Loading...
HomeMy WebLinkAboutCT 02-21; VILLAGES OF LA COSTA GREENS 1.12; HYDRAULIC STUDY; 2003-08-20HUNSAKER ^ASSOCIATES SAN DIECO, INC. PLANNING ENGINEERING SURVEYING IRVINE LOSANGELES RIVERSIDE SAN DIEGO HYDRAULIC STUDY for LA COSTA GREENS - PHASE 1 NEIGHBORHOOD 1.12 City of Carlsbad, California Prepared for: Real Estate Collateral Managennent Company c/o Morrow Development 1903 Wright Place Suite 180 Carlsbad, CA 92008 w.o. 2352-71 August 20, 2003 DAVE HAMMAR LEX WILLIMAN ALISA VIALPANDO 10179 Huennekens St. San Diego, CA 92121 (858) 558-4500 PH (858)558-1414 FX www.HunsakerSD.com lnfo@HunsakerSD.com Rgfynyond L. Martin, R.C.E. Project Manager Hunsaker & Associates San Diego, Inc, CT op SJ h:\isport5\2352\071\a01.doc W.O. 2352-71 S^1/2003 4:13 PM La Costa Greens - Phase I (Neighborhoods 1.12) Hydraulic Study TABLE OF CONTENTS SECTION Chapter 1 - Executive Summary Introduction Existing Condition Proposed Condition Summary of Results Conclusion References Chapter 2 - Methodology & Model Development City of Carlsbad Drainage Design Criteria storm Drain System Analysis Chapter 3 - Hydraulic Analysis (StormCAD Model Output) III Chapter 4 - Inlet & Catch Basin Sizing iV Inlet Sizing Catch Basin Sizing Brow Ditch Sizing Chapter 5 - Exhibits Exhibit A Hydraulic Map - Neighborhood 1.12 Reference Maps Ultimate Condition Hydrology Map - Neighborhoods 1.09, 1.10 and 1.12-North Ultimate Condition Hydrology Map - Neighborhoods 1.12 South, 1.13and 1.14 SJ h:\reports\2352\071\aO1.doc W.O 2352-71 aai/2003 3:58 PM La Costa Greens - Phase I (Neighborhoods 1.12) Hydraulic Study EXECUTIVE SUMMARY Introduction The purpose ofthis study is to analyze hydraulic conditions forthe proposed storm drain system pertaining to Neighborhood 1.12 ofthe La Costa Greens Phase I project site. This report is an addendum to the "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens Phase I Neighborhoods 1.08 Through 1.14" prepared by Hunsaker & Associates, and dated August 4, 2003. All hydrologic data used in this report was obtained from the previously mentioned study. La Costa Greens Phase I consists of Neighborhoods 1.08 through 1.14 in the southeast comer of Local Facilities Management Plan Zone 10 (see Vicinity Map below). This report will address: • Hydraulic calculations for the proposed storm drain system. • Curb inlet and catch basin sizing. OF UARCOS ll PROJECT SITE VICINITYMAF NTS SJ h:\report5\2352\071\a01.doc W.O. 2352-71 aCI/2003 3:58 PM La Costa Greens - Phase I (Neighborhoods 1.12) Hydraulic Study Existing Condition The site is located in the La Costa Greens Phase I project site area. Neighborhood 1.12 is bordered to the southeast by an existing neighborhood, to the south by Neighborhood 1.13, and to the west by Alicante Road (see Exhibit A). Located in the Batiquitos watershed, the site consists of primarily undisturbed terrain covered with natural vegetation with portions being mass-graded, as shown on Drawing No. 397-2A. Natural runoff from the undeveloped site flows in a westerly direction to an unnamed tributary of San Marcos Creek, which then flows in a southerly direction along the site boundary ofthe La Costa Greens Golf Course, west ofthe Phase I development area. All the runoff eventually drains under Alga Road via three 96" RCP culverts, as shown in Drawing No. 397-2, and discharges into San Marcos Creek towards Batiquitos Lagoon. Proposed Condition The proposed project consists of single-family residential homes. Runoff from the developed area will be collected on Amber Lane partially by the existing system (from drawing 397-2) and drain north to Lapis Road and west to Neighborhood 1.10. Runoff will also be collected to the proposed system and drain south to an existing storm drain and drain south through Neighborhood 1.13 then to Alga Road. See "Master Hydrology Study and Revised Hydraulic Study for La Costa Greens Phase 1 Neighborhoods 1.08 through 1.14," prepared by Hunsaker & Associates, dated August 4, 2003. Summarv of Results As mentioned before, this hydraulic study is an addendum to the hydraulic section in the previously referenced Hunsaker & Associates report. In this report, the proposed storm drain system was analyzed with the StormCAD software. Using a starting downstream water surface elevation based on a free outfall at the discharge locations, the program calculated the hydraulic grade line for the RCP storm drain system (see Chapter 3). Storni drain layout can be visually depicted on "Hydraulic Map - Neighborhood 1.12' which is located in Chapter 5 as Exhibit A of this report. All proposed curb inlets and catch basins were sized to ensure the capacity of handling 100-year ultimate condition peak flows (see Chapter 4). All hydrologic data used to size the curb inlets and catch basin was also obtained from the previously referenced Hunsaker & Associates report. Conclusion Storm drain design results in no adverse impact. Construction ofthe proposed storm drain improvements as shown herein will safely collect and convey peak discharge through the development. SJ h:\reports\2362\071\a01 .doc W.O. 2352-71 a/21/2003 3:58 PM La Costa Greens - Phase I (Neighborhoods 1.12) Hydraulic Study References "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens Phase I Neighborhoods 1.08 Through 1.14"; Hunsaker & Associates; August 4, 2003. Drawing No. 397-2A Grading Plans for La Costa Greens Phase I; O'Day Consultants; January 16, 2003. Drawing No. 397-2 Improvement Plans for La Costa Greens Phase I; O'Day Consultants; January 16, 2003. "Standards for Design and Construction of Pubiic Worl<s improvements in the City of Carlsbad"; City of Carlsbad, California; April 1993. "City of San Diego Regionai Standard Drawings"; Section D - Drainage Systems; March 2000. SJ h:\rBports\2352\071\a01.doc W.O. 2352-71 8/21/2003 2:57 PM La Costa Greens - Phase I (Neighborhood 1.12) Hydraulic Study CHAPTER 2 METHODOLOGY & MODEL DEVELOPMENT Storm Drain System Analysis SJ h:\reportsU352\071Va01.doc W.O. 2352-71 8/21/2003 2:57 PM La Costa Greens - Phase I (Neighborhoods 1.12) Hydraulic Study Storm Drain Hvdraulic Analvsis Computer Software - StonnCAD Design Storm - 100-Year Retum Interval Storm drain systems in this analysis were sized to prevent street flooding and to predict outlet velocities to receiving channels. The StonnCAD computer program, developed by Haested Methods, was used to predict hydraulic grade lines, pipe flow travel times, and velocities in the stonn drain systems. Required input includes the peak flowrate at each inlet, upstream and downstream inverts, pipe lengths, and rim elevations. Flow calculations are valid for both pressure and varied flow situations, including hydraulic jumps, backwater, and drawdown curves. The gravity network solution is solved using a numerical model that utilizes both the direct step and standard step gradually varied fiow methods. Junction losses are modeled using the standard method, which calculates structure headloss based on the structure's exit velocity (velocity at the upstream end of the downstream pipe). The exit velocity head is multiplied by a user-entered coefficient to determine the loss according to the following formula... Hs= K*Vo^/2g Where Hs = structure headloss (ft.) K = headloss coefficient Vo = exit pipe velocity (ft/s) G = gravitational acceleration (ft/s^) Typical headloss coefficients used for the standard method range from 0.5 to 1.0 depending on the number of pipes meeting at the junction and the confluence angle. For a trunkline only with no bend at the junction, a headloss coefficient of 0.5 is selected. For three or more entrance lines confluencing at a junction, a value of 1.0 is selected. SJ h:trBpoitsl2352V071\a01.doc W.O. 2352-71 8/21/2003 2:57 PM La Costa Greens - Phase I (Neighborhood 1.12) Hydraulic Study CHAPTER 3 HYDRAULIC ANALYSIS (STORMCAD MODEL OUTPUT) SJ h:\reDOlts\2352\071\a01.doc W.O. 2352-71 8/21/2003 2:57 PM Scenario: La Costa Greens BASIN DEV-6 604 603D ^ • < • 607 P-36 \ P-37 "0 I Ol Neighborhood 1.12 614 Title: LA COSTA GREENS - 1.12, 1.13, & 1.14 h:\stormcad\2352\7l\pa 1.l2.stm 08/21/03 03:37:28 PM © Haestad Methods, Inc. 617 Hunsaker & Associates - San Diego, Inc. 37 Brookside Road Waterbury, CT 06708 USA H-203-756-1666 Project Engineer: H&A Employee StormCAD v5.5 [5.5003] Page 1 of 1 Scenario: La Costa Greens Combined Pipe\Node Report Label Upstrean' Downstrean-Upstreanr •ovi/nstrean Upstream Downstrean Hydraulic Hydraulic Velocity Velocity Mannings Full System Constructed Length Section Node Node Invert Invert Ground Ground Grade Grade In Out n Capacity Known Slope (ft) Size Elevation Elevation Elevation Elevation Line In Line Out (ft/s) (ft/s) (cfs) Flow (%) (ft) (ft) (ft) (ft) (ft) (ft) (ft) (ft/s) (cfs) (cfs) (%) P-12 610 617 280.16 256.25 297.60 262.20 281.64 257.15 13.62 21.68 0.013 35.72 24.03 11.56 206.79 18 inch P-13 609 610 291.04 280.49 300.06 297.60 292.36 283.09 7.41 6.93 0.013 29.46 12.24 7.86 134.15 18 inch P-14 608 609 318.76 291.37 329.25 300.06 320.08 292.79 7.41 7.07 0.013 34.08 12.24 10.52 260.24 18 inch P-15 604 608 334.78 319.09 344.87 329.25 3B6.!8 zzm 7.41 7.07 0.013 27.90 12^ 7.05 222.40 18 inch P-36 603 604 336.36 335.11 345.11 344.87 337.09 336.87 4.29 2.08 0.013 46.97 3.67 20.00 6.25 18 Inch P-37 607 604 338.63 335.11 345.11 344.87 339.80 336.87 6.17 5.15 0.013 38.46 9.10 13.41 26.25 18 inch P-39 614 610 286.08 280.49 293.08 297.60 286.67 283.09 3.75 1.36 0.013 25.17 2.40 5.74 97.34 18 Inch ,1^ Dor 7 Title: LA COSTA GREENS - 1.12, 1.13, & 1.14 h:\stormcad\2352\71\pa 1.12.stm 08/21/03 03:36:50 PM © Haestad Methods, Inc. Hunsaker & Associates - San Diego, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Project Engineer: H&A Employee StormCAD v5.5 [5.5003] Page 1 of 1 La Costa Greens - Phase I (Neighborhood 1.12) Hydraulic Study CHAPTER 4 INLET & CATCH BASIN SIZING Inlet Sizing SJ h:\rapoitsl2352\071\a01.doc W.o. 2352-71 a/21/2003 2:57 PM CURB INLET SIZING LA COSTA GREENS - NEIGHBORHOOD 1.12 Type of Inlet Inlet at Node Street Slope^ S (%) Surface Flow^ Q (cfs) Gutter Depression a (ft) Flow Depth^ y(ft) Required Length of Opening* (ft) Use Length ^ (ft) ON-GRADE 603 1.00% 3.7 0.33 0.36 9.2 11 ON-GRADE 607 1.00% 9.1 0.33 0.46 18.5 20 1 From street profiles in Improvement Plans 2 From AES ouput 3 From Manning's Equation: Q = (1.49/n)*A*S^'^*R^^ The hydraulic radius, R, and area. A, are expressed as a function of the flow depth, y. Typical cross-section of a Type G gutter is used for the analysis. 4 Per City of Carlsbad Standards From Equation: Q = 0.7L(a+y)'^3/2 5 Length shown on plans (Required Length of Opening + 1 foot) 8/21/2003 H:\EXCEL\2352\71\lnletSlzlng 112-Carlsbad.xls La Costa Greens - Phase I (Neighborhood 1.12) Hydraulic Study CHAPTER 4 INLET & CATCH BASIN SIZING Catch Basin Sizing SJ h:\repoitsV2352W71\a01.doo W.o. 2352-71 8/21/2003 2:57 PM CATCH BASIN TYPE "F" Per Regional Standard Drawings (March 2000) - Drawing D-7: 3' y = 0.689" (Centroid) Q^ = 0.6AV(2gh) Q^ax = 0.6AV(2gh) Qmax = 0.6(1.875+0.1875)[V(2)(32.2)(1.125-0.689)] 0 max = 6.56 cfs per opening NEIGHBORHOODS 1.12 At Node #: 614 Q= 2.40 cfs One Opening: East Side RECHECK Q'S 8/21/2003 H:\EXCEL\2352\69\Catch Basin F 112.xls BROW DITCH SIZING LA COSTA GREENS - NEIGHBORHOOD 1.12 Brow Ditch Conveyed Brow Ditch Brow Ditch ID Node^ Flow^ (cfs) Size^(ft) Type^ R 2.24 2 "B" S 2.40 2 Modified "D" T 0.93 2 Modified "D" JJ 2.32 2 "B" KK 2.32 2 "B" LL 2.24 2 "B" MM 1.47 2 "B" 1 Brow dtches R-T are proposed brow ditches. 1 Sizing for brow ditches JJ-MM is a revision of the referenced O'Day report. 1 Refer to Developed Condition Hydrology Maps (Sections 9.3 and 9.5) 2 Flows from AES output (Section 3.2 and 3.4) 3 Refer to Sheet 3 in Grading Plans for brow ditch details 3 Referto San Diego Regional Standard Drawings, Dwg. D-75, for brow ditch details Maximum Capacities for Brow Ditches Brow Ditch Maximum Brow Ditch Brow Ditch Type Flow (cfs) Size (ft) Min. Slope (%) "B" 2.73 2 1.00 Modified "D" 2.73 2 1.00 Modified "D" 13.98 3 1.00 NOTES: Based on a brow ditch minimum slope, s = 1.00%, and Manning's n = 0.015 Refer to attached FlowMaster output for calculations (Section 6.2) Refer to Sheet 3 In Grading Plans for Modified Type "D" Brow Ditch Detail Refer to San Diego Regional Standard Drawings, Dwg. D-75, for Type "B" Brow Ditch Detail Type "B" brow ditches will be used where slope and/or wall constraints are present 8/21/2003 H:\EXCEL\2352\71\BDitch 112.xls La Costa Greens - Phase I (Neighborhood 1.12) Hydraulic Study CHAPTER 5 EXHIBITS Exhibit A - Ultimate Condition Hydraulic Map Neighborhood 1.12 - South SJ h:\repons\2352\071\a01.doc W.O. 2352-71 8/21/2003 3:28 PM