed questionnaire is required when multiple development applications for the same project are submitted concurrently. In addition to this questionnaire, you must also complete, sign and submit a Project Threat Assessment Form with construction permits for the project. Please start by completing Section 1 and follow the instructions. When completed, sign the form at the end and submit this with your application to the city. SECTION 1 NEW DEVELOPMENT Does your project meet one or more of the following criteria: YES NO 1. Housing subdivisions of 10 or more dwelling units. Examples: single family homes, multi-family homes, condominium and apartments 2. Commercial – greater than 1-acre. Any development other than heavy industry or residential. Examples: hospitals; laboratories and other medical facilities; educational institutions; recreational facilities; municipal facilities; commercial nurseries; multi-apartment buildings; car wash facilities; mini-malls and other business complexes; shopping malls; hotels; office buildings; public warehouses; automotive dealerships; airfields; and other light industrial facilities. 3. Heavy Industrial / Industry- greater than 1 acre. Examples: manufacturing plants, food processing plants, metal working facilities, printing plants, and fleet storage areas (bus, truck, etc.). 4. Automotive repair shop. A facility categorized in any one of Standard Industrial Classification (SIC) codes 5013, 5014, 5541, 7532-7534, and 7536-7539 5. Restaurants. Any facility that sells prepared foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption (SIC code 5812), where the land area for development is greater than 5,000 square feet. Restaurants where land development is less than 5,000 square feet shall meet all SUSMP requirements except for structural treatment BMP and numeric sizing criteria requirements and hydromodification requirements. E-34 Page 2 of 3 REV 1/14/11 Development Services Land Development Engineering 1635 Faraday Avenue 760-602-2750 www.carlsbadca.gov STORM WATER STANDARDS QUESTIONNAIRE E-34 6. Hillside development. Any development that creates more than 5,000 square feet of impervious surface and is located in an area with known erosive soil conditions, where the development will grade on any natural slope that is twenty-five percent (25%) or greater. 7. Environmentally Sensitive Area (ESA)1. All development located within or directly adjacent2 to or discharging directly3 to an ESA (where discharges from the development or redevelopment will enter receiving waters within the ESA), which either creates 2,500 square feet or more of impervious surface on a proposed project site or increases the area of imperviousness of a proposed project site 10% or more of its naturally occurring condition. 8. Parking lot. Area of 5,000 square feet or more, or with 15 or more parking spaces, and potentially exposed to urban runoff 9. Streets, roads, highways, and freeways. Any paved surface that is 5,000 square feet or greater used for the transportation of automobiles, trucks, motorcycles, and other vehicles 10. Retail Gasoline Outlets. Serving more than 100 vehicles per day and greater than 5,000 square feet 11. Coastal Development Zone. Any project located within 200 feet of the Pacific Ocean and (1) creates more than 2500 square feet of impervious surface or (2) increases impervious surface on property by more than 10%. 12. More than 1-acre of disturbance. Project results in the disturbance of 1-acre or more of land and is considered a Pollutant-generating Development Project4. 1 Environmentally Sensitive Areas include but are not limited to all Clean Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies designated with the RARE beneficial use by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); areas designated as preserves or their equivalent under the Multi Species Conservation Program within the Cities and County of San Diego; and any other equivalent environmentally sensitive areas which have been identified by the Copermittees. 2 “Directly adjacent” means situated within 200 feet of the Environmentally Sensitive Area. 3 “Discharging directly to” means outflow from a drainage conveyance system that is composed entirely of flows from the subject development or redevelopment site, and not commingled with flow from adjacent lands. 4 Pollutant-generating Development Projects are those projects that generate pollutants at levels greater than background levels. In general, these include all projects that contribute to an exceedance to an impaired water body or which create new impervious surfaces greater than 5000 square feet and/or introduce new landscaping areas that require routine use of fertilizers and pesticides. In most cases linear pathway projects that are for infrequent vehicle use, such as emergency or maintenance access, or for pedestrian or bicycle use, are not considered Pollutant-generating Development Projects if they are built with pervious surfaces or if they sheet flow to surrounding pervious surfaces. INSTRUCTIONS:: Section 1 Results: If you answered YES to ANY of the questions above, your project is subject to Priority Development Project requirements. Skip Section 2 and please proceed to Section 3. Check the “meets PRIORITY DEVELOPMENT PROJECT requirements” box in Section 3. Additional storm water requirements will apply per the SUSMP. If you answered NO to ALL of the questions above, then please proceed to Section 2 and follow the instructions. E-34 Page 3 of 3 REV 1/14/11 Development Services Land Development Engineering 1635 Faraday Avenue 760-602-2750 www.carlsbadca.gov STORM WATER STANDARDS QUESTIONNAIRE E-34 SECTION 2 SIGNIFICANT REDEVELOPMENT INSTRUCTIONS: Complete the questions below regarding your project YES NO 1. Project results in the disturbance of 1-acre or more of land and is considered a Pollutant-generating Development Project *? INSTRUCTIONS: If you answered NO, please proceed to question 2. If you answered YES, then you ARE a significant redevelopment and you ARE subject to PRIORITY DEVELOPMENT PROJECT requirements. Please check the “meets PRIORITY DEVELOPMENT PROJECT requirements” box in Section 3 below. 2. Is the project redeveloping an existing priority project type? (Priority projects are defined in Section 1) INSTRUCTIONS: If you answered YES, please proceed to question 3. If you answered NO, then you ARE NOT a significant redevelopment and your project is subject to STANDARD STORMWATER REQUIREMENTS. Please check the “does not meet PDP requirements” box in Section 3 below. 3. Is the work limited to trenching and resurfacing associated with utility work; resurfacing and reconfiguring surface parking lots and existing roadways; new sidewalk; bike lane on existing road and/or routine maintenance of damaged pavement such as pothole repair? Resurfacing/reconfiguring parking lots is where the work does not expose underlying soil during construction. INSTRUCTIONS: If you answered NO, then proceed to question 4. If you answered YES, then you ARE NOT a significant redevelopment and your project is subject to STANDARD STORMWATER REQUIREMENTS. Please check the “does not meet PDP requirements” box in Section 3 below. 4. Will your redevelopment project create, replace, or add at least 5,000 square feet of impervious surfaces on existing developed property or will your project be located within 200 feet of the Pacific Ocean and (1) create 2500 square feet or more of impervious surface or (2) increases impervious surface on the property by more than 10%? Replacement of existing impervious surfaces includes any activity that is not part of routine maintenance where impervious material(s) are removed, exposing underlying soil during construction. INSTRUCTIONS: If you answered YES, you ARE a significant redevelopment, and you ARE subject to PRIORITY DEVELOPMENT PROJECT requirements. Please check the “meets PRIORITY DEVELOPMENT PROJECT requirements” box in Section 3 below. Review SUSMP to find out if SUSMP requirements apply to your project envelope or the entire project site. If you answered NO, then you ARE NOT a significant redevelopment and your project is subject to STANDARD STORMWATER REQUIREMENTS. Please check the “does not meet PDP requirements” box in Section 3 below. *for definition see Footnote 4 on page 2 SECTION 3 QUESTIONNAIRE RESULTS My project meets PRIORITY DEVELOPMENT PROJECT (PDP) requirements and must comply with additional stormwater criteria per the SUSMP and I understand I must prepare a Storm Water Management Plan for submittal at time of application. I understand flow control (hydromodification) requirements may apply to my project. Refer to SUSMP for details. My project does not meet PDP requirements and must only comply with STANDARD STORMWATER REQUIREMENTS per the SUSMP. As part of these requirements, I will incorporate low impact development strategies throughout my project. Applicant Information and Signature Box This Box for City Use Only Address: Assessor’s Parcel Number(s): Applicant Name: Applicant Title: Applicant Signature: Date: City Concurrence: YES NO By: Date: Project ID: APPENDIX A DOKKEN ENGINEERING’S HEC-RAS ANALYSES BUENA VISTA LAGOON LOCATION HYDRAULIC STUDY . SECTION 9 Buena Vista Lagoon Location Hydraulic Study DOKKEN ENGINEERING w w w .dok k 1 ne nJlnt erl n1.com I BUENA VISTA LAGOON LOCATION HYDRAULIC REPORT . regions with velocities close or equal to zero, were used in the model near the constriction points. The entire 100-year flow passes through the lagoon at a slow, almost stagnant rate. 9.3.4 Discharge Based on FIS data, Table 4 -Summary of Discharge: Buena Vista Creek -Upstream of Interstate Highway 5, 8,500 cfs was selected as the 100-year flood discharge. 9.4 HEC-RAS OUTPUT The water surface elevations, which are displayed in the appendices and output of this study, are based on flooding that would occur during a l 00-year storm. Appendix B contains water surface elevations, channel velocities, top widths, Froude Numbers, and bottom elevations for each cross section. Water surface elevations decreased immediately after the I-5 Bridge due to the sudden contraction and expansion formed in the lagoon by the existing 1-5 Bridge. Since Buena Vista Lagoon is a fairly flat waterway, the water surface elevations remain uniform upstream and downstream of the bridge. In effect, the lagoon's flat bottom lacks the change in elevation to achieve higher flow velocities and thus produces a level water surface profile. As shown in Table A, no significant increase to the existing l 00-year floodplain would occur from the 1-5 bridge replacement. The replacement bridge would result in a lowering of the floodplain upstream the 1-5 Bridge by approximately 6 inches. Table A: Floodplain Comparison River Existing Proposed Change in Existing Proposed Change Station Q Total w.s. w.s. Elevation Top Top in Elevation Elevation Width Width Width (cfs) (ft) (ft) (ft) (ft) (ft) (ft) 7947 8500 15.75 15.26 -0.49 934.46 912.6 -21 .86 7865 8500 15.76 15.28 -0.48 1205.4 1193.87 -11.53 7697 8500 15.77 15.29 -0.48 1208.66 1200.76 -7.90 7483 8500 15.76 15.28 -0.48 1260.07 1255.28 -4.79 7282 8500 15.76 15.28 -0.48 1415.89 1406.2 -9.69 7136 8500 15.76 15.28 -0.48 1554.97 1544.01 -10.96 6964 8500 15.76 15.28 -0.48 1585.09 1582.05 -3.04 6803 8500 15.76 15.28 -0.48 1610.37 1585.69 -24.68 6648 8500 15.76 15.28 -0.48 1686.39 1677.56 -8.83 6511 8500 15.76 15.28 -0.48 1655.38 1639.75 -15.63 6381 8500 15.76 15.28 -0.48 1608.53 1594.83 -13.70 6279 8500 15.76 15.28 -0.48 1595.29 1562.22 -33.07 6168 8500 15.76 15.28 -0.48 1547.69 1544.9 -2.79 6060 8500 15.76 15.28 -0.48 1562.11 1559.88 -2.23 5939 8500 15.76 15.28 -0.48 1561 .86 1559.71 -2.15 5816 8500 15.76 15.28 -0.48 1559.09 1557.32 -1.77 5670 8500 15.76 15.28 -0.48 1519.46 1513.41 -6.05 5522 8500 15.76 15.28 -0.48 1489.76 1487.18 -2.58 5368 8500 15.76 15.28 -0.48 1460.43 1457.99 -2.44 5244 8500 15.76 15.28 -0.48 1314.36 1311 .03 -3.33 9-8 February 2008 BUENA VISTA LAGOON LOCATION HYDRAULIC REPORT 5089 8500 15.76 15.27 -0.49 1237.75 1234.37 -3.38 4974 8500 15.75 15.26 -0.49 1114.1 1110.44 -3.66 4887 8500 15.18 14.64 -0.54 924.71 905.96 -18.75 4867* 8500 14.81 N/A N/A 913.65 N/A N/A 4700 8500 1-5 BridQe 4607 8500 12.95 13.13 0.18 560.83 568.41 7.58 4529 8500 13.89 13.89 0.00 789.07 789.07 0.00 4400 8500 13.92 13.92 0.00 887.72 887.72 0.00 4288 8500 13.93 13.93 0.00 1261.72 1261.72 0.00 4110 8500 13.93 13.93 0.00 1199.97 1199.97 0.00 3872 8500 13.93 13.93 0.00 1359.49 1359.49 0.00 3623 8500 13.93 13.93 0.00 1442.3 1442.3 0.00 3420 8500 13.93 13.93 0.00 1682.14 1682.14 0.00 3149 8500 13.93 13.93 0.00 1789.06 1789.06 0.00 2862 8500 13.93 13.93 0.00 1816.98 1816.98 0.00 2630 8500 13.93 13.93 0.00 1782.09 1782.09 0.00 2447 8500 13.93 13.93 0.00 1745.88 1745.88 0.00 2292 8500 13.93 13.93 0.00 1668.46 1668.46 0.00 2123 8500 13.93 13.93 0.00 1695.11 1695.11 0.00 2005 8500 13.93 13.93 0.00 1892.59 1892.59 0.00 1859 8500 13.93 13.93 0.00 1815.9 1815.9 0.00 1780 8500 13.93 13.93 0.00 1755.61 1755.61 0.00 1681 8500 13.92 13.92 0.00 1737.24 1737.24 0.00 1647 8500 13.82 13.82 0.00 1677.12 1677.12 0.00 1600 8500 Carlsbad Boulevard Culvert BridQe 1580 8500 13.74 13.74 0.00 1740.14 1740.14 0.00 1311 8500 13.79 13.79 0.00 1742.06 1742.06 0.00 1078 8500 13.69 13.69 0.00 408.41 408.41 0.00 1050 8500 NCTD Railroad Bridge 1039 8500 13.69 13.69 0.00 383.33 383.33 0.00 726 8500 13.73 13.73 0.00 1667.25 1667.25 0.00 397 8500 13.42 13.42 0.00 1528.37 1528.37 0.00 180 8500 12.00 12.00 0.00 568.21 568.21 0.00 0 8500 11 .19 11 .19 0.00 1429.65 1429.65 0.00 * Cross section only in existing model 9.4.1 Warning Messages Warning messages encountered during the proposed model include the following: The velocity head has changed by more than 0. 5 ft (0.15 m). This may indicate the need for additional cross sections, displayed at cross sections #180, #397, #4607, #4700, and #4974. This message is common at constrictions such as bridges and additional cross sections are not normally added. The conveyance ratio (upstream conveyance divided by downstream conveyance) is less than 0. 7 or greater than 1.4. This may indicate the need for additional cross sections, displayed at cross sections #180, #397, #726, #1039, #1050, #1078, #131 1, #1580, #1681 , 9-9 February 2008 LEGEND I PLOODPLAIN PlllA D HOODPLAIN PllOPOIE W AllaA TIH PLO -PnC lllHll STATIOll cao.. ••cTIOll .. HCTION • IANK CllO __ lllOHT OYP ROH HCTION ll:lllAHIC C Ll!l'T OY a HCTION · --IL CllOS llAlll CHANN lllACH LINOTH --YllllANIC •••••••••• lllOHT 0 AIOI lll!ACH Lt:HOTH •••••••·• LIFT OYl!::.L lllACH LaNOTH llA .. CHA LEGEND• Pl•A PLOOOPLAlll PROPOllD PLDODPLAIN ( l ... P,.OTIYI l'LOW AlllA # 011011 llCTIOll lllVH ITATIOll lllUT OYlllSAH CllOH llOTIOM Lin OYllllAMK CROii llOTIOll •AIM CMAlllllL OllOaa alCTIOll lll•HT OYUHlltC lllAON LIM•TN LIPT OVlftlAllK ftlACH LlllOTH ~ •Alll CHAlllllL lllACH LlllOTM H MOTii• ·• l••loatea ereH aeotl•• ... , I• Hlltl•I ••*I --, ....... Pl•A z ... 'fl ............... . ......... .... ... ........... .. ..... • DOKKEN IUlllA VllTA LAOOOllll·I 011011 llCTIOll 11 N • I N II: II: ll I N • LOCATIOlla ~!f~··-a.; i1loo, u NIU 11!111 S1'•U H PllftUARY IOOI HEC-RAS Plan: ExistingBV River: Existing Reach: Buena Vista Profile: Flow1 Reach River Sta Profile OTotal Min Ch El W.S. Elev CritW.S. E.G. Elev E.G. Slope VelChnl Flow Area ToPWidth Froude#Chl Ccfs) (ft) (ft) (ft) (ft) (Mt) (ftls) (sq ft) (ft) Buena Vista 7947 Flow1 8500.00 0.00 15.75 4.12 15.79 0.000038 1.72 5028.66 934.46 0.08 Buena Vista 7865 Flow1 8500.00 -2.00 15.76 1.50 15.78 0.000016 1.19 7315.54 1205.40 0.05 Buena Vista 7697 Flow1 8500.00 ·4.00 15.77 0.56 15.78 0.000006 0.79 12049.31 1208.66 0.03 Buena Vista 7483 Flow1 8500.00 1.00 15.76 3.73 15.78 0.000013 0.87 10529.84 1260.07 0.05 Buena Vista 7282 Flow1 8500.00 1.00 15.76 15.77 0.000010 0.76 12255.38 1415.89 0.04 Buena V-ista 7136 Flow1 8500.00 0.00 15.76 15.77 0.000007 0.64 14270.92 1554.97 0.03 Buena Vista 6964 Flow1 8500.00 1.00 15.76 15.77 0.000006 0.59 14985.79 1585.09 0.03 Buena Vista 6803 Flow1 8500.00 0.00 15.76 15.77 0.000004 0.51 17030.76 1610.37 0.03 Buena Vista 6648 Flow1 8500.00 0.00 15.76 15.77 0.000004 0.52 17427.74 1686.39 0.03 Buena Vista 6511 Flow1 8500.00 1.00 15.76 15.77 0.000004 0.51 17746.60 1655.38 0.03 Buena Vista 6381 Flow1 8500.00 0.00 15.76 15.77 0.000003 0.48 19045.38 1608.53 0.02 Buena Vista 6279 Flow1 8500.00 0.00 15.76 15.77 0.000002 0.42 21452.93 1595.29 0.02 Buena Vista 6168 Flow1 8500.00 0.00 15.76 15.77 0.000002 0.38 22629.76 1547.69 0.02 Buena Vista 6060 Flow1 8500.00 0.00 15.76 15.77 0.000002 0.38 22710.90 1562.11 0.02 Buena Vista 5939 Flow1 8500.00 0.00 15.76 15.77 0.000002 0.38 22700.15 1561.86 0.02 Buena Vista 5816 Flow1 8500.00 0.00 15.76 15.77 0.000002 0.37 22956.98 1559.09 0.02 Buena Vista 5670 Flow1 8500.00 0.00 15.76 15.76 0.000002 0.38 22445.93 1519.46 0.02 Buena Vista 5522 Flow1 8500.00 0.00 15.76 15.76 0.000002 0.39 21750.33 1489.76 0.02 Buena Vista 5368 FIOW1 8500.00 0.00 15.76 1.18 15.76 0.000002 0.41 20945.81 1460.43 0.02 Buena Vista 5244 Flow1 8500.00 0.00 15.76 1.50 15.76 0.000002 0.48 17839.00 1314.36 0.02 Buena Vista 5089 Flow1 8500.00 0.00 15.76 1.64 15.76 0.000004 0.60 14413.73 1237.75 0.03 -Buena Vista 4974 Flow1 8500.00 0.00 15.75 2.66 15.76 0.000012 1.04 8721.34 11 14.10 0.05 Buena Vista 4887 Flow1 8500.00 1.00 15.18 9.13 15.71 0.000567 5.82 1460.17 924.71 0.31 Buena Vista 4867 Flow1 8500.00 1.00 14.81 9.24 15.61 0.000823 7.18 1184.18 913.65 0.37 Buena Vista 4700 Bridqe Buena Vista 4607 Flow1 8500.00 0.00 12.95 10.29 14.62 0.002103 10.80 909.32 560.83 0.57 Buena Vista 4529 Flow1 8500.00 -7.00 13.89 2.28 13.97 0.000066 2.19 3975.31 769.07 0.11 Buena Vista 4400 Flow1 8500.00 ·1.00 13.92 1.75 13.95 0.000024 1.36 6320.95 867.72 0.o7 Buena Vista 4288 Flow1 8500.00 -2.00 13.93 0.12 13.94 0.000007 0.76 11273.59 1261.72 0.03 Buena Vista 4110 Flow1 8500.00 -2.00 13.93 13.94 0.000003 0.49 17376.66 1199.97 0.02 Buena Vista 3872 Flow1 8500.00 ·2.00 13.93 13.9i 0.000003 0.49 18241.63 1359.49 0.02 ---·---....... Buena Vista 3623 Fiow1 8500.00 -2.00 13.93 13.94 0.000002 0.42 20622.91 1442.30 0.02 Buena Vista 3420 Flow1 8500.00 -2.00 13.93 13.94 0.000001 0.36 23988.75 16B2.14 0.02 Buena Vista 3149 Flow1 8500.00 ·1.00 13.93 13.94 0.000001 0.33 25674.53 1769.06 0.02 Buena Vista 2862 Flow1 8500.00 ·2.00 13.93 13.94 0.000001 0.32 26544.76 1616.98 O.Q1 Buena Vista 2630 Flow1 8500.00 -3.00 13.93 13.94 0.000001 0.32 26648.20 1782.09 O.D1 Buena Vista 2447 Flow1 8500.00 -2.00 13.93 13.93 0.000002 0.40 22623.41 1745.88 0.02 Buena Vista 2292 Flow1 8500.00 -2.00 13.93 13.93 0.000002 0.42 21576.38 1668.46 0.02 Buena Vista 2123 Flow1 6500.00 ·1.00 13.93 0.22 13.93 0.000002 0.45 20302.66 1695.11 0.02 Buena Vista 2005 Flow1 8500.00 ·1.00 13.93 0.31 13.93 0.000002 0.46 19173.12 1892.59 0.02 Buena Vista 1859 Flow1 8500.00 -1.00 13.93 0.77 13.93 0.000003 0.53 16430.98 1815.90 0.02 Buena Vista 1780 Flow1 8500.00 ·1.00 13.93 0.85 13.93 0.000004 0.55 15549.74 1755.61 0.03 Buena Vista 1661 Flow1 8500.00 ·3.00 13.92 4.36 13.93 0.000012 0.88 10962.95 1737.24 0.05 Buena Vista 1647 Flow1 8500.00 -3.00 13.82 11.60 13.92 0.000258 4.02 4273.20 1677.12 0.20 Buena Vista 1600 Brid~ ··-Buena Vista 1580 Flow1 8500.00 ·3.00 13.74 11.45 13.86 0.000265 4.17 4020.62 1740.14 0.20 Buena Vista 1311 Flow1 8500.00 -4.00 13.79 0.67 13.80 0.000010 0.93 9126.33 1742.06 0.04 Buena Vista 1078 Flow1 8500.00 ·1.00 13.69 2.92 13.79 0.000076 2.55 3557.91 408.41 0.12 Buena Vista 1050 Bridge Buena V-ista 1039 Flow1 8500.00 ·1.00 13.69 2.86 13.78 0.000073 2.45 3601.48 3B3.33 0.12 Buena Vista 726 Flow1 8500.00 ·1.00 13.73 . 2.55 13.75 0.000011 0.87 10474.23 1667.25 0.04 Buena Vista 397 Flow1 8500.00 0.00 13.42 9.69 13.71 0.000566 5.41 2902.33 1528.37 0.30 Buena Vista 180 Flow1 8500.00 -1.00 12.00 12.00 13.39 0.002352 10.76 1351.05 568.21 0.59 Buena Vista 0 Flow1 8500.00 2.00 11.19 8.16 11.23 0.000137 1.98 6152.88 1429.65 0.14 ) AGUA HEDIONDA LAGOON LOCATION HYDRAULIC STUDY SECTION 8 Agua Hedionda Lagoon Location Hydraulic Study DOKKEN ENO J NEE RI NG www.•okk••••floe•rlnf.C'ODI AGUA HEDIONDA LAGOON LOCATION HYDRAULIC STUDY 8.3.3 Starting Water Elevation The Agua Hedionda Lagoon was run under a subcritical flow regime. The downstream segment of the lagoon flowing into the Pacific Ocean is categorized as a FEMA Zone AE, which has a determined base flood elevation. The downstream starting water surface elevation was input as 11.18 ft (NA VD 88). 8.3.4 Discharge For the purposes of the floodplain analysis, 9,850 cfs was identified as the peak 100-year sto1m discharge. Discharge information was obtained from the Federal Emergency Management Agency Flood Insurance Study, San Diego County, California, Volume 1 of 7 (July 2002), at El Camino Real. 8.4 HEC-RAS OUTPUT The water surface elevations which, are displayed in the appendices and output of this study, are based on flooding that would occur during a l 00-year storm. Appendix B contains water surface elevations, channel velocity, top width, flow regime, and bottom elevations for each cross section. As shown in Table A, no significant changes to the existing l 00-year floodplain would occur from the I-5 Bridge replacement. TABLE A: Floodplain Comparison River Q Existing Proposed Change in Existing Proposed Change Station Total W.S. Elev. W.S. Elev. Elevation Top Width Top Width in Width (cfs) (ft) (ft) (ft) (ft) (ft) (ft) 6860 9850 12.27 12.33 0.06 1811.56 1813.23 1.67 5638 9850 12.26 12.33 0.07 1578.85 1579.24 0.39 4633 9850 12.26 12.33 0.07 1564.59 1564.85 0.26 3981 9850 12.26 12.33 0.07 1863.25 1863.75 0.50 3576 9850 12.22 12.28 0.06 1048.38 1049.38 1.00 3552* 9850 12.21 N/A N/A 1024.99 N/A N/A 3400 9850 1-5 BridQe 3296 9850 12.12 12.12 0.00 1118.88 1118.88 0.00 2973 9850 12.13 12.13 0.00 1081.45 1081.45 0.00 2676 9850 12.13 12.13 0.00 1059.03 1059.03 0.00 2451 9850 11 .87 11 .87 0.00 151 .95 151.95 0.00 2400 9850 NCTD Railroad Trestle BridQe 2348 9850 11.51 11.51 0.00 151 .09 151.09 0.00 1833 9850 11.68 11 .68 0.00 2321.18 2321 .18 0.00 1251 9850 11 .68 11 .68 0.00 825.89 825.89 0.00 618 9850 11 .67 11.67 0.00 629.02 629.02 0.00 321 9850 11 .66 11.66 0.00 516.98 516.98 0.00 106 9850 11 .26 11 .26 0.00 251.27 251 .27 0.00 75 9850 Carlsbad Boulevard BridQe 0 9850 11.18 11.18 0.00 249.21 249.21 0.00 * Cross section only in existing model 8-8 February 2008 ( LEGEND• ODl'LAIN FlllA PLO FLOOD1'LAIN PllOPOHD FLOW AlllA -PPICTIYI lllHll ITATION CllOH llCTIOll llOH llCTIOll IHAlllC C lllQHT OV OH IECTIOH lllANIC Cll LIFT OVE OH HCTtON HllEL Cll H llAIN CHA CH LEWQT llU1NK lllA lllQNT OVI CH LEHOTH ••••·••••• AHK lll!A LEFT OVIRI lllACH LlllQTH llAIN CHANNIL N ONDA LA DOKKE AGUA H::!. HCTION C LOCATION• ~~:!_~====-:f~.~l~N;'"'ij• s .. •INSS .,, ... , •• "°" ,.,,., ~U··••:'.":'..' L-----~ E!·~,m. u wm ___ _ ( LEGEND• Pl•A HOOOl'LAIM PllOPOllO fLOODPLAIN -l'l'•cTrn now •••• • CIOll HCT-llYH 8TATIOll lllGHT OYIHAalt CllOH HCTIOa LIPT OYllllAllK CllOll IECTIOM •Atll CHAaalL CllOH HCTIOll lllGHT OYllllAllK lllACH LallGTH LIFT OYlll8AMK llEACH LIHGTH ~ Ula CNA-L HACH Ull8TH ( . • -· --..... _, ... "'7 .......... ----............ z. .... -· ... . ·--·----·-- AQUA HllrtOHDll LAGOOll/ l•I Cll018 ll!CTIOll LOCATIOll8 PllllUAllY 20Ge HEC-RAS Plan: ExistingAHL River: Agua Hedlonda Reach: 1 Profile: PF 1 Reach River Sta Profile OTotal Min Ch El W.S. Elev CrilW.S. E.G. Elev E.G. Slope VelChnl Flow Area Top Width Froude #Chi {els) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) {sq ft) (ft) 1 6860 PF1 9850.00 -6.81 12.27 12.27 0.000001 0.36 28390.56 1811.56 0.02 1 5638 PF1 9850.00 -7.81 12.26 12.27 0.000001 0.38 26405.65 1578.85 0.02 1 4633 PF 1 9850.00 -6.81 12.26 12.27 0.000001 0.38 26392.34 1564.59 0.02 -1 3981 PF 1 9850.00 -10.81 12.26 -5.39 12.26 0.000002 0.45 22283.34 1863.25 0.02 1 3576 PF1 9850.00 -25.80 12.22 -16.75 12.26 0.000014 1.69 5984.83 1048.38 0.05 1 3552 PF 1 9850.00 -25.80 12.21 -17.74 12.26 0.000015 1.70 5908.30 1024.99 0.06 1 3400 Bridge -· 1 3296 PF 1 9850.00 -25.80 12.12 -15.63 12.15 0.000010 1.36 7332.46 1118.88 0.05 1 2973 PF 1 9850.00 -11.81 12.13 -7.61 12.14 0.000005 0.77 12844.06 1081.45 0.03 1 2676 PF1 9850.00 -25.81 12.13 -14.57 12.14 0.000006 0.97 10297.05 1059.03 0.04 1 2451 PF1 9850.00 -9.81 11.87 -2.28 12.11 0.000128 3.98 2551.94 151.95 0.16 1 2400 Bridge 1 2348 PF1 9850.00 -9.81 11.51 -2.28 11.76 0.000135 4.04 2519.91 151.09 0.16 1 1833 PF 1 9850.00 -17.81 11.68 -15.35 11.69 0.000000 0.28 35315.71 2321.18 0.01 1 1251 PF1 9850.00 -17.81 11.68 11.68 0.000003 0.63 16014.37 825.89 0.02 1 618 PF1 9850.00 -19.81 11 .67 11.68 0.000007 0.92 10960.75 629.02 0.04 1 321 PF 1 9850.00 -17.81 11 .66 11.68 0.000012 1.24 8471.83 516.98 0.05 1 106 PF1 9850.00 -3.81 11.26 4.10 11.64 0.000365 5.24 2237.35 251 .27 0.26 1 75 Bridge 1 0 PF1 9850.00 -3.81 11.18 4.11 11.56 0.000374 5.28 2216.26 249.21 0.26 -- BATIQUITOS LAGOON LOCATION HYDRAULIC STUDY . SECTION 7 Batiquitos Lagoon Location Hydraulic Study DOKKEN ENG I NEE RI NG ww w .do k kentnll neerl n1.com BATIQUITOS LAGOON LOCATION HYDRAULIC STUDY undergone major development and this value was estimated to be low. The Hydrologic Summary in the San Marcos Creek Bridge at West Carlsbad Blvd (1994) as-builts, was used to establish the l 00-year flood through the lagoon. According to the report, the 100-year base flood flow at the Carlsbad Boulevard Bridge is 12,000 cfs. 7.4 HEC-RAS OUTPUT The water surface elevations displayed in the appendices and output of this study are based on flooding that would occur during a 100-year storm. Appendix 8 contains water surface elevations, channel velocities, to p widths, Froude Numbers, and bottom elevations for each cross section list in Table A. Table A: Floodplain Comparison River Existing W.S. Proposed W.S. Change in Existing Top Proposed Top Change in Station Elevation (ft) Elevation (ft) Elevation (ft) Width (ft) Width (ft) Top Width (ft) 9724 11 .37 10.53 -0.84 1526.92 1482.77 -44.15 9162 11.36 10.52 -0.84 1665.57 1644 -21.57 8558 11.33 10.48 -0.85 1298.03 1246.88 -51.15 7922 11.32 10.46 -0.86 1719.03 1648.06 -70.97 7547 11 .32 10.46 -0.86 1528.84 1506.62 -22.22 6962 11 .31 10.46 -0.85 1572.21 1548.45 -23.76 6431 11 .3 10.45 -0.85 1967 1945.4 -21.6 5864 11 .29 10.43 -0.86 1911 .35 1886.7 -24.65 5293 11.29 10.42 -0.87 1993.45 1591.98 -401 .47 4871 11.28 10.41 -0.87 2173.11 2167.86 -5.25 4407 11.27 10.41 -0.86 2898.08 2780.56 -11 7.52 4209 11.23 10.19 -1 .04 3055.56 3016.29 -39.27 4159* 10.96 N/A N/A 3067.71 N/A N/A --- 4000 1-5 Bridge 3797 9.64 9.67 0.03 2200.43 2201.92 1.49 3581 9.8 9.8 0.00 1907.17 1907.1 7 0 3204 9.8 9.8 0.00 1594.47 1594.47 0 2754 9.8 9.8 0.00 1270.86 1270.87 0.01 2428 9.8 9.8 0.00 1657.88 1657.88 0 2076 9.8 9.8 0.00 2099.63 2099.64 0.01 1740 9.78 9.78 0.00 2060.58 2060.58 0 1454 9.46 9.46 0.00 239.8 239.8 0 ---- 1300 NCTD Railroad Bridge 1207 8.76 8.76 0.00 278.54 278.54 0 976 8.9 8.9 0.00 1636.29 1636.29 0 874 8.72 8.72 0.00 456.59 456.59 0 581 8.26 8.26 0.00 232.83 232.83 0 - --400 Carlsbad Boulevard Bridge 342 7.39 7.39 0.00 220.55 220.55 0 47 7.17 7.17 0.00 170.28 170.28 0 *Indicates cross section only in existing model The lagoon bottom elevations are fa irly fl at and the flow velocities within the lagoon are less than 2 ft/s. The velocity increases at the three bridges where the flow contracts under the crossings and then slows down again as the flow expands into the next downstream section of the lagoon. Table A indicates that the proposed 1-5 Bridge would reduce the fl ow constriction at the DO KK EN ENG I NEE RI NG 7-7 February 2008 "•• .dokkenen1I nee rl n 1.eom ,.. . ) --------------·---- legend -o-ftMUW FIGURE 0·4 Grading Plan for Mitigated Alternative 8 lll\llQIJITOS IAGOON ENHANCEMENT POOJECT Elll/EIS Clly of CorlSIXJ<l US. /'Jmy C:0<p•ol Erl(Jlnecrs LEGEND• ---n:llA ,LOOOl'LAIN # PROPOHO 'LOOOPLAIN 1111,,ICTIVI PLOW AlllA CllOll HCTIOll lllHll ITATIOll lllONT OVllllAIOt CllOll HCTIOll LIFT OVllllAlllC CllOll llCTIOll llAlll CNAlllllL CllOll IECTIOll lllQKT OVllllAlllC lllACK LlllQTK Ll'T OVllllAKIC lllACH LENGTH llAIN CKANNIL lllACN LINQTK 1(4DOKKEN ~15 IUrt• ~ • I N It It ll I N • -..u IATIQUITOI LAQOOll/l·I CllOll llCTIOll LOCATIOlll ,HllUAllY aooe HEC-RAS Plan: BL Exist River: Batiquitos Reach: 1 Profile: PF 1 ------..--.--· -Reach River Sta Profile QTotal Min Ch El W.S. Elev CritW.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude #Chi (els) (11) (11) (11) (11) (ft/11) (ft/s) (sq 11) (11) 1 9724 PF 1 12000.00 -2.18 11.37 11.38 0.000024 1.12 12231.76 1526.92 0.06 ------··----1 9162 PF1 12000.00 -2.18 11.36 11.37 0.000019 1.02 13538.79 1665.57 0.06 ---------1 8558 PF 1 12000.00 -2.18 11.33 11.36 0.000035 1.36 9973.96 1298.03 0.08 --1------I----1 7922 PF1 12000.00 -2.18 11.32 11.34 0.000024 1.22 12244.24 1719.03 0.06 ---- 1 7547 PF1 12000.00 -2.18 11.32 11.33 0.000008 0.76 16745.06 1528.84 0.04 ----·I------~--1 6962 PF 1 12000.00 -3.18 ~ -0.82 11.32 0.000008 ~-~ ~5~ 1572.21 0.04 ------~ 1 6431 PF 1 12000.00 -3.18 11.30 -0.93 11.32 0.000011 0.94 13387.49 1967.00 0.05 --,_ --------1 5864 PF1 12000.00 -3.18 11.29 -0.78 11.31 0.000015 1.10 11637.82 1911.35 0.05 --·--1 5293 PF 1 12000.00 -3.18 11.29 -0.69 11.30 0.000014 0.98 12758.45 1993.45 0.05 f-_,__ 1 4871 PF1 12000.00 -3.18 11.28 -0.25 11.29 0.000015 1.04 12614.78 2173.11 0.05 -f----· ---·-----1 4407 PF1 12000.00 -4.18 11.27 -1.54 11.29 0.000010 0.92 13579.51 2898.08 0.04 ----1 4209 PF1 12000.00 -4.18 11.23 0.85 11.28 0.000049 1.82 6582.54 3055.56 0.09 ---·--·-·--1 4159 PF 1 12000.00 -4.18 10.96 2.86 11.25 0.001048 4.34 2765.97 3067.71 0.22 ---· -------1 4000 Bridge -- 1 3797 PF 1 12000.00 -4.18 9.64 0.74 9.90 0.000213 4.08 2941.05 2200.43 0.20 1 3581 PF 1 12000.00 -5.18 9.80 -3.30 9.82 0.000010 0.95 ~2574.48 1907.17 0.04 --1 3204 PF1 12000.00 -5.00 9.80 -3.41 9.81 0.000006 0.74 16485.04 1594.47 0.03 -~ --r---1 2754 PF1 12000.00 -5.18 9.80 -3.51 9.81 0.000007 0.73 16536.97 1270.86 0.03 --1 2428 PF 1 12000.00 -5.18 9.80 9.81 0.000003 0.55 22514.18 1657.88 0.03 1 2076 PF1 12000.00 -5.18 9.80 -3.65 9.81 0.000005 0.68 17987.88 2099.63 0.03 -1 1740 PF1 12000.00 -5.18 9.78 -2.73 9.80 0.000020 1.19 10060.15 2060.58 0.06 --·-,___ ·f--->------1 1454 PF1 12000.00 -5.18 9.46 1.42 9.76 0.000321 4.42 2715.52 239.80 0.23 -1 1300 Bridge >------1 1207 PF1 12000.00 -5.18 8.76 9.04 0.000269 4.46 2978.39 278.54 0.22 ----f---1 976 PF 1 12000.00 -5.18 8.90 -2.33 8.95 0.000041 1.83 6710.87 1636.29 0.09 ---I- 1 874 PF 1 12000.00 -5.18 8.72 -0.63 8.92 0.000162 3.60 3480.47 456.59 0.17 ------1 581 PF1 12000.00 -5.18 8.26 1.86 8.82 0.002188 6.27 2123.91 232.83 0.31 1 400 Bridge ---·--, 1 342 PF1 12000.00 -5.18 7.39 8.08 0.000736 6.93 1926.47 220.55 0.35 ---------1 47 PF1 12000.00 -5.83 7.17 0.79 7.87 0.000652 6.99 1881.59 170.28 0.34 --- APPENDIX B 10-YEAR RATIONAL METHOD ANALYSES 10.0 9.0 8.0 7.0 ~ 0 .r: ]i .r: 6.0 5.0 4.0 3.0 2.0 g 1.0 ~0.9 ·~o.s ~o E .7 0.6 0.5 0.4 0.3 0.2 0.1 1' ., " .......... ...... 1' .... , ..... " .. ......... ... ,, ., .... r..... ........... ..... ~ ....~ ..... ~ ...... .... .... ........... ...... r-., .. ... ...... ' ' "" '"' '• ~ ........... ..... .. ......... .. r-. ., ~ ..... i-.,, .... ' • .. , I' ..... r-. .. .... .. ...... ' ...... ~ ..... ....... ...... .... .. ........... "'r-.. "r-. • ...... ...... .. .. . , ........... ~ .. ....... .... ......... .. ..... ' r-. .... ...... ...... 'r-. ' . ..... i-.,, ' "'r..... .. ' 'r-. ......... .... ......... ~ ..... r-., ...... .. I I I ' 5 6 7 8 9 10 15 20 ~~ ~ ... ~ .. ~~ .. ~~ ~ .. ~ .. ~~ .. ~~ .. ~ .. .. ~ .. .. ~ 30 Minutes I I I I ~ .. ..... ~ .. .. ~ .. ~ .. ~ ... ~ ~ ~ .. .. .. .. ~ ... ~ ..... ~ .. ~ ~ .. "'~ .. 40 50 Duration I = I = p6 = D = EQUATION 7.44 P6 D-0·645 Intensity (in/hr) 6-Hour Precipitation (in) Duration (min) ...... ...... ... ...... ..... r..... i'r-. ...... ..... r-.r-. ..... r-.. ..... l•i-.. ...... ...... ..... ..... r-., ... • • .. I• .. ........... ... .. • • ..... ~ .. 'I' i'oi-. ... ... ... ...... ...... ~ .. '~ ..... ....r-.. ..... ~ ...... ,, ........... "r-. ..... ..... l•r-., ............ r....., 2 l'o .. ... .... ...... .. ... .... "'"' ...... l'o .... 3 Hours .. .. .. .. .. .. .. 4 .. 5 6 Ol ± 0 c: .... -0 iil 0 6.0 -g: 5.5 ~ 5.0 g 4.5 s= 0 4.0 ~ 3.5~ 3.0 2.5 2.0 1.5 1.0 Intensity-Duration Design Chart -Template Directions for Application: (1 ) From precipitation maps determine 6 hr and 24 hr amounts for the selected frequency. These maps are included in the County Hydrology Manual (10, 50, and 100 yr maps included in the Design and Procedure Manual). (2) Adjust 6 hr precipitation (if necessary) so that it is within the range of 45% to 65% of the 24 hr precipitation (not applicaple to Desert). (3) Plot 6 hr precipitation on the right side of the chart . (4) Draw a line through the point parallel to the plotted lines. (5) This line is the intensity-duration curve for the location being analyzed. Application Form: (a) Selected frequency ___ year p (b) P6 = __ in., P24 = __ ·p 6 = 3c2i 24 (c) Adjusted P6<2> = ___ in. (d) Ix= __ min . (e) I = __ in./hr. Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. 1 1.5i 2 2.5 3 3.5~ 4 4.5 5 5.5 6 Duration I I I I I I . t I I I I I 5-2-.-63~3-.9-5+5-.2-7~6-.5-9-7~.-90~9.-2-2-t-0.~54~1-1.-86~1-3.-17~1-4.-49~1-5.~81 P6 7 2.12 3.18 4.24 5.30 6.36 7.4n2.48 9.54 10.60 11.66 12.72 10 1.68 2.53 3.37 4.2.!_. 5.05 5.90 6.74 7.58ffl8.42~.27 10.11 15 1.30 1.95 2.59 3.24 3~ 5.19 5.84 6.49 7.13 7.78 -20 1.08 1.622.15 2.69 3.23 3. n 4.31 4.85 5.39 5.93 6.46 25 0.93 1.40 1.87 2.33 2.80 3.27 3.73 4.20 4.67 5.13 5.60 30 0.83 1.24 1.66 2.07 2.49 2.90 3.32 3.73 4.15 4.56 4.98 40 0.69 1.03 1.38 1.72 2.07 2.41 2.76 3.10 3.45 3.79 4.13 50 0.60 0.90 1.19 1.49 1.79 2.09 2.39 2.69 2.98 3.281_3.58 60 0.53 0.80 1.06 1.33 1.59 1 86 2.12 2.39 2.65 2.92 3.18 90 0.41 0.61 0.82 1.02 1.23 1.43 1.63 1.84 2.04 2.25 2.45 120 0.34 0.51 0.68 0.85 t.02 1.191 1.36 1 .53~ 1.70 t.87 2.04 150 0.29_:0.44 _p.59_[o.73 ~0.8~03 1.18 1.32 1.47 1.62_,_1.76 180 0.26 0.39 0.52 0.65 0.78 0.91 1.04 1.18 1.31 1.44 1.57 240 0.22 0.33 0.43 0.54 0.65 0.76 0.87 0.98 1.08 1.19 1.30 300 0.19_.0.28 0.38 0.47 0.56 0.66 0.75 0.85 0.94 1.03 1.13 360 0.17 0.25 0.33 0.42 0.50 0.58 0.67 0.75 0.84 0.92 1.00 FIGURE ~ 10.0 9.0 8.0 7.0 ~ 0 .r: ]i .r: 6.0 5.0 4.0 3.0 2.0 g 1.0 ~0.9 ·~o.s ~o E .7 0.6 0.5 0.4 0.3 0.2 0.1 1' ., " .......... ...... 1' .... , ..... " .. ......... ... ,, ., .... r..... ........... ..... ~ ....~ ..... ~ ...... .... .... ........... ...... r-., .. ... ...... ' ' "" '"' '• ~ ........... ..... .. ......... .. r-. ., ~ ..... i-.,, .... ' • .. , I' ..... r-. .. .... .. ...... ' ...... ~ ..... ....... ...... .... .. ........... "'r-.. "r-. • ...... ...... .. .. . , ........... ~ .. ....... .... ......... .. ..... ' r-. .... ...... ...... 'r-. ' . ..... i-.,, ' "'r..... .. ' 'r-. ......... .... ......... ~ ..... r-., ...... .. I I I ' 5 6 7 8 9 10 15 20 ~~ ~ ... ~ .. ~~ .. ~~ ~ .. ~ .. ~~ .. ~~ .. ~ .. .. ~ .. .. ~ 30 Minutes I I I I ~ .. ..... ~ .. .. ~ .. ~ .. ~ ... ~ ~ ~ .. .. .. .. ~ ... ~ ..... ~ .. ~ ~ .. "'~ .. 40 50 Duration I = I = p6 = D = EQUATION 7.44 P6 D-0·645 Intensity (in/hr) 6-Hour Precipitation (in) Duration (min) ...... ...... ... ...... ..... r..... i'r-. ...... ..... r-.r-. ..... r-.. ..... l•i-.. ...... ...... ..... ..... r-., ... • • .. I• .. ........... ... .. • • ..... ~ .. 'I' i'oi-. ... ... ... ...... ...... ~ .. '~ ..... ....r-.. ..... ~ ...... ,, ........... "r-. ..... ..... l•r-., ............ r....., 2 l'o .. ... .... ...... .. ... .... "'"' ...... l'o .... 3 Hours .. .. .. .. .. .. .. 4 .. 5 6 Ol ± 0 c: .... -0 iil 0 6.0 -g: 5.5 ~ 5.0 g 4.5 s= 0 4.0 ~ 3.5~ 3.0 2.5 2.0 1.5 1.0 Intensity-Duration Design Chart -Template Directions for Application: (1 ) From precipitation maps determine 6 hr and 24 hr amounts for the selected frequency. These maps are included in the County Hydrology Manual (10, 50, and 100 yr maps included in the Design and Procedure Manual). (2) Adjust 6 hr precipitation (if necessary) so that it is within the range of 45% to 65% of the 24 hr precipitation (not applicaple to Desert). (3) Plot 6 hr precipitation on the right side of the chart . (4) Draw a line through the point parallel to the plotted lines. (5) This line is the intensity-duration curve for the location being analyzed. Application Form: (a) Selected frequency ___ year p (b) P6 = __ in., P24 = __ ·p 6 = 3c2i 24 (c) Adjusted P6<2> = ___ in. (d) Ix= __ min . (e) I = __ in./hr. Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. 1 1.5i 2 2.5 3 3.5~ 4 4.5 5 5.5 6 Duration I I I I I I . t I I I I I 5-2-.-63~3-.9-5+5-.2-7~6-.5-9-7~.-90~9.-2-2-t-0.~54~1-1.-86~1-3.-17~1-4.-49~1-5.~81 P6 7 2.12 3.18 4.24 5.30 6.36 7.4n2.48 9.54 10.60 11.66 12.72 10 1.68 2.53 3.37 4.2.!_. 5.05 5.90 6.74 7.58ffl8.42~.27 10.11 15 1.30 1.95 2.59 3.24 3~ 5.19 5.84 6.49 7.13 7.78 -20 1.08 1.622.15 2.69 3.23 3. n 4.31 4.85 5.39 5.93 6.46 25 0.93 1.40 1.87 2.33 2.80 3.27 3.73 4.20 4.67 5.13 5.60 30 0.83 1.24 1.66 2.07 2.49 2.90 3.32 3.73 4.15 4.56 4.98 40 0.69 1.03 1.38 1.72 2.07 2.41 2.76 3.10 3.45 3.79 4.13 50 0.60 0.90 1.19 1.49 1.79 2.09 2.39 2.69 2.98 3.281_3.58 60 0.53 0.80 1.06 1.33 1.59 1 86 2.12 2.39 2.65 2.92 3.18 90 0.41 0.61 0.82 1.02 1.23 1.43 1.63 1.84 2.04 2.25 2.45 120 0.34 0.51 0.68 0.85 t.02 1.191 1.36 1 .53~ 1.70 t.87 2.04 150 0.29_:0.44 _p.59_[o.73 ~0.8~03 1.18 1.32 1.47 1.62_,_1.76 180 0.26 0.39 0.52 0.65 0.78 0.91 1.04 1.18 1.31 1.44 1.57 240 0.22 0.33 0.43 0.54 0.65 0.76 0.87 0.98 1.08 1.19 1.30 300 0.19_.0.28 0.38 0.47 0.56 0.66 0.75 0.85 0.94 1.03 1.13 360 0.17 0.25 0.33 0.42 0.50 0.58 0.67 0.75 0.84 0.92 1.00 FIGURE ~ f-f--33•-a, >->-f-sr:: ~ ~ ~ :rr "' ~ ~ !:t: ;: ,... ,. ,... 32j3 fi ~ I !! ~ I "i i I ~·~- County of San Diego Hydrology Manual Rainfall Isopluvials 10 Year Rainfall Event-6 Houn lsopluvial (inches) I J 33•3p• -~ County of San Diego Hydrology Manual Rainfall lsopluvials 10 Year Rainfall Event-24 Hours lsopluvial (inches) San Diego County Hydrology :Manual Date• June 2003 Table 3-1 Section• Page• RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use Runoff Coefficient "C" Soil T e NRCS Elements Coun Elements % I1APER. A B Undisturbed Natural Terrain (Natural) Penn anent Open Space O* 0.20 0.25 Low Density Residential (LDR) Residential, 1.0 DU/A or less 10 0.27 0.32 Low Density Residential (LDR) Residential, 2.0 DU/A or less 20 0.34 0.38 Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41 Medium Density Residential (MDR) Residential, 4.3 DU/A or less 30 0.41 0.45 Medium Density Residential (MDR) Residential, 7.3 DU/A or less 40 0.48 0.5 1 Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54 Medium Density Residential (MDR) Residential, 14.5 DU/A or less 50 0.55 0.58 High Density Residential (HDR) Residential, 24.0 DU/A or less 65 0.66 0.67 High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77 Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 Commercial/Industrial (Limited I.) Limited Industrial 90 0.83 0.84 Commercial/Industrial General I. General Industrial 95 0.87 0.87 c 0.30 0.36 0.42 0.45 0.48 0.54 0.57 0.60 0.69 0.78 0.78 0.8 1 0.84 0.84 0.87 3 6 of26 D 0.35 0.41 0.46 0.49 0 52 0.57 0.60 0.63 0.71 0.79 0.79 0.82 0.85 0.85 0.87 *The values associated with 0% impervious may be used for direct calculation of the runoff coefficient as described in Section 3.1.2 (representing the pervious runoff coefficient, Cp, for the soil type), or for areas that will remain undisturbed in perpetuity. Justification must be given that the area will remain natural forever (e.g., the area is located in Cleveland National Forest). DU/A = dwelling units per acre NRCS =National Resources Conservation Service 3-6 San Diego County Hydrology :Manual Date: June 2003 Section: Page: 3 12 of 26 Note that the Initial Time of Concentration should be reflective of the general land-use at the upstream end of a drainage basin. A single lot with an area of two or less acres does not have a significant effect where the drainage basin area is 20 to 600 acres. Table 3-2 provides limits of the length (Maximum Length (LM)) of sheet flow to be used in hydrology studies. Initial Ti values based on average C values for the Land Use Element are also included. These values can be used in planning and design applications as described below. Exceptions may be approved by the "Regulating Agency" when submitted with a detailed study. Table 3-2 MAXIMUM OVERLAND FLOW LENGTH (LM) & INITIAL TIME OF CONCENTRATION (Ti) Element* DU/ .5% 1% 2% 3% 5% 10% Acre LM Ti LM Ti LM Ti LM Ti LM Ti LM Ti Natural 50 13.2 70 12.5 85 10.9 100 10.3 100 8.7 100 6.9 LDR 1 50 12.2 70 11.5 85 10.0 100 9.5 100 8.0 100 6.4 LDR 2 50 11.3 70 10.5 85 9.2 100 8.8 100 7.4 100 5.8 LDR 2.9 50 10.7 70 10.0 85 8.8 95 8.1 100 7.0 100 5.6 MDR 4.3 50 10.2 70 9.6 80 8.1 95 7.8 100 6.7 100 5.3 MDR 7.3 50 9.2 65 8.4 80 7.4 95 7.0 100 6.0 100 4.8 MDR 10.9 50 8.7 65 7.9 80 6.9 90 6.4 100 5.7 100 4.5 MDR 14.5 50 8.2 65 7.4 80 6.5 90 6.0 100 5.4 100 4.3 HDR 24 50 6.7 65 6.1 75 5.1 90 4.9 95 4.3 100 3.5 HDR 43 50 5.3 65 4.7 75 4.0 85 3.8 95 3.4 100 2.7 N.Com 50 5.3 60 4.5 75 4.0 85 3.8 95 3.4 100 2.7 G.Com 50 4.7 60 4.1 75 3.6 85 3.4 90 2.9 100 2.4 O.P./Com 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2 Limited I. 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2 General I. 50 3.7 60 3.2 70 2.7 80 2.6 90 2.3 100 1.9 *See Table 3-1 for more detailed description 3-12 I-w w u. z w (.) z ~ (/) 0 w (/) 0::: ::::> 0 (.) 0::: w i 2.50% slope 2.0 -+----l-'#11 1001--~---'1~·5~---1--~----------~"i":..~--..._---~· 0 EXAMPLE: Given: Watercourse Distance (D) = 70 Feet Slope (s) = 1.3% Runoff Coefficient (C) = 0.41 Overland Flow Time (T) = 9.5 Minutes SOURCE: Airport Drainage, Federal Aviation Administration, 1965 T = 1.8 (1.1-C) VD 3\fS 20 (/) w I-::::> z ~ z w ~ i== ~ 0 ....J u. 0 z ::J 0::: w > 0 FIGURE Rational Formula -Overland Time of Flow Nomograph 3.3 1 San Diego County Rational Hydrology Program CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2009 Version 7.8 Rational method hydrology program based on San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 12/08/12 ------------------------------------------------------------------------ City of Carlsbad Hydromodification Exemption Study Major Basin 100 10-Year Flow Rate ------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** ------------------------------------------------------------------------ Program License Serial Number 4028 ------------------------------------------------------------------------ Rational hydrology study storm event year is 10.0 English (in-lb) input data Units used Map data precipitation entered: 6 hour, precipitation(inches) = 1.700 24 hour precipitation(inches) = 3.100 P6/P24 = 54.8% San Diego hydrology manual 'C' values used ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 100.000 to Point/Station 101.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [LOW DENSITY RESIDENTIAL ] (1.0 DU/A or Less ) Impervious value, Ai = 0.100 Sub-Area C Value = 0.270 Initial subarea total flow distance = 244.000(Ft.) Highest elevation = 182.000(Ft.) Lowest elevation = 162.000(Ft.) Elevation difference = 20.000(Ft.) Slope = 8.197 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 8.20 %, in a development type of 1.0 DU/A or Less In Accordance With Figure 3-3 2 Initial Area Time of Concentration = 7.41 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.2700)*( 100.000^.5)/( 8.197^(1/3)]= 7.41 The initial area total distance of 244.00 (Ft.) entered leaves a remaining distance of 144.00 (Ft.) Using Figure 3-4, the travel time for this distance is 0.94 minutes for a distance of 144.00 (Ft.) and a slope of 8.20 % with an elevation difference of 11.80(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 0.939 Minutes Tt=[(11.9*0.0273^3)/( 11.80)]^.385= 0.94 Total initial area Ti = 7.41 minutes from Figure 3-3 formula plus 0.94 minutes from the Figure 3-4 formula = 8.35 minutes Rainfall intensity (I) = 3.218(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.270 Subarea runoff = 0.747(CFS) Total initial stream area = 0.860(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 101.000 to Point/Station 102.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 162.000(Ft.) End of street segment elevation = 161.000(Ft.) Length of street segment = 171.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 2.106(CFS) Depth of flow = 0.322(Ft.), Average velocity = 1.544(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 11.370(Ft.) Flow velocity = 1.54(Ft/s) Travel time = 1.85 min. TC = 10.19 min. Adding area flow to street Rainfall intensity (I) = 2.829(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [LOW DENSITY RESIDENTIAL ] 3 (2.0 DU/A or Less ) Impervious value, Ai = 0.200 Sub-Area C Value = 0.340 Rainfall intensity = 2.829(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.324 CA = 1.259 Subarea runoff = 2.814(CFS) for 3.020(Ac.) Total runoff = 3.562(CFS) Total area = 3.880(Ac.) Street flow at end of street = 3.562(CFS) Half street flow at end of street = 3.562(CFS) Depth of flow = 0.375(Ft.), Average velocity = 1.749(Ft/s) Flow width (from curb towards crown)= 14.019(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 102.000 to Point/Station 103.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 161.000(Ft.) End of street segment elevation = 73.000(Ft.) Length of street segment = 1802.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 15.814(CFS) Depth of flow = 0.427(Ft.), Average velocity = 5.604(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 16.585(Ft.) Flow velocity = 5.60(Ft/s) Travel time = 5.36 min. TC = 15.55 min. Adding area flow to street Rainfall intensity (I) = 2.154(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.700 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.300 [COMMERCIAL area type ] (Neighborhod Commercial ) Impervious value, Ai = 0.800 Sub-Area C Value = 0.769 Rainfall intensity = 2.154(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area 4 (Q=KCIA) is C = 0.679 CA = 13.055 Subarea runoff = 24.562(CFS) for 15.340(Ac.) Total runoff = 28.124(CFS) Total area = 19.220(Ac.) Street flow at end of street = 28.124(CFS) Half street flow at end of street = 28.124(CFS) Depth of flow = 0.500(Ft.), Average velocity = 6.818(Ft/s) Warning: depth of flow exceeds top of curb Note: depth of flow exceeds top of street crown. Distance that curb overflow reaches into property = 0.01(Ft.) Flow width (from curb towards crown)= 18.000(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 103.000 to Point/Station 104.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 73.000(Ft.) Downstream point/station elevation = 42.000(Ft.) Pipe length = 2380.00(Ft.) Slope = 0.0130 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 28.124(CFS) Nearest computed pipe diameter = 27.00(In.) Calculated individual pipe flow = 28.124(CFS) Normal flow depth in pipe = 18.19(In.) Flow top width inside pipe = 25.32(In.) Critical Depth = 22.13(In.) Pipe flow velocity = 9.87(Ft/s) Travel time through pipe = 4.02 min. Time of concentration (TC) = 19.57 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 103.000 to Point/Station 104.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.857(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (Neighborhod Commercial ) Impervious value, Ai = 0.800 Sub-Area C Value = 0.760 Time of concentration = 19.57 min. Rainfall intensity = 1.857(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.717 CA = 25.907 Subarea runoff = 19.993(CFS) for 16.910(Ac.) Total runoff = 48.117(CFS) Total area = 36.130(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 5 Process from Point/Station 104.000 to Point/Station 105.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 42.000(Ft.) Downstream point/station elevation = 39.890(Ft.) Pipe length = 450.00(Ft.) Slope = 0.0047 Manning's N = 0.013 No. of pipes = 2 Required pipe flow = 48.117(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 24.058(CFS) Normal flow depth in pipe = 21.38(In.) Flow top width inside pipe = 27.16(In.) Critical Depth = 20.04(In.) Pipe flow velocity = 6.43(Ft/s) Travel time through pipe = 1.17 min. Time of concentration (TC) = 20.74 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 104.000 to Point/Station 105.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1 Stream flow area = 36.130(Ac.) Runoff from this stream = 48.117(CFS) Time of concentration = 20.74 min. Rainfall intensity = 1.789(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 106.000 to Point/Station 107.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Initial subarea total flow distance = 249.000(Ft.) Highest elevation = 86.500(Ft.) Lowest elevation = 72.000(Ft.) Elevation difference = 14.500(Ft.) Slope = 5.823 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 90.00 (Ft) for the top area slope value of 5.82 %, in a development type of General Commercial In Accordance With Figure 3-3 Initial Area Time of Concentration = 2.85 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.8000)*( 90.000^.5)/( 5.823^(1/3)]= 2.85 6 The initial area total distance of 249.00 (Ft.) entered leaves a remaining distance of 159.00 (Ft.) Using Figure 3-4, the travel time for this distance is 1.16 minutes for a distance of 159.00 (Ft.) and a slope of 5.82 % with an elevation difference of 9.26(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 1.156 Minutes Tt=[(11.9*0.0301^3)/( 9.26)]^.385= 1.16 Total initial area Ti = 2.85 minutes from Figure 3-3 formula plus 1.16 minutes from the Figure 3-4 formula = 4.00 minutes Calculated TC of 4.004 minutes is less than 5 minutes, resetting TC to 5.0 minutes for rainfall intensity calculations Rainfall intensity (I) = 4.479(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.800 Subarea runoff = 4.945(CFS) Total initial stream area = 1.380(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 107.000 to Point/Station 108.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 72.000(Ft.) End of street segment elevation = 52.000(Ft.) Length of street segment = 1260.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 18.830(CFS) Depth of flow = 0.528(Ft.), Average velocity = 4.050(Ft/s) Warning: depth of flow exceeds top of curb Note: depth of flow exceeds top of street crown. Distance that curb overflow reaches into property = 1.41(Ft.) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 18.000(Ft.) Flow velocity = 4.05(Ft/s) Travel time = 5.18 min. TC = 9.19 min. Adding area flow to street Rainfall intensity (I) = 3.025(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 7 Decimal fraction soil group D = 0.000 [HIGH DENSITY RESIDENTIAL ] (43.0 DU/A or Less ) Impervious value, Ai = 0.800 Sub-Area C Value = 0.760 Rainfall intensity = 3.025(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.764 CA = 10.794 Subarea runoff = 27.707(CFS) for 12.750(Ac.) Total runoff = 32.652(CFS) Total area = 14.130(Ac.) Street flow at end of street = 32.652(CFS) Half street flow at end of street = 32.652(CFS) Depth of flow = 0.634(Ft.), Average velocity = 4.674(Ft/s) Warning: depth of flow exceeds top of curb Note: depth of flow exceeds top of street crown. Distance that curb overflow reaches into property = 6.71(Ft.) Flow width (from curb towards crown)= 18.000(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 108.000 to Point/Station 109.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 52.000(Ft.) Downstream point/station elevation = 48.000(Ft.) Pipe length = 456.00(Ft.) Slope = 0.0088 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 32.652(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 32.652(CFS) Normal flow depth in pipe = 21.23(In.) Flow top width inside pipe = 27.29(In.) Critical Depth = 23.34(In.) Pipe flow velocity = 8.78(Ft/s) Travel time through pipe = 0.87 min. Time of concentration (TC) = 10.05 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 108.000 to Point/Station 109.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.854(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Time of concentration = 10.05 min. Rainfall intensity = 2.854(In/Hr) for a 10.0 year storm 8 Effective runoff coefficient used for total area (Q=KCIA) is C = 0.770 CA = 13.010 Subarea runoff = 4.484(CFS) for 2.770(Ac.) Total runoff = 37.136(CFS) Total area = 16.900(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 109.000 to Point/Station 105.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 48.000(Ft.) Downstream point/station elevation = 44.000(Ft.) Pipe length = 490.00(Ft.) Slope = 0.0082 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 37.136(CFS) Nearest computed pipe diameter = 33.00(In.) Calculated individual pipe flow = 37.136(CFS) Normal flow depth in pipe = 21.87(In.) Flow top width inside pipe = 31.21(In.) Critical Depth = 24.34(In.) Pipe flow velocity = 8.89(Ft/s) Travel time through pipe = 0.92 min. Time of concentration (TC) = 10.97 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 109.000 to Point/Station 105.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2 Stream flow area = 16.900(Ac.) Runoff from this stream = 37.136(CFS) Time of concentration = 10.97 min. Rainfall intensity = 2.698(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 110.000 to Point/Station 111.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Initial subarea total flow distance = 740.000(Ft.) Highest elevation = 58.200(Ft.) Lowest elevation = 44.000(Ft.) Elevation difference = 14.200(Ft.) Slope = 1.919 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: 9 The maximum overland flow distance is 75.00 (Ft) for the top area slope value of 1.92 %, in a development type of General Commercial In Accordance With Figure 3-3 Initial Area Time of Concentration = 3.76 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.8000)*( 75.000^.5)/( 1.919^(1/3)]= 3.76 The initial area total distance of 740.00 (Ft.) entered leaves a remaining distance of 665.00 (Ft.) Using Figure 3-4, the travel time for this distance is 5.34 minutes for a distance of 665.00 (Ft.) and a slope of 1.92 % with an elevation difference of 12.76(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 5.336 Minutes Tt=[(11.9*0.1259^3)/( 12.76)]^.385= 5.34 Total initial area Ti = 3.76 minutes from Figure 3-3 formula plus 5.34 minutes from the Figure 3-4 formula = 9.10 minutes Rainfall intensity (I) = 3.044(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.800 Subarea runoff = 13.395(CFS) Total initial stream area = 5.500(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 111.000 to Point/Station 112.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 44.000(Ft.) Downstream point/station elevation = 42.100(Ft.) Pipe length = 380.00(Ft.) Slope = 0.0050 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 13.395(CFS) Nearest computed pipe diameter = 24.00(In.) Calculated individual pipe flow = 13.395(CFS) Normal flow depth in pipe = 16.80(In.) Flow top width inside pipe = 21.99(In.) Critical Depth = 15.81(In.) Pipe flow velocity = 5.70(Ft/s) Travel time through pipe = 1.11 min. Time of concentration (TC) = 10.21 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 111.000 to Point/Station 112.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.826(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) 10 Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Time of concentration = 10.21 min. Rainfall intensity = 2.826(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.800 CA = 8.704 Subarea runoff = 11.205(CFS) for 5.380(Ac.) Total runoff = 24.600(CFS) Total area = 10.880(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 112.000 to Point/Station 105.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 44.000(Ft.) Downstream point/station elevation = 42.550(Ft.) Pipe length = 290.00(Ft.) Slope = 0.0050 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 24.600(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 24.600(CFS) Normal flow depth in pipe = 21.21(In.) Flow top width inside pipe = 27.31(In.) Critical Depth = 20.27(In.) Pipe flow velocity = 6.63(Ft/s) Travel time through pipe = 0.73 min. Time of concentration (TC) = 10.94 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 112.000 to Point/Station 105.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 3 Stream flow area = 10.880(Ac.) Runoff from this stream = 24.600(CFS) Time of concentration = 10.94 min. Rainfall intensity = 2.703(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 48.117 20.74 1.789 2 37.136 10.97 2.698 3 24.600 10.94 2.703 Qmax(1) = 1.000 * 1.000 * 48.117) + 0.663 * 1.000 * 37.136) + 0.662 * 1.000 * 24.600) + = 89.027 Qmax(2) = 1.000 * 0.529 * 48.117) + 11 1.000 * 1.000 * 37.136) + 0.998 * 1.000 * 24.600) + = 87.141 Qmax(3) = 1.000 * 0.527 * 48.117) + 1.000 * 0.997 * 37.136) + 1.000 * 1.000 * 24.600) + = 86.997 Total of 3 streams to confluence: Flow rates before confluence point: 48.117 37.136 24.600 Maximum flow rates at confluence using above data: 89.027 87.141 86.997 Area of streams before confluence: 36.130 16.900 10.880 Results of confluence: Total flow rate = 89.027(CFS) Time of concentration = 20.741 min. Effective stream area after confluence = 63.910(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 105.000 to Point/Station 105.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.789(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Time of concentration = 20.74 min. Rainfall intensity = 1.789(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.748 CA = 50.877 Subarea runoff = 2.004(CFS) for 4.070(Ac.) Total runoff = 91.031(CFS) Total area = 67.980(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 105.000 to Point/Station 113.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 44.000(Ft.) Downstream point/station elevation = 39.770(Ft.) Pipe length = 900.00(Ft.) Slope = 0.0047 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 91.031(CFS) Nearest computed pipe diameter = 48.00(In.) Calculated individual pipe flow = 91.031(CFS) Normal flow depth in pipe = 36.42(In.) 12 Flow top width inside pipe = 41.07(In.) Critical Depth = 34.69(In.) Pipe flow velocity = 8.90(Ft/s) Travel time through pipe = 1.69 min. Time of concentration (TC) = 22.43 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 105.000 to Point/Station 113.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.701(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Time of concentration = 22.43 min. Rainfall intensity = 1.701(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.753 CA = 56.629 Subarea runoff = 5.310(CFS) for 7.190(Ac.) Total runoff = 96.341(CFS) Total area = 75.170(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 113.000 to Point/Station 114.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 36.000(Ft.) Downstream point/station elevation = 34.970(Ft.) Pipe length = 220.00(Ft.) Slope = 0.0047 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 96.341(CFS) Nearest computed pipe diameter = 48.00(In.) Calculated individual pipe flow = 96.341(CFS) Normal flow depth in pipe = 38.53(In.) Flow top width inside pipe = 38.20(In.) Critical Depth = 35.70(In.) Pipe flow velocity = 8.92(Ft/s) Travel time through pipe = 0.41 min. Time of concentration (TC) = 22.84 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 113.000 to Point/Station 114.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1 Stream flow area = 75.170(Ac.) 13 Runoff from this stream = 96.341(CFS) Time of concentration = 22.84 min. Rainfall intensity = 1.681(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 115.000 to Point/Station 116.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Initial subarea total flow distance = 760.000(Ft.) Highest elevation = 52.000(Ft.) Lowest elevation = 43.700(Ft.) Elevation difference = 8.300(Ft.) Slope = 1.092 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 60.00 (Ft) for the top area slope value of 1.09 %, in a development type of General Commercial In Accordance With Figure 3-3 Initial Area Time of Concentration = 4.06 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.8000)*( 60.000^.5)/( 1.092^(1/3)]= 4.06 The initial area total distance of 760.00 (Ft.) entered leaves a remaining distance of 700.00 (Ft.) Using Figure 3-4, the travel time for this distance is 6.90 minutes for a distance of 700.00 (Ft.) and a slope of 1.09 % with an elevation difference of 7.64(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 6.896 Minutes Tt=[(11.9*0.1326^3)/( 7.64)]^.385= 6.90 Total initial area Ti = 4.06 minutes from Figure 3-3 formula plus 6.90 minutes from the Figure 3-4 formula = 10.96 minutes Rainfall intensity (I) = 2.700(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.800 Subarea runoff = 3.197(CFS) Total initial stream area = 1.480(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 116.000 to Point/Station 117.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 43.700(Ft.) End of street segment elevation = 38.000(Ft.) Length of street segment = 663.000(Ft.) 14 Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 8.366(CFS) Depth of flow = 0.457(Ft.), Average velocity = 2.495(Ft/s) Note: depth of flow exceeds top of street crown. Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 18.000(Ft.) Flow velocity = 2.50(Ft/s) Travel time = 4.43 min. TC = 15.39 min. Adding area flow to street Rainfall intensity (I) = 2.169(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Rainfall intensity = 2.169(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.800 CA = 6.208 Subarea runoff = 10.270(CFS) for 6.280(Ac.) Total runoff = 13.467(CFS) Total area = 7.760(Ac.) Street flow at end of street = 13.467(CFS) Half street flow at end of street = 13.467(CFS) Depth of flow = 0.523(Ft.), Average velocity = 2.959(Ft/s) Warning: depth of flow exceeds top of curb Note: depth of flow exceeds top of street crown. Distance that curb overflow reaches into property = 1.16(Ft.) Flow width (from curb towards crown)= 18.000(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 117.000 to Point/Station 118.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 38.000(Ft.) Downstream point/station elevation = 37.000(Ft.) Pipe length = 200.00(Ft.) Slope = 0.0050 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 13.467(CFS) 15 Nearest computed pipe diameter = 24.00(In.) Calculated individual pipe flow = 13.467(CFS) Normal flow depth in pipe = 16.88(In.) Flow top width inside pipe = 21.93(In.) Critical Depth = 15.84(In.) Pipe flow velocity = 5.71(Ft/s) Travel time through pipe = 0.58 min. Time of concentration (TC) = 15.97 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 117.000 to Point/Station 118.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.118(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Time of concentration = 15.97 min. Rainfall intensity = 2.118(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.800 CA = 11.320 Subarea runoff = 10.506(CFS) for 6.390(Ac.) Total runoff = 23.973(CFS) Total area = 14.150(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 118.000 to Point/Station 114.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 38.000(Ft.) Downstream point/station elevation = 35.950(Ft.) Pipe length = 410.00(Ft.) Slope = 0.0050 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 23.973(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 23.973(CFS) Normal flow depth in pipe = 20.79(In.) Flow top width inside pipe = 27.68(In.) Critical Depth = 19.99(In.) Pipe flow velocity = 6.60(Ft/s) Travel time through pipe = 1.04 min. Time of concentration (TC) = 17.01 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 118.000 to Point/Station 114.000 **** CONFLUENCE OF MINOR STREAMS **** 16 ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2 Stream flow area = 14.150(Ac.) Runoff from this stream = 23.973(CFS) Time of concentration = 17.01 min. Rainfall intensity = 2.034(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 96.341 22.84 1.681 2 23.973 17.01 2.034 Qmax(1) = 1.000 * 1.000 * 96.341) + 0.827 * 1.000 * 23.973) + = 116.161 Qmax(2) = 1.000 * 0.745 * 96.341) + 1.000 * 1.000 * 23.973) + = 95.708 Total of 2 streams to confluence: Flow rates before confluence point: 96.341 23.973 Maximum flow rates at confluence using above data: 116.161 95.708 Area of streams before confluence: 75.170 14.150 Results of confluence: Total flow rate = 116.161(CFS) Time of concentration = 22.839 min. Effective stream area after confluence = 89.320(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 114.000 to Point/Station 119.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 38.000(Ft.) Downstream point/station elevation = 35.520(Ft.) Pipe length = 460.00(Ft.) Slope = 0.0054 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 116.161(CFS) Nearest computed pipe diameter = 51.00(In.) Calculated individual pipe flow = 116.161(CFS) Normal flow depth in pipe = 39.19(In.) Flow top width inside pipe = 43.03(In.) Critical Depth = 38.61(In.) Pipe flow velocity = 9.93(Ft/s) Travel time through pipe = 0.77 min. Time of concentration (TC) = 23.61 min. 17 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 114.000 to Point/Station 119.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.646(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 The area added to the existing stream causes a a lower flow rate of Q = 114.515(CFS) therefore the upstream flow rate of Q = 116.161(CFS) is being used Time of concentration = 23.61 min. Rainfall intensity = 1.646(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.762 CA = 69.581 Subarea runoff = 0.000(CFS) for 2.040(Ac.) Total runoff = 116.161(CFS) Total area = 91.360(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 119.000 to Point/Station 120.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 36.000(Ft.) Downstream point/station elevation = 33.460(Ft.) Pipe length = 470.00(Ft.) Slope = 0.0054 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 116.161(CFS) Nearest computed pipe diameter = 51.00(In.) Calculated individual pipe flow = 116.161(CFS) Normal flow depth in pipe = 39.14(In.) Flow top width inside pipe = 43.09(In.) Critical Depth = 38.61(In.) Pipe flow velocity = 9.94(Ft/s) Travel time through pipe = 0.79 min. Time of concentration (TC) = 24.40 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 119.000 to Point/Station 120.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.611(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] 18 (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 The area added to the existing stream causes a a lower flow rate of Q = 113.134(CFS) therefore the upstream flow rate of Q = 116.161(CFS) is being used Time of concentration = 24.40 min. Rainfall intensity = 1.611(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.762 CA = 70.213 Subarea runoff = 0.000(CFS) for 0.790(Ac.) Total runoff = 116.161(CFS) Total area = 92.150(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 120.000 to Point/Station 121.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 38.000(Ft.) Downstream point/station elevation = 23.440(Ft.) Pipe length = 350.00(Ft.) Slope = 0.0416 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 116.161(CFS) Nearest computed pipe diameter = 36.00(In.) Calculated individual pipe flow = 116.161(CFS) Normal flow depth in pipe = 25.59(In.) Flow top width inside pipe = 32.64(In.) Critical depth could not be calculated. Pipe flow velocity = 21.62(Ft/s) Travel time through pipe = 0.27 min. Time of concentration (TC) = 24.67 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 120.000 to Point/Station 121.000 **** CONFLUENCE OF MAIN STREAMS **** ______________________________________________________________________ The following data inside Main Stream is listed: In Main Stream number: 1 Stream flow area = 92.150(Ac.) Runoff from this stream = 116.161(CFS) Time of concentration = 24.67 min. Rainfall intensity = 1.600(In/Hr) Program is now starting with Main Stream No. 2 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 130.000 to Point/Station 131.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 19 Decimal fraction soil group D = 0.000 [LOW DENSITY RESIDENTIAL ] (1.0 DU/A or Less ) Impervious value, Ai = 0.100 Sub-Area C Value = 0.270 Initial subarea total flow distance = 290.000(Ft.) Highest elevation = 183.000(Ft.) Lowest elevation = 161.000(Ft.) Elevation difference = 22.000(Ft.) Slope = 7.586 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 7.59 %, in a development type of 1.0 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration = 7.60 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.2700)*( 100.000^.5)/( 7.586^(1/3)]= 7.60 The initial area total distance of 290.00 (Ft.) entered leaves a remaining distance of 190.00 (Ft.) Using Figure 3-4, the travel time for this distance is 1.20 minutes for a distance of 190.00 (Ft.) and a slope of 7.59 % with an elevation difference of 14.41(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 1.198 Minutes Tt=[(11.9*0.0360^3)/( 14.41)]^.385= 1.20 Total initial area Ti = 7.60 minutes from Figure 3-3 formula plus 1.20 minutes from the Figure 3-4 formula = 8.80 minutes Rainfall intensity (I) = 3.110(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.270 Subarea runoff = 0.983(CFS) Total initial stream area = 1.170(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 131.000 to Point/Station 132.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 161.000(Ft.) End of street segment elevation = 86.000(Ft.) Length of street segment = 2618.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 20 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 6.350(CFS) Depth of flow = 0.352(Ft.), Average velocity = 3.676(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 12.869(Ft.) Flow velocity = 3.68(Ft/s) Travel time = 11.87 min. TC = 20.67 min. Adding area flow to street Rainfall intensity (I) = 1.793(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.550 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.450 [LOW DENSITY RESIDENTIAL ] (2.9 DU/A or Less ) Impervious value, Ai = 0.250 Sub-Area C Value = 0.429 Rainfall intensity = 1.793(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.418 CA = 6.501 Subarea runoff = 10.674(CFS) for 14.400(Ac.) Total runoff = 11.657(CFS) Total area = 15.570(Ac.) Street flow at end of street = 11.657(CFS) Half street flow at end of street = 11.657(CFS) Depth of flow = 0.422(Ft.), Average velocity = 4.253(Ft/s) Flow width (from curb towards crown)= 16.340(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 132.000 to Point/Station 133.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 86.000(Ft.) Downstream point/station elevation = 80.000(Ft.) Pipe length = 370.00(Ft.) Slope = 0.0162 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 11.657(CFS) Nearest computed pipe diameter = 18.00(In.) Calculated individual pipe flow = 11.657(CFS) Normal flow depth in pipe = 13.01(In.) Flow top width inside pipe = 16.12(In.) Critical Depth = 15.60(In.) Pipe flow velocity = 8.53(Ft/s) Travel time through pipe = 0.72 min. Time of concentration (TC) = 21.39 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 134.000 to Point/Station 133.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.754(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.150 21 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.850 [COMMERCIAL area type ] (Neighborhod Commercial ) Impervious value, Ai = 0.800 Sub-Area C Value = 0.785 Time of concentration = 21.39 min. Rainfall intensity = 1.754(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.498 CA = 9.918 Subarea runoff = 5.737(CFS) for 4.350(Ac.) Total runoff = 17.394(CFS) Total area = 19.920(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 133.000 to Point/Station 135.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 80.000(Ft.) Downstream point/station elevation = 65.210(Ft.) Pipe length = 850.00(Ft.) Slope = 0.0174 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 17.394(CFS) Nearest computed pipe diameter = 21.00(In.) Calculated individual pipe flow = 17.394(CFS) Normal flow depth in pipe = 14.63(In.) Flow top width inside pipe = 19.31(In.) Critical Depth = 18.29(In.) Pipe flow velocity = 9.72(Ft/s) Travel time through pipe = 1.46 min. Time of concentration (TC) = 22.85 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 133.000 to Point/Station 135.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.681(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (14.5 DU/A or Less ) Impervious value, Ai = 0.500 Sub-Area C Value = 0.550 Time of concentration = 22.85 min. Rainfall intensity = 1.681(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.521 CA = 18.773 Subarea runoff = 14.160(CFS) for 16.100(Ac.) Total runoff = 31.553(CFS) Total area = 36.020(Ac.) 22 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 135.000 to Point/Station 136.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 61.000(Ft.) Downstream point/station elevation = 58.640(Ft.) Pipe length = 550.00(Ft.) Slope = 0.0043 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 31.553(CFS) Nearest computed pipe diameter = 33.00(In.) Calculated individual pipe flow = 31.553(CFS) Normal flow depth in pipe = 24.73(In.) Flow top width inside pipe = 28.61(In.) Critical Depth = 22.40(In.) Pipe flow velocity = 6.61(Ft/s) Travel time through pipe = 1.39 min. Time of concentration (TC) = 24.24 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 135.000 to Point/Station 136.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.618(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Time of concentration = 24.24 min. Rainfall intensity = 1.618(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.501 CA = 35.136 Subarea runoff = 25.301(CFS) for 34.090(Ac.) Total runoff = 56.855(CFS) Total area = 70.110(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 136.000 to Point/Station 137.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 58.000(Ft.) Downstream point/station elevation = 41.370(Ft.) Pipe length = 660.00(Ft.) Slope = 0.0252 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 56.855(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 56.855(CFS) Normal flow depth in pipe = 21.70(In.) 23 Flow top width inside pipe = 26.84(In.) Critical Depth = 28.43(In.) Pipe flow velocity = 14.95(Ft/s) Travel time through pipe = 0.74 min. Time of concentration (TC) = 24.97 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 136.000 to Point/Station 137.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.587(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (14.5 DU/A or Less ) Impervious value, Ai = 0.500 Sub-Area C Value = 0.550 Time of concentration = 24.97 min. Rainfall intensity = 1.587(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.519 CA = 57.603 Subarea runoff = 34.575(CFS) for 40.850(Ac.) Total runoff = 91.430(CFS) Total area = 110.960(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 137.000 to Point/Station 138.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 42.000(Ft.) Downstream point/station elevation = 38.960(Ft.) Pipe length = 400.00(Ft.) Slope = 0.0076 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 91.430(CFS) Nearest computed pipe diameter = 45.00(In.) Calculated individual pipe flow = 91.430(CFS) Normal flow depth in pipe = 32.39(In.) Flow top width inside pipe = 40.42(In.) Critical Depth = 35.26(In.) Pipe flow velocity = 10.75(Ft/s) Travel time through pipe = 0.62 min. Time of concentration (TC) = 25.59 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 137.000 to Point/Station 138.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 2 in normal stream number 1 Stream flow area = 110.960(Ac.) 24 Runoff from this stream = 91.430(CFS) Time of concentration = 25.59 min. Rainfall intensity = 1.562(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 139.000 to Point/Station 140.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Initial subarea total flow distance = 350.000(Ft.) Highest elevation = 51.000(Ft.) Lowest elevation = 49.000(Ft.) Elevation difference = 2.000(Ft.) Slope = 0.571 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 50.00 (Ft) for the top area slope value of 0.57 %, in a development type of General Commercial In Accordance With Figure 3-3 Initial Area Time of Concentration = 4.60 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.8000)*( 50.000^.5)/( 0.571^(1/3)]= 4.60 The initial area total distance of 350.00 (Ft.) entered leaves a remaining distance of 300.00 (Ft.) Using Figure 3-4, the travel time for this distance is 4.61 minutes for a distance of 300.00 (Ft.) and a slope of 0.57 % with an elevation difference of 1.71(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 4.610 Minutes Tt=[(11.9*0.0568^3)/( 1.71)]^.385= 4.61 Total initial area Ti = 4.60 minutes from Figure 3-3 formula plus 4.61 minutes from the Figure 3-4 formula = 9.21 minutes Rainfall intensity (I) = 3.020(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.800 Subarea runoff = 2.996(CFS) Total initial stream area = 1.240(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 140.000 to Point/Station 141.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 49.000(Ft.) End of street segment elevation = 41.000(Ft.) Length of street segment = 941.000(Ft.) 25 Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 10.559(CFS) Depth of flow = 0.486(Ft.), Average velocity = 2.728(Ft/s) Note: depth of flow exceeds top of street crown. Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 18.000(Ft.) Flow velocity = 2.73(Ft/s) Travel time = 5.75 min. TC = 14.96 min. Adding area flow to street Rainfall intensity (I) = 2.209(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (General Commercial ) Impervious value, Ai = 0.850 Sub-Area C Value = 0.800 Rainfall intensity = 2.209(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.800 CA = 8.168 Subarea runoff = 15.047(CFS) for 8.970(Ac.) Total runoff = 18.042(CFS) Total area = 10.210(Ac.) Street flow at end of street = 18.042(CFS) Half street flow at end of street = 18.042(CFS) Depth of flow = 0.578(Ft.), Average velocity = 3.178(Ft/s) Warning: depth of flow exceeds top of curb Note: depth of flow exceeds top of street crown. Distance that curb overflow reaches into property = 3.90(Ft.) Flow width (from curb towards crown)= 18.000(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 141.000 to Point/Station 138.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 41.000(Ft.) Downstream point/station elevation = 39.670(Ft.) Pipe length = 555.00(Ft.) Slope = 0.0024 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 18.042(CFS) 26 Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 18.042(CFS) Normal flow depth in pipe = 22.22(In.) Flow top width inside pipe = 26.30(In.) Critical Depth = 17.27(In.) Pipe flow velocity = 4.63(Ft/s) Travel time through pipe = 2.00 min. Time of concentration (TC) = 16.96 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 141.000 to Point/Station 138.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 2 in normal stream number 2 Stream flow area = 10.210(Ac.) Runoff from this stream = 18.042(CFS) Time of concentration = 16.96 min. Rainfall intensity = 2.037(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 91.430 25.59 1.562 2 18.042 16.96 2.037 Qmax(1) = 1.000 * 1.000 * 91.430) + 0.767 * 1.000 * 18.042) + = 105.266 Qmax(2) = 1.000 * 0.663 * 91.430) + 1.000 * 1.000 * 18.042) + = 78.625 Total of 2 streams to confluence: Flow rates before confluence point: 91.430 18.042 Maximum flow rates at confluence using above data: 105.266 78.625 Area of streams before confluence: 110.960 10.210 Results of confluence: Total flow rate = 105.266(CFS) Time of concentration = 25.594 min. Effective stream area after confluence = 121.170(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 138.000 to Point/Station 121.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 48.000(Ft.) 27 Downstream point/station elevation = 26.170(Ft.) Pipe length = 740.00(Ft.) Slope = 0.0295 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 105.266(CFS) Nearest computed pipe diameter = 36.00(In.) Calculated individual pipe flow = 105.266(CFS) Normal flow depth in pipe = 27.19(In.) Flow top width inside pipe = 30.96(In.) Critical depth could not be calculated. Pipe flow velocity = 18.39(Ft/s) Travel time through pipe = 0.67 min. Time of concentration (TC) = 26.27 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 138.000 to Point/Station 121.000 **** CONFLUENCE OF MAIN STREAMS **** ______________________________________________________________________ The following data inside Main Stream is listed: In Main Stream number: 2 Stream flow area = 121.170(Ac.) Runoff from this stream = 105.266(CFS) Time of concentration = 26.27 min. Rainfall intensity = 1.536(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 116.161 24.67 1.600 2 105.266 26.27 1.536 Qmax(1) = 1.000 * 1.000 * 116.161) + 1.000 * 0.939 * 105.266) + = 215.025 Qmax(2) = 0.960 * 1.000 * 116.161) + 1.000 * 1.000 * 105.266) + = 216.820 Total of 2 main streams to confluence: Flow rates before confluence point: 116.161 105.266 Maximum flow rates at confluence using above data: 215.025 216.820 Area of streams before confluence: 92.150 121.170 Results of confluence: Total flow rate = 216.820(CFS) Time of concentration = 26.265 min. Effective stream area after confluence = 213.320(Ac.) 28 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 121.000 to Point/Station 121.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.536(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [HIGH DENSITY RESIDENTIAL ] (43.0 DU/A or Less ) Impervious value, Ai = 0.800 Sub-Area C Value = 0.760 The area added to the existing stream causes a a lower flow rate of Q = 212.041(CFS) therefore the upstream flow rate of Q = 216.820(CFS) is being used Time of concentration = 26.27 min. Rainfall intensity = 1.536(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.639 CA = 138.006 Subarea runoff = 0.000(CFS) for 2.660(Ac.) Total runoff = 216.820(CFS) Total area = 215.980(Ac.) End of computations, total study area = 215.980 (Ac.) 1 San Diego County Rational Hydrology Program CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2009 Version 7.8 Rational method hydrology program based on San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 12/08/12 ------------------------------------------------------------------------ City of Carlsbad Hydromodification Exemption Study Major Basin 200 10-Year Flow Rate ------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** ------------------------------------------------------------------------ Program License Serial Number 4028 ------------------------------------------------------------------------ Rational hydrology study storm event year is 10.0 English (in-lb) input data Units used Map data precipitation entered: 6 hour, precipitation(inches) = 1.700 24 hour precipitation(inches) = 3.100 P6/P24 = 54.8% San Diego hydrology manual 'C' values used ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 200.000 to Point/Station 201.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (Office Professional ) Impervious value, Ai = 0.900 Sub-Area C Value = 0.830 Initial subarea total flow distance = 740.000(Ft.) Highest elevation = 95.000(Ft.) Lowest elevation = 88.000(Ft.) Elevation difference = 7.000(Ft.) Slope = 0.946 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 60.00 (Ft) for the top area slope value of 0.95 %, in a development type of Office Professional In Accordance With Figure 3-3 2 Initial Area Time of Concentration = 3.83 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.8300)*( 60.000^.5)/( 0.946^(1/3)]= 3.83 The initial area total distance of 740.00 (Ft.) entered leaves a remaining distance of 680.00 (Ft.) Using Figure 3-4, the travel time for this distance is 7.13 minutes for a distance of 680.00 (Ft.) and a slope of 0.95 % with an elevation difference of 6.43(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 7.127 Minutes Tt=[(11.9*0.1288^3)/( 6.43)]^.385= 7.13 Total initial area Ti = 3.83 minutes from Figure 3-3 formula plus 7.13 minutes from the Figure 3-4 formula = 10.96 minutes Rainfall intensity (I) = 2.700(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.830 Subarea runoff = 7.529(CFS) Total initial stream area = 3.360(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 201.000 to Point/Station 202.000 **** IMPROVED CHANNEL TRAVEL TIME **** ______________________________________________________________________ Upstream point elevation = 88.000(Ft.) Downstream point elevation = 84.100(Ft.) Channel length thru subarea = 692.000(Ft.) Channel base width = 3.000(Ft.) Slope or 'Z' of left channel bank = 4.000 Slope or 'Z' of right channel bank = 4.000 Estimated mean flow rate at midpoint of channel = 9.490(CFS) Manning's 'N' = 0.040 Maximum depth of channel = 3.000(Ft.) Flow(q) thru subarea = 9.490(CFS) Depth of flow = 0.825(Ft.), Average velocity = 1.827(Ft/s) Channel flow top width = 9.598(Ft.) Flow Velocity = 1.83(Ft/s) Travel time = 6.31 min. Time of concentration = 17.28 min. Critical depth = 0.531(Ft.) Adding area flow to channel Rainfall intensity (I) = 2.013(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (Office Professional ) Impervious value, Ai = 0.900 Sub-Area C Value = 0.830 Rainfall intensity = 2.013(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.830 CA = 5.652 3 Subarea runoff = 3.850(CFS) for 3.450(Ac.) Total runoff = 11.379(CFS) Total area = 6.810(Ac.) Depth of flow = 0.900(Ft.), Average velocity = 1.917(Ft/s) Critical depth = 0.586(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 201.000 to Point/Station 202.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1 Stream flow area = 6.810(Ac.) Runoff from this stream = 11.379(CFS) Time of concentration = 17.28 min. Rainfall intensity = 2.013(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 203.000 to Point/Station 204.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 0.500 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.500 [MEDIUM DENSITY RESIDENTIAL ] (4.3 DU/A or Less ) Impervious value, Ai = 0.300 Sub-Area C Value = 0.465 Initial subarea total flow distance = 950.000(Ft.) Highest elevation = 167.000(Ft.) Lowest elevation = 130.000(Ft.) Elevation difference = 37.000(Ft.) Slope = 3.895 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 95.00 (Ft) for the top area slope value of 3.90 %, in a development type of 4.3 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration = 7.08 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.4650)*( 95.000^.5)/( 3.895^(1/3)]= 7.08 The initial area total distance of 950.00 (Ft.) entered leaves a remaining distance of 855.00 (Ft.) Using Figure 3-4, the travel time for this distance is 4.93 minutes for a distance of 855.00 (Ft.) and a slope of 3.90 % with an elevation difference of 33.30(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 4.930 Minutes Tt=[(11.9*0.1619^3)/( 33.30)]^.385= 4.93 Total initial area Ti = 7.08 minutes from Figure 3-3 formula plus 4.93 minutes from the Figure 3-4 formula = 12.01 minutes Rainfall intensity (I) = 2.545(In/Hr) for a 10.0 year storm 4 Effective runoff coefficient used for area (Q=KCIA) is C = 0.465 Subarea runoff = 1.988(CFS) Total initial stream area = 1.680(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 204.000 to Point/Station 205.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 130.000(Ft.) End of street segment elevation = 86.000(Ft.) Length of street segment = 875.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 4.708(CFS) Depth of flow = 0.299(Ft.), Average velocity = 4.250(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 10.180(Ft.) Flow velocity = 4.25(Ft/s) Travel time = 3.43 min. TC = 15.44 min. Adding area flow to street Rainfall intensity (I) = 2.164(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.100 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.900 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.561 Rainfall intensity = 2.164(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.536 CA = 3.395 Subarea runoff = 5.360(CFS) for 4.660(Ac.) Total runoff = 7.349(CFS) Total area = 6.340(Ac.) Street flow at end of street = 7.349(CFS) Half street flow at end of street = 7.349(CFS) Depth of flow = 0.339(Ft.), Average velocity = 4.717(Ft/s) Flow width (from curb towards crown)= 12.193(Ft.) 5 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 205.000 to Point/Station 205.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.164(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.150 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.850 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.556 Time of concentration = 15.44 min. Rainfall intensity = 2.164(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.549 CA = 9.395 Subarea runoff = 12.983(CFS) for 10.780(Ac.) Total runoff = 20.332(CFS) Total area = 17.120(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 205.000 to Point/Station 205.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.164(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (Office Professional ) Impervious value, Ai = 0.900 Sub-Area C Value = 0.830 Time of concentration = 15.44 min. Rainfall intensity = 2.164(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.558 CA = 9.859 Subarea runoff = 1.006(CFS) for 0.560(Ac.) Total runoff = 21.338(CFS) Total area = 17.680(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 205.000 to Point/Station 202.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 86.000(Ft.) Downstream point/station elevation = 84.100(Ft.) Pipe length = 170.00(Ft.) Slope = 0.0112 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 21.338(CFS) Nearest computed pipe diameter = 24.00(In.) Calculated individual pipe flow = 21.338(CFS) 6 Normal flow depth in pipe = 17.67(In.) Flow top width inside pipe = 21.15(In.) Critical Depth = 19.84(In.) Pipe flow velocity = 8.61(Ft/s) Travel time through pipe = 0.33 min. Time of concentration (TC) = 15.77 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 205.000 to Point/Station 202.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2 Stream flow area = 17.680(Ac.) Runoff from this stream = 21.338(CFS) Time of concentration = 15.77 min. Rainfall intensity = 2.135(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 11.379 17.28 2.013 2 21.338 15.77 2.135 Qmax(1) = 1.000 * 1.000 * 11.379) + 0.943 * 1.000 * 21.338) + = 31.499 Qmax(2) = 1.000 * 0.913 * 11.379) + 1.000 * 1.000 * 21.338) + = 31.726 Total of 2 streams to confluence: Flow rates before confluence point: 11.379 21.338 Maximum flow rates at confluence using above data: 31.499 31.726 Area of streams before confluence: 6.810 17.680 Results of confluence: Total flow rate = 31.726(CFS) Time of concentration = 15.771 min. Effective stream area after confluence = 24.490(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 202.000 to Point/Station 206.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 84.100(Ft.) Downstream point/station elevation = 82.900(Ft.) Pipe length = 240.00(Ft.) Slope = 0.0050 Manning's N = 0.013 7 No. of pipes = 1 Required pipe flow = 31.726(CFS) Nearest computed pipe diameter = 33.00(In.) Calculated individual pipe flow = 31.726(CFS) Normal flow depth in pipe = 23.34(In.) Flow top width inside pipe = 30.03(In.) Critical Depth = 22.48(In.) Pipe flow velocity = 7.07(Ft/s) Travel time through pipe = 0.57 min. Time of concentration (TC) = 16.34 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 202.000 to Point/Station 206.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.087(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (Office Professional ) Impervious value, Ai = 0.900 Sub-Area C Value = 0.830 Time of concentration = 16.34 min. Rainfall intensity = 2.087(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.640 CA = 16.167 Subarea runoff = 2.015(CFS) for 0.790(Ac.) Total runoff = 33.741(CFS) Total area = 25.280(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 202.000 to Point/Station 206.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.087(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.200 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.800 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.552 Time of concentration = 16.34 min. Rainfall intensity = 2.087(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.617 CA = 20.948 Subarea runoff = 9.976(CFS) for 8.660(Ac.) Total runoff = 43.717(CFS) Total area = 33.940(Ac.) 8 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 206.000 to Point/Station 207.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 82.900(Ft.) Downstream point/station elevation = 71.380(Ft.) Pipe length = 758.00(Ft.) Slope = 0.0152 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 43.717(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 43.717(CFS) Normal flow depth in pipe = 21.52(In.) Flow top width inside pipe = 27.02(In.) Critical Depth = 26.44(In.) Pipe flow velocity = 11.59(Ft/s) Travel time through pipe = 1.09 min. Time of concentration (TC) = 17.43 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 206.000 to Point/Station 207.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.002(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [COMMERCIAL area type ] (Office Professional ) Impervious value, Ai = 0.900 Sub-Area C Value = 0.830 Time of concentration = 17.43 min. Rainfall intensity = 2.002(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.648 CA = 25.695 Subarea runoff = 7.720(CFS) for 5.720(Ac.) Total runoff = 51.437(CFS) Total area = 39.660(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 207.000 to Point/Station 207.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.002(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.450 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.550 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 9 Sub-Area C Value = 0.529 Time of concentration = 17.43 min. Rainfall intensity = 2.002(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.604 CA = 38.181 Subarea runoff = 24.994(CFS) for 23.580(Ac.) Total runoff = 76.431(CFS) Total area = 63.240(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 207.000 to Point/Station 208.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 70.000(Ft.) Downstream point/station elevation = 39.000(Ft.) Pipe length = 1320.00(Ft.) Slope = 0.0235 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 76.431(CFS) Nearest computed pipe diameter = 33.00(In.) Calculated individual pipe flow = 76.431(CFS) Normal flow depth in pipe = 25.50(In.) Flow top width inside pipe = 27.66(In.) Critical depth could not be calculated. Pipe flow velocity = 15.52(Ft/s) Travel time through pipe = 1.42 min. Time of concentration (TC) = 18.85 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 207.000 to Point/Station 208.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.903(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (14.5 DU/A or Less ) Impervious value, Ai = 0.500 Sub-Area C Value = 0.550 Time of concentration = 18.85 min. Rainfall intensity = 1.903(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.596 CA = 43.851 Subarea runoff = 7.033(CFS) for 10.310(Ac.) Total runoff = 83.465(CFS) Total area = 73.550(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 208.000 to Point/Station 209.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ 10 Upstream point/station elevation = 39.000(Ft.) Downstream point/station elevation = 30.110(Ft.) Pipe length = 440.00(Ft.) Slope = 0.0202 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 83.465(CFS) Nearest computed pipe diameter = 36.00(In.) Calculated individual pipe flow = 83.465(CFS) Normal flow depth in pipe = 26.20(In.) Flow top width inside pipe = 32.04(In.) Critical Depth = 33.61(In.) Pipe flow velocity = 15.13(Ft/s) Travel time through pipe = 0.48 min. Time of concentration (TC) = 19.33 min. End of computations, total study area = 73.550 (Ac.) 1 San Diego County Rational Hydrology Program CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2009 Version 7.8 Rational method hydrology program based on San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 12/08/12 ------------------------------------------------------------------------ City of Carlsbad Hydromodification Exemption Study Major Basin 300 10-Year Flow Rate ------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** ------------------------------------------------------------------------ Program License Serial Number 4028 ------------------------------------------------------------------------ Rational hydrology study storm event year is 10.0 English (in-lb) input data Units used Map data precipitation entered: 6 hour, precipitation(inches) = 1.700 24 hour precipitation(inches) = 3.100 P6/P24 = 54.8% San Diego hydrology manual 'C' values used ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 300.000 to Point/Station 301.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Initial subarea total flow distance = 280.000(Ft.) Highest elevation = 341.000(Ft.) Lowest elevation = 329.000(Ft.) Elevation difference = 12.000(Ft.) Slope = 4.286 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 4.29 %, in a development type of 7.3 DU/A or Less In Accordance With Figure 3-3 2 Initial Area Time of Concentration = 6.87 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.4800)*( 100.000^.5)/( 4.286^(1/3)]= 6.87 The initial area total distance of 280.00 (Ft.) entered leaves a remaining distance of 180.00 (Ft.) Using Figure 3-4, the travel time for this distance is 1.43 minutes for a distance of 180.00 (Ft.) and a slope of 4.29 % with an elevation difference of 7.71(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 1.432 Minutes Tt=[(11.9*0.0341^3)/( 7.71)]^.385= 1.43 Total initial area Ti = 6.87 minutes from Figure 3-3 formula plus 1.43 minutes from the Figure 3-4 formula = 8.30 minutes Rainfall intensity (I) = 3.230(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.480 Subarea runoff = 2.139(CFS) Total initial stream area = 1.380(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 301.000 to Point/Station 302.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 329.000(Ft.) Downstream point/station elevation = 327.200(Ft.) Pipe length = 360.00(Ft.) Slope = 0.0050 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 2.139(CFS) Nearest computed pipe diameter = 12.00(In.) Calculated individual pipe flow = 2.139(CFS) Normal flow depth in pipe = 8.50(In.) Flow top width inside pipe = 10.91(In.) Critical Depth = 7.50(In.) Pipe flow velocity = 3.60(Ft/s) Travel time through pipe = 1.67 min. Time of concentration (TC) = 9.97 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 302.000 to Point/Station 303.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 306.000(Ft.) End of street segment elevation = 230.000(Ft.) Length of street segment = 987.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 3 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 10.444(CFS) Depth of flow = 0.353(Ft.), Average velocity = 6.031(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 12.885(Ft.) Flow velocity = 6.03(Ft/s) Travel time = 2.73 min. TC = 12.70 min. Adding area flow to street Rainfall intensity (I) = 2.456(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Rainfall intensity = 2.456(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.480 CA = 7.613 Subarea runoff = 16.555(CFS) for 14.480(Ac.) Total runoff = 18.694(CFS) Total area = 15.860(Ac.) Street flow at end of street = 18.694(CFS) Half street flow at end of street = 18.694(CFS) Depth of flow = 0.419(Ft.), Average velocity = 6.935(Ft/s) Flow width (from curb towards crown)= 16.200(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 303.000 to Point/Station 304.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 230.000(Ft.) Downstream point/station elevation = 219.970(Ft.) Pipe length = 660.00(Ft.) Slope = 0.0152 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 18.694(CFS) Nearest computed pipe diameter = 21.00(In.) Calculated individual pipe flow = 18.694(CFS) Normal flow depth in pipe = 16.45(In.) Flow top width inside pipe = 17.30(In.) Critical Depth = 18.79(In.) Pipe flow velocity = 9.25(Ft/s) Travel time through pipe = 1.19 min. Time of concentration (TC) = 13.89 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 303.000 to Point/Station 304.000 4 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1 Stream flow area = 15.860(Ac.) Runoff from this stream = 18.694(CFS) Time of concentration = 13.89 min. Rainfall intensity = 2.318(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 305.000 to Point/Station 306.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 1.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.540 Initial subarea total flow distance = 130.000(Ft.) Highest elevation = 344.000(Ft.) Lowest elevation = 335.000(Ft.) Elevation difference = 9.000(Ft.) Slope = 6.923 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 6.92 %, in a development type of 7.3 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration = 5.29 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.5400)*( 100.000^.5)/( 6.923^(1/3)]= 5.29 The initial area total distance of 130.00 (Ft.) entered leaves a remaining distance of 30.00 (Ft.) Using Figure 3-4, the travel time for this distance is 0.30 minutes for a distance of 30.00 (Ft.) and a slope of 6.92 % with an elevation difference of 2.08(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 0.300 Minutes Tt=[(11.9*0.0057^3)/( 2.08)]^.385= 0.30 Total initial area Ti = 5.29 minutes from Figure 3-3 formula plus 0.30 minutes from the Figure 3-4 formula = 5.59 minutes Rainfall intensity (I) = 4.169(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.540 Subarea runoff = 1.216(CFS) Total initial stream area = 0.540(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 306.000 to Point/Station 307.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** 5 ______________________________________________________________________ Top of street segment elevation = 335.000(Ft.) End of street segment elevation = 280.000(Ft.) Length of street segment = 1260.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 8.573(CFS) Depth of flow = 0.362(Ft.), Average velocity = 4.635(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 13.335(Ft.) Flow velocity = 4.64(Ft/s) Travel time = 4.53 min. TC = 10.12 min. Adding area flow to street Rainfall intensity (I) = 2.843(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.250 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.750 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.525 Rainfall intensity = 2.843(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.526 CA = 5.573 Subarea runoff = 14.627(CFS) for 10.060(Ac.) Total runoff = 15.842(CFS) Total area = 10.600(Ac.) Street flow at end of street = 15.842(CFS) Half street flow at end of street = 15.842(CFS) Depth of flow = 0.434(Ft.), Average velocity = 5.373(Ft/s) Flow width (from curb towards crown)= 16.962(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 307.000 to Point/Station 308.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 280.000(Ft.) Downstream point/station elevation = 275.260(Ft.) Pipe length = 375.00(Ft.) Slope = 0.0126 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 15.842(CFS) 6 Nearest computed pipe diameter = 21.00(In.) Calculated individual pipe flow = 15.842(CFS) Normal flow depth in pipe = 15.42(In.) Flow top width inside pipe = 18.55(In.) Critical Depth = 17.64(In.) Pipe flow velocity = 8.37(Ft/s) Travel time through pipe = 0.75 min. Time of concentration (TC) = 10.87 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 307.000 to Point/Station 308.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.715(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Time of concentration = 10.87 min. Rainfall intensity = 2.715(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.518 CA = 6.653 Subarea runoff = 2.221(CFS) for 2.250(Ac.) Total runoff = 18.063(CFS) Total area = 12.850(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 308.000 to Point/Station 304.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 253.000(Ft.) Downstream point/station elevation = 219.110(Ft.) Pipe length = 480.00(Ft.) Slope = 0.0706 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 18.063(CFS) Nearest computed pipe diameter = 18.00(In.) Calculated individual pipe flow = 18.063(CFS) Normal flow depth in pipe = 10.55(In.) Flow top width inside pipe = 17.73(In.) Critical depth could not be calculated. Pipe flow velocity = 16.80(Ft/s) Travel time through pipe = 0.48 min. Time of concentration (TC) = 11.34 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 308.000 to Point/Station 304.000 **** CONFLUENCE OF MINOR STREAMS **** 7 ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2 Stream flow area = 12.850(Ac.) Runoff from this stream = 18.063(CFS) Time of concentration = 11.34 min. Rainfall intensity = 2.641(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 18.694 13.89 2.318 2 18.063 11.34 2.641 Qmax(1) = 1.000 * 1.000 * 18.694) + 0.878 * 1.000 * 18.063) + = 34.547 Qmax(2) = 1.000 * 0.817 * 18.694) + 1.000 * 1.000 * 18.063) + = 33.332 Total of 2 streams to confluence: Flow rates before confluence point: 18.694 18.063 Maximum flow rates at confluence using above data: 34.547 33.332 Area of streams before confluence: 15.860 12.850 Results of confluence: Total flow rate = 34.547(CFS) Time of concentration = 13.886 min. Effective stream area after confluence = 28.710(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 304.000 to Point/Station 309.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 220.000(Ft.) Downstream point/station elevation = 214.080(Ft.) Pipe length = 296.00(Ft.) Slope = 0.0200 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 34.547(CFS) Nearest computed pipe diameter = 27.00(In.) Calculated individual pipe flow = 34.547(CFS) Normal flow depth in pipe = 18.09(In.) Flow top width inside pipe = 25.39(In.) Critical Depth = 24.03(In.) Pipe flow velocity = 12.21(Ft/s) Travel time through pipe = 0.40 min. Time of concentration (TC) = 14.29 min. 8 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 304.000 to Point/Station 309.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1 Stream flow area = 28.710(Ac.) Runoff from this stream = 34.547(CFS) Time of concentration = 14.29 min. Rainfall intensity = 2.275(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 310.000 to Point/Station 311.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Initial subarea total flow distance = 382.000(Ft.) Highest elevation = 296.000(Ft.) Lowest elevation = 264.000(Ft.) Elevation difference = 32.000(Ft.) Slope = 8.377 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 8.38 %, in a development type of 7.3 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration = 5.50 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.4800)*( 100.000^.5)/( 8.377^(1/3)]= 5.50 The initial area total distance of 382.00 (Ft.) entered leaves a remaining distance of 282.00 (Ft.) Using Figure 3-4, the travel time for this distance is 1.56 minutes for a distance of 282.00 (Ft.) and a slope of 8.38 % with an elevation difference of 23.62(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 1.563 Minutes Tt=[(11.9*0.0534^3)/( 23.62)]^.385= 1.56 Total initial area Ti = 5.50 minutes from Figure 3-3 formula plus 1.56 minutes from the Figure 3-4 formula = 7.06 minutes Rainfall intensity (I) = 3.586(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.480 Subarea runoff = 2.754(CFS) Total initial stream area = 1.600(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 9 Process from Point/Station 311.000 to Point/Station 312.000 **** IMPROVED CHANNEL TRAVEL TIME **** ______________________________________________________________________ Upstream point elevation = 264.000(Ft.) Downstream point elevation = 255.500(Ft.) Channel length thru subarea = 132.000(Ft.) Channel base width = 0.500(Ft.) Slope or 'Z' of left channel bank = 2.000 Slope or 'Z' of right channel bank = 2.000 Manning's 'N' = 0.015 Maximum depth of channel = 1.000(Ft.) Flow(q) thru subarea = 2.754(CFS) Depth of flow = 0.306(Ft.), Average velocity = 8.081(Ft/s) Channel flow top width = 1.725(Ft.) Flow Velocity = 8.08(Ft/s) Travel time = 0.27 min. Time of concentration = 7.33 min. Critical depth = 0.539(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 312.000 to Point/Station 313.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 255.500(Ft.) End of street segment elevation = 218.000(Ft.) Length of street segment = 724.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 8.242(CFS) Depth of flow = 0.349(Ft.), Average velocity = 4.902(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 12.690(Ft.) Flow velocity = 4.90(Ft/s) Travel time = 2.46 min. TC = 9.79 min. Adding area flow to street Rainfall intensity (I) = 2.903(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 10 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Rainfall intensity = 2.903(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.480 CA = 4.709 Subarea runoff = 10.918(CFS) for 8.210(Ac.) Total runoff = 13.672(CFS) Total area = 9.810(Ac.) Street flow at end of street = 13.672(CFS) Half street flow at end of street = 13.672(CFS) Depth of flow = 0.405(Ft.), Average velocity = 5.533(Ft/s) Flow width (from curb towards crown)= 15.492(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 313.000 to Point/Station 309.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 218.000(Ft.) Downstream point/station elevation = 212.960(Ft.) Pipe length = 970.00(Ft.) Slope = 0.0052 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 13.672(CFS) Nearest computed pipe diameter = 24.00(In.) Calculated individual pipe flow = 13.672(CFS) Normal flow depth in pipe = 16.83(In.) Flow top width inside pipe = 21.97(In.) Critical Depth = 15.98(In.) Pipe flow velocity = 5.81(Ft/s) Travel time through pipe = 2.78 min. Time of concentration (TC) = 12.57 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 313.000 to Point/Station 309.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2 Stream flow area = 9.810(Ac.) Runoff from this stream = 13.672(CFS) Time of concentration = 12.57 min. Rainfall intensity = 2.471(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 34.547 14.29 2.275 2 13.672 12.57 2.471 Qmax(1) = 1.000 * 1.000 * 34.547) + 11 0.921 * 1.000 * 13.672) + = 47.135 Qmax(2) = 1.000 * 0.880 * 34.547) + 1.000 * 1.000 * 13.672) + = 44.067 Total of 2 streams to confluence: Flow rates before confluence point: 34.547 13.672 Maximum flow rates at confluence using above data: 47.135 44.067 Area of streams before confluence: 28.710 9.810 Results of confluence: Total flow rate = 47.135(CFS) Time of concentration = 14.290 min. Effective stream area after confluence = 38.520(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 309.000 to Point/Station 309.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.275(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Time of concentration = 14.29 min. Rainfall intensity = 2.275(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.490 CA = 24.802 Subarea runoff = 9.296(CFS) for 12.140(Ac.) Total runoff = 56.431(CFS) Total area = 50.660(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 309.000 to Point/Station 314.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 210.000(Ft.) Downstream point/station elevation = 202.530(Ft.) Pipe length = 725.00(Ft.) Slope = 0.0103 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 56.431(CFS) Nearest computed pipe diameter = 36.00(In.) Calculated individual pipe flow = 56.431(CFS) Normal flow depth in pipe = 25.13(In.) Flow top width inside pipe = 33.06(In.) Critical Depth = 29.22(In.) 12 Pipe flow velocity = 10.72(Ft/s) Travel time through pipe = 1.13 min. Time of concentration (TC) = 15.42 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 309.000 to Point/Station 314.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.167(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.670 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.330 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.500 Time of concentration = 15.42 min. Rainfall intensity = 2.167(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.494 CA = 46.588 Subarea runoff = 44.503(CFS) for 43.590(Ac.) Total runoff = 100.934(CFS) Total area = 94.250(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 314.000 to Point/Station 315.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 206.000(Ft.) Downstream point/station elevation = 200.500(Ft.) Pipe length = 235.00(Ft.) Slope = 0.0234 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 100.934(CFS) Nearest computed pipe diameter = 36.00(In.) Calculated individual pipe flow = 100.934(CFS) Normal flow depth in pipe = 29.16(In.) Flow top width inside pipe = 28.25(In.) Critical depth could not be calculated. Pipe flow velocity = 16.46(Ft/s) Travel time through pipe = 0.24 min. Time of concentration (TC) = 15.65 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 314.000 to Point/Station 315.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.145(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 13 Decimal fraction soil group D = 0.000 [LOW DENSITY RESIDENTIAL ] (2.9 DU/A or Less ) Impervious value, Ai = 0.250 Sub-Area C Value = 0.380 Time of concentration = 15.65 min. Rainfall intensity = 2.145(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.489 CA = 48.401 Subarea runoff = 2.896(CFS) for 4.770(Ac.) Total runoff = 103.830(CFS) Total area = 99.020(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 315.000 to Point/Station 316.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 197.000(Ft.) Downstream point/station elevation = 176.530(Ft.) Pipe length = 890.00(Ft.) Slope = 0.0230 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 103.830(CFS) Nearest computed pipe diameter = 39.00(In.) Calculated individual pipe flow = 103.830(CFS) Normal flow depth in pipe = 27.09(In.) Flow top width inside pipe = 35.92(In.) Critical Depth = 36.53(In.) Pipe flow velocity = 16.87(Ft/s) Travel time through pipe = 0.88 min. Time of concentration (TC) = 16.53 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 315.000 to Point/Station 316.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.071(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Time of concentration = 16.53 min. Rainfall intensity = 2.071(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.488 CA = 55.937 Subarea runoff = 12.012(CFS) for 15.700(Ac.) Total runoff = 115.842(CFS) Total area = 114.720(Ac.) 14 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 316.000 to Point/Station 317.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 158.000(Ft.) Downstream point/station elevation = 154.720(Ft.) Pipe length = 205.00(Ft.) Slope = 0.0160 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 115.842(CFS) Nearest computed pipe diameter = 42.00(In.) Calculated individual pipe flow = 115.842(CFS) Normal flow depth in pipe = 31.45(In.) Flow top width inside pipe = 36.43(In.) Critical Depth = 38.62(In.) Pipe flow velocity = 14.99(Ft/s) Travel time through pipe = 0.23 min. Time of concentration (TC) = 16.76 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 316.000 to Point/Station 317.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.053(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Time of concentration = 16.76 min. Rainfall intensity = 2.053(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.487 CA = 56.950 Subarea runoff = 1.061(CFS) for 2.110(Ac.) Total runoff = 116.902(CFS) Total area = 116.830(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 317.000 to Point/Station 318.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 154.000(Ft.) Downstream point/station elevation = 148.210(Ft.) Pipe length = 362.00(Ft.) Slope = 0.0160 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 116.902(CFS) Nearest computed pipe diameter = 42.00(In.) Calculated individual pipe flow = 116.902(CFS) Normal flow depth in pipe = 31.69(In.) Flow top width inside pipe = 36.15(In.) Critical Depth = 38.72(In.) 15 Pipe flow velocity = 15.00(Ft/s) Travel time through pipe = 0.40 min. Time of concentration (TC) = 17.16 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 317.000 to Point/Station 318.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1 Stream flow area = 116.830(Ac.) Runoff from this stream = 116.902(CFS) Time of concentration = 17.16 min. Rainfall intensity = 2.022(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 320.000 to Point/Station 321.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Initial subarea total flow distance = 155.000(Ft.) Highest elevation = 186.000(Ft.) Lowest elevation = 183.000(Ft.) Elevation difference = 3.000(Ft.) Slope = 1.935 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 80.00 (Ft) for the top area slope value of 1.94 %, in a development type of 7.3 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration = 8.01 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.4800)*( 80.000^.5)/( 1.935^(1/3)]= 8.01 The initial area total distance of 155.00 (Ft.) entered leaves a remaining distance of 75.00 (Ft.) Using Figure 3-4, the travel time for this distance is 0.99 minutes for a distance of 75.00 (Ft.) and a slope of 1.94 % with an elevation difference of 1.45(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 0.991 Minutes Tt=[(11.9*0.0142^3)/( 1.45)]^.385= 0.99 Total initial area Ti = 8.01 minutes from Figure 3-3 formula plus 0.99 minutes from the Figure 3-4 formula = 9.00 minutes Rainfall intensity (I) = 3.065(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.480 16 Subarea runoff = 0.368(CFS) Total initial stream area = 0.250(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 321.000 to Point/Station 322.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 183.000(Ft.) End of street segment elevation = 165.000(Ft.) Length of street segment = 855.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 4.894(CFS) Depth of flow = 0.342(Ft.), Average velocity = 3.073(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 12.335(Ft.) Flow velocity = 3.07(Ft/s) Travel time = 4.64 min. TC = 13.64 min. Adding area flow to street Rainfall intensity (I) = 2.345(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Rainfall intensity = 2.345(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.480 CA = 3.994 Subarea runoff = 8.996(CFS) for 8.070(Ac.) Total runoff = 9.364(CFS) Total area = 8.320(Ac.) Street flow at end of street = 9.364(CFS) Half street flow at end of street = 9.364(CFS) Depth of flow = 0.414(Ft.), Average velocity = 3.589(Ft/s) Flow width (from curb towards crown)= 15.931(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 17 Process from Point/Station 322.000 to Point/Station 323.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 165.000(Ft.) Downstream point/station elevation = 158.300(Ft.) Pipe length = 410.00(Ft.) Slope = 0.0163 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 9.364(CFS) Nearest computed pipe diameter = 18.00(In.) Calculated individual pipe flow = 9.364(CFS) Normal flow depth in pipe = 11.06(In.) Flow top width inside pipe = 17.52(In.) Critical Depth = 14.19(In.) Pipe flow velocity = 8.21(Ft/s) Travel time through pipe = 0.83 min. Time of concentration (TC) = 14.47 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 323.000 to Point/Station 324.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 158.300(Ft.) End of street segment elevation = 156.000(Ft.) Length of street segment = 506.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 15.683(CFS) Depth of flow = 0.612(Ft.), Average velocity = 2.431(Ft/s) Warning: depth of flow exceeds top of curb Note: depth of flow exceeds top of street crown. Distance that curb overflow reaches into property = 5.60(Ft.) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 18.000(Ft.) Flow velocity = 2.43(Ft/s) Travel time = 3.47 min. TC = 17.94 min. Adding area flow to street Rainfall intensity (I) = 1.965(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.600 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.400 18 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.516 Rainfall intensity = 1.965(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.503 CA = 11.171 Subarea runoff = 12.585(CFS) for 13.910(Ac.) Total runoff = 21.949(CFS) Total area = 22.230(Ac.) Street flow at end of street = 21.949(CFS) Half street flow at end of street = 21.949(CFS) Depth of flow = 0.683(Ft.), Average velocity = 2.656(Ft/s) Warning: depth of flow exceeds top of curb Note: depth of flow exceeds top of street crown. Distance that curb overflow reaches into property = 9.17(Ft.) Flow width (from curb towards crown)= 18.000(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 324.000 to Point/Station 325.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 156.000(Ft.) Downstream point/station elevation = 154.710(Ft.) Pipe length = 430.00(Ft.) Slope = 0.0030 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 21.949(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 21.949(CFS) Normal flow depth in pipe = 24.00(In.) Flow top width inside pipe = 24.00(In.) Critical Depth = 19.10(In.) Pipe flow velocity = 5.22(Ft/s) Travel time through pipe = 1.37 min. Time of concentration (TC) = 19.31 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 324.000 to Point/Station 325.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.873(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.600 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.400 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.516 Time of concentration = 19.31 min. Rainfall intensity = 1.873(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area 19 (Q=KCIA) is C = 0.507 CA = 16.476 Subarea runoff = 8.918(CFS) for 10.280(Ac.) Total runoff = 30.867(CFS) Total area = 32.510(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 325.000 to Point/Station 326.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 158.000(Ft.) Downstream point/station elevation = 156.110(Ft.) Pipe length = 315.00(Ft.) Slope = 0.0060 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 30.867(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 30.867(CFS) Normal flow depth in pipe = 23.86(In.) Flow top width inside pipe = 24.21(In.) Critical Depth = 22.71(In.) Pipe flow velocity = 7.38(Ft/s) Travel time through pipe = 0.71 min. Time of concentration (TC) = 20.03 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 325.000 to Point/Station 326.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.830(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.400 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.600 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.534 Time of concentration = 20.03 min. Rainfall intensity = 1.830(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.511 CA = 20.064 Subarea runoff = 5.856(CFS) for 6.720(Ac.) Total runoff = 36.722(CFS) Total area = 39.230(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 326.000 to Point/Station 327.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 156.000(Ft.) Downstream point/station elevation = 154.860(Ft.) Pipe length = 190.00(Ft.) Slope = 0.0060 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 36.722(CFS) 20 Nearest computed pipe diameter = 33.00(In.) Calculated individual pipe flow = 36.722(CFS) Normal flow depth in pipe = 24.38(In.) Flow top width inside pipe = 29.00(In.) Critical Depth = 24.21(In.) Pipe flow velocity = 7.80(Ft/s) Travel time through pipe = 0.41 min. Time of concentration (TC) = 20.43 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 327.000 to Point/Station 327.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.807(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.400 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.400 Decimal fraction soil group D = 0.200 [LOW DENSITY RESIDENTIAL ] (2.0 DU/A or Less ) Impervious value, Ai = 0.200 Sub-Area C Value = 0.396 Time of concentration = 20.43 min. Rainfall intensity = 1.807(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.487 CA = 24.175 Subarea runoff = 6.954(CFS) for 10.380(Ac.) Total runoff = 43.676(CFS) Total area = 49.610(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 327.000 to Point/Station 327.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.807(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.600 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.200 Decimal fraction soil group D = 0.200 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.510 Time of concentration = 20.43 min. Rainfall intensity = 1.807(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.490 CA = 27.627 Subarea runoff = 6.238(CFS) for 6.770(Ac.) Total runoff = 49.914(CFS) Total area = 56.380(Ac.) 21 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 327.000 to Point/Station 328.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 159.000(Ft.) Downstream point/station elevation = 156.500(Ft.) Pipe length = 250.00(Ft.) Slope = 0.0100 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 49.914(CFS) Nearest computed pipe diameter = 33.00(In.) Calculated individual pipe flow = 49.914(CFS) Normal flow depth in pipe = 25.50(In.) Flow top width inside pipe = 27.66(In.) Critical Depth = 27.92(In.) Pipe flow velocity = 10.13(Ft/s) Travel time through pipe = 0.41 min. Time of concentration (TC) = 20.84 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 327.000 to Point/Station 328.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.784(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.150 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.850 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (4.3 DU/A or Less ) Impervious value, Ai = 0.300 Sub-Area C Value = 0.469 Time of concentration = 20.84 min. Rainfall intensity = 1.784(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.485 CA = 36.083 Subarea runoff = 14.444(CFS) for 18.010(Ac.) Total runoff = 64.358(CFS) Total area = 74.390(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 328.000 to Point/Station 318.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 163.000(Ft.) Downstream point/station elevation = 153.200(Ft.) Pipe length = 980.00(Ft.) Slope = 0.0100 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 64.358(CFS) Nearest computed pipe diameter = 36.00(In.) Calculated individual pipe flow = 64.358(CFS) Normal flow depth in pipe = 28.41(In.) Flow top width inside pipe = 29.37(In.) Critical Depth = 30.91(In.) 22 Pipe flow velocity = 10.75(Ft/s) Travel time through pipe = 1.52 min. Time of concentration (TC) = 22.36 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 328.000 to Point/Station 318.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2 Stream flow area = 74.390(Ac.) Runoff from this stream = 64.358(CFS) Time of concentration = 22.36 min. Rainfall intensity = 1.704(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 329.000 to Point/Station 330.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Initial subarea total flow distance = 974.000(Ft.) Highest elevation = 230.000(Ft.) Lowest elevation = 210.000(Ft.) Elevation difference = 20.000(Ft.) Slope = 2.053 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 80.00 (Ft) for the top area slope value of 2.05 %, in a development type of 7.3 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration = 7.85 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.4800)*( 80.000^.5)/( 2.053^(1/3)]= 7.85 The initial area total distance of 974.00 (Ft.) entered leaves a remaining distance of 894.00 (Ft.) Using Figure 3-4, the travel time for this distance is 6.53 minutes for a distance of 894.00 (Ft.) and a slope of 2.05 % with an elevation difference of 18.35(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 6.529 Minutes Tt=[(11.9*0.1693^3)/( 18.35)]^.385= 6.53 Total initial area Ti = 7.85 minutes from Figure 3-3 formula plus 6.53 minutes from the Figure 3-4 formula = 14.38 minutes Rainfall intensity (I) = 2.266(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.480 23 Subarea runoff = 2.066(CFS) Total initial stream area = 1.900(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 330.000 to Point/Station 331.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 210.000(Ft.) End of street segment elevation = 174.000(Ft.) Length of street segment = 625.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 7.831(CFS) Depth of flow = 0.338(Ft.), Average velocity = 5.043(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 12.172(Ft.) Flow velocity = 5.04(Ft/s) Travel time = 2.07 min. TC = 16.45 min. Adding area flow to street Rainfall intensity (I) = 2.078(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Rainfall intensity = 2.078(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.480 CA = 6.504 Subarea runoff = 11.448(CFS) for 11.650(Ac.) Total runoff = 13.515(CFS) Total area = 13.550(Ac.) Street flow at end of street = 13.515(CFS) Half street flow at end of street = 13.515(CFS) Depth of flow = 0.397(Ft.), Average velocity = 5.744(Ft/s) Flow width (from curb towards crown)= 15.104(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 24 Process from Point/Station 331.000 to Point/Station 332.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 174.000(Ft.) Downstream point/station elevation = 158.000(Ft.) Pipe length = 400.00(Ft.) Slope = 0.0400 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 13.515(CFS) Nearest computed pipe diameter = 18.00(In.) Calculated individual pipe flow = 13.515(CFS) Normal flow depth in pipe = 10.50(In.) Flow top width inside pipe = 17.75(In.) Critical Depth = 16.41(In.) Pipe flow velocity = 12.63(Ft/s) Travel time through pipe = 0.53 min. Time of concentration (TC) = 16.98 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 332.000 to Point/Station 332.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.036(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Time of concentration = 16.98 min. Rainfall intensity = 2.036(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.480 CA = 17.088 Subarea runoff = 21.276(CFS) for 22.050(Ac.) Total runoff = 34.790(CFS) Total area = 35.600(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 332.000 to Point/Station 318.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 164.000(Ft.) Downstream point/station elevation = 147.830(Ft.) Pipe length = 86.00(Ft.) Slope = 0.1880 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 34.790(CFS) Nearest computed pipe diameter = 18.00(In.) Calculated individual pipe flow = 34.790(CFS) Normal flow depth in pipe = 11.78(In.) Flow top width inside pipe = 17.12(In.) Critical depth could not be calculated. Pipe flow velocity = 28.39(Ft/s) 25 Travel time through pipe = 0.05 min. Time of concentration (TC) = 17.03 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 332.000 to Point/Station 318.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 3 Stream flow area = 35.600(Ac.) Runoff from this stream = 34.790(CFS) Time of concentration = 17.03 min. Rainfall intensity = 2.032(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 116.902 17.16 2.022 2 64.358 22.36 1.704 3 34.790 17.03 2.032 Qmax(1) = 1.000 * 1.000 * 116.902) + 1.000 * 0.768 * 64.358) + 0.995 * 1.000 * 34.790) + = 200.912 Qmax(2) = 0.843 * 1.000 * 116.902) + 1.000 * 1.000 * 64.358) + 0.839 * 1.000 * 34.790) + = 192.104 Qmax(3) = 1.000 * 0.992 * 116.902) + 1.000 * 0.761 * 64.358) + 1.000 * 1.000 * 34.790) + = 199.763 Total of 3 streams to confluence: Flow rates before confluence point: 116.902 64.358 34.790 Maximum flow rates at confluence using above data: 200.912 192.104 199.763 Area of streams before confluence: 116.830 74.390 35.600 Results of confluence: Total flow rate = 200.912(CFS) Time of concentration = 17.164 min. Effective stream area after confluence = 226.820(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 318.000 to Point/Station 333.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ 26 Upstream point/station elevation = 162.000(Ft.) Downstream point/station elevation = 149.490(Ft.) Pipe length = 340.00(Ft.) Slope = 0.0368 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 200.912(CFS) Nearest computed pipe diameter = 45.00(In.) Calculated individual pipe flow = 200.912(CFS) Normal flow depth in pipe = 32.34(In.) Flow top width inside pipe = 40.46(In.) Critical depth could not be calculated. Pipe flow velocity = 23.64(Ft/s) Travel time through pipe = 0.24 min. Time of concentration (TC) = 17.40 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 318.000 to Point/Station 333.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.004(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [HIGH DENSITY RESIDENTIAL ] (24.0 DU/A or Less ) Impervious value, Ai = 0.650 Sub-Area C Value = 0.660 Time of concentration = 17.40 min. Rainfall intensity = 2.004(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.489 CA = 113.381 Subarea runoff = 26.256(CFS) for 4.940(Ac.) Total runoff = 227.168(CFS) Total area = 231.760(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 333.000 to Point/Station 334.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 139.000(Ft.) Downstream point/station elevation = 131.270(Ft.) Pipe length = 210.00(Ft.) Slope = 0.0368 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 227.168(CFS) Nearest computed pipe diameter = 45.00(In.) Calculated individual pipe flow = 227.168(CFS) Normal flow depth in pipe = 36.09(In.) Flow top width inside pipe = 35.86(In.) Critical depth could not be calculated. Pipe flow velocity = 23.94(Ft/s) Travel time through pipe = 0.15 min. Time of concentration (TC) = 17.55 min. 27 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 333.000 to Point/Station 334.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.993(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (14.5 DU/A or Less ) Impervious value, Ai = 0.500 Sub-Area C Value = 0.550 Time of concentration = 17.55 min. Rainfall intensity = 1.993(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.492 CA = 119.871 Subarea runoff = 11.711(CFS) for 11.800(Ac.) Total runoff = 238.879(CFS) Total area = 243.560(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 334.000 to Point/Station 335.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 126.000(Ft.) Downstream point/station elevation = 108.250(Ft.) Pipe length = 355.00(Ft.) Slope = 0.0500 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 238.879(CFS) Nearest computed pipe diameter = 45.00(In.) Calculated individual pipe flow = 238.879(CFS) Normal flow depth in pipe = 32.86(In.) Flow top width inside pipe = 39.95(In.) Critical depth could not be calculated. Pipe flow velocity = 27.64(Ft/s) Travel time through pipe = 0.21 min. Time of concentration (TC) = 17.76 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 334.000 to Point/Station 335.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.977(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 28 Sub-Area C Value = 0.480 Time of concentration = 17.76 min. Rainfall intensity = 1.977(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.491 CA = 129.605 Subarea runoff = 17.387(CFS) for 20.280(Ac.) Total runoff = 256.266(CFS) Total area = 263.840(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 335.000 to Point/Station 336.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 108.000(Ft.) Downstream point/station elevation = 91.750(Ft.) Pipe length = 325.00(Ft.) Slope = 0.0500 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 256.266(CFS) Nearest computed pipe diameter = 45.00(In.) Calculated individual pipe flow = 256.266(CFS) Normal flow depth in pipe = 34.92(In.) Flow top width inside pipe = 37.52(In.) Critical depth could not be calculated. Pipe flow velocity = 27.86(Ft/s) Travel time through pipe = 0.19 min. Time of concentration (TC) = 17.96 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 335.000 to Point/Station 336.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.963(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [HIGH DENSITY RESIDENTIAL ] (43.0 DU/A or Less ) Impervious value, Ai = 0.800 Sub-Area C Value = 0.760 Time of concentration = 17.96 min. Rainfall intensity = 1.963(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.495 CA = 132.258 Subarea runoff = 3.415(CFS) for 3.490(Ac.) Total runoff = 259.681(CFS) Total area = 267.330(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 335.000 to Point/Station 336.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ 29 Rainfall intensity (I) = 1.963(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Time of concentration = 17.96 min. Rainfall intensity = 1.963(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.494 CA = 135.191 Subarea runoff = 5.758(CFS) for 6.110(Ac.) Total runoff = 265.439(CFS) Total area = 273.440(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 336.000 to Point/Station 337.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 91.000(Ft.) Downstream point/station elevation = 84.190(Ft.) Pipe length = 300.00(Ft.) Slope = 0.0227 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 265.439(CFS) Nearest computed pipe diameter = 54.00(In.) Calculated individual pipe flow = 265.439(CFS) Normal flow depth in pipe = 39.89(In.) Flow top width inside pipe = 47.45(In.) Critical depth could not be calculated. Pipe flow velocity = 21.07(Ft/s) Travel time through pipe = 0.24 min. Time of concentration (TC) = 18.20 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 336.000 to Point/Station 337.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.947(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (14.5 DU/A or Less ) Impervious value, Ai = 0.500 Sub-Area C Value = 0.550 Time of concentration = 18.20 min. Rainfall intensity = 1.947(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.495 CA = 136.346 30 Subarea runoff = 0.011(CFS) for 2.100(Ac.) Total runoff = 265.450(CFS) Total area = 275.540(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 337.000 to Point/Station 338.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 83.000(Ft.) Downstream point/station elevation = 77.070(Ft.) Pipe length = 190.00(Ft.) Slope = 0.0312 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 265.450(CFS) Nearest computed pipe diameter = 51.00(In.) Calculated individual pipe flow = 265.450(CFS) Normal flow depth in pipe = 37.50(In.) Flow top width inside pipe = 45.00(In.) Critical depth could not be calculated. Pipe flow velocity = 23.76(Ft/s) Travel time through pipe = 0.13 min. Time of concentration (TC) = 18.33 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 337.000 to Point/Station 338.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.938(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [LOW DENSITY RESIDENTIAL ] (2.9 DU/A or Less ) Impervious value, Ai = 0.250 Sub-Area C Value = 0.380 Time of concentration = 18.33 min. Rainfall intensity = 1.938(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.491 CA = 139.690 Subarea runoff = 5.233(CFS) for 8.800(Ac.) Total runoff = 270.683(CFS) Total area = 284.340(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 338.000 to Point/Station 339.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 78.000(Ft.) Downstream point/station elevation = 66.120(Ft.) Pipe length = 260.00(Ft.) Slope = 0.0457 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 270.683(CFS) Nearest computed pipe diameter = 48.00(In.) 31 Calculated individual pipe flow = 270.683(CFS) Normal flow depth in pipe = 34.97(In.) Flow top width inside pipe = 42.69(In.) Critical depth could not be calculated. Pipe flow velocity = 27.57(Ft/s) Travel time through pipe = 0.16 min. Time of concentration (TC) = 18.49 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 338.000 to Point/Station 339.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.927(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [LOW DENSITY RESIDENTIAL ] (2.0 DU/A or Less ) Impervious value, Ai = 0.200 Sub-Area C Value = 0.340 Time of concentration = 18.49 min. Rainfall intensity = 1.927(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.486 CA = 143.345 Subarea runoff = 5.557(CFS) for 10.750(Ac.) Total runoff = 276.240(CFS) Total area = 295.090(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 339.000 to Point/Station 340.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 64.000(Ft.) Downstream point/station elevation = 22.000(Ft.) Pipe length = 1110.00(Ft.) Slope = 0.0378 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 276.240(CFS) Nearest computed pipe diameter = 48.00(In.) Calculated individual pipe flow = 276.240(CFS) Normal flow depth in pipe = 38.86(In.) Flow top width inside pipe = 37.69(In.) Critical depth could not be calculated. Pipe flow velocity = 25.35(Ft/s) Travel time through pipe = 0.73 min. Time of concentration (TC) = 19.22 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 340.000 to Point/Station 341.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ 32 Upstream point/station elevation = 22.000(Ft.) Downstream point/station elevation = 21.090(Ft.) Pipe length = 325.00(Ft.) Slope = 0.0028 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 276.240(CFS) Nearest computed pipe diameter = 78.00(In.) Calculated individual pipe flow = 276.240(CFS) Normal flow depth in pipe = 63.56(In.) Flow top width inside pipe = 60.59(In.) Critical Depth = 53.56(In.) Pipe flow velocity = 9.53(Ft/s) Travel time through pipe = 0.57 min. Time of concentration (TC) = 19.78 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 340.000 to Point/Station 341.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.845(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.950 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.050 Decimal fraction soil group D = 0.000 [LOW DENSITY RESIDENTIAL ] (1.0 DU/A or Less ) Impervious value, Ai = 0.100 Sub-Area C Value = 0.275 Time of concentration = 19.78 min. Rainfall intensity = 1.845(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.452 CA = 158.703 Subarea runoff = 16.498(CFS) for 55.950(Ac.) Total runoff = 292.738(CFS) Total area = 351.040(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 341.000 to Point/Station 342.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 22.000(Ft.) Downstream point/station elevation = 18.920(Ft.) Pipe length = 1100.00(Ft.) Slope = 0.0028 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 292.738(CFS) Nearest computed pipe diameter = 81.00(In.) Calculated individual pipe flow = 292.738(CFS) Normal flow depth in pipe = 63.28(In.) Flow top width inside pipe = 66.97(In.) Critical Depth = 54.55(In.) Pipe flow velocity = 9.76(Ft/s) Travel time through pipe = 1.88 min. Time of concentration (TC) = 21.66 min. 33 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 341.000 to Point/Station 342.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.740(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [INDUSTRIAL area type ] (General Industrial ) Impervious value, Ai = 0.950 Sub-Area C Value = 0.870 The area added to the existing stream causes a a lower flow rate of Q = 277.948(CFS) therefore the upstream flow rate of Q = 292.738(CFS) is being used Time of concentration = 21.66 min. Rainfall intensity = 1.740(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.454 CA = 159.764 Subarea runoff = 0.000(CFS) for 1.220(Ac.) Total runoff = 292.738(CFS) Total area = 352.260(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 342.000 to Point/Station 343.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 20.000(Ft.) Downstream point/station elevation = 19.220(Ft.) Pipe length = 280.00(Ft.) Slope = 0.0028 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 292.738(CFS) Nearest computed pipe diameter = 81.00(In.) Calculated individual pipe flow = 292.738(CFS) Normal flow depth in pipe = 63.47(In.) Flow top width inside pipe = 66.71(In.) Critical Depth = 54.55(In.) Pipe flow velocity = 9.74(Ft/s) Travel time through pipe = 0.48 min. Time of concentration (TC) = 22.14 min. End of computations, total study area = 352.260 (Ac.) 1 San Diego County Rational Hydrology Program CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2009 Version 7.8 Rational method hydrology program based on San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 12/08/12 ------------------------------------------------------------------------ City of Carlsbad Hydromodification Exemption Study Major Basin 400 10-Year Flow Rate ------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** ------------------------------------------------------------------------ Program License Serial Number 4028 ------------------------------------------------------------------------ Rational hydrology study storm event year is 10.0 English (in-lb) input data Units used Map data precipitation entered: 6 hour, precipitation(inches) = 1.700 24 hour precipitation(inches) = 3.100 P6/P24 = 54.8% San Diego hydrology manual 'C' values used ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 400.000 to Point/Station 401.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Initial subarea total flow distance = 646.000(Ft.) Highest elevation = 331.000(Ft.) Lowest elevation = 309.000(Ft.) Elevation difference = 22.000(Ft.) Slope = 3.406 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 95.00 (Ft) for the top area slope value of 3.41 %, in a development type of 7.3 DU/A or Less In Accordance With Figure 3-3 2 Initial Area Time of Concentration = 7.23 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.4800)*( 95.000^.5)/( 3.406^(1/3)]= 7.23 The initial area total distance of 646.00 (Ft.) entered leaves a remaining distance of 551.00 (Ft.) Using Figure 3-4, the travel time for this distance is 3.70 minutes for a distance of 551.00 (Ft.) and a slope of 3.41 % with an elevation difference of 18.77(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 3.701 Minutes Tt=[(11.9*0.1044^3)/( 18.77)]^.385= 3.70 Total initial area Ti = 7.23 minutes from Figure 3-3 formula plus 3.70 minutes from the Figure 3-4 formula = 10.93 minutes Rainfall intensity (I) = 2.705(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.480 Subarea runoff = 3.284(CFS) Total initial stream area = 2.530(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 401.000 to Point/Station 402.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 309.000(Ft.) End of street segment elevation = 230.000(Ft.) Length of street segment = 1121.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 16.691(CFS) Depth of flow = 0.410(Ft.), Average velocity = 6.525(Ft/s) Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 15.770(Ft.) Flow velocity = 6.52(Ft/s) Travel time = 2.86 min. TC = 13.79 min. Adding area flow to street Rainfall intensity (I) = 2.328(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] 3 (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Rainfall intensity = 2.328(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.480 CA = 12.893 Subarea runoff = 26.725(CFS) for 24.330(Ac.) Total runoff = 30.010(CFS) Total area = 26.860(Ac.) Street flow at end of street = 30.010(CFS) Half street flow at end of street = 30.010(CFS) Depth of flow = 0.484(Ft.), Average velocity = 7.815(Ft/s) Note: depth of flow exceeds top of street crown. Flow width (from curb towards crown)= 18.000(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 402.000 to Point/Station 403.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 230.000(Ft.) Downstream point/station elevation = 210.280(Ft.) Pipe length = 290.00(Ft.) Slope = 0.0680 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 30.010(CFS) Nearest computed pipe diameter = 21.00(In.) Calculated individual pipe flow = 30.010(CFS) Normal flow depth in pipe = 13.27(In.) Flow top width inside pipe = 20.26(In.) Critical depth could not be calculated. Pipe flow velocity = 18.73(Ft/s) Travel time through pipe = 0.26 min. Time of concentration (TC) = 14.05 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 402.000 to Point/Station 403.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.300(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.800 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.200 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.492 Time of concentration = 14.05 min. Rainfall intensity = 2.300(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.481 CA = 13.473 Subarea runoff = 0.979(CFS) for 1.180(Ac.) Total runoff = 30.988(CFS) Total area = 28.040(Ac.) 4 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 403.000 to Point/Station 404.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 210.000(Ft.) Downstream point/station elevation = 181.500(Ft.) Pipe length = 475.00(Ft.) Slope = 0.0600 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 30.988(CFS) Nearest computed pipe diameter = 21.00(In.) Calculated individual pipe flow = 30.988(CFS) Normal flow depth in pipe = 14.18(In.) Flow top width inside pipe = 19.67(In.) Critical depth could not be calculated. Pipe flow velocity = 17.92(Ft/s) Travel time through pipe = 0.44 min. Time of concentration (TC) = 14.49 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 403.000 to Point/Station 404.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.254(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.500 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.500 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.510 Time of concentration = 14.49 min. Rainfall intensity = 2.254(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.485 CA = 15.988 Subarea runoff = 5.056(CFS) for 4.930(Ac.) Total runoff = 36.044(CFS) Total area = 32.970(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 404.000 to Point/Station 405.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 176.000(Ft.) Downstream point/station elevation = 164.700(Ft.) Pipe length = 565.00(Ft.) Slope = 0.0200 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 36.044(CFS) Nearest computed pipe diameter = 27.00(In.) Calculated individual pipe flow = 36.044(CFS) Normal flow depth in pipe = 18.66(In.) 5 Flow top width inside pipe = 24.95(In.) Critical Depth = 24.36(In.) Pipe flow velocity = 12.30(Ft/s) Travel time through pipe = 0.77 min. Time of concentration (TC) = 15.26 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 404.000 to Point/Station 405.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1 Stream flow area = 32.970(Ac.) Runoff from this stream = 36.044(CFS) Time of concentration = 15.26 min. Rainfall intensity = 2.181(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 406.000 to Point/Station 407.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Initial subarea total flow distance = 428.000(Ft.) Highest elevation = 247.000(Ft.) Lowest elevation = 219.000(Ft.) Elevation difference = 28.000(Ft.) Slope = 6.542 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 6.54 %, in a development type of 7.3 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration = 5.97 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.4800)*( 100.000^.5)/( 6.542^(1/3)]= 5.97 The initial area total distance of 428.00 (Ft.) entered leaves a remaining distance of 328.00 (Ft.) Using Figure 3-4, the travel time for this distance is 1.93 minutes for a distance of 328.00 (Ft.) and a slope of 6.54 % with an elevation difference of 21.46(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 1.931 Minutes Tt=[(11.9*0.0621^3)/( 21.46)]^.385= 1.93 Total initial area Ti = 5.97 minutes from Figure 3-3 formula plus 1.93 minutes from the Figure 3-4 formula = 7.90 minutes 6 Rainfall intensity (I) = 3.335(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.480 Subarea runoff = 2.914(CFS) Total initial stream area = 1.820(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 407.000 to Point/Station 408.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 219.000(Ft.) End of street segment elevation = 188.000(Ft.) Length of street segment = 731.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 18.552(CFS) Depth of flow = 0.457(Ft.), Average velocity = 5.538(Ft/s) Note: depth of flow exceeds top of street crown. Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 18.000(Ft.) Flow velocity = 5.54(Ft/s) Travel time = 2.20 min. TC = 10.10 min. Adding area flow to street Rainfall intensity (I) = 2.846(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Rainfall intensity = 2.846(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.480 CA = 11.990 Subarea runoff = 31.216(CFS) for 23.160(Ac.) Total runoff = 34.130(CFS) Total area = 24.980(Ac.) Street flow at end of street = 34.130(CFS) Half street flow at end of street = 34.130(CFS) Depth of flow = 0.547(Ft.), Average velocity = 6.799(Ft/s) Warning: depth of flow exceeds top of curb 7 Note: depth of flow exceeds top of street crown. Distance that curb overflow reaches into property = 2.34(Ft.) Flow width (from curb towards crown)= 18.000(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 408.000 to Point/Station 409.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 188.000(Ft.) Downstream point/station elevation = 187.440(Ft.) Pipe length = 56.00(Ft.) Slope = 0.0100 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 34.130(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 34.130(CFS) Normal flow depth in pipe = 20.91(In.) Flow top width inside pipe = 27.58(In.) Critical Depth = 23.84(In.) Pipe flow velocity = 9.35(Ft/s) Travel time through pipe = 0.10 min. Time of concentration (TC) = 10.20 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 408.000 to Point/Station 409.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.828(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.950 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.050 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.483 Time of concentration = 10.20 min. Rainfall intensity = 2.828(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.480 CA = 13.681 Subarea runoff = 4.565(CFS) for 3.500(Ac.) Total runoff = 38.695(CFS) Total area = 28.480(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 409.000 to Point/Station 410.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 188.000(Ft.) Downstream point/station elevation = 175.800(Ft.) Pipe length = 610.00(Ft.) Slope = 0.0200 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 38.695(CFS) 8 Nearest computed pipe diameter = 27.00(In.) Calculated individual pipe flow = 38.695(CFS) Normal flow depth in pipe = 19.73(In.) Flow top width inside pipe = 23.95(In.) Critical Depth = 24.87(In.) Pipe flow velocity = 12.44(Ft/s) Travel time through pipe = 0.82 min. Time of concentration (TC) = 11.02 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 409.000 to Point/Station 410.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.691(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.400 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.600 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.516 Time of concentration = 11.02 min. Rainfall intensity = 2.691(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.484 CA = 15.461 Subarea runoff = 2.913(CFS) for 3.450(Ac.) Total runoff = 41.608(CFS) Total area = 31.930(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 410.000 to Point/Station 405.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 162.000(Ft.) Downstream point/station elevation = 145.200(Ft.) Pipe length = 420.00(Ft.) Slope = 0.0400 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 41.608(CFS) Nearest computed pipe diameter = 24.00(In.) Calculated individual pipe flow = 41.608(CFS) Normal flow depth in pipe = 18.14(In.) Flow top width inside pipe = 20.62(In.) Critical depth could not be calculated. Pipe flow velocity = 16.34(Ft/s) Travel time through pipe = 0.43 min. Time of concentration (TC) = 11.44 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 410.000 to Point/Station 405.000 **** CONFLUENCE OF MINOR STREAMS **** 9 ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2 Stream flow area = 31.930(Ac.) Runoff from this stream = 41.608(CFS) Time of concentration = 11.44 min. Rainfall intensity = 2.626(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 36.044 15.26 2.181 2 41.608 11.44 2.626 Qmax(1) = 1.000 * 1.000 * 36.044) + 0.831 * 1.000 * 41.608) + = 70.603 Qmax(2) = 1.000 * 0.750 * 36.044) + 1.000 * 1.000 * 41.608) + = 68.638 Total of 2 streams to confluence: Flow rates before confluence point: 36.044 41.608 Maximum flow rates at confluence using above data: 70.603 68.638 Area of streams before confluence: 32.970 31.930 Results of confluence: Total flow rate = 70.603(CFS) Time of concentration = 15.260 min. Effective stream area after confluence = 64.900(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 405.000 to Point/Station 405.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.181(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.050 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.950 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.537 Time of concentration = 15.26 min. Rainfall intensity = 2.181(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.491 CA = 36.593 Subarea runoff = 9.202(CFS) for 9.580(Ac.) 10 Total runoff = 79.805(CFS) Total area = 74.480(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 405.000 to Point/Station 411.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 146.000(Ft.) Downstream point/station elevation = 136.320(Ft.) Pipe length = 242.00(Ft.) Slope = 0.0400 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 79.805(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 79.805(CFS) Normal flow depth in pipe = 23.91(In.) Flow top width inside pipe = 24.14(In.) Critical depth could not be calculated. Pipe flow velocity = 19.04(Ft/s) Travel time through pipe = 0.21 min. Time of concentration (TC) = 15.47 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 405.000 to Point/Station 411.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.162(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 1.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.540 Time of concentration = 15.47 min. Rainfall intensity = 2.162(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.493 CA = 38.440 Subarea runoff = 3.286(CFS) for 3.420(Ac.) Total runoff = 83.091(CFS) Total area = 77.900(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 411.000 to Point/Station 412.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 136.000(Ft.) Downstream point/station elevation = 117.830(Ft.) Pipe length = 395.00(Ft.) Slope = 0.0460 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 83.091(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 83.091(CFS) 11 Normal flow depth in pipe = 23.20(In.) Flow top width inside pipe = 25.12(In.) Critical depth could not be calculated. Pipe flow velocity = 20.38(Ft/s) Travel time through pipe = 0.32 min. Time of concentration (TC) = 15.79 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 411.000 to Point/Station 412.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.133(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.670 Decimal fraction soil group D = 0.330 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.550 Time of concentration = 15.79 min. Rainfall intensity = 2.133(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.496 CA = 40.667 Subarea runoff = 3.650(CFS) for 4.050(Ac.) Total runoff = 86.741(CFS) Total area = 81.950(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 412.000 to Point/Station 413.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 116.000(Ft.) Downstream point/station elevation = 107.990(Ft.) Pipe length = 176.00(Ft.) Slope = 0.0455 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 86.741(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 86.741(CFS) Normal flow depth in pipe = 24.38(In.) Flow top width inside pipe = 23.42(In.) Critical depth could not be calculated. Pipe flow velocity = 20.32(Ft/s) Travel time through pipe = 0.14 min. Time of concentration (TC) = 15.94 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 412.000 to Point/Station 413.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.120(In/Hr) for a 10.0 year storm 12 Decimal fraction soil group A = 0.330 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.330 Decimal fraction soil group D = 0.340 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.530 Time of concentration = 15.94 min. Rainfall intensity = 2.120(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.501 CA = 48.506 Subarea runoff = 16.116(CFS) for 14.780(Ac.) Total runoff = 102.857(CFS) Total area = 96.730(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 413.000 to Point/Station 414.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 108.000(Ft.) Downstream point/station elevation = 87.490(Ft.) Pipe length = 260.00(Ft.) Slope = 0.0789 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 102.857(CFS) Nearest computed pipe diameter = 30.00(In.) Calculated individual pipe flow = 102.857(CFS) Normal flow depth in pipe = 22.10(In.) Flow top width inside pipe = 26.42(In.) Critical depth could not be calculated. Pipe flow velocity = 26.53(Ft/s) Travel time through pipe = 0.16 min. Time of concentration (TC) = 16.10 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 413.000 to Point/Station 414.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.107(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.500 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.250 Decimal fraction soil group D = 0.250 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.517 Time of concentration = 16.10 min. Rainfall intensity = 2.107(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.503 CA = 55.565 Subarea runoff = 14.196(CFS) for 13.640(Ac.) 13 Total runoff = 117.052(CFS) Total area = 110.370(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 414.000 to Point/Station 415.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 86.000(Ft.) Downstream point/station elevation = 85.000(Ft.) Pipe length = 100.00(Ft.) Slope = 0.0100 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 117.052(CFS) Nearest computed pipe diameter = 45.00(In.) Calculated individual pipe flow = 117.052(CFS) Normal flow depth in pipe = 35.63(In.) Flow top width inside pipe = 36.55(In.) Critical Depth = 39.23(In.) Pipe flow velocity = 12.47(Ft/s) Travel time through pipe = 0.13 min. Time of concentration (TC) = 16.24 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 414.000 to Point/Station 415.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1 Stream flow area = 110.370(Ac.) Runoff from this stream = 117.052(CFS) Time of concentration = 16.24 min. Rainfall intensity = 2.095(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 415.000 to Point/Station 415.000 **** USER DEFINED FLOW INFORMATION AT A POINT **** ______________________________________________________________________ User specified 'C' value of 0.480 given for subarea Rainfall intensity (I) = 1.277(In/Hr) for a 10.0 year storm User specified values are as follows: TC = 35.00 min. Rain intensity = 1.28(In/Hr) Total area = 260.320(Ac.) Total runoff = 171.000(CFS) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 415.000 to Point/Station 415.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2 Stream flow area = 260.320(Ac.) Runoff from this stream = 171.000(CFS) Time of concentration = 35.00 min. Rainfall intensity = 1.277(In/Hr) 14 Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 117.052 16.24 2.095 2 171.000 35.00 1.277 Qmax(1) = 1.000 * 1.000 * 117.052) + 1.000 * 0.464 * 171.000) + = 196.377 Qmax(2) = 0.609 * 1.000 * 117.052) + 1.000 * 1.000 * 171.000) + = 242.321 Total of 2 streams to confluence: Flow rates before confluence point: 117.052 171.000 Maximum flow rates at confluence using above data: 196.377 242.321 Area of streams before confluence: 110.370 260.320 Results of confluence: Total flow rate = 242.321(CFS) Time of concentration = 35.000 min. Effective stream area after confluence = 370.690(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 415.000 to Point/Station 416.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 67.000(Ft.) Downstream point/station elevation = 28.750(Ft.) Pipe length = 778.00(Ft.) Slope = 0.0492 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 242.321(CFS) Nearest computed pipe diameter = 45.00(In.) Calculated individual pipe flow = 242.321(CFS) Normal flow depth in pipe = 33.47(In.) Flow top width inside pipe = 39.29(In.) Critical depth could not be calculated. Pipe flow velocity = 27.49(Ft/s) Travel time through pipe = 0.47 min. Time of concentration (TC) = 35.47 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 415.000 to Point/Station 416.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1 Stream flow area = 370.690(Ac.) 15 Runoff from this stream = 242.321(CFS) Time of concentration = 35.47 min. Rainfall intensity = 1.266(In/Hr) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 417.000 to Point/Station 417.000 **** USER DEFINED FLOW INFORMATION AT A POINT **** ______________________________________________________________________ User specified 'C' value of 0.500 given for subarea Rainfall intensity (I) = 2.205(In/Hr) for a 10.0 year storm User specified values are as follows: TC = 15.00 min. Rain intensity = 2.21(In/Hr) Total area = 23.750(Ac.) Total runoff = 26.100(CFS) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 417.000 to Point/Station 417.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.205(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 1.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.570 Time of concentration = 15.00 min. Rainfall intensity = 2.205(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.515 CA = 15.608 Subarea runoff = 8.319(CFS) for 6.550(Ac.) Total runoff = 34.419(CFS) Total area = 30.300(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 417.000 to Point/Station 416.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 120.000(Ft.) Downstream point/station elevation = 68.200(Ft.) Pipe length = 740.00(Ft.) Slope = 0.0700 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 34.419(CFS) Nearest computed pipe diameter = 21.00(In.) Calculated individual pipe flow = 34.419(CFS) Normal flow depth in pipe = 14.48(In.) Flow top width inside pipe = 19.43(In.) Critical depth could not be calculated. Pipe flow velocity = 19.45(Ft/s) Travel time through pipe = 0.63 min. 16 Time of concentration (TC) = 15.63 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 417.000 to Point/Station 416.000 **** CONFLUENCE OF MINOR STREAMS **** ______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2 Stream flow area = 30.300(Ac.) Runoff from this stream = 34.419(CFS) Time of concentration = 15.63 min. Rainfall intensity = 2.147(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 242.321 35.47 1.266 2 34.419 15.63 2.147 Qmax(1) = 1.000 * 1.000 * 242.321) + 0.590 * 1.000 * 34.419) + = 262.612 Qmax(2) = 1.000 * 0.441 * 242.321) + 1.000 * 1.000 * 34.419) + = 141.221 Total of 2 streams to confluence: Flow rates before confluence point: 242.321 34.419 Maximum flow rates at confluence using above data: 262.612 141.221 Area of streams before confluence: 370.690 30.300 Results of confluence: Total flow rate = 262.612(CFS) Time of concentration = 35.472 min. Effective stream area after confluence = 400.990(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 416.000 to Point/Station 418.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 28.750(Ft.) Downstream point/station elevation = 18.690(Ft.) Pipe length = 214.00(Ft.) Slope = 0.0470 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 262.612(CFS) Nearest computed pipe diameter = 48.00(In.) Calculated individual pipe flow = 262.612(CFS) Normal flow depth in pipe = 33.80(In.) Flow top width inside pipe = 43.82(In.) 17 Critical depth could not be calculated. Pipe flow velocity = 27.79(Ft/s) Travel time through pipe = 0.13 min. Time of concentration (TC) = 35.60 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 416.000 to Point/Station 418.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 1.263(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.080 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.020 Decimal fraction soil group D = 0.900 [LOW DENSITY RESIDENTIAL ] (1.0 DU/A or Less ) Impervious value, Ai = 0.100 Sub-Area C Value = 0.398 The area added to the existing stream causes a a lower flow rate of Q = 258.450(CFS) therefore the upstream flow rate of Q = 262.612(CFS) is being used Time of concentration = 35.60 min. Rainfall intensity = 1.263(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.484 CA = 204.664 Subarea runoff = 0.000(CFS) for 21.460(Ac.) Total runoff = 262.612(CFS) Total area = 422.450(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 418.000 to Point/Station 419.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 28.000(Ft.) Downstream point/station elevation = 21.600(Ft.) Pipe length = 1600.00(Ft.) Slope = 0.0040 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 262.612(CFS) Nearest computed pipe diameter = 72.00(In.) Calculated individual pipe flow = 262.612(CFS) Normal flow depth in pipe = 57.75(In.) Flow top width inside pipe = 57.37(In.) Critical Depth = 53.27(In.) Pipe flow velocity = 10.80(Ft/s) Travel time through pipe = 2.47 min. Time of concentration (TC) = 38.07 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 418.000 to Point/Station 419.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ 18 Rainfall intensity (I) = 1.209(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 1.000 [MEDIUM DENSITY RESIDENTIAL ] (10.9 DU/A or Less ) Impervious value, Ai = 0.450 Sub-Area C Value = 0.600 The area added to the existing stream causes a a lower flow rate of Q = 248.060(CFS) therefore the upstream flow rate of Q = 262.612(CFS) is being used Time of concentration = 38.07 min. Rainfall intensity = 1.209(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.485 CA = 205.120 Subarea runoff = 0.000(CFS) for 0.760(Ac.) Total runoff = 262.612(CFS) Total area = 423.210(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 419.000 to Point/Station 420.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 10.000(Ft.) Downstream point/station elevation = 9.020(Ft.) Pipe length = 245.00(Ft.) Slope = 0.0040 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 262.612(CFS) Nearest computed pipe diameter = 72.00(In.) Calculated individual pipe flow = 262.612(CFS) Normal flow depth in pipe = 57.75(In.) Flow top width inside pipe = 57.37(In.) Critical Depth = 53.27(In.) Pipe flow velocity = 10.80(Ft/s) Travel time through pipe = 0.38 min. Time of concentration (TC) = 38.45 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 419.000 to Point/Station 420.000 **** CONFLUENCE OF MAIN STREAMS **** ______________________________________________________________________ The following data inside Main Stream is listed: In Main Stream number: 1 Stream flow area = 423.210(Ac.) Runoff from this stream = 262.612(CFS) Time of concentration = 38.45 min. Rainfall intensity = 1.202(In/Hr) Program is now starting with Main Stream No. 2 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 19 Process from Point/Station 430.000 to Point/Station 431.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 0.200 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.150 Decimal fraction soil group D = 0.650 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.547 Initial subarea total flow distance = 665.000(Ft.) Highest elevation = 134.500(Ft.) Lowest elevation = 51.000(Ft.) Elevation difference = 83.500(Ft.) Slope = 12.556 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 12.56 %, in a development type of 7.3 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration = 4.28 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] TC = [1.8*(1.1-0.5475)*( 100.000^.5)/( 12.556^(1/3)]= 4.28 The initial area total distance of 665.00 (Ft.) entered leaves a remaining distance of 565.00 (Ft.) Using Figure 3-4, the travel time for this distance is 2.28 minutes for a distance of 565.00 (Ft.) and a slope of 12.56 % with an elevation difference of 70.94(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 2.284 Minutes Tt=[(11.9*0.1070^3)/( 70.94)]^.385= 2.28 Total initial area Ti = 4.28 minutes from Figure 3-3 formula plus 2.28 minutes from the Figure 3-4 formula = 6.56 minutes Rainfall intensity (I) = 3.759(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.547 Subarea runoff = 6.647(CFS) Total initial stream area = 3.230(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 431.000 to Point/Station 432.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 51.000(Ft.) End of street segment elevation = 14.000(Ft.) Length of street segment = 830.000(Ft.) Height of curb above gutter flowline = 6.0(In.) Width of half street (curb to crown) = 18.000(Ft.) Distance from crown to crossfall grade break = 8.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020 Slope from grade break to crown (v/hz) = 0.020 Street flow is on [1] side(s) of the street 20 Distance from curb to property line = 10.000(Ft.) Slope from curb to property line (v/hz) = 0.020 Gutter width = 1.500(Ft.) Gutter hike from flowline = 1.500(In.) Manning's N in gutter = 0.0150 Manning's N from gutter to grade break = 0.0180 Manning's N from grade break to crown = 0.0180 Estimated mean flow rate at midpoint of street = 25.415(CFS) Depth of flow = 0.493(Ft.), Average velocity = 6.373(Ft/s) Note: depth of flow exceeds top of street crown. Streetflow hydraulics at midpoint of street travel: Halfstreet flow width = 18.000(Ft.) Flow velocity = 6.37(Ft/s) Travel time = 2.17 min. TC = 8.73 min. Adding area flow to street Rainfall intensity (I) = 3.126(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.300 Decimal fraction soil group D = 0.700 [MEDIUM DENSITY RESIDENTIAL ] (4.3 DU/A or Less ) Impervious value, Ai = 0.300 Sub-Area C Value = 0.508 Rainfall intensity = 3.126(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.513 CA = 14.113 Subarea runoff = 37.468(CFS) for 24.300(Ac.) Total runoff = 44.114(CFS) Total area = 27.530(Ac.) Street flow at end of street = 44.114(CFS) Half street flow at end of street = 44.114(CFS) Depth of flow = 0.591(Ft.), Average velocity = 7.403(Ft/s) Warning: depth of flow exceeds top of curb Note: depth of flow exceeds top of street crown. Distance that curb overflow reaches into property = 4.53(Ft.) Flow width (from curb towards crown)= 18.000(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 432.000 to Point/Station 433.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 14.000(Ft.) Downstream point/station elevation = 12.950(Ft.) Pipe length = 150.00(Ft.) Slope = 0.0070 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 44.114(CFS) Nearest computed pipe diameter = 33.00(In.) Calculated individual pipe flow = 44.114(CFS) Normal flow depth in pipe = 26.95(In.) Flow top width inside pipe = 25.53(In.) Critical Depth = 26.43(In.) Pipe flow velocity = 8.49(Ft/s) 21 Travel time through pipe = 0.29 min. Time of concentration (TC) = 9.03 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 432.000 to Point/Station 433.000 **** CONFLUENCE OF MAIN STREAMS **** ______________________________________________________________________ The following data inside Main Stream is listed: In Main Stream number: 2 Stream flow area = 27.530(Ac.) Runoff from this stream = 44.114(CFS) Time of concentration = 9.03 min. Rainfall intensity = 3.060(In/Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr) 1 262.612 38.45 1.202 2 44.114 9.03 3.060 Qmax(1) = 1.000 * 1.000 * 262.612) + 0.393 * 1.000 * 44.114) + = 279.937 Qmax(2) = 1.000 * 0.235 * 262.612) + 1.000 * 1.000 * 44.114) + = 105.775 Total of 2 main streams to confluence: Flow rates before confluence point: 262.612 44.114 Maximum flow rates at confluence using above data: 279.937 105.775 Area of streams before confluence: 423.210 27.530 Results of confluence: Total flow rate = 279.937(CFS) Time of concentration = 38.448 min. Effective stream area after confluence = 450.740(Ac.) End of computations, total study area = 450.740 (Ac.) 1 San Diego County Rational Hydrology Program CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2009 Version 7.8 Rational method hydrology program based on San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 12/08/12 ------------------------------------------------------------------------ City of Carlsbad Hydromodification Exemption Study Major Basin 500 10-Year Flow Rate ------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** ------------------------------------------------------------------------ Program License Serial Number 4028 ------------------------------------------------------------------------ Rational hydrology study storm event year is 10.0 English (in-lb) input data Units used Map data precipitation entered: 6 hour, precipitation(inches) = 1.700 24 hour precipitation(inches) = 3.100 P6/P24 = 54.8% San Diego hydrology manual 'C' values used ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 500.000 to Point/Station 501.000 **** INITIAL AREA EVALUATION **** ______________________________________________________________________ Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Initial subarea total flow distance = 250.000(Ft.) Highest elevation = 50.000(Ft.) Lowest elevation = 48.000(Ft.) Elevation difference = 2.000(Ft.) Slope = 0.800 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 65.00 (Ft) for the top area slope value of 0.80 %, in a development type of 7.3 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration = 9.69 minutes TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)] 2 TC = [1.8*(1.1-0.4800)*( 65.000^.5)/( 0.800^(1/3)]= 9.69 The initial area total distance of 250.00 (Ft.) entered leaves a remaining distance of 185.00 (Ft.) Using Figure 3-4, the travel time for this distance is 2.79 minutes for a distance of 185.00 (Ft.) and a slope of 0.80 % with an elevation difference of 1.48(Ft.) from the end of the top area Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr) = 2.790 Minutes Tt=[(11.9*0.0350^3)/( 1.48)]^.385= 2.79 Total initial area Ti = 9.69 minutes from Figure 3-3 formula plus 2.79 minutes from the Figure 3-4 formula = 12.48 minutes Rainfall intensity (I) = 2.483(In/Hr) for a 10.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.480 Subarea runoff = 1.156(CFS) Total initial stream area = 0.970(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 501.000 to Point/Station 502.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 48.000(Ft.) Downstream point/station elevation = 47.100(Ft.) Pipe length = 180.00(Ft.) Slope = 0.0050 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 1.156(CFS) Nearest computed pipe diameter = 9.00(In.) Calculated individual pipe flow = 1.156(CFS) Normal flow depth in pipe = 7.29(In.) Flow top width inside pipe = 7.06(In.) Critical Depth = 5.93(In.) Pipe flow velocity = 3.02(Ft/s) Travel time through pipe = 0.99 min. Time of concentration (TC) = 13.48 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 501.000 to Point/Station 502.000 **** SUBAREA FLOW ADDITION **** ______________________________________________________________________ Rainfall intensity (I) = 2.363(In/Hr) for a 10.0 year storm Decimal fraction soil group A = 1.000 Decimal fraction soil group B = 0.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 [MEDIUM DENSITY RESIDENTIAL ] (7.3 DU/A or Less ) Impervious value, Ai = 0.400 Sub-Area C Value = 0.480 Time of concentration = 13.48 min. Rainfall intensity = 2.363(In/Hr) for a 10.0 year storm Effective runoff coefficient used for total area (Q=KCIA) is C = 0.480 CA = 2.491 Subarea runoff = 4.731(CFS) for 4.220(Ac.) Total runoff = 5.887(CFS) Total area = 5.190(Ac.) 3 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 502.000 to Point/Station 503.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 47.000(Ft.) Downstream point/station elevation = 30.000(Ft.) Pipe length = 60.00(Ft.) Slope = 0.2833 Manning's N = 0.013 No. of pipes = 1 Required pipe flow = 5.887(CFS) Nearest computed pipe diameter = 9.00(In.) Calculated individual pipe flow = 5.887(CFS) Normal flow depth in pipe = 5.38(In.) Flow top width inside pipe = 8.83(In.) Critical depth could not be calculated. Pipe flow velocity = 21.35(Ft/s) Travel time through pipe = 0.05 min. Time of concentration (TC) = 13.52 min. End of computations, total study area = 5.190 (Ac.) HMP LEGEND: --••••• V/h1 IUZJ EXEMPTION GRAPHIC SCALE I 000 0 500 I 000 MAJOR DRAINAGE BASIN BOUNDARY NAlURAL FLOW PAlH HYDROMODIFICA TION EXEMPT AREA HYDROMODIFICA TION EXEMPT AREA IF FUlURE DRAINAGE IMPROVEMENTS ARE CONSTRUCTED EXHIBIT L"~--""'l·•-""'lm• --l--11111 1 INCH = 500 FEET