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CT 01-09; LA COSTA TOWN SQUARE COMMERCIAL; WATER QUALITY TECHNICAL REPORT; 2013-05-03
oi HYDROMODIFICATION SCREENING FOR LECORO COFY LA COSTA TOWN SQUARE (CT 01-09 & DWG 409-4C) May 3, 2013 Wayne W. Chang, mS, PE 46548 Cliang( Civil Engineering»Hydrolog)* ° Hydraulics ° Sedinnentation P.O. Box 9496 Rancho Santa Fe, CA 92067 (858) 692-0760 -TABLE OF CONTENTS - Introduction 1 Domain of Analysis 2 Initial Desktop Analysis 5 Field Screening 6 Conclusion 10 Figures 11 APPENDICES A. SCCWRP Initial Desktop Analysis B. SCCWRP Field Screening Data MAP POCKET Study Area Exhibit Watershed Exhibit As-Built Reference Drawings INTRODUCTION The City of Carlsbad's January 14, 2011, Standard Urban Storm Water Management Plan (SUSMP) outlines low flow thresholds for hydromodification analyses. The thresholds are based on a percentage of the pre-project 2-year flow (Qi), i.e., 0.1 Q2 (low flow threshold and high susceptibility to erosion), O.3Q2 (medium flow threshold and medium susceptibility to erosion), or O.5Q2 (high flow threshold and low susceptibility to erosion). A threshold of 0.1 Q2 represents a downstream receiving conveyance system with a high susceptibility to erosion. This is the default value used for hydromodification analyses and will result in the most conservative (greatest) on-site facility sizing. A threshold of O.3Q2 or O.5Q2 represents downstream receiving conveyance systems with a medium or low susceptibility to erosion, respectively. In order to qualify for a medium or low susceptibility rating, a project must perform a channel screening analysis based on a "hydromodification screening tool" procedure developed by the Southem California Coastal Water Research Project (SCCWRP). The SCCWRP results are compared with the critical shear stress calculator results from the County of San Diego's BMP Sizing Calculator to establish the appropriate susceptibility threshold of low, medium, or high. VICINITY MAP cmr OF OCEAHSIOE cmr OF SAN MARCOS PAOIHC OCEAN PROJECT SITE CITY OF ENCINITAS Vicinity Map This report provides hydromodification screening analyses for the La Costa Town Square project being designed by O'Day Consultants, Inc. The project is located east of the intersection of Rancho Santa Fe Road and La Costa Avenue in the city of Carlsbad (see the Vicinity Map and the Study Area Exhibit in the map pocket). The site covers 66 acres and is currently undeveloped. The project proposes mixed-use development with single-family residential lots on the easterly portion of the site and commercial/retail development on the westerly portion of the site. The project is subject to hydromodification requirements because it is a priority development project. A variety of best management practices (bioretention basins, bioswales, pavers, proprietary filters, etc.) will be incorporated throughout the site to treat and/or detain runoff from the development areas. Under pre-project conditions, the site is undeveloped, covered with grasses, brush, and some trees, and moderately sloping in a southerly direction. Surface runoff travels across the site as sheet flow or in natural drainages and enters a series of existing storm drain systems along La Costa Avenue. The storm drain systems convey the runoff in a southerly direction into an unnamed natural stream that flows in a westerly direction and is tributary to Encinitas Creek. Under post-project conditions, storm runoff from the site will be conveyed within a series of on- site drainage facilities constructed by the project. The runoff will continue to be conveyed to the existing storm drain systems along La Costa Avenue and will enter the unnamed natural stream at three current storm drain discharge locations. The SCCWRP screening tool requires both office and field work to establish the vertical and lateral susceptibility of a natural downstream receiving chaimel to erosion. In this case, the natural downstream receiving channel is the urmamed stream. The vertical and lateral assessments are performed independently of each other although the lateral results can be affected by the vertical rating. A screening analysis was performed to assess the low flow threshold for the project's points of compliance, which are at each of the three storm drain outlets into the urmamed natural stream. The initial step in performing the SCCWRP screening analysis is to establish the domain of analysis and the study reaches within the domain. This is followed by office and field components of the screening tool along with the associated analyses and results. The following sections cover these procedures in sequence. DOMAIN OF ANALYSIS SCCWRP defines an upstream and downstream domain of analysis, which establish the study limits. The County of San Diego's HMP specifies the downstream domain of analysis based on the SCCWRP criteria. The HMP indicates that the downstream domain is the first point where one of these is reached: • at least one reach downstream of the first grade control point • tidal backwater/lentic waterbody • equal order tributary • accumulation of 50 percent drainage area for stream systems or 100 percent drainage area for urban conveyance systems (storm drains, hardened channels, etc.) The upstream limit is defined as: • proceed upstream for 20 channel top widths or to the first grade control point, whichever comes first. Identify hard points that can check headward migration and evidence of active headcutting. SCCWRP defines the maximum spatial unit, or reach (a reach is circa 20 charmel widths), for assigning a susceptibility rating within the domain of analysis to be 200 meters (656 feet). If the domain of analysis is greater than 200 meters, the study area should be subdivided into smaller reaches of less than 200 meters for analysis. Most of the units in the HMP's SCCWRP analysis are metric. Metric units are used in this report only where given so in the HMP. Otherwise English units are used. Downstream Domain of Analvsis The downstream domain of analysis for the study area is determined by assessing and comparing the four bullet items above. As discussed in the Introduction, the project has a point of compliance (POC) at each of the three storm drain outlets into the unnamed natural stream (see the easterly, central, and westerly POCs on the Study Area Exhibit in the map pocket). All of the storm runoff from the project site enters the unnamed natural stream at one of these three POCs. Camino de Los Coches crosses the unnamed natural stream at two locations (east and west). Culverts exist at both crossings to convey the stream fiow through the road (see as-built drawing 205-2 in the map pocket). The easterly (upstream-most) POC is approximately 390 feet upstream of the easterly Camino de Los Coches crossing. The central POC is on the downstream side of the easterly Camino de Los Coches crossing. The westerly (downstream-most) POC is on the downstream side of the westerly Camino de Los Coches crossing. The downstream domain of analysis will be below the downstream-most (westerly) POC and was assessed as follows. Per the first bullet item, the first permanent grade control point was located below the westerly POC through a site investigation. The unnamed natural stream flows westerly towards Calle Barcelona, which contains culverts to convey flow through the road. During the site investigation, no permanent grade controls were observed in the unnamed natural stream between the westerly POC and Calle Barcelona. Therefore, the first permanent grade control downstream of the westerly POC will be at the Calle Barcelona culverts. The culverts are double 60-inch reinforced concrete pipe (see as-built drawing 231-7 in the map pocket) within the Calle Barcelona road embankment. The culverts and embankment form a permanent grade control within the unnamed natural stream. The second bullet item is the tidal backwater or lentic (standing or still water such as ponds, pools, marshes, lakes, etc.) waterbody location. The nearest significant tidal backwater or lentic waterbody is Batiquitos Lagoon, which is nearly 3 miles downstream of Calle Barcelona. Therefore, the lentic waterbody is further downstream than the permanent grade control at Calle Barcelona. The final two bullet items are related to the tributary drainage area. The overall tributary drainage area to Calle Barcelona was delineated using USGS quadrangle mapping and covers approximately 858 acres (see the Watershed Exhibit in the map pocket). The Watershed Exhibit reveals that the unnamed nattiral stream does not confluence with a larger watercourse that would increase the tributary area by 50 to 100 percent between the westerly POC and Calle Barcelona. Therefore, Calle Barcelona is closer to the westerly POC than a 50 or 100 percent tributary. Based on the above information, the permanent grade control created by Calle Barcelona and its reinforced concrete pipe (RCP) culverts meet the HMP criteria for the downstream domain of analysis because it is the first point reached from the four bullet items. The tidal/lentic waterbody and 50/100 percent tributary areas are downstream of the permanent grade control. Per the first bullet item, the downstream domain of analysis begins one reach below the culverts. As outlined above, a reach is not to exceed 200 meters (656 feet). Therefore, the downstream domain of analysis for the study reach was selected as 200 meters downstream of the Calle Barcelona culverts. Upstream Domain of Analvsis The upstream domain of analysis will be above the upstream-most (easterly) POC. The first grade control point upstream of the easterly POC occurs at the double 48-inch RCP culverts under La Costa Avenue. The culverts convey flow in the unnamed natural stream through La Costa Avenue and are shown on Drawing 397-IB included in the map pocket. The culverts are just over 330 feet (101 meters) upstream of the easterly POC and the outlet of the culverts establish the upstream domain of analysis location. Studv Reaches within Domain of Analvsis The total domain of analysis (or overall study reach) extends from 200 meters below Calle Barcelona on the downstream end to the outlet of the La Costa Avenue culverts on the upstream end. The total domain of analysis covers approximately 6,530 feet (1,990 meters). The domain of analysis was subdivided into four natural study reaches with similar characteristics (see the Study Area Exhibit). Reach 1 (uppermost reach) extends 707 feet (215 meters) from the upstream domain of analysis location at the La Costa Avenue culverts down to the culvert entrance at the easterly Camino de Los Coches crossing. Reach 2 extends 2,026 feet (618 meters) from the culvert outlet at the easterly Camino de Los Coches crossing to an existing inlet near the upper end of Stagecoach Community Park (see Figure 6 and as-built drawing 261-9A). Reach 3 extends 2,089 feet (637 meters) from the culvert outlet at the westerly Camino de Los Coches crossing to the culvert entrance at Calle Barcelona. Reach 4 extends 656 feet (200 meters) from the culvert outlet at Calle Barcelona to the downstream domain of analysis location. The existing hardened conveyances within the overall study reach do not need to be analyzed because they are non-erodible. The hardened conveyances include the reinforced concrete culverts under both ends of Camino de Los Coches and under Calle Barcelona. Furthermore, flow is conveyed through Stagecoach Community Park by a combination of an underground storm drain (see as-built drawing 261-9A) and a concrete/rock-lined lined swale (see Figures 7 and 8). Since neither of these drainage conveyances is erodible, they do not need to be evaluated. Reaches 1, 2, and 3 are longer than the 656 feet (200 meters) maximum reach length specified by SCCWRP. Review of topographic mapping, aerial photographs, and field conditions reveals that the physical (chaimel geometry and longitudinal slope), vegetative, hydraulic, and soil conditions within each of these reaches are relatively uniform. Subdividing the reaches into smaller subreaches of less than 656 feet will not yield significantly varying results within a reach. Although the screening tool was applied across the entire length of each of these three reaches, the results will be similar for shorter subreaches within each reach. INITIAL DESKTOP ANALYSIS After the domain of analysis is established, SCCWRP requires an "initial desktop analysis" that involves office work. The initial desktop analysis establishes the watershed area, mean annual precipitation, valley slope, and valley width. These terms are defined in Form 1, which is included in Appendix A. SCCWRP recommends the use of National Elevation Data (NED) to determine the watershed area, valley slope, and valley width. The NED data is similar to USGS mapping. For this report, USGS mapping was used to delineate the off-site watershed areas, while O'Day's proposed condition drainage basins were used for the on-site areas. The watershed areas tributary to each study reach are shown on the Watershed Exhibit in the map pocket. The mean annual precipitation is provided by the County of San Diego's BMP Sizing Calculator (see Appendix A) and is 13.3 inches. The valley slopes of Reaches 1, 2, 3, and 4 were determined from the 2-foot contour interval mapping prepared for the project, where available, and the City's 2-foot contour interval topographic mapping in the remaining areas. The valley slope is the longitudinal slope of the channel bed along the flow line, so it is determined by dividing the elevation difference within a reach by the flow path. The 2-foot contour mapping sources were used because they will provide more precise results than NED data. The valley width is the bottom width of the creek channel. The average valley width within each reach was estimated from the 2-foot contour interval topographic mapping, field observations, and review of aerial photographs. The valley slope and valley width for each reach are summarized in Table 1. Reach Tributary Area, sq. mi. Valley Slope, m/m Valley Width, m 1 0.72 0.0269 19.8 r 2 0.88 0.0355 11.6 r 3 1.34 0.0172 14.3 4 1.44 0.0091 13.4 Table L Summary of Valley Slope and Valley Width These values were input to a spreadsheet to calculate the simulated peak flow, screening index, and valley width index outlined in Form 1. The input data and results are tabulated in Appendix A. This completes the initial desktop analysis. FIELD SCREENING After the initial desktop analysis is complete, a field assessment must be performed. The field assessment is used to establish a natural channel's vertical and lateral susceptibility to erosion. SCCWRP states that although they are admittedly linked, vertical and lateral susceptibility are assessed separately for several reasons. First, vertical and lateral responses are primarily controlled by different types of resistance, which, when assessed separately, may improve ease of use and lead to increased repeatability compared to an integrated, cross-dimensional assessment. Second, the mechanistic differences between vertical and lateral responses point to different modeling tools and potentially different management strategies. Having separate screening ratings may better direct users and managers to the most appropriate tools for subsequent analyses. The field screening tool uses combinations of decision trees and checklists. Decision trees are typically used when a question can be answered fairly definitively and/or quantitatively (e.g., dso < 16 mm). Checklists are used where answers are relatively qualitative (e.g., the condition ofa grade control). Low, meditim, high, and very high ratings are applied separately to the vertical and lateral analyses. When the vertical and lateral analyses retum divergent values, the most conservative value shall be selected as the flow threshold for the hydromodification analyses. Visual observation reveals that each study reach contains a densely vegetated chaimel (see the figures following the report text). The vegetative density extends relatively uniformly across the channel bottom and sides. Due to the vegetative cover, riprap energy dissipaters at each POC, and lack of erosion noted during the site investigation, the vertical and lateral stability was anticipated to have a limited susceptibility to erosion. Vertical Stabilitv The purpose of the vertical stability decision tree (Figure 6-4 in the County of San Diego HMP) is to assess the state of the channel bed with a particular focus on the risk of incision (i.e., down cutting). The decision tree is included in Figure 18. The first step is to assess the channel bed resistance. There are three categories defined as follows: 1. Labile Bed - sand-dominated bed, little resistant substrate. 2. Transitional/Intermediate Bed - bed typically characterized by gravel/small cobble. Intermediate level of resistance of the substrate and uncertain potential for armoring. 3. Threshold Bed (Coarse/Armored Bed) - armored with large cobbles or larger bed material or highly-resistant bed substrate (i.e., bedrock). Channel bed resistance is a function of the bed material and vegetation. The figures after this report text show photographs of the unnamed natural stream channel in each study reach. The vegetative cover along and adjacent to the flowline of each reach was so dense that they were either difficult to access or not possible to access at all unless the vegetation was trimmed. The figures show dense vegetation throughout all four reaches. The vegetation consists of a variety of mature grasses, reeds, shmbs, and trees. Vegetation prevents bed incision because its root stmcture binds soil and because the aboveground vegetative growth reduces flow velocities. Table 5-13 from the Cotmty of San Diego's Drainage Design Manual outlines maximum permissible velocities for various charmel linings (see Table 5-13 in Appendix B). Maximum permissible velocity is defined in the manual as the velocity below which a channel section will remain stable, i.e., not erode. Table 5-13 indicates that a fully-lined channel with unreinforced vegetation has a maximum permissible velocity of 5 feet per second (fps). Due to the dense cover and mature vegetation, the permissible velocity when erosion can initiate is likely greater than 5 fps in most of the natural channel areas. Table 5-13 indicates that 5 fps is equivalent to an unvegetated channel containing cobbles (grain size from 64 to 256 mm) and shingles (rounded cobbles). In comparison, coarse gravel (19 to 75 mm) has a maximum permissible velocity of 4 fps. Based on this information, the uniformly vegetated natural canyon has an equivalent grain size of at least 64 mm, which is comparable to a transitional/intermediate bed. The majority of the channel reaches could not be or were difficult to access by foot due to the thick, mature vegetation. Figures 14 through 17 show photographs of the bed material where access was possible. A gravelometer is included in the photographs for reference. Each square on the gravelometer indicates grain size in millimeters (the squares range from 2 mm to 180 mm). The figures show that there are larger gravel-sized particles in the study reaches, which supports the selection of 64 mm for the equivalent grain size. Based on the photographs and site investigation, the bed material and resistance is within the transitional/intermediate bed category. There was no evidence of a threshold bed condition. However, some bed areas contained smaller grain sizes typically found in a labile bed. There are several factors that establish the erodibility of a channel such as the flow rate (i.e., size of the tributary area), grade controls, channel slope, vegetative cover, channel planform, etc. The Introduction of the SCCWRP Hydromodification Screening Tools: Field Manual identifies several of these factors. When multiple factors influence erodibility, it is appropriate to perform the more detailed SCCWRP analysis, which is to analyze a channel according to SCCWRP's transitional/intermediate bed procedure. This requires the most rigorous steps and will generate the appropriate results given the range of factors that define erodibility. Dr. Eric Stein from SCCWRP, who co-authored the Hydromodification Screening Tools: Field Manual in the Final Hydromodification Management Plan (HMP), indicated that it would be appropriate to analyze channels with multiple factors that impact erodibility using the transitional/intermediate bed procedure. Based on this and the information in the prior two paragraphs, the transitional/intermediate bed procedure was used to produce more accurate results. Transitional/intermediate beds cover a wide susceptibility/potential response range and need to be assessed in greater detail to develop a weight of evidence for the appropriate screening rating. The three primary risk factors used to assess vertical susceptibility for channels with transitional/intermediate bed materials are: 1. Armoring potential - three states (Checklist 1) 2. Grade control - three states (Checklist 2) 3. Proximity to regionally-calibrated incision/braiding threshold (Mobility Index Threshold - Probability Diagram) These three risk factors are assessed using checklists and a diagram (see Appendix B), and the results of each are combined to provide a final vertical susceptibility rating for the intermediate/transitional bed-material group. Each checklist and diagram contains a Category A, B, or C rating. Category A is the most resistant to vertical changes while Category C is the most susceptible. Checklist 1 determines armoring potential of the channel bed. The channel bed along each of the four reaches is within category B, which represents intermediate bed material within unknown armoring potential due to a surface veneer and dense vegetation. The soil was probed and penetration was relatively difficult through the underlying layer. Due to the dense vegetative growth, the armoring potential could have been rated higher, but Category B was conservatively (i.e., more potential for chaimel incision) chosen. Checklist 2 determines grade control characteristics of the channel bed. SCCWRP states that grade controls can be natural. Examples are vegetation or confluences with a larger waterbody. As indicated above and verified with photographs, each reach contains dense vegetation (see the figures). The plant roots and fallen tree tmnks (see Figure 5) serve as a natural grade control. The spacing of these is much closer than the 50 meters identified in the checklist. Further evidence of the effectiveness of the natural grade controls is the absence of headcutting and mass wasting (large vertical erosion of a channel bank). Based on this information, each reach is within Category A on Checklist 2. The Mobility Index Threshold is a probability diagram that depicts the risk of incising or braiding based on the potential stream power of the valley relative to the median particle diameter. The threshold is based on regional data Irom Dr. Howard Chang of Chang Consultants and others. The probability diagram is based on dso as well as the Screening Index determined in the initial desktop analysis (see Appendix A), dso is derived from field conditions. As discussed above, the equivalent grain size for the densely-vegetated channels is at least 64 mm. The Mobility Index Threshold diagram shows that the 50 percent probability of incising or braiding for a dso of 64 mm has an index of at least 0.101 (in red rectangle on diagram). The Screening Index for each reach calculated in Appendix A varies from 0.021 to 0.065. Since each reach's Screening Index value is less than the 50 percent value, each reach falls within Category A. The overall vertical rating is determined from the Checklist 1, Checklist 2, and Mobility Index Threshold results. The scoring is based on the following values: Category A = 3, Category B = 6, Category C = 9 The vertical rating score is based on these values and the equation: 1/2 1/2 Vertical Rating = [(armoring x grade control) x screening index score] = [(6 X 3)^^^ X = 3.6 Since the vertical rating is less than 4.5, each reach has a low vertical susceptibility. Lateral Stabilitv The purpose of the lateral decision tree (Figure 6-5 from County of San Diego HMP included in Figure 19) is to assess the state of the channel banks with a focus on the risk of widening. Channels can widen from either bank failure or through fluvial processes such as chute cutoffs, avulsions, and braiding. Widening through fluvial avulsions/active braiding is a relatively straightforward observation. If braiding is not already occurring, the next logical step is to assess the condition of the banks. Banks fail through a variety of mechanisms; however, one of the most important distinctions is whether they fail in mass (as many particles) or by fluvial detachment of individual particles. Although much research is dedicated to the combined effects of weakening, fluvial erosion, and mass failure, SCCWRP found it valuable to segregate bank types based on the inference of the dominant failure mechanism (as the management approach may vary based on the dominant failure mechanism). A decision tree (Form 4 in Appendix B) is used in conducting the lateral susceptibility assessment. Definitions and photographic examples are also provided below for terms used in the lateral susceptibility assessment. The first step in the decision tree is to determine if lateral adjustments are occurring. The adjustments can take the form of extensive mass wasting (greater than 50 percent of the banks are exhibiting planar, slab, or rotational failures and/or scalloping, undermining, and/or tension cracks). The adjustments can also involve extensive fluvial erosion (significant and frequent bank cuts on over 50 percent of the banks). Neither mass wasting nor extensive fluvial erosion was evident within any of the reaches during a field investigation. The banks are intact in the photographs included in the figures. Due to the dense vegetation, photographs representative of the banks were difficult to take. Nonetheless, the dense vegetation supports the absence of large lateral adjustments. The next step in the Form 4 decision tree is to assess the consolidation of the bank material. The banks were moderate to well-consolidated. This determination was made because the banks were difficult to penetrate with a probe. In addition, the banks showed limited evidence of cmmbling and were composed of well-packed particles. Form 6 (see Appendix B) is used to assess the probability of mass wasting. Form 6 identifies a 10, 50, and 90 percent probability based on the bank angle and bank height. The topographic mapping indicates that the maximum natural bank angle is no greater than 2 to 1 (horizontal to vertical) or 26.6 degrees in any of the reaches. Form 6 shows that the probably of mass wasting and bank failure has less than 10 percent risk for a 26.6 degree bank angle or less regardless of the bank height. The final two steps in the Form 4 decision tree are based on the braiding risk determined from the vertical rating as well as the Valley Width Index (VWI) calculated in Appendix A. If the vertical rating is high, the braiding risk is considered to be greater than 50 percent. Excessive braiding can lead to lateral bank failure. For the Reaches 1 through 4, the vertical rating is low, so the braiding risk is less than 50 percent. Furthermore, a VWI greater than 2 represents channels unconfined by bedrock or hilislope and, hence, subject to lateral migration. The VWI calculations in the spreadsheet in Appendix A show that the VWI for each reach is much less than 2. From the above steps, the lateral susceptibility rating is low for each of the four study reaches (red circles are included on the Form 4: Lateral Susceptibility Field Sheet decision tree in Appendix B showing the decision path). CONCLUSION The SCCWRP channel screening tools were used to assess the downstream channel susceptibility for the La Costa Town Center project being designed by O'Day Consultants, Inc. The project mnoff will ultimately be collected by one of three existing storm drain systems that outlet into an unnamed natural stream south of the site. The unnamed natural stream flows in a westerly direction and is tributary to Encinitas Creek. Each outlet is a point of compliance. Based on the points of compliance, the unnamed natural stream was assessed from 200 meters downstream of Calle Barcelona on the lower end to La Costa Avenue on the upper end (domain of analysis). The assessment was performed based on office analyses and field work. The results indicate a low susceptibility for vertical and lateral channel erosion for the entire study area. The HMP requires that these results be compared with the critical stress calculator results incorporated in the County of San Diego's BMP Sizing Calculator. The BMP Sizing Calculator critical stress results are included in Appendix B for Reaches 1 through 4. Based on these values, the critical stress results retumed a low susceptibility to erosion. Therefore, the SCCWRP analyses and critical stress calculator demonstrate that the project can be designed assuming a low susceptibility, i.e., O.5Q2. The SCCWRP results are consistent with the physical condition of the natural channel within the domain of analysis, which is densely-vegetated throughout. None of the four study reaches exhibit signs of extensive, ongoing erosion. 10 Figure 1. Looking Downstream towards Reach 1 from Upper End Figure 2. Looking Upstream towards Reach 1 from Lower End 11 Figure 3. Looking Downstream towards Reach 2 from Upper End Figure 4. Middle Portion of Reach 2 12 Figure 5. Looking Upstream towards Reach 2 from Lower End Figure 6. Inlet at Lower End of Reach 2 13 Figure 7. Concrete/Rock Swale near Upper End of Stagecoach Community Park Figure 8. Concrete/Rock Swale near Lower End of Stagecoach Community Park 14 Figure 9. Looking Downstream towards Reach 3 from Upper End Figure 10. Middle Portion of Reach 3 15 c Figure 11. Looking Upstream towards Reach 3 from Lower End Figure 12. Looking Downstream towards Reach 4 from Upper End (Calle Barcelona) 16 Figure 13. Lower End of Reach 4 Figure 14. Gravelometer in Upper Portion of Study Reach (Reach 1) 17 Figure 15. Gravelometer in Middle Portion of Study Reach (Reach 2) Figure 16. Gravelometer in Middle Portion of Study Reach (Reach 3) 18 Figure 17. Gravelometer in Lower Portion of Study Reach (Reach 4) 19 I CHANNEL BED RESISTANCE | LABiLE BED • Sen<J-(Jo«iun8led • dsn < 16 mm • % surface sand > 2S% • Loo&ely-packdd HIGH IIVTERIV1EDIATE BED • Mcxterat^y-to loo&eiy- pad(«d cotJble I gravel • Hardpan of uncertari deplti. «xtenl enxia^lity COARSE/ARMORED BED • dso > 12Bmm • Boulder / large cobble • bghlly-packed • <5% sand • Continuous bedrock • Continuous ooncrets EXAMINE RISK FACTORS • grade oonlrol • armoring potenhal • pntxlmily tc incision threstiold LOW go b bed erodibility checklists arnJ incision diagram check list Fii out SCCWRP scoring crit«rla to determine If the recoivmg cliannel hsQS HIGH, MEDIUM, or LOW susceptibiity Figure 6-4. SCCWRP Vertical Susceptibility Figure 18. SCCWRP Vertical Channel Susceptibility Matrix 20 ^ HO ^ • F«ily s-ipofed J becKosk bank stetiitzsKn in pood ««d*on < Mo evideno i/ dniSe • Fuly KnlineO. djtecfl)' connwttd lowididB Matentetf ar viell<i]nHilclaled i i< 111 11 I I a.! I I I >i 1 < Hone, ar finri&l oiljr imied lo benda Brdo}r*trtcilor» rMSS WAsriNGOR EXTENSIVE FLUVIAL EROSION OR CHUTE CUTCfF FDHMATON MED HIQH VW«»2 AH, BANK Sl BAT A COM&OLIQATED NClUDir^ T067 Pntrty or unccnsaldiiliicl &wili hMiglil <f 1?% loeistK: ll fisii, tor sn§(e AND VWi ?3 Come I rU'StanI toe, d >-«*tnm I F#«9 urconnldaled ANDVWI>2 braiding Figure S-5. Lateral Channel Susceptibility Figure 19. SCCWRP Lateral Channel Susceptibility Matrix 21 APPENDIX A SCCWRP INITIAL DESKTOP ANALYSIS FORM 1: INITIAL DESKTOP ANALYSIS Complete all shaded sections. IF required at multiple locations, circle one ofthe following site types: Applicant Site / Upstream Extent / Downstream Extent Location: Latitude: 33.0820 Longitude: -117.2319 Description (river name, crossing streets, etc.): La Costa Town Square East of Rancho Santa Fe Road and La Costa Avenue GIS Parameters: The international System of Units (SI) is used throughout the assessment as the field standard and for consistency with the broader scientific community. However, as the singular exception, US Customary units are used for contributing drainage area (A) and mean annual precipitation (P) to apply regional flow equations after the USGS. See SCCWRP Technical Report 607 for example measurements and "Screening Tool Data Entrv.xls" for automated calculations. Form 1 Table 1. Initial desktop analysis in GIS. Symbol Variable Description and Source Value (A 0) Q) C 15 5 Q. C Area (mi') Mean annual precipitation (in) Contributing drainage area to screening location via published Hydrologic Unit Codes (HUCs) and/or < 30 m National Elevation Data (NED), USGS seamless server Area-weighted annual precipitation via USGS delineated polygons using records from 1900 to 1960 (which was more significant in hydrologic models than polygons delineated from shorter record lengths) CO Sv Wv Valley slope Valley slope at site via NED, measured over a relatively homogenous (m/m) valley segment as dictated by hilislope configuration, tributary confluences, etc., over a distance of up to ~500 m or 10% ofthe main- channel length from site to drainage divide Valley width Valley bottom width at site between natural valley walls as dictated by (m) clear breaks in hilislope on NED raster, irrespective of potential armoring from floodplain encroachment, levees, etc. (imprecise measurements have negligible effect on rating iri wide valleys where VWI is » 2, as defined in lateral decision tree) See attached Form 1 table on next page for calculated values for each reach. Form 1 TabI e 2. Simplif ied peak fio w, screening index, and valley width index. Values for this table should be calculated in the sequence shown in this table, using values from Form 1 Table 1. Symbol Dependent Variable Equation Required Units Value Qiocfs Qio 10-yr peak flow (ft^/s) 10-yr peak flow (m^/s) Qiocfs= 18.2*A°^^*P°^' Qio = 0.0283 * Qiocfs A (mi') P(in) Qiocfs (ft^/s) See attached Form 1 table INDEX Wref 10-yr screening index (m^^/s°^) Reference width (m) INDEX = Sv*Qio°^ Wref = 6.99 * Qio ""^^ Sv (m/m) Qio (m^/s) Qio (m^/s) on next page for calculated values for each VWI Valley width index (m/m) VWI = Wv/Wref Wv(m) Wref (m) reach. {Sheet 1 of 1) B-3 SCCWRP FORM 1 ANALYSES Area Mean Annual Precip. Valley Slope Reach A, sq. mi. P, inches Sv, m/m 1 0.72 13.3 0.0269 2 561.66 13.3 0.0355 3 857.71 13.3 0.0172 4 922.26 13.3 0.0091 Valley Width Wv, m 19.8 11.6 14.3 13.4 10-Year Flow QlOcfs, cfs 101 32921 47582 50683 10-Year Flow QIO, cms 2.8 931.7 1346.6 1434.3 Reach 1 2 3 4 10-Year Screening Index INDEX 0.045 1.085 0.632 0.346 Reference Width Wref, m 11.1 139.6 164.1 168.7 Valley Width Index VWI, m/m 1.79 0.08 0.09 0.08 Notes: The areas were obtained from the Watershed Exhibit. The mean annual precipitation was obtained from the County of San Diego's BMP Calculator. The valley slope was determined from the elevations and flow lengths from the Study Area Exhibit. The valley width was estimated from the topographic mapping on the Study Area Exhibit and a site investigation. The 10-year flow, screening index, reference width, and valley width index are calculated from the equations on Form 1. I now San Diego BMP Sizing Calculator Home Contacts Legal Map data provided by OpenStreeftlap Map Details Result View Define Drainage Basins Basin: Tributary to Unnamed Natural Stream Project La Costa Town Center U IJ ^''1" u Manage Your Basins Create a new Basin cFjcking the New iH^on and scroB down to view entry. Mematively, select an exisfir^ Basin from tabte and vtew f»operties betow. CTick Edft btrtton to cttange Basin properties tt^ press Save to commit ctranges. Description: j La Costa Town Center Design Goal: |Tr«sabnent + Flow Cotttd Rainfall Basin: |p&^i^«t|e~ Point of Compliance: Unnaiied Nahsd Stream 13 Project B^ln Area (ac): 922.2S 13 Mean Annual Preclpition (In): 13.3 APPENDIX B SCCWRP FIELD SCREENING DATA Chapters. Open Channels Table 5-13 IVIaximum Permissible Velocities for Lined and Unlined Channels Material or Lining Maximum Permissible Average Velocity* (ft/sec) Natural and Improved Unlined Channels Fine Sand, Colloidal 1.50 Sandy Loam, Noncolloidal 1.75 Silt Loam, Noncolloidal 2.00 Alluvial Silts, Noncolloidal 2.00 Ordinary Firm Loam 2.50 Volcanic Ash 2.50 Stiff Clay, Very Colloidal 3.75 Alluvial Silts. Collodal 3.75 Shales And Hardpans 6.00 Fine Gravel 2.50 Graded Loam To Cobbles When Noncolloidal 3.75 Giaded Sills To Cobbles When ColluiUal 4.00 Coarse Gravel, Noncolloidal 4.00 Cobbles And Shingles 5.00 Sandy Silt 2.00 Silty Clay 2.50 Clay 6.00 Poor Sedimentary Rock 10.0 Fully-Lined Channels Unreinforced Vegetation 5.0 Reinforced Turf 10.0 Loose Riprap per Table 5-2 Grouted Riprap 25.0 Gabions 15.0 Soil Cement 15.0 Concrete 35.0 • Maximum pemiissible velocity listed here is basic guideline; Ivgtrer design velocities may be used, provided appropriate teclmlcal documentation from manufacturer San Diego County Drainage Design Manual Page 5-43 July 2005 Form 3 Support Materials Form 3 Checklists 1 and 2, along with information recording in Form 3 Table 1, are intended to support the decisions pathways illustrated in Form 3 Overall Vertical Rating for Intermediate/Transitional Bed. Form 3 Checklist 1: Armoring Potential A A mix of coarse gravels and cobbles that are tightly packed with <5% surface material of diameter <2 mm B Intermediate to A and C or hardpan of unknown resistance, spatial extent (longitudinal and depth), or unknown armoring potential due to surface veneer covering gravel or coarser layer encountered with probe C Gravels/cobbles that are loosely packed or >25% surface material of diameter <2 mm Form 3 Figure 2. Armoring potential photographic supplement for assessing intermediate beds (16 < dso < 128 mm) to be used in conjunction with Form 3 Checklist 1. (Sheet 2 of 4) REACH 1 THROUGH 4 RESULTS B-7 Form 3 Checklist 2: Grade Control B Grade control is present with spacing <50 m or 2/Sv m • No evidence of failure/ineffectiveness, e.g., no headcutting (>30 cm), no active mass wasting (analyst cannot say grade control sufficient if mass- wasting checklist indicates presence of bank failure), no exposed bridge pilings, no culverts/structures undermined • Hard points in serviceable condition at decadal time scale, e.g., no apparent undermining, flanking, failing grout • If geologic grade control, rock should be resistant igneous and/or metamorphic; For sedimentary/hardpan to be classified as 'grade control', it should be of demonstrable strength as indicated by field testing such as hammer test/borings and/or inspected by appropriate stakeholder Intermediate to A and C - artificial or geologic grade control present but spaced 2/Sv m to 4/Sv m or potential evidence of failure or hardpan of uncertain resistance Grade control absent, spaced >100 m or >4/S„ m, of ineffectiveness or clear evidence ome undermining at road crossi substantial undermining Form 3 Figure 3. Grade-control (condition) photographic supplement for assessing intermediate beds (16 < dso < 128 mm) to be used in conjunction with Form 3 Checklist 2. (Sheet 3 of 4) REACH 1 THROUGH 4 RESULTS B-8 Note: the equivalent d50 in each reach taking dense vegetation into account is 64 mm. The Screening Index Values from the spreadsheet in Appendix A (0.021 to 0.065) for each reach are less than the 50% Risk values for 64 mm (0.101), so the risk of incising is less than 50%. Regionally-Calibrated Screening Index Threshold for Incising/Braiding For transitional bed channels (dso between 16 and 128 mm) or labile beds (channel not incised past critical bank height), use Form 3 Figure 3 to determine Screening Index Score and complete Form 3 Table 1. y Q i 0.1 0 0.01 w 0.001 ••}- 1 1—t—t "1 r t r ••}- 1 1—t—t "1 r t r — -••^ ' ** 1 1 1—1—1 Cl 1 1 1—1—r-T'T TT 0.1 stable 10% risk ^ dso (miTfi) X Braided 50% risk -t- 100 Incising 90% risk GIS-derived: \ 0-yr flow & valley slope Field-derived: d^g (100-pebble count) Model Type (mm) 50% Risk 1 SvQto"-^ 128 0,145 c o 96 0,125 tn E a; E 80 0.114 <$. QL ^ 64 0,101 0 A" 1 -i' o —1 48 0.087 0 A" 1 -i' o —1 32 0,070 0 A" 1 -i' o —1 16 0,049 8 0.031 d) E 4) p 4 0.026 <;tlr 1 = 16 2 0,022 1 0,018 0.5 0.015 Form 3 Figure 4. Probability of incising/braiding based on logistic regression of Screening Index and dso to be used in conjunction with Form 3 Table 1. Form 3 Table 1. Values for Screening Index Threshold (probability of incising/braiding) to be used in conjunction with Form 3 Figure 4 (above) to complete Form 3 Overall Vertical Rating for Intermediate/Transitional Bed (below).. Screening Index Score: A = <50% probability of incision for current Qio, valley slope, and dso; B = Hardpan/dso indeterminate; and C = >50% probability of incising/braiding for current Qio, valley slope, and dso- dso (mm) From Form 2 e *r\ 0.5 /.^1.5i_0.5v <i *n 0 * /m^ 5, o.5> Ov Oio (m /s ) i>vUio tm /s ) 50% risk of incising/braiding l-rom t-orm 7 ^^^^ ^^^^^ ^^^^ ^ Figure 3 above Screening Index Score (A, B, C) Overall Vertical Rating for Intermediate/Transitional Bed Calculate the overall Vertical Rating for Transitional Bed channels using the formula below. Numeric values for responses to Form 3 Checklists and Table 1 as follows: A = 3, B = 6, C = 9. Vertical Rating = ^{(^Jarmoring * grade control ) * screening index score} Vertical Susceptibility based on Vertical Rating: <4.5 = LOW; 4.5 to 7 = MEDIUM; and >7 = HIGH. CS/?eef 4oMj REACH 1 THROUGH 4 RESULTS B-9 FORM 4: LATERAL SUSCEPTIBILTY FIELD SHEET Circle appropriate nodes/pathway for proposed site OR use sequence of questions provided in Form 5. LOW rmored / bedrock bank stabilization in good condition No evidence of chute formation / avulsions Fully confined, directly d to hilislope, (Sheet 1 of1) REACH 1 THROUGH 4 RESULTS B-10 FORM 6: PROBABILITY OF MASS WASTING BANK FAILURE If mass wasting is not currently extensive and the banks are moderately- to well-consolidated, measure bank height and angle at several locations (i.e., at least three locations that capture the range of conditions present in the study reach) to estimate representative values for the reach. Use Form 6 Figure 1 below to determine if risk of bank failure is >10% and complete Form 6 Table 1. Support your results with photographs that include a protractor/rod/tape/person for scale. Bank Angle (degrees) (from Field) Bank Height (m) ' (from Field) Corresponding Bank Height for 10% Risk of Mass Wasting (m) (from Form 6 Figure 1 below) Bank Failure Risk (<10% Risk) (>10% Risk) Left Bank <26.6(2:1) Varies Any <10% Risk Right Bank <26.6(2:1) Varies Any <10% Risk probability of mass wasting in moderately/well consolidated banks O Stable 10% Risk 50% Risk 90% Risk X Unstable 4 \ 0 ^ 0 ^ 0 CP , CP § 0 00 oo cv \ \ x>ft o 0 ^ 0 X X X X X \ 0 ^ 0 ^ 0 CP , CP § 0 00 oo cv \ \ x>ft o 0 ^ 0 xX X X \ 0 ^ 0 ^ 0 CP , CP § 0 00 oo cv 0 c9^ 00 0 0 00 X X iiuilly unit.- ii:;;:;)]; (JD/ i'j'-'/.j 30 7.6 35 4.7 40 ZJ 45 2.1 50 1.5 55 1.1 60 0.85 65 0.66 70 0.52 80 0.34 90 0.24 30 40 50 60 70 80 90 Bank Angle (degrees) Bank height and angle schematic Form 6 Figure 1. Probability Mass Wasting diagram. Bank Angle:Height/% Risk table, and Band Height:Angle schematic. Probability is less than 10% for the existing bank angles (2:1 = 26.6 degrees) in Reaches 1 - 5. (Sheet 1 of 1) REACH 1 THROUGH 4 RESULTS B - 12 alc^.v^co Horr •onta Lege Map data provided by Opert StreetMap Map Details Result View .11 CRITICAL STRESS CALCULATOR RESULTS FOR REACH 1 Tributary to Unnamed Natural Define Drainage Basins Basin; Stream Project La Costa Town Center POC Manage Your Point of Compliance (POC) Analyze the receiving water at the 'Point of Compliance' by completing this form. Click Edit and enter the appropriate fields, then click the Update button to calculate the critical flow and low-flow threshold condition. Finally, click Save to commit the changes. Cancel Save Update Channel Susceptibility: LOW Low Flow Threshold: 0.5Q2 Channel Assessed: |Yes Watershed Area (ac): 462.43 ^ X^;;^;:^' iLow(Vertical) Susceptibility: ' Lateral Susceptibility: Low (Lateral) 13 Material: Vegetation Roughness: 0.100 Channel Top Width (ft): 115.0 Channel Bottom Width (ft): 65.0 Channel Height (ft): 6.0 Channel Slope: 0.0269 Large View IHB Map data provided by Open Streetf.lap Map Details Result View CRITICAL STRESS CALCULATOR RESULTS FOR REACH 2 Define Drainage Basins Basin Tributary to Unnamed Natural Stream Project La Costa Town Center Manage Your Point of Compliance (POC) Analyze the receiving water at the 'Point of Compliance' by completing this form. Click Edit and enter the appropnate fields, then click the Update button to calculate the critical flow and low-flow threshold condition. Finally, click Save to commit the changes. Channel Susceptibility: ILOW Low Flow Threshold: 0.5Q2 Cancel Save Update Channel Assessed: lYes Watershed Area (ac): 561.66 Vertical Susceptibility: Lateral Susceptibility: Low (Vertical) Low (Lateral) Material: Vegetation Roughness: 0.100 Channel Top Width (ft): 115.0 Channel Bottom Width (ft): 38.0 Channel Height (ft): 6.0 Channel Slope: {0.0355 Large Viev Map data provided by OpenStreetMap Map Details Result View CRITICAL STRESS CALCULATOR RESULTS FOR REACH 3 Define Drainage Basins Tributary to Unnamed Natural Stream Project La Costa Town Center Manage Your Point of Compliance (POC) /Analyze the receiving water at the 'Point of Compliance' by completing this fonm. Click Edit and enter the appropriate fields, then click the Update button to calculate the critical flow and low-flow threshold condition. Finally, click Save to commit the changes. Cancel Save Update Channel Susceptibility: Low Flow Threshold: {D.5Q2 Channel Assessed: |Yes Watershed Area (ac): 857.71 Vertical Susceptibility: Lateral Susceptibility: Low (Vertical) Low (Lateral) Large View Material: Vegetation Roughness: 0.100 Channel Top Width (ft): 100.0 Channel Bottom Width (ft): 47.0 Channel Height (ft): 6.0 Channel Slope: 0.0172 Map data provided by OpenStreetMap Map Details Resuitview CRITICAL STRESS CALCULATOR RESULTS FOR REACH 4 Define Drainage Basins Basin Tributary to Unnamed Natural Stream Project La Costa Town Center Manage Your Point of Compliance (POC) Analyze the receiving water at the 'Point of Compliance' by completing this fonn. Click Edit and enter the appropriate fields, then click the Update button to calculate the critical flow and low-flow threshold condition. Finally, click Save to commit the changes. Cancel Save • Update Channel Susceptibility: ILOW Low Flow Threshold: |0.5Q2 Channel Assessed: |Yes Watershed Area (ac): 922.26 Vertical Susceptibility: Lateral Susceptibility: Low (Vertical) Low (Lateral) Large Viev Material: Vegetation Roughness: 0.100 Channel Top Width (ft): 200.0 Channel Bottom Width (ft): 44.0 Channel Height (ft): 4.0 Channel Slope: 0.0091 DRAINAGE BASIN BOUNDARY STUDY REACHES NOTE: THE ON-SITE DRAINAGE BASIN DELINEATION IS BASED ON O'DAY CONSULTANTS. INC.'S PROPOSED CONDITION DELINEATION. WATERSHED EXHIBIT LA COSTA TOWN CENTER 1" = 500' 500 EXISTING INLET AT UPPER END OF STAGECOACH COMMUNITY PARK EXISTING CONCRETE SWALE THROUGH STAGECOACH Op^ COMMUNITY PARK "'ones WESTERLY P.O.C. LEGEND: EASTERLY P.O.C. AV. UPSTREAM DOMAIN OF ANALYSIS LOCATION (AT OUTLET OF LA COSTA AVENUE CULVERTS) EXISTING DRAINAGE FACILITIES PROPOSED DRAINAGE FACILITIES STUDY REACHES •DOWNSTREAM DOMAIN OF ANALYSIS LOCATION STUDY AREA EXHIBIT LA COSTA TOWN CENTER flAOlUS »EM«»tS A B ISS.OO' f pvc: a. 200 A B M TVtO'OO' W 5' PX a 200 CENTERUNE DATA A B£MmC/DCLTA RCUAmS irti'39-330.00' 1 rra/C 2 M jrto'ao' r SEWER DATA IKUAIIKS ! 3M.00' ns.es' »' PVC ! M 7r40'00' w 204.43-»• PX 3 H 7f40'00' » 204.32' ^ »' PVC WATER DATA DAaus IfNGTK REUAMKS > 3S7.00' f2X53' »• .-MT a 130 cras'35' O.CO' 5' PX a. <TO J N 7V40'00' » 330.03' f PX a. tso H 7S42W W 50.53' «• PX a ISO STORM DRAIN DATA BfAmNC/OCLTA RADIUS R€UARKS H ix5i'4a' e 212.17' «• RCP -23000- } H lTS2 4a- C 21343' 45' RCP -23000" 3 H ir4r<a' e 24' RCP - ISSOC 4 4rir4i-22.30' " 15.53' le' RCP -13S0D- 5 M itnow t 7500' 4f RCP -135004 9 N 7140 00' W 209.35' 144" RCP -133004 / N W 32.43' tte' RCP -ISSOC CVRB DATA .a t 8[A.i}NC./ataA ffADiUS UNOTH ReUARKS .a t irixl7' JSO.OO' 55jr »• rrpe a etc 2 K 7f40W W 313.52' »" TfPt c c*c 3 e4-4riy JO.OO' 44.33' «• npc c ate JO.OO' 4340' e' nPE c c*c « H 71-40'00' W 330.03' «• TYPt a c*c 5 >r!2 43' JM.OO' 121.75' 5' np€ c etc 7 tToi'se' J53.H)' 50.73' 5' IffWW CURS e teoroo'co' 1.00' 1371' 5' UCDUN CURB 9 IXOi'Jl' 345.00' 7554' U' uaXAM CURS 10 taovow 5.00' 1371' 5' UeOiW CURB ^ ! N 7r40'00' w 3f3.e2' e' ua>m CURS !2 1KrOO'04' 3.00' I37t' 5' ueouM CURB TJ M 7r40'00' W 31152-5' UCDIAM CURB ' (Sf HArtR rKHT jo/rm • 4' UNcms r Btva BOTH CNOS BENCH MARK 1(302., I93S' IN CONC. UON. ANO LA SJJ Jf /WM) 39 USL NLX CB. ZOO- EXIST. A.C PAVEMENT 210- A 't*'^ ^EXISTING PROFILE- tooo- v.c. /e-A.c. exisT/N6 s'r.c.p. WITHCOfJC.eNC. •57 73 200 - SLY.CB. /m - FUTUl^E ZOCVC -TOPOFS'A.C.BSRM FUTUKE TOP- OF CURB mc. TEMPORARV PAVEMENT roPOFO/m i Si-eo.oo I 10'. S-l-AKt^T S.D.Ree.STO.DWG.D-S I T.C.'I7I.SS am 9 n.00% SUPEHeLEVATION ruANsmoN \4i'A, S6— euouHo -7? i -e-B.o 3S0' - i'J£L. Z'A.C.ON SEUCTIVS RASe -/- -cove CumCMCHT -10'-1'BOX mvEBT eeteOiQO 'B'TYPeINLET \SD. REC.STD. DWe.D-S '171.55 lO-xE-BOX CULVERT- , -3-•4- 5 TEfimSPfMM mTEH (TYP) i see OETM m i emm nm \ Ml SION ESTANCIA PROFILE SCALES: HORIZ./'•SO' VERT. f'S- \ NLKCB. OF, • A.C''-_0''KA -8- V IS SS'- li'H.C.II -/SO SLY.CB. SUPERELEVATION TRANSITION '10- KSfSO.M P£NCm StNTA Fe RO&O Of 00 MISION ESTANCIA CONNECT. Jamsk J u I IMKE SMOOW TKANSniON TO MEET EXISTINO PAVEMENT PARK SITE . ROCK SLOPE PROTECTION-J/t TC S'THICK.ESO cu.m 'ORAINAOe eAsetfENT DOC'SO-SSCillOATE m'< FOR BOX CULVERT"! PROFIL e, SECTION A-A AND WINSmLLS SEE SHEET N9JS- 47 ^—1 '^LOPE PROTECTION Turn, 45 Cif^D. ~ '/era -//-13- STORM DRAIN DATA "1 NO. DELTA OR BRG. RADIUS LENGTH REMAftKS (b H OTSO'OO'W -t}.BI' IS'm moo © H.iiV30'00"<H ,-:. IB.ii' 16' ' " '. Ill.OO' .IO''S' BOXCOLm ! ' 1 4 J>ARK ^Eoi 8 tBO 21 {sE^zosC^ J<<iA^ fLwtmTpmmom Fim» AC 8Em re s' reffP m eurre/t CURB DATA NO. DELTA OR BRG. RADIUS LENGTH REMARKS B N /5°06'O7'-tV Z^73 ^ - is-a/Tfa CD A.Tssor- a N67'30'00-H' -/OOOOO f/67'30'00-V iOOO.OO • Furwe m d.7'3607' /ose-736 93' tFiTTvae 11 f/7S'0607'if E<r.Z3 ' FijTm z /r7^6607-It' 767. OO • e-xc ge^*f m i,9'f'30O0-57 73' m l„S5-3O'Q0-s?'e3 • ^ N7'f'6e'07W 77P OO '. SEWER DATA NO. DELTA ORBRG. RADIUS LENGTH REMARKS H iT 30' 00' /C -JS0.03' • V.CJ> H tT 30' 00'K -m,iif' • VCP -^> <¥> WATER OATA NO. DELTA OR BRG RADIUS LENGTH REMARKS _m_ V75'0£'07'W -274.e3' IS"A.CP-CL ISO _0 0-7'Je'07-3SO-131.35' : '^67'30'00'iV -323. OS' 'jer'so'oo'tv -3ZO.0O' ^67'30'OO'IV -356.91' » - « VZZ'SO'OO-E 6.50' lO'A.C.P-Cl. I&O v^i'jooo'E -Z6.00\ 6 xCP-C^-iSO PCAN . SCALE \ 17 I Jt ' 7 . 7 \\\ \U\ lOOC »• 7'P-e<97767 ^/ ' a4r£.^777y/ir/9?7 JXIC7C SlOPEl/torECTXIN / / yt'^S^v^:^n/xxp£fD-4o, see SECTTON^ SNT/S S97S 07.70 - L'^S; W/OTI/PSP, wjcur_^opr mu STOEEP, /.7'rmr P/ITEP / / D1AINA6E EASEMENT DOC. * AJOT£i /i£P£R TO *^20S-tO 3N£BT'4- FOfL AS-3U/LT O/^M/S/OAJ £SrA^JC/A AlVIINO DE LOS COCHES ^WEST END 10' X 6' BOX CUL'VERIIP"^^^^"^'*^ COMPANY ' MW,*^ *'*'^i^5<.ffisf»vl. ENGINEERS LAND SURVEYORS v,^ 3088 PlO PICO osfv/E. su't J02,CABLse4i5,caLiF, saooe; /ENGINEi/^-tft 7-33-K pep e844S BENCH MAA OESCRlPTION: sro BRONZE DISC IN CONC MON LOCATION ! ABOUT eOO'NORTH OF STA g6N9S 7B RANCHO SANTA FE ROAO -RS454-NEAR FENCE EAST SIDE OF ROAD. RECORD FROM' COUNTY BENCH LEVEL J-030E ELEVATION: 176 IB DATUM :US.Ci6S. UC conPEcrto pitOrK.E ''ftw OfOoro 9*00 • . . , -, PRIVATE CONTRACT CITY OF ENGINEERING CARLSBAD DEPAPTMENT PLANS FOR THE WPROVEMENT OF MISION ESTANCIA - OFFSITE IN SANTA FE -KNOLLS (CT. 75-9(B)UN, I) BY jCHKD BY I FIELD 8r PROJECT NO O'^TE /0-Tt-Sa SCiLES HORIZ, ;;AS NOTED zbs-z FULL SU.BEPELEVATION 260 NLKCB.— /FUTURE TOP ^ / lop cupa « / ^ Aet TSSa ? MOO 'P" CATCH BASIN (4'x4' IF TO IP.) TOP' esa. 7 (FVTUPE VI/ILET). P7g, 240. TOP OF PftRf,P£T ELev?45.Z X, 260 f 4757' i3'too(PDee4-5'if'Xz TRANSITION FUTUPE ^ SOPEG. STO. DWG. D-7S 4D-8I SKEW li7^37'04-I 73' i 2'MAK icAP ASS'r. 77'COfXC -10 'CONCRETE CUTOFF (C7PSS -B-COA/CJ ^ BOX CULVERT NO. Z MISION ESTANCIA STA.42*30.88 SCALE • HORIZ I'-50' VERT /••«• 260 SLY.CB.- FUTUPP y^OP CUPt • X^a PUTUPE It £6/ 0 • —260 5496' NBLY. CB. 260 -AfAC 'TOP OF IS"A.C tVATER MAIN -/O'x5B0Xa7iyER'' i tens sat MOO'F" ^'•CATCHBASIN (4U4' IFW IF) T0P-aS7.9S (FUTUPE '8'INLET) El 5496' (3 I.TO^ 38 FULL SUPERELEVATION Cu •ll.NI 39 ,40 41 42 MISION ESTANCIA wxs'BOP CULVERT PROFILE SCALES : HORIZ r • 50' VERT r-f CLASS -B-CONC. CUTOFFmLL- 10-THICK, 5.0'DEEP NOTE- CONSTRUCT STORM SYSTEM WITH ^'"IZl^.Z THISPROJECT. 1:1^^^ L - 7eS.40' \ DRAINAOE EASEMENT. ze.mo \ TRANSITION •260 A/3 CURB RETURN SCALES HORIZ. /'• EO' VERT l''E' V.C 260 5WLY CB. MNIODV.C CFUTURE) 43 <V 45 "^^^•.^pocp scope pearphxw lo TON. ^'1 4.3- TP/ar. L.-45' tr/lpNPEiePLW. - v/coTOPP ivAU 6.4'Peep^r 'ftj-ttt TP/CP. P/iTEP 6UNXET-IP'TV/a- S • iS'xoaee&tre pep D\4O. ^^^ymoaiH TS 'F'CO ' UvL'-LiL'. I44_*e3jq yiCOSTA^VE_-_ ' ast'es.ss Misidn ESTANCIA' ex7?7r/oiz>t S7>.Aiea S7X3. aitra, ^ p W57 ( TVPE -n-PEPiecrops _4/±^?f .^l-^IO/VESTANCJAj^ OfOO.OO CALLE GAVANZO e-Ai47f 4777} CAP yfSSEAtSiy %^.p.rxc,ia£ 4/v£>'£^^o~ srTfeersxffyv ifTjO. Tf^a ero. 7>K'<7, M- 9 KtOT£'. QEF£R TODVY&**2OS-Z0 SNE£T y xaA/7!7 ^m9^12aS-S &p/i&£T a ^^-^/y/zy PLAN SCALE r-so' FUTURE IMPPOVEmNT 60!-PHAINAGE EASEMENT, DOC * LIOHT CLASS. M£TI/0O\S """^ ^x30' I'THICK, .'. \ ASUI.VO. \ !ef>S£et 'rCAK£_S4s\N ^ SLOPf f^ fPl77UP£ '3'l^tEr)\ ^ V CAMINO DE LOS COCHES (EAST S ClViL ENOlNEERS-LiSROSl-'R'/EYORS * - ' SOaa =10 P CO DRIVE, SUitt ?02. CiRi-S3iO,CALlF 9J00S 10* X 5' BOX CULVERT CLCPHO,:.; -j^ • " f : PHIViTE C0\TR4CT BOJtXULVERTN' P, SECTION 'A-A tWINGIVA SEE SHEET Nf IS RICK ENGINEERING COM.PANY ENGINEER OF WORK POP P3448 .FUTURE CURB DATA J2L DELTA OR BRG /I • SO'OO OO' ^ ' 90'00 00" 71 •_ IS'/S'bo"^ • I'js'oa" RADIUS 35' 35' 932' 8 US' LENGTH 54.93' 54.98' 3^I3J3- S4.00' REMARKS 6' G CURB NO DELTA ORBRG. EUTUPE WATER DATA, NSS'OO'OO'IV "J'7r43''47-^ £'_Z'37'Sr N76-06'00-E RADIUS LENGTH 57.00' j45 72 47 73' 22.00' REMARKS STORM' DRAIN DATA . NO DELTA OR BRG. RADIUS LENGTH ' S& 6if REMARKS "iT'PcFiooiFP MI9'34 40"IV I LENGTH ' S& 6if REMARKS "iT'PcFiooiFP NiS'SS'Se-W -• 47.S7' /S-R.CReOOO-0 Ql NJ54'40'00-£. -.'49. 10' lO'xs'soxcuivEpr 8) N36'WO0"W •-r S5.00' ia"PCP-s}ooD ei - BENCH MARK DESCRIPTION : STO BRONZE DISC IN CONC MON LOCATION: ABOUT SOO NORTH OF STA. eeitSB JZ RANCHO SANTA FE ROAD -RS 4S4- NEAP FENCE EAST SIDE OF ROAO ' RECORD FROM: COUNTY BENCH LEVEL J-030g ELEVATION: 176 IS DATUM: USCt OS. 0-CARLSBAD 0EP.iRT>,'EhT 16 PLANS FOR THE IMPROVEMENT OF MISIO'N ESTANCIA-OFFSITE (SANTA FE KNOLLS CT. 75-9(B) UN,I) r..eQt)e4 IHXD SY 'lEtO BY DATE /o-tt-la AS AIOTEO 20S-2 msm-At.':^:, 1« ISAPrFffkA ^—jo'lusc iCUR3\ ^ Sts^ W£^smi^^m^Rmiesik3:± ^^^^ SCAIE poeir /"'40' veer /••'»' 10 NOTE: TOP OFN'LY COPB IS 0.3Z' BELOIV 4 ELEVATm, TOP OF SLY OTPS TS 7P24'B£lOM i ELEVATION L SHOWN •i/irwpufcoeB 77 13 I POPfaP-is^ias^^~ ?—' 15 mTEPNOTE -•- I /QfOSi CONNECT TO E7IST I ' /z"4.cp. cavrpAcroP ro ' vcptpy £7Acr uxATioN I € DEpm PRIOR TO com. I X scEcoNHCcrmocTAns^fr. I Q AO. 3. ^ li IF IZ" tVATEPMAIN IS ALREADY CONSTRUCTED AT TtlE TINS: THIS NOIkSTAPrS: J, LRMM'C IO- BLIND FCP. ON S^y, AT STA.IS^eSia OILU BAPCCLOHA ANO CONfgCT f"' ^ WW tO'FUS.14.C7> ADAPTER. ' l^^t ^fl^^^S^?*^^ **^***^ '^^ aoNNexr TO le'ACP \ Tf^ JlklS^, 'SJ^'^f 1'^'=^'° INTERLINE. IZ-FLa.»ACPAOAPTEP Ir INSTALL /Z'SLINO FLG. AT ORAHCH. REMOVE N>- TAPPINO ^LV£ AT STA.IZS*tiS/C PANCHO SANTA FE Po. ANO INSTALL 10-BUm FLS CURB DATA Ti-.io'za's^'' A/47'E5'44'If N42*Z6'44-W DELTA OR BRG AiaO'OO'OO" /V4t'es'4f'iv N4g'E5'4^-t¥ ^'OO'OO" : zrST'ST" , ISO'OO OO N42'S6'44"IV •IT4i'ia' TAPEP •nT'30'25' •I5'0I'0I' see TAPCR N4Z'Z5'44'N N1Z'{,Z'23'N t^lS'STAr N8S''430iii'£ 4« ll'53'll- RADIUS 4ii4' as- 6' IBS' PER GS-ll 400' 450' LENGTH 54.93' 9117' 173.58^^ 54'J3' 9LIT' /i9.se Eoasi ZS.rS' II3.TS I49.ZS' 45' sez' is&oo' 120.00' ss.oa I09.IT T0.Z4' 33 34 FUTURE CURB * <t'A.C. BERM a-AC SEPAI d-TyPESia'Ps d-TYPE •G'CUPB NO La .a CI STORM DRAIN DATA DELTA ORBRG. N47'34'Ai'E N47'34'ki"C A=n'Z9'37- N4Z'Z5'A4"IV L'Z4'5Z'50- A=5'04'35' N7Z'S2'Z3-£ ia \£-l7'24'3l' Ne9-43'0C'£ A'4S'00'00' NZZ'SS'll'N N39'43'0ii'£ RADIUS 200' 471' 471' 40T SO' LENGTH /3O.O0 130.00' ai.Oi,' 39.<><i' Z04S3 41.73' liSEB' I23.<i7' 5 43- 7a 6.9' 30.^9' 500' REMARKS aO-PCP 24' PCP03X>-o: 24" C.MP.eZCA ~IS'PCP (1350-0) 24" CUP (12. SA.) SEWER & WATER ONLY "AS BUILT" BAPPY'C. BENDER RCE 23446 CATE CimuiP_ 45' IO' 10' ;ALLE BARCELt>NA DOUBLE 60" RCP CULVERT^ TETTUPEO CONCRCTE Of INTEPLOCPING PAVERS R-1.83' L DETAIL: NOSE fl APE NO SCALE -nrr W-^^ OK H"g.«.*-<-*5 "AS BUILT" SRRYOBENDER^ RCE. 28448 ENGIKEEB OF WORX SEWER DATA \DELTA ORBRG N42'25'44"IV * NOTE: FOR a" A C. BERM DATA SEE SHT NO 3. \N42'25'44'tv \&'ZT204C- \£'ZO'30'24" \NB9'43'0<>"£ RADIUS SOO' 500' LENGTH 205.00' 1075' 230.C4 173.95' 33.79' REMARKS NO 6'VCP WATER DATA DELTA ORBRG N4Z'25'44"lt' ^'23'Z6'oy &'I9'Z3'0;' N N89'43'0<,'e RADIUS SIO' SIO' LENGTH 273':C ZS3.AI' 172 54' 3379' REMARKS 12-AEPCL. ISO SHEET BENCH MARK ' 5 DESCRIPTION: STO. BRONZE DISC IN CONC MDN. i 'JO^^^"- '^S9"lSOO' NORTH OF STA 251^96.72 \ RHO. STA. FE RO.-R.S454- NEAR FENCE EAST SIDE OF ROAD IREOORD FROM: COUNTY BENCH LEVELS J-0302 ^ ; ELEVATION- /TG. 18 DATUM: USC. B G.S By a. ^ UlOtY C. (BENDER /A -AS BJiLT f n'JitiP R.C.E. 2844 RICK ENGINEERING COMPANY HANNCm- CIVIL ENSmeePS LAMD SUPVEYOKS SSS S. MNCHO SANTA FC PD. SUITE 100 SAN UARCOS.CALlF. $iOS» PHONE T44.4t00 som PKI PICO oe, amsaui, CALIF atooa PHONC n*-49»r PPMTt CONTKACT KVIS/OHS CITY OF CARLSBAD £7vefff/7?/iv6 LSEmSTMEHT PLANS FOR THE IMPROVEMENT OF CALLE BARCELONA (VISTA SANTA FE UNIT NO I) CTBHG wc L-7qr/ CITY ENOINEEfl own BY FSO CHKO BY FiFinnv PROJECT Ni. CT8I-I6 SCALES, . , HORZi AS VCR. NOTED DRAWING IP JOB tfiZilZL INLET AT UPPER END OF STAGECOACH COMMUNITY PARK STORM DRAIN DATA NO. DELTA OR BRG RADIUS LENGTH REMARKS a A7 22'3£>'00'£. a'RCP 1350 D @ AI.£7^30'W.t '•217' 18'R.C.P 13500 a a M4I*£. i A uaa' 30'P.CF l3SO:D a a 7V.4/'£. t WRCP I3SO-D a a 7VS3'ii7-t ilK.OO' }0'PCP.I35O'D @ N.QT33Wt -' eeooo' n'PCP 13500 A764'>IV. t t16' 24'P.Cr. I3S0-D 770^ hf. t ZfRCP.IBSOD 7/65'^. ^per. 13500 7\7ZPm'^ r2^-/f''777:P2oaii i N. 67'30'Vli Z5.00' 3i'PCP 1350-D fJ. 4P£. i 20.00' 30'P.CR I3f0-0 7*liX?77^7£0 7y/'£ '£'CA7Z>7 3PS77V TYPE 'r' CATCH BASIN W/ 8R0V< OiTCH INTO SIPC RICK EKat^^^•^.^;Gr COKCVIKY CmL CHGINlUtS: PUUMNC CONSUUUTS : tUtVEYOilS $429 FRiAllS ROAD ftAK OCOO. CAtrOflMA 421 ID »l4) 341424. JOB* PlO PCO DfiiyC CAm.SIIAO.CAiJFOWaA43M4 (4143 224 .442 944 & ftAMMO SANtA FE no 4A2I MAflCOS. CA. 4204S [414} 2M UOC eOPVErOATA ^roPO FEATUPES EXISTA^ OF 6-1-eh ,„ ^ A/yycmi^ap^ T^'ArMHi^ occaPeo AFTEP SAID DATE APE A/Or3HOW!VC3A7 TT^E PtAMQ HORIZONTAL CONTROL NOTE: ALL HORIZONTAL CONTROL TO BE SCALED WrrH MINIMUM DIMENSIONS HELD AS SHOWN.FOR IMPROVEMENTS SEE IMPROVEMENTS PLANS BY OTHERS. ENGINEER OF WORK '•VIA: BARRV CieCWCT RCE. 28448 DATE ORAWN SY J,0,f.C. DESIGNED BY CHECKED BY BENCH MARK DESCRIPTION • STD. BRONZE DISC, IN CONC, MON LOCATION, ABOUT 200'NORTH OF STA, 261» 98.72 RANCHO SANTA FE ROAD-R.S.454 - NEAR FENCE EAST SIDE OF ROAC RECORD FROM J COUNTV BENCH LEVELS J-0302 ELEVATION • 176 IB DATUM : U.S.C d G S, 55M n- ,Je^~Txx>To'&-^cib. ^(jsWeOi Pe%l -A'CO TO Wce^ A ACQ SdTTER GRADING PLANS FOR' STAGECOACH PARK SITE BE; iin?9 crrt twGiNTnr DWN BY: CHKD BY: Fmj>BY: PROJECT NO. fte •2,85,65 SCAtES: M0tlSl".40' OHAWKO NO.