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Home My WebLink AboutCUP 01-04; Church of Jesus Christ LDS; Conditional Use Permit (CUP) (6)- -.. -.. ---------------- - - ----------- TABLE OF CONTENTS INTRODUCTION PROJECT DESCRIPTION STORM WATER MANAGEMENT SYSTEM DESIGN EROSION AND SEDIMENT CONTROL BEST MANAGEMENT PRACTICE DOWNSTREAM ANALYSIS EXECUTIVE SUMMARY LIST OF TABLES: Table 1-Summary of gutter spread calculations Table 2-Storm water runoff calculations -10-year storm Table 3-Storm water runoff calculations -100-year storm Table 6-Basin intake capacity calculations Table 4-Storm drainage pipe flow calculations -10-year storm Table 5-Storm drainage pipe flow calculations-1 00-year storm LIST OF FIGURES: Exhibit A -Location map Exhibit B -Pre-development drainage map Exhibit C -Post-development drainage map Exhibit D -Schematic drainage diagram Exhibit E -City Master Drainage Plan Exhibit F-FIRM Flood Insurance Map ATTACHMENTS Hydraulic calculations -----.. -------------- --- ---------- - INTRODUCTION This drainage study report is being submitted to the City of Carlsbad as a reference to the LOS Church located at Camino De Los Coches and Via Caliendo, a part of the NW 114 Quarter of Section 6, Township 13 South, Range 3 West, City of Carlsbad, County of San Diego, California. The square footage of the said development is 6.82 acres. The site is in a Zone X (outside the 100 & 500 year flood plan) according to FEMA Flood Insurance Rate Map, Community Panel No. 1053 of 2375, dated June 19, 1997. According to site investigation there is no historical significance on or near the site, and no environmental liability was found at the site. The site after development will be used for community service purpose. Therefore, there will be no on-site industry activities and their associated discharge. This report intends to present the existing storm water drainage conditions and the proposed storm water management for this development. Control measures and detailed calculations are included in the report. PROJECT DESCRIPTION Existing Conditions: The site is currently undeveloped vacant land. There is a creek (an unnamed tributary of Encinitas Creek) along the west boundary of the site. Runoff released from a 24" RCP pipe across Camino De Los Coshes drains into the creek through the project site. Storm water from the site drains directly into the creek. There is no existing on-site storm water management system. Post-Development Conditions: The proposed development consists of a LOS Church located on 6.82 ac site. The total acreage of impervious surface areas is 3.23 acres or 47.4% total acreage. Runoff from the controlled drainage areas drains into five catch basins and discharges into the creek through underground storm sewers. A 24" RCP storm drain is installed by connecting to the existing 24" RCP to divert drainage into the creek. Exhibit D shows a schematic drainage diagram for the project site. -------------------- - - ----------- - EROSION & SEDIMENT CONTROL Erosion and sediment control measures are designed and installed to prevent the escape of sediment from the site during the construction of the proposed development. Site Erosion Control Plan shows the erosion and sediment control measures and specifications. Sediment control measures shall be installed and maintained per local jurisdictional requirement and specifications. Sequence o(Major Activities: 1. Install stabilized construction entrance 2. Install silt fence 3. Site clearing 4. Remove and stockpile topsoil 5. Perform site grading operations 6. Stabilize denuded areas and stockpiles 7. Install curb inlets and storm drains 8. Install sediment filters 9. Begin building construction 10. Install utilities, curb and gutter 11. Complete grading and install permanent sodding and planting 12. Complete final pavement 13. Remove structural controls and re-seed any areas disturbed by the removal after all construction activity and the site is stabilized. BEST MANAGEMENT PRACTICE The proposed project/site incorporates a combination of Best Management Practice (BMP) measures to handle the storm water runoff and pollution mitigation requirements. The BMP measures meet the requirements of the National Pollutant Discharge Elimination System (NPDES), the San Diego Regional Water Quality Control Board (SDRWQCB) and the City of Carlsbad. Some of the BMP measures implemented include: Installing stormceptors to remove pollutants and sediments. Directing runoff through vegetated areas. Developing and enhancing vegetation and wildlife habitat areas along the existing drainage channel. Protecting the drainage channel embankment from erosion by seeding, vegetation and rip rap. Controlling storm water discharge velocities by using energy dissipators. ------------------ ...... - - - - --------- - increase downstream of 0.04 inch. Therefore, the impact of this development upon down stream would be negligible. Table 2. Summary of Storm Water Runoff Calculations (10-yr Storm) Drainage Controlled Runoff Tc Intensity Peak discharge structure drainage area coefficient (min) (inlhr) (cfs) (ac) 1 (inlet) 0.11 0.85 5 8 0.75 2 (inlet) 0.54 0.85 5 8 3.67 2A (inlet) 0.13 0.85 5 8 0.88 4 (stormceptor) 0.54 0.85 5 8 3.67 5A 2.25 0.85 5 8 15.30 (stormceptor) None 3.25 0.35 7 7 7.96 (Uncontrolled) Note: see Post-Development Map (Exhibit C) for drainage layout and controlled drainage areas. Table 3. Summary of Storm Water Runoff Calculations (100-yr Storm) Drainage Controlled Runoff Tc Intensity Peak discharge structure drainage area coefficient (min) (inlhr) (cfs) (ac) 1 (inlet) 0.11 0.85 5 11 1.03 2 (inlet) 0.54 0.85 5 11 5.05 2A (inlet) 0.13 0.85 5 11 1.22 4 (stormceptor) 0.54 0.85 5 11 5.05 5A (stormceptor) 2.25 0.85 5 11 21.04 None 3.25 0.35 7 10 11.38 (Uncontrolled) Note: see Post-Development Map (Exhibit C) for drainage layout and controlled drainage areas. Table 4. Summary of Inlet Intake Capacity Calculations Inlet structure Drainage area Discharge (cfs) Discharge (cfs) Inlet size *Basin intake # (ac) (10-yr storm) (100-yr storm) cllJ)acity (cfs) 1 (inlet) 0.11 0.65 0.92 15" dia. grate 1.8 2 (inlet) 0.54 3.21 4.59 1-grate inlet 10.9 2A (inlet) 0.13 0.77 1.10 15" dia. grate 1.8 4 (stormceptor) 0.54 3.21 4.59 1-grate inlet 10.9 5A (stormceptor) 2.25 13.39 19.12 1-grate inlet 21.7 Note: see Post-development Map for drainage structure layout and controlled drainage areas. *Assuming 20% clogging factor and 0.6 foot water depth. ----Table 5. Storm Drainage Pipe Calculations (10-yr Storm) -Storm Drain Controlled Runoff Tc Intensity Peak Pipe drainage ... drainage coefficient (min) (inlhr) discharge capacity area (ac) (cfs) (cfs) -P-1 0.11 0.85 5 8 0.75 3.61 -P-2 0.65 0.85 5 8 4.41 5.89 -P-2A 0.13 0.85 5 8 0.88 8.07 P-3 0.78 0.85 5 8 5.10 7.47 -P-4 1.32 0.85 5 8 8.97 23.80 -P-5 -----6.08 ... P-5A 2.25 0.85 5 8 15.30 23.80 -P-6 -33.89 --Note: see Post-Development Map for drainage layout and controlled drainage areas. ---Table 6. Storm Drainage Pipe Calculations (100-yr Storm) -Storm Drain Controlled Runoff Tc Intensity Peak Pipe drainage -drainage coefficient (min) (inlhr) discharge capacity area (ac) (cfs) (cfs) -P-1 0.11 0.85 5 11 1.03 3.61 -P-2 0.65 0.85 5 11 6.06 5.89 -P-2A 0.13 0.85 5 11 1.21 8.07 -P-3 0.78 0.85 5 11 7.01 11.27 P-4 1.32 0.85 5 11 12.33 20.43 P-5 - -- --4.90 -P-5A 2.25 0.85 5 11 21.04 20.43 -P-6 33.89 ---Note: see Post-Development Map for drainage layout and controlled drainage areas. -------- --------- ------ - - ----------------- ATTACHMENT HYDRAULIC CALCULATIONS ---.. -.. ---------- --- - - - --------- 07/06/01 Creek Cross Section A-A: Pre-development Worksheet for Irregular Channel (/po-yr) Project Description Project File Worksheet Flow Element Method c:\mz\haestad\fmw\lds-carl.fm2 Creek Cross Section A-A Irregular Channel Manning's Formula Solve For Water Elevation Input Data Channel Slope 0.030000 ft/ft Elevation range: 211.00 ft to 219.00 ft. Station (ft) Elevation (ft) 0.00 219.00 10.00 217.00 20.00 215.20 30.00 213.50 40.00 212.00 47.00 211.00 53.00 212.00 77.00 219.00 Discharge 999.76 cfs Results Wtd. Mannings Coefficient 0.050 Water Surface Elevation 215.46 ft Flow Area 110.31 ft2 Wetted Perimeter 47.22 ft Top Width 46.29 ft Height 4.46 ft Critical Depth 215.52 ft Critical Slope 0.027871 fVft Velocity 9.06 fVs Velocity Head 1.28 ft Specific Energy 216.73 ft Froude Number 1.04 Flow is supercritical. Start Station 0.00 End Station 77.00 Roughness 0.050 ,.. 12:23:16 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 - FlowMaster v5.13 Page 1 of 1 ------------------ - --- ----------- 07/06/01 Cross Section A-A (pre-development) Cross Section for Irregular Channel Project Description Project File Worksheet Flow Element Method c:\mz\haestad\fmw\lds-carl.fm2 Creek Cross Section A-A Irregular Channel Manning's Formula Solve For Water Elevation Section Data Wtd. Mannings Coefficient Channel Slope Water Surface Elevation Discharge 219. ,... ~ 0.050 0.030000 ft/ft 215.46 ft 999.76 cfs 0 \ ~ 0 218. 217. 216. c .Q 215. 1ii > (!) jjj 0 0 1\ ~ \ /{)()-)/!'; \ \. \ I~ I '<V 2,/ S"; t/-6 ~ 1F ~ ,... I 1/ I I I I 0 \ I~ 0 "' 214. 213. 212. 0 0 211. 0.0 10.0 20.0 \ I \; I 30.0 40.0 50.0 Station (ft) ~ ~ 60.0 70.0 80.0 -12:28:55 PM Haestad Methods. Inc. 37 Brookside Road Waterbury. CT 06708 (203) 755·1666 FlowMaster v5.13 Page 1 of 1 - --- - ---------- - - - - - ..... --------- 07/06/01 Creek Cross Section A-A: Post-development Worksheet for Irregular Channel {!Po-yr.} Project Description Project File Worksheet Flow Element Method c:\mz\haestad\fmw\lds-carl.fm2 Creek Cross Section A-A Irregular Channel Manning's Formula Solve For Water Elevation Input Data Channel Slope 0.030000 ft/ft Elevation range: 211.00 ft to 219.00 ft. Station (ft) Elevation (ft) 0.00 219.00 10.00 217.00 20.00 215.20 30.00 213.50 40.00 212.00 47.00 211.00 53.00 212.00 77.00 219.00 Discharge 1,023.81 cfs Results Wtd. Mannings Coefficient 0.050 Water Surface Elevation 215.50 ft Flow Area 112.26 ft2 Wetted Perimeter 47.61 ft Top Width 46.67 ft Height 4.50 ft Critical Depth 215.57 ft Critical Slope 0.027779 ftlft Velocity 9.12 ft/s Velocity Head 1.29 ft Specific Energy 216.79 ft Froude Number 1.04 Flow is supercritical. Start Station 0.00 End Station 77.00 Roughness 0.050 -12:24:08 PM Haestad Methods. Inc. 37 Brookside Road Waterbury. CT 06708 {203) 755-1666 - FlowMaster v5. 13 Page 1 of 1 ------------------------ - - ------- - Cross Section A-A (post-development) Cross Section for Irregular Channel Project Description Project File Worksheet Flow Element Method Solve For Section Data c:\mz\haestad\fmw\lds-carl.fm2 Creek Cross Section A-A Irregular Channel Manning's Formula Water Elevation Wtd. Mannings Coefficient Channel Slope 0.050 0.030000 ft/ft Water Surface Elevation Discharge 219. ~ ~ ~ 215.50 ft 1,023.81 cfs 0 \ ~ 0 218. 217. ~ ~ 0 \ ~ /t?t?-YJ•, 216. c .Q 215. iii > Q) w 214. 213. 212. 0 0 0 0 0 \ ~ \. \ \ f\ \ ~ 21.5:5: ~ .. ~ N 7 1\; l7 ,... I I I I I r I~ '~ 211. 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 07/06/01 12:28:03 PM Station (ft) Haestad Methods. Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FfowMaster v5.13 Page 1 of 1 ---------... -------- --- ...... - ----------- 07/03/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-1: 10• PVC@ 2% SLOPE .Worksheet for Circular Channel c:\mz\haestad\fmw\lds-carl.fm2 Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.012 0.020000 ft/ft 0.83 ft Diameter 10.00 in Results Discharge 3.45 cfs Flow Area 0.55 ft2 Wetted Perimeter 2.51 ft Top Width 0.11 ft Critical Depth 0.78 ft Percent Full 99.60 Critical Slope 0.018232 ft/ft Velocity 6.32 ft/s Velocity Head 0.62 ft Specific Energy 1.45 ft Froude Number 0.49 Maximum Discharge 3.61 cfs Full Flow Capacity 3.36 cfs Full Flow Slope 0.021097 ft/ft Flow is subcritical. 02:56:25 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5. 13 Page 1 of 1 -------------------- --------------- 07/03/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-2: 12• HOPE @ 2.01% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\lds-carl.fm2 Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.012 0.020100 ft/ft 1.00 ft Diameter 12.00 in Results Discharge 5.47 cfs Flow Area 0.79 ft2 Wetted Perimeter 3.14 ft Top Width 0.3e-7 ft Critical Depth 0.94 ft Percent Full 100.00 Critical Slope 0.017370 ft/ft Velocity 6.97 ft/s Velocity Head 0.75 ft Specific Energy 1.75 ft Froude Number 0.24e-3 Maximum Discharge 5.89 cfs Full Flow Capacity 5.47 cfs Full Flow Slope 0.020100 ft/ft Flow is subcritical. -02:57:22 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 - FlowMaster v5.13 Page 1 of 1 --- -------------------- - - ------- - Project Description Project File Worksheet Flow Element Method Solve For Input Data P-4: 15• HOPE @ 10% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\lds-carl. fm2 Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.012 0.1 00000 ft/ft 1.25 ft Diameter 15.00 in Results Discharge 22.13 cfs Flow Area 1.23 ft2 Wetted Perimeter 3.93 ft Top Width 0.00 ft Critical Depth 1.25 ft Percent Full 100.00 Critical Slope 0.095960 ft/ft Velocity 18.03 ft/s Velocity Head 5.05 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 23.80 cfs Full Flow Capacity 22.13 cfs Full Flow Slope 0.1 00000 ft/ft 07/03/01 03:09:33 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 -------------------- ----------------- 07/03101 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-5: 1 o• PVC @ 5.68% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\lds-carl.fm2 Stonn Drain Circular Channel Manning's Fonnula Discharge Mannings Coefficient Channel Slope Depth 0.012 0.056800 ft/ft 0.83 ft Diameter 10.00 in Results Discharge 5.66 cfs Flow Area 0.55 ft2 Wetted Perimeter 2.62 ft Top Width 0.00 ft Critical Depth 0.83 ft Percent Full 100.00 Critical Slope 0.052401 ft/ft Velocity 10.37 ft/s Velocity Head 1.67 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 6.08 cfs Full Flow Capacity 5.66 cfs Full Flow Slope 0.056800 ft/ft 03:31:44 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755·1666 FlowMaster v5.13 Page 1 of 1 -------------------- - - - ----------- ·~------·~---------------------------···---···------ 07/03/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-SA: 15" HOPE @ 1 0% SLOPE Worksheet f9r Circular Channel c:\mz\haestad\fmw\lds-carl.fm2 Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.012 0.1 00000 tvft 1.25 ft Diameter 15.00 in Results Discharge 22.13 cfs Flow Area 1.23 ft2 Wetted Perimeter 3.93 ft Top Width 0.00 ft Critical Depth 1.25 ft Percent Full 100.00 Critical Slope 0.095960 tvft Velocity 18.03 tvs Velocity Head 5.05 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 23.80 cfs Full Flow Capacity 22.13 cfs Full Flow Slope 0.1 00000 tvft 03:11:09 PM Haestad Methods. Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5. 13 Page 1 of 1 -.. -.. ---------------- - --- - ------- - • Project Description Project File Worksheet Flow Element Method Solve For Input Data P·6: 24" RCP@ 1.94% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\lds~arl.fm2 Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope 0.013 0.019400 ft/ft Depth 2.00 ft Diameter 24.00 in Results Discharge 31.51 cfs Flow Area 3.14 ft2 Wetted Perimeter 6.28 ft Top Width 0.00 ft Critical Depth 1.88 ft Percent Full 100.00 Critical Slope 0.016769 ftlft Velocity 10.03 ftls Velocity Head 1.56 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 33.89 cfs Full Flow Capacity 31.51 cfs Full Flow Slope 0.019400 ftlft 07/03101 03:12:28 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755·1666 FlowMaster v5.13 Page 1 of 1 -------------------• --• - -------• --- STORM DRAINAGE STUDY REPORT for LDSCHURCH City of Carlsbad County of Leucadia State of California Project No. 45001000 Engineer of Record: Mark Thompson, PE One West Third Street, Suite 100 Tulsa, Ok 74103 918-295-4413 Date: February 23, 2001 ---- ---• -------- --- -----.. ---• • - TABLE OF CONTENTS INTRODUCTION PROJECT DESCRIPTION STORM WATER MANAGEMENT SYSTEM DESIGN EROSION AND SEDIMENT CONTROL BEST MANAGEMENT PRACTICE DOWNSTREAM ANALYSIS EXECUTIVE SUMMARY LIST OF TABLES: Table 1 -Summary of gutter spread calculations Table 2-Storm water runoff calculations -10-year storm Table 3-Storm water runoff calculations -100-year storm Table 6-Basin intake capacity calculations Table 4-Storm drainage pipe flow calculations -10-year storm Table 5-Storm drainage pipe flow calculations -100-year storm LIST OF FIGURES: Exhibit A -Location map Exhibit B -Pre-development drainage map Exhibit C -Post-development drainage map Exhibit D -Schematic drainage diagram Exhibit E -City Master Drainage Plan Exhibit F-FIRM Flood Insurance Map ATTACHMENTS Hydraulic calculations ----.. --• ------.. -• • • • • -• -• • • -• -• -• • • .. - INTRODUCTION This drainage study report is being submitted to the City of Carlsbad as a reference to the LDS Church located at Camino De Los Coches and Via Caliendo, a part of the NW 1/4 Quarter of Section 6, Township 13 South, Range 3 West, City of Carlsbad, Leucadia County, California. The square footage of the said development is 6.82 acres. The site is in a Zone X (outside the 100 & 500 year flood plan) according to FEMA Flood Insurance Rate Map, Community Panel No. 1053 of 2375, dated June 19, 1997. According to site investigation there is no historical significance on or near the site, and no environmental liability was found at the site. The site after development will be used for community service purpose. Therefore, there will be no on-site industry activities and their associated discharge. This report intends to present the existing storm water drainage conditions and the proposed storm water management for this development. Control measures and detailed calculations are included in the report. PROJECT DESCRIPTION Existing Conditions: The site is currently undeveloped vacant land. There is a creek (an unnamed tributary of Encinitas Creek) along the west boundary of the site. Runoff released from a 24" RCP pipe across Camino De Los Coshes drains into the creek through the project site. Storm water from the site drains directly into the creek. There is no existing on-site storm water management system. Post-Development Conditions: The proposed development consists of a LDS Church located on 6.82 ac site. The total acreage of impervious surface areas is 2.42 acres or 35.5% total acreage . Runoff from the controlled drainage areas drains into five catch basins and discharged into the creek through underground storm sewers. A 24" RCP storm drain is installed by connecting to the existing 24" RCP to divert drainage into the creek. Exhibit D shows a schematic drainage diagram for the project site . --.. -.. -• .. ---- ---• -• -• -• -• -• -• .. • -• ---- EROSION & SEDIMENT CONTROL Erosion and sediment control measures are designed and installed to prevent the escape of sediment from the site during the construction of the proposed development. Site Erosion Control Plan shows the erosion and sediment control measures and specifications. Sediment control measures shall be installed and maintained per local jurisdictional requirement and specifications . Sediment Yield Calculations: The universal soil loss equation (USLE) was used to estimate annual sediment yield from the disturbed areas. Sediment Yield (A) = R x K x LS x C x P x (AREA) Total disturbed area (AREA)= 3.9 ac Rainfall erosion index (R) = 200 Soil erodibility factor (K) = 0.32 Length-slope factor (LS) = 1.3 Cover factor (C) = 0.45 Erosion control factor (P) = 1.0 A= (200)(0.32)(1.3)(0.45)(1.0)(3.9) = 146 tons/year The estimated annual soil loss from the total disturbed area is about 146 tons . Sequence o(Major Activities: 1. Install stabilized construction entrance 2. Install silt fence 3. Site clearing 4. Remove and stockpile topsoil 5. Perform site grading operations 6. Stabilize denuded areas and stockpiles 7. Install curb inlets and storm drains 8. Install sediment filters 9. Begin building construction 10. Install utilities, curb and gutter 11. Complete grading and install permanent sodding and planting 12. Complete final pavement 13. Remove structural controls and re-seed any areas disturbed by the removal after all construction activity and the site is stabilized. ---• .. -.. • .. --- -.. • • • • • -• • • • • • • • • • IIIII --- BEST MANAGEMENT PRACTICE All waste contaminants during the construction activities shall be managed per the City of Carlsbad and County of San Diego requirements. The contractor shall periodically water the site to control dust. The contractor and developer shall contact the proper government agencies for any environmental emergencies and take proper actions per city, county and state specifications and procedures . DOWNSTREAM ANALYSIS The site is located in a Zone X (outside the 100 & 500 year flood plan) according to FEMA Flood Insurance Rate Map, Community Panel No. 1053 of 2375, dated June 19, 1997 (see attached. The FEMA Flood Insurance Map). The 100-year peak runoff flow rate will increase from 24.8 cfs to 35.5 cfs after development. Based on the Drawing No 296-5 in the Master Drainage and Storm Water Quality Management Plan of the City of Carlsbad dated March 1994, the controlled drainage area by the creek at Section A-A is about 400 acres (see attached Master Plan Map). The drainage from the 400-acres watershed passes through the creek with an estimated flow rate of about 1000 cfs from 100-year storm (assuming intensity of 5 inches and runoff coefficient of 0.5). The study indicated that increased flow due to this development results in a negligible water surface increase downstream of 0.25 inch (see attached hydraulic calculations). Therefore, the impact of this development upon down stream would be negligible . EXECUTIVE SUMMARY The proposed development consists of a LDS Church located on an approximately 6.82 acres site. The total acreage of impervious surface areas is about 2.42 acres or 35.5% of the site . Storm water management system for the site consists of drainage water collection system and on- site underground drainage pipes. Drainage from an existing storm sewer underneath the Camino De Los Coches is diverted away from the development area using a 24" RCP storm sewer and discharged into the creek. The total pre-development peak discharge from the site for a 10-year and 100-year storm is 14.3 cfs and 20.7 cfs, respectively. The post-development peak discharge from the site from 10-year storm and 100-year storm is 24.9 cfs and 31.9 cfs, respectively. The -• -.. -.. Ill -• -.. ------• • • • • • • .. Ill:: • -• -• • • - Table 5. Storm Drainage Pipe Calculations (10-yr Storm) Storm Drain Control Runoff Tc Intensity Peak drainage coefficient (min) (inlhr) discharge area (ac) (cfs) P-1 0.11 0.85 5 8 0.75 P-2 0.65 0.85 5 8 4.41 P-3 0.13 0.85 5 8 0.88 P-4 0.78 0.85 5 8 5.10 P-5 1.32 0.85 5 8 8.97 P-6 - ---- P-7 2.25 0.85 5 8 15.30 P-8 - ---- P-9 ----- P-10 - --- - Note: see Post-Development Map for drainage layout and controlled drainage areas. Table 6. Storm Drainage Pipe Calculations (100-yr Storm) Storm Drain Control Runoff Tc Intensity Peak drainage coefficient (min) (inlhr) discharge area (ac) (cfs) P-1 0.11 0.85 5 11 10.3 P-2 0.65 0.85 5 11 6.06 P-3 0.13 0.85 5 11 1.21 P-4 0.78 0.85 5 11 7.01 P-5 1.32 0.85 5 11 12.33 P-6 - --- - P-7 2.25 0.85 5 11 21.04 P-8 ----- P-9 ----- P-10 - ---- Note: see Post-Development Map for drainage layout and controlled drainage areas . Pipe drainage capacity (cfs) 2.19 6.17 3.10 11.27 20.43 4.90 20.43 31.99 31.99 31.99 Pipe drainage capacity (cfs) 2.19 6.17 3.10 11.27 20.43 4.90 20.43 31.99 31.99 31.99 ------------------------ -- ----• • -• -• ATTACHMENT HYDRAULIC CALCULATIONS --------------- -• .. • • • .. • • • • • • • .. .. • • .. • 02/23/01 Creek Flow Capacity Worksheet for Irregular Channel ( /(ltl-'fl" sro~tH -PilE-J)&-l/.iU.Pf'tH~7) Project Description Project File Worksheet Flow Element Method Solve For c:\mz\haestad\fmw\wal-mart. fm2 channel Input Data Irregular Channel Manning's Formula Discharge Channel Slope 0.030000 fVft Water Surface Elevation 215.08 ft Elevation range: 211.00 ft to 219.00 ft. Station (ft) Elevation (ft) 0.00 219.00 42.00 47.00 53.00 77.00 Results Wtd. Mannings Coefficient Discharge Flow Area Wetted Perimeter Top Width Height Critical Depth 212.00 211.00 212.00 219.00 0.035 999.76 84.10 40.92 40.04 4.08 215.75 cfs ft2 ft ft ft ft Critical Slope 0.013658 fVft Velocity 11.89 fVs Velocity Head 2.20 ft Specific Energy 217.28 ft Froude Number 1.45 Flow is supercritical. Start Station 0.00 End Station 77.00 Roughness 0.035 -11 :06:54 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 • FlowMaster v5.13 Page 1 of 1 -------------- • • • -• -• - • • -• - • • fill Creek Cross Section A-A Cross Section for Irregular Channel ( pll.e-.P~f/~t-u~t~t~/.17) Project Description Project File Worksheet Flow Element Method c:\mz\haestad\fmw\wal-mart. fm2 channel Solve For Section Data Irregular Channel Manning's Formula Discharge 0.035 Wtd. Mannings Coefficient Channel Slope 0. 030000 ft/ft Water Surface Elevation Discharge 219. ..... ~ 215.08 ft 999.76 cfs 0 \ ~ 0 218. 217 . 216. £ - c .Q 215. <a > Q) ijj 214. 213. 212. 0 \ ~ \ \ /tiP 0 \ 0 0 0 0 ~ \ \ -.::7 ;;us;. ~ [\ \; ~a I~ I v ..... I I I I I ·~ ~ 211. 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 • • 02123/01 -11 :07:07 AM • Station (ft) Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 ---• ---• ---• -----• -• -• -• • • -• -• • • • • -• -• 02/23/01 Creek Flow Capacity Worksheet for Irregular Channel ( f>C)_$-r -Pl!VcUf'Mefl/1') Project Description Project File Worksheet Flow Element Method c:\mz\haestad\fmw\wal-mart. fm2 channel Solve For Input Data Irregular Channel Manning's Formula Discharge Channel Slope 0.030000 tvtt Water Surface Elevation 215.1 0 ft Elevation range: 211.00 ft to 219.00 ft. Station (ft) Elevation (ft) 0.00 219.00 42.00 47.00 53.00 77.00 Results Wtd. Mannings Coefficient Discharge Flow Area Wetted Perimeter Top Width Height Critical Depth 212.00 211.00 212.00 219.00 0.035 1,012.53 84.90 41.11 40.23 4.10 215.77 Start Station 0.00 cfs ft2 ft ft ft ft Critical Slope 0.013635 tvtt Velocity 11.93 tvs Velocity Head 2.21 ft Specific Energy 217.31 ft Froude Number 1.45 Flow is supercritical. End Station 77.00 Roughness 0.035 11:04:33AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 {203) 755-1666 FlowMaster v5. 13 Page 1 of 1 ---• -• ---• -• ---• .. • -• ---------• -• -• -• 02/23/01 Creek Cross Section A-A Cross Section for Irregular Channel (_pos-r -Pl::Vt:"Wf'Mc~T) Project Description Project File Worksheet Flow Element Method c:\mz\haestad\fmw\wal-mart. fm2 channel Solve For Section Data Irregular Channel Manning's Formula Discharge Wtd. Mannings Coefficient Channel Slope 0.035 0.030000 ft/ft Water Surface Elevation Discharge 219. "" ~ 215.10 ft 1,012.53 cfs 0 \ ~ 0 218. 217 . 216. £ - c .Q 215. a; > G) ijj 0 0 \ I~ \ 1\ /M \ ~ ~:PIS"· /0 ~ "' I I I I I 0 \ ~ 0 214. 213. 212 . 0 0 211. 0.0 10.0 20.0 \ I ~ \ \; v ~ 30.0 40.0 50.0 60.0 70.0 80.0 Station (ft) -11 :05:27 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 .. ---• --• .. • .. • -.. -• -• .. • [II • -1111 • • • • .. .. • • • • • • 02/23/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-1: 10" PVC@ 1% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart. fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.010000 ft/ft 0.83 ft Diameter 10.00 in Results Discharge 2.19 cfs Flow Area 0.55 ft2 Wetted Perimeter 2.62 ft Top Width 0.00 ft Critical Depth 0.66 ft Percent Full 100.00 Critical Slope 0.010604 ft/ft Velocity 4.02 ft/s Velocity Head 0.25 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 2.36 cfs Full Flow Capacity 2.19 cfs Full Flow Slope 0.010000 ft/ft • 11:14:55AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 --• -• -• .. • .. • -.. -• -• -• .. • -• -----• -• -• .. • .. • 02/23/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-2: 12" RCP @ 3% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart. fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.030000 ft/ft 1.00 ft Diameter 12.00 in Results Discharge 6.17 cfs Flow Area 0.79 ft2 Wetted Perimeter 3.14 ft Top Width 0.00 ft Critical Depth 0.96 ft Percent Full 100.00 Critical Slope 0.026131 ft/ft Velocity 7.86 ft/s Velocity Head 0.96 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 6.64 cfs Full Flow Capacity 6.17 cfs Full Flow Slope 0.030000 ft/ft 11:51:25 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 --- ---• Ill • -• ---• -• .. -• • -.. • • • • • • 02/23/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-3: 1 0" PVC @ 2% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart. fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.020000 ft/ft 0.83 ft Diameter 10.00 in Results Discharge 3.10 cfs Flow Area 0.55 ft2 Wetted Perimeter 2.62 ft Top Width 0.00 ft Critical Depth 0.76 ft Percent Full 100.00 Critical Slope 0.017456ft/ft Velocity 5.68 ft/s Velocity Head 0.50 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 3.33 cfs Full Flow Capacity 3.10 cfs Full Flow Slope 0.020000 ft/ft • 11 :26:34 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 -• • --.. • -• - • -• -.. - - -------- "' • • • -• 02/23/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-4: 12" RCP @ 10% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart. fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.1 00000 ft/ft 1.00 ft Diameter 12.00 in Results Discharge 11.27 cfs Flow Area 0.79 ft2 Wetted Perimeter 3.14 ft Top Width 0.00 ft Critical Depth 1.00 ft Percent Full 100.00 Critical Slope 0.094943 ft/ft Velocity 14.34 ft/s Velocity Head 3.20 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 12.12 cfs Full Flow Capacity 11.27 cfs Full Flow Slope 0.1 00000 ft/ft 11:51:07 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 --.. -• .. • .. • -• -- • -• ---- - - ----• -• • • -.. 02/23101 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-5: 15" RCP @ 10% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart. fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.1 00000 ft/ft 1.00 ft Diameter 15.00 in Results Discharge 19.97 cfs Flow Area 1.05 ft2 Wetted Perimeter 2.77 ft Top Width 1.00 ft Critical Depth 1.25 ft Percent Full 80.00 Critical Slope 0.090842 ft/ft Velocity 18.97 ft/s Velocity Head 5.59 ft Specific Energy 6.59 ft Froude Number 3.26 Maximum Discharge 21.97 cfs Full Flow Capacity 20.43 cfs Full Flow Slope 0.095544 ft/ft Flow is supercritical. 11:53:33AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 • • .. -... -• .. .. • -• -.. .. • -II !Ill II -- -• -• • • • 02123/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-6: 1 0" PVC @ 5% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart. fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.050000 ft/ft 0.83 ft Diameter 10.00 in Results Discharge 4.90 cfs Flow Area 0.55 ft2 Wetted Perimeter 2.62 ft Top Width 0.00 ft Critical Depth 0.82 ft Percent Full 100.00 Critical Slope 0.045096 ft/ft Velocity 8.98 ft/s Velocity Head 1.25 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 5.27 cfs Full Flow Capacity 4.90 cfs Full Flow Slope 0.050000 ft/ft • 11 :56:35 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 ill FlowMaster v5.13 Page 1 of 1 ---... -----------• -• ------- --• • -• • • 02/23/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-7: 15" RCP @ 10% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart. fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.1 00000 ft/ft 1.25 ft Diameter 15.00 in Results Discharge 20.43 cfs Flow Area 1.23 ft2 Wetted Perimeter 3.93 ft Top Width 0.33e-7 ft Critical Depth 1.25 ft Percent Full 100.00 Critical Slope 0.095288 ft/ft Velocity 16.65 ft/s Velocity Head 4.31 ft Specific Energy 5.56 ft Froude Number 0.48e-3 Maximum Discharge 21.97 cfs Full Flow Capacity 20.43 cfs Full Flow Slope 0.1 00000 ft/ft Flow is subcritical. -11 :55:57 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 • FlowMaster v5.13 Page 1 of 1 -.. • -• -• -• -• -• • • - -• --.. iill .. • -• • • .. .. 02/23/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-8: 24" RCP @ 2% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart.fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.020000 ft/ft 2.00 ft Diameter 24.00 in Results Discharge 31.99 cfs Flow Area 3.14 ft2 Wetted Perimeter 6.28 ft Top Width 0.6e-7 ft Critical Depth 1.89 ft Percent Full 100.00 Critical Slope 0.017296 ft/ft Velocity 10.18 ft/s Velocity Head 1.61 ft Specific Energy 3.61 ft Froude Number 0.25e-3 Maximum Discharge 34.41 cfs Full Flow Capacity 31.99 cfs Full Flow Slope 0.020000 ft/ft Flow is subcritical. 1!11111 11 :58:40 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 -.. -• .. .. • ---.. -• -• --.. -----------• • • -• --02/23101 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-9: 24" RCP @ 2% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart.fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.020000 ft/ft 2.00 ft Diameter 24.00 in Results Discharge 31.99 cfs Flow Area 3.14 ft2 Wetted Perimeter 6.28 ft Top Width 0.6e-7 ft Critical Depth 1.89 ft Percent Full 100.00 Critical Slope 0.017296 ft/ft Velocity 10.18 ftls Velocity Head 1.61 ft Specific Energy 3.61 ft Froude Number 0.25e-3 Maximum Discharge 34.41 cfs Full Flow Capacity 31.99 cfs Full Flow Slope 0.020000 ft/ft Flow is subcritical. 11:58:51 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 FlowMaster v5.13 Page 1 of 1 ----- • -• • ... • -• -• -• .. • .. • ---• .. ---.. 02/23/01 Project Description Project File Worksheet Flow Element Method Solve For Input Data P-1 0: 24" RCP @ 2% SLOPE Worksheet for Circular Channel c:\mz\haestad\fmw\wal-mart.fm2 CMP Storm Drain Circular Channel Manning's Formula Discharge Mannings Coefficient Channel Slope Depth 0.013 0.020000 fVft 2.00 ft Diameter 24.00 in Results Discharge 31.99 cfs Flow Area 3.14 ft2 Wetted Perimeter 6.28 ft Top Width 0.6e-7 ft Critical Depth 1.89 ft Percent Full 100.00 Critical Slope 0.017296 fVft Velocity 10.18 fVs Velocity Head 1.61 ft Specific Energy 3.61 ft Froude Number 0.25e-3 Maximum Discharge 34.41 cfs Full Flow Capacity 31.99 cfs Full Flow Slope 0.020000 fVft Flow is subcritical. -11 :59:00 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 -FlowMaster v5.13 Page 1 of 1