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Home My WebLink About3338; Agua Hedionda & Calavera Creek Dredging; Agua Hedionda Creek Floodplain Study; 2009-01-01T. AGUA HEDIONDA CREEK FLOODPLAIN STUDY Carlsbad, CA January 2009 Prepared For: Ladwig Design Group 2234 Faraday Avenue Carlsbad, CA 92008 Prepared By: Lyle Engineering, Inc. 1030 Lighthouse Road Carlsbad, CA 92011 Scott R. Lyle, P.E., C TABLE OF CONTENTS SECTION PAGE 1. INTRODUCTION 1 1.1 PURPOSE OF STUDY 1 1.2 SCOPE 1 2. DATA COLLECTION 1 2.1 HYDROLOGIC ANALYSES 1 2.2 HYDRAULIC ANALYSES 1 3. ALTERNATIVE ANALYSES 2 4. CONCLUSION 3 5. REFERENCES 3 TABLE OF APPENDICES APPENDIX I SUPPORTING TABLES AND FIGURES Vicinity Map APPENDIX II CALCULATIONS HEC-RAS Results Earthwork Sections APPENDIX III MAPS Existing Conditions - HEC-RAS Work Map Alternative 1 - HEC-RAS Work Map Agua Hedionda Creek Floodplain Study 1. INTRODUCTION 1.1 Purpose of Study This study summarizes the floodplain and grading impacts due to proposed channel and bridge improvements along Agua Hedionda Creek from Rancho Carlsbad Drive upstream to the future College Boulevard crossing in Carlsbad, California. The creek traverses through the Rancho Carlsbad Golf Course and an existing equestrian center within the study reach (see Vicinity Map). The purpose of this study is to evaluate channel and bridge alternatives along Agua Hedionda Creek to enhance the existing creek riparian corridor while increasing opportunities for development. These improvements must minimize impacts to environmentally sensitive areas while conveying 100-year flows and reducing overbank flooding within the property. The proposed bridge crossing at Rancho Carlsbad Drive will be designed to convey the 100-year flow without increasing backwater elevations and minimizing overtopping flows in the overbank areas. 1.2 Scope This study involves the hydraulic analysis of an approximate 0.5 mile reach of Agua Hedionda Creek. Channel grading and bridge widening scenarios were analyzed before selecting an alternative that meets the project's objective. Approximate earthwork calculations were performed for input into the project's overall cost estimate. 2. DATA COLLECTION 2.1 Hydrologic Analyses Updated hydrologic analyses performed by Lyle Engineering, Inc. for the Dos Colinas (West Senior Living) project dated January 15, 2009 were used for this project. A peak 100-year discharge of 7,338 cubic feet per second (cfs) was used for the reach from Rancho Carlsbad Drive to the proposed College Boulevard creek crossing. 2.2 Hydraulic Analyses The existing conditions model prepared by Lyle Engineering, Inc. for the Dos Colinas (West Senior Living) project was used as the base model for the alternative analyses. The starting water surface elevation for this model was extracted from the Brown & Caldwell CLOMR model dated June 2008. The existing conditions model was revised to include proposed grading improvements from the Senior Living and Affordable Housing projects, and the College Boulevard Bridge crossing. This model was then revised to incorporate proposed channel grading and bridge improvements as described under Section 3 of this study. Agua Hedionda Creek Floodplain Study Both existing and proposed conditions hydraulic models tie into the FEMA effective water surface elevations and floodway limits at the upstream and downstream study limits. See attached HEC-RAS results and Work Maps attached to the back of this study. 3. ALTERNATIVE ANALYSES The following hydraulic models were prepared to determine the optimum channel configuration and bridge opening to contain the 100-year flow within the channel banks through the property. References to left and right bank grading improvements are based on looking in the downstream direction. Existing Conditions Model: There is a large backwater area immediately downstream of Section 3314 (immediately upstream of Rancho Carlsbad Drive) along the right overbank (see HEC-RAS Workmap Existing Conditions Sheet 1 of 2). Hydraulic depths in this area are less than one foot and velocities are less than two feet per second (fps) during a 100-year event. Based on FEMA Guidelines, this area is designated as a shaded Zone X which is considered as an area of 100-year flooding with average depths of less than one foot. These areas are identified in the community Flood Insurance Study as areas of moderate or minimal hazard from the principal source of flood in the area. Flood insurance is available in participating communities but is not required by regulation in these zones. Alternative 1 Model: This model includes proposed channel improvements from the upstream face of Rancho Carlsbad Drive (Section 300.5) to the future crossing of College Boulevard (Section 5218). Proposed channel improvements include: widening of the channel bottom; varying channel banks from 2:1 to 4:1; and, incorporating islands to restore existing riparian habitat. A Manning's roughness coefficient of 0.06 was used for the entire reach and the existing creek flow gradient was preserved for this model. This model also includes proposed grading improvements from the Senior Living and Affordable Housing projects, and the College Boulevard Bridge crossing. Results show that 100-year water surface elevations are significantly lower from Section 3955 (approximately 1000 feet upstream of Rancho Carlsbad Drive) to Section 5183 (downstream face of proposed College Boulevard Bridge) as compared to Existing Conditions. There is very little change in water surface elevations from Rancho Carlsbad Drive to approximately 800 feet upstream of Rancho Carlsbad Drive (approximately the midpoint of the second proposed island). The existing Rancho Carlsbad Bridge is still a major impediment to flood flows and creates a significant backwater. The bridge abutments are subject to significant scour due to 100-year flows overtopping the road crossing. These impacts result in Alternative 1 not containing the 100-year flow within its banks for the first 800 feet upstream of Rancho Carlsbad Drive. Agua Hedionda Creek Floodplain Study Alternative 1 with new bridge at Rancho Carlsbad Drive: This model includes the Alternative 1 channel improvements and widening of the existing bridge at Rancho Carlsbad Drive. Several alternatives were evaluated for the Rancho Carlsbad Drive crossing of Agua Hedionda Creek. The existing crossing consists of a triple 12 foot wide by 11 foot high opening. The selected alternative is a clear span bridge with a width of 80 feet and height of 10 feet. This bridge opening combined with the proposed Alternative 1 grading results in 100-year water surface elevations being contained within the proposed graded channel banks with no overbank spilling. This alternative also reduces water surface elevations to below 60 feet NGVD29 for the critical 1000 feet upstream of the Rancho Carlsbad Drive crossing. Refer to Appendix II for HEC-RAS results. 4. CONCLUSION The proposed channel and bridge improvements will contain the 100-year flow within the graded banks with no overbank spilling. Approximately 100,000 cubic yards will need to be excavated and transported from the site to construct the proposed grading alignment. The widening of the Rancho Carlsbad Drive crossing will reduce backwater impacts and result in 100-year flows being conveyed under the road crossing. Based on review of the existing topographic mapping, it is feasible that a smooth transition could be graded from the wider bridge downstream to the existing channel (which has a bottom width of approximately 60 feet). It does not appear that any existing structures will be impacted. Final resolution of the bridge design and associated grading impacts will need to be determined by structural and geotechnical engineers. The proposed bridge widening will reduce flooding impacts at the Rancho Carlsbad Drive crossing. Under existing conditions, larger flood events overtop the road and erode the bridge/culvert abutments. The proposed bridge widening will convey 100-year flows under the road crossing and mitigate potential erosion that may have occurred under existing conditions. 5. REFERENCES U.S. Army Corps of Engineers, HEC-RAS River Analysis System. Version 3.1.3, May 2006 Yen Te Chow, Open-Channel Hydraulics. 1959 Harry H. Barnes, Roughness Characteristics of Natural Channels. USGS Paper 1849, 1967 Lyle Engineering, Inc., Agua Hedionda Creek Hydraulic Analyses for Dos Colinas (West Senior Living), January 15,2009. APPENDIX I: SUPPORTING TABLES AND FIGURES Shopptngtown Pla/a Cammo Real N STUDY REACH : .1: • McClelian-PalDTia -1 Airpon CarfebadRaceway \•• '"' 0 Date: 01/27/2009 Scale: N.T.S. Path: DWG Name: VICINITY MAP Plotting View: NONE Designer: SRL Proj Mgr: LYLE ENGINEERING, INC. 1030 LIGHTHOUSE ROAD CARLSBAD, CA 92011 (760)703-1477 (760) 603-8128 FAX VICINITY MAP AGUA HEDIONDA CREEK ALTERNATIVE ANALYSES CITY OF CARLSBAD, CA JOB NUMBER: 08-29 OF 1 SHEET APPENDIX II: CALCULATIONS Existing Conditions HEC-RAS Results HEC-RAS Plan: AHC CLOMR EX River: Agua Hedionda Reach: Reach 1 Reach Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach! Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach! Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach! Reach 1 Reach! Reach! Reach! Reach! River Sta 300.12 300.12 30040 300.50 300.50 3116 3116 3104 3194 3314 3314 3486 3496 3616 3616 3955 3955 4105 4105 4260 4260 4520 4520 4708 4708 4948 4948 S183 51S3 5303 5303 5508 5508 CCA0QvtfO 5598 5833 5933 6188 6188 6323 6323 6443 6443 6463 6463 6619 6619 Q Total (eft) 7338.00 7338.00 Culvert 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 MinChEl M 44.89 44.89 45.11 45.11 45.59 45.59 46.22 46.22 47.25 47.25 48.22 48.22i 48.77 48.77 49.73 49.73 51.00 51.00 52.80 52.80] 54.70 54.70 56.90 56.90 58.84 58.84 59.75 59.75 60.31 60.31 61.55 61.55 62.00 62.00 64.31 64.31 65.31 65.31 66.70 66.70 69.40 69.40 73.19 73.19 73.60 73.60 W.S. Bev W 55.76 55.76 60.43 61.10 60.14 61.02 60.90 61.09 60.90 61.27 61.60 62.46 61.87 62.85 66.17 66.22 67.41 68.35 67.70 68.63 69.32 69.52 70.81 71.78 72.09 72.72 73.69 74.68 74.29 75.14 73.98 74.97 75.31 75.86 78.91 79.07 79.49 79.64 80.24 8039 80.62 80.83 81.13 81.16 82.18 82.36 CritW.S. W 53.78 53.78 54.00 54.00 60.90 61.27 66.17 66.22 69.32 69.52 72.09 72.72 71.75 E.G. Etev 00 57.61 57.61 61.04 61.72 61.25 61.84 61.42 61.96 61.91 62.89 62.31 63.37 62.79 63.71 67.29 68.19 67.70 68.75 67.98 69.03 70.23 71.06 71.06 72.32 72.83 73.92 74.14 75.10 74.51 75.39 76.13 76.73 77.24 77.57 79.37 79.55 80.22 80.41 81.01 81.21 81.54 81.67 82.07 82.24 83.25 83.37 EG. Slope (TO 0.003433 0.003433 0.000682 0.000687 0.001682 0.001141 0.001132 0.001614 0.002205 0.002815 0.002076 0.001958 0.001992 0.001482 0.002263 0.003319 0.001907 0.001915 0.001989 0.002059 0.008694 0.012526 0.002225 0.003424 0.007906 0.009659 0.004920 0.003317 0.001987 0.001813 0.012629 0.009049 0.011727 0.009664 0.002758 0.002765 0.004198 0.004194 0.005102 0.005109 0009320 0.008171 0.011167 0.012258 0.008761 0.007753 VelChnl (Ws) 10.92 10.92 6.38 6.33 8.85 7.73 7.05 8.53 9.65 11.19 8.21 8.58 8.33 7.80 10.16 12.34 4.93 5.23 4.77 5.17 8.91 10.73 4.51 5.88 8.78 10.14 6.19 5.55 4.05 4.17 11.78 10.66 11.16 10.51 5.61 5.68 6.98 7.05 7.17 7.26 7.79 7.46 7.97 8.38 8.44 8.15 Flow Area («)«) 671 .99 671 .99 1244.93 1156.87 1038.13 1198.05 1561.87 1202.01 1380.61 956.15 1571.03 1184.23 1317.04 1108.31 1332.53 826.73 1790.88 1468.88 1793.96 1439.10 1093.15 783.40 1815.67 1251.98 1254.57 925.25 1450.42 1442.90 2000.92 1828.61 624.29 691.52 660.76 704.16 1391.13 1324.23 1090.85 1049.23 1068.63 1017.90 963.71 1000.64 950.55 883.14 897.96 913.48 Top Width m 87.70 87.70 390.00 95.00 1203.20 225.00 1214.83 273.77 1153.51 300.00 1346.64 300.00 1010.25 210.00 592.26 210.00 470.21 210.00 487.18 210.00 515.04 220.00 562.14 260.74 716.83 347.19 588.78 365.00 571.87 358.00 68.85 68.00 77.09 80.64 275.95 175.00 16398 115.00 190.59 125.00 198.63 190.00 250.06 200.00 233^ 200.00 Froude#Chl 0.70 0.70 0.33 0.32 0.50 0.42 0.41 0.49 0.56 0.64 0.53 0.53 0.54 0.47 0.52 0.62 0.27 0.27 0.27 0.28 0.54 0.64 0.26 0.31 0.50 0.56 0.41 0.34 0.27 0.26 0.67 0.58 0.64 0.58 0.32 0.33 0.40 0.40 0.44 0.44 0.56 0.53 0.61 0.64 0.69 0.65 HEC-RAS Plan: AHC CLOMR EX River: Agua Hedionda Reach: Reach 1 (Continued) Reach Reach 1 Reach 1 River Sta 7014 7014 Q Total (cfc) 7328.00 7328.00 MinChEl (ft) 82.00 82.00 W.S. Etev W 88.28 88.95 CcftW,S. («) 88.28 88.95 E.G. Etev m 89.66 90.69 E.G. Slope (ft/ft) 0.014858 0.016196 Vet CM (Ws) 9.62 10.62 Row Area (sqft) 791.31 694.56 Top Width TO 296.06 200.00 Froude#Chl 0.97 0.99 HEC-RAS Plan: AHC CLOMR EX River: Agua Hedionda Reach: Reach 1 Reach Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach! Reach 1 Reach 1 Reach 1 Reach! Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach! Reach! Reach! Reach! Reach! Reach! Reach! Reach! Reach! Reach! Reach! Reach 1 Reach! Reach! Reach! Reach! Reach! Reach! Reach! River Sta 300.12 300.12 300.30 300.50 300.50 3116 3116 3194 31B4 3314 3314 3496 3496 3816 3616 3955 3955 4105 4105 4260 4260 4520 4520 4708 4708 4948 4948 5163 5183 5303 5303 5508 5508 5598 5S98 5933 5933 6188 6188 6323 6323 6443 6443 6463 6463 8619 6619 7014 7014 W.S.B6V (ft) 55.76 55.76 Culvert 60.43 61.10 60.14 61.02 60.90 61.09 60.90 61.27 61.60 62.46 61.87 62.85 66.17 66.22 67.41 68.35 67.70 68.63 69.32 69.52 70.81 71.78 72.09 72.72 73.69 74.68 74.29 75.14 73.98 74.97 75.31 75.86 78.91 79.07 79.49 79.64 80.24 80.39 80.62 80.83 81.13 81.16 82.18 82.36 88.28 88.95 Prof Delta WS « 0.00 0.67 0.88 0.19 0.37 0.86 0.98 0.05 0.94 0.93 0.20 0.98 0.64 0.99 0.85 0.99 0.55 0.16 0.16 0.15 0.21 0.03 0.18 0.67 E.G. Bev («) 57.61 57.61 61.04 61.72 61.25 61.84 61.42 61.96 61.91 62.89 62.31 63.37 62.79 63.71 67.29 68.19 67.70 68.75 67.98 69.03 70.23 71.06 71.06 72.32 72.83 73.92 74.14 75.10 74.51 75.39 76.13 76.73 77.24 77.57 79.37 79.55 80.22 80.41 81.01 81.21 81.54 81.67 82.07 82.24 83.25 83.37 89.66 90.69 TopWdthAct (ft) 87.70 87.70 145.00 95.00 260.00 225.00 363.77 268.77 600.00 300.00 742.01 300.00 635.98 210.00 592.26 210.00 470.21 210.00 487.18 210.00 515.04 220.00 562.14 260.74 716.83 347.19 588.78 365.00 571.87 358.00 68.85 68.00 77.09 80.64 275.95 175.00 163.98 115.00 190.59 125.00 198.63 190.00 250.06 200.00 233.69 200.00 296.06 200.00 QUft «*» 185.59 452.30 725.34 2940.05 1899.52 1142.48 670.87 319.19 199.13 10.10 20.28 302.60 1.30 1621.41 1352.25 2833.13 2265.06 2577.07 1496.87 5645.77 4945.15 2969.07 1933.21 3256.94 3028.42 2707.80 1864.67 6.93 13.36 12.18 28.16 750.08 632.05 98.51 52.95 241.83 60.54 220.08 267.91 396.20 437.16 32.83 12.37 59.97 127.80 Q Channel «*) 7338.00 7338.00 6976.01 7328.00 6644.30 6330.47 4332.13 5345.50 4941.98 5970.07 4697.98 5491.99 6193.48 6558.03 4914.74 5992.07 4381.92 5074.52 3882.64 4613.08 4737.73 5831.13 1682.05 2382.86 3604.97 4443.60 3998.21 4084.34"" ~~ 4481.23 5156.57 7315.20 7306.08 7309.37 7284.92 6447.49 6643.69 7041.11 7234.10 7031.30 7251.10 7025.59 6962.45 5972.72 6317.71 7094.29 7115.31 6872.68 7200.20 Q Right (•*) 166.40 231.40 272.19 55.82 82.97 1243.54 687.06 2310.83 1636.88 1124.42 749.69 2110.66 1334.63 1324.67 901.24 612.23 449.86 13.20 0.17 753.96 951.19 72.85 215.24 138.97 306.76 5.86 8.56 6.45 14.92 130.43 52.26 188.38 40.95 54.88 16.36 82.34 97.64 959.08 573.13 200.89 200.33 395.36 EncStaL (ft) 180.90 180.00 400.00 325.00 300.00 245.00 66.00 260.00 205.00 235.00 390.00 350.00 300.00 273.00 255.00 429.00 250.00 165.00 60.00 95.00 20.00 10.00 5.00 25.00 ChStaL (ft) 180.00 180.00 180.00 180.00 504.58 504.58 499.25 499.25 410.11 410.11 271.28 271.28 70.16 70.16 265.33 265.33 280.03 280.03 336.22 336.22 547.95 547.95 593.02 593.02 602.63 602.63 513.91 513.91 410.43 410.43 430.61 430.61 335.77 335.77 210.56 210.56 64.05 64.05 101.16 101.16 49.04 49.04 45.71 45.71 6.61 6.61 34.24 34.24 ChStaR (ft) 275.00 275.00 275.00 275.00 582.54 582.54 565.60 565.60 466.11 466.11 349.57 349.57 169.05 169.05 305.38 305.38 365.67 365.67 421.79 421.79 610.39 610.39 632.72 632.72 646.20 646.20 605.00 605.00 564.28 564.28 495.90 495.90 404.391 404.39 334.55 334.55 171.92 171.92 217.79 217.79 200.38 200.38 186.37 186.37 185.58 185.58 267.26 267.26 EncStaR TO 272.90 275.00 625.00 625.00 600.00 545.00 276.00 470.00 415.00 445.00 610.00 630.00 ~ 700.00 638.00 613.00 497.00 445.00 340.00 175.00 220.00 210.00 210.00 205.00 225.00 90-Agua Hedionda Creek CLOMR - Existing 1/13/2009 80- 40- 1000 Legend WS 100-year Floodpl Ground 2000 3000 Main Channel Distance (ft) 4000 5000 Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 7014 Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 6619 'I Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 6463 0 100 200 400 500 Station (ft) Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 6443 100 200 300 400 500 Station (ftt Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 6323 100 200 300 400 500 600 Station (ft] Agua Hedionda Creek CLOMR- Existing 1/13/200! 0 100 200 300 400 500 600 700 Station (ft) Agua Hedionda Creek CLOMR - Existing 1/13/2009 90- - 0 100 200 300 400 500 Station (ft) Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 5598 0 100 200 300 400 500 600 700 Station (ft) Agua Hedionda Creek CLOMR - Existing 1/13/2009 Legend WS 100-year Floodpl 0 100 200 300 400 Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 5303 Agua Hedionda Creek CLOMR - Existing 1 /13/2009 RS = 5183 Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 4948 Agua Hedionda Creek CLOMR - Existing 1/13/2009 .035 4*-.06->H .035 Agua Hedionda Creek CLOMR - Existing 1/13/2009 .035 Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS=3496 a Hedionda Creek CLOMR- Existing 1/13/2009 RS = 3314 Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 3194 0 200 400 600 800 1000 1200 1400 1600 Station (ft) Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 3116 200 400 600 800 1000 1200 Station (ft) Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 300.50 Rctio Carlsbad Drive U/S Face 0 200 400 600 BOO 1000 1200 1400 Station (ft) Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 300.30 Culv Culvert #1(3 1Zx 11'Boxes) 200 400 600 800 1000 1200 1400 1600 Station (ft) Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 300.30 Curv Cufvert #1 (3 1Z x 11' Boxes) 100 200 300 400 Station (ft) Agua Hedionda Creek CLOMR - Existing 1/13/2009 RS = 3O0.12 Reno Carlsbad Drive D/S Face ~&d> j/y Encroacnr ^ Alternative 1 w/ RCD Bridge HEC-RAS Results HEC-RAS Plan: AHCALT1RCD River: Agua Hedionda Reach: Reach 1 Profile: 100-year Floodpl Reach Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach! Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 Reach 1 River Sta 300.12 300.30 300.50 3024 3088 3148 3188 3236 3291 3374 3583 3621 3756 3877 3953 4244 4290 4397 4523 4550 4617 4665 4709 4782 4939 5051 5069 5106 5156 5188 5218 5250 5368 5508 5598 5933 6188 6323 6443 6463 6619 7014 Q Total (cfs) 7338.00 Bridge 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 Bridge 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 7328.00 Min Ch El (ft) 44.89 45.11 45.30 45.81 46.29 46.60 46.98 47.42 48.08 48.64 48.74 49.10 49.42 49.63 52.32 52.74 53.71 54.73 54.95 55.49 55.88 56.67 58.03 58.71 59.19 59.27 59.43 59.65 59.78 59.94 60.67 61.55 62.00 64.31 65.31 66.70 69.40 73.19 73.60 82.00 W.S. Etev («) 55.76 56.90 57.56 57.68 57.88 57.94 58.01 58.30 58.57 59.31 59.37 60.09 60.72 60.93 61.91 62.00 62.47 63.59 64.12 64.67 64.77 65.12 64.89 68.12 68.99 69.05 68.68 69.53 70.21 70.68 75.07 75.91 76.44 79.11 79.63 80.34 80.70 81.18 82.19 88.28 CritW.S. (ft) 51.26 51.49 64.30 70.68 72.12 71.77 88.28 E.G. Elev (ft) 56.86 57.84 57.93 58.08 58.22 58.33 58.54 58.76 59.08 59.77 59.95 60.64 61.16 61.43 62.33 62.54 63.34 64.65 64.89 65.25 65.61 65.93 67.14 68.96 69.51 69.59 70.14 70.78 71.03 74.21 76.08 77.20 77.85 79.54 80.33 81.08 81.59 82.09 83.26 89.66 E.G. Slope (ft/ft) 0.001655 0.001288 0.002123 0.002347 0.001980 0.002924 0.004174 0.003810 0.003476 0.003087 0.004935 0.005279 0.003503 0.003135 0.002995 0.004898 0.009164 0.010841 0.006034 0.004376 0.008286 0.006113 0.022924 0.006189 0.003591 0.004486 0.013800 0.010350 0.005257 0.027903 0.005330 0.006173 0.007609 0.002496 0.003963 0.004867 0.008887 0.010701 0.008690 0.014858 Vel Chnl (ft/s) 8.43 7.76 4.91 5.06 4.65 4.99 5.81 5.46 5.73 5.44 6.07 5.92 5.34 5.65 5.18 5.86 7.49 8.25 7.04 6.13 7.37 7.21 12.04 7.36 5.81 5.94 9.68 8.95 7.30 15.10 8.44 9.32 9.68 5.42 6.85 7.05 7.67 7.85 842 9.62 Bow Area (sqft) 870.58 944.60 1491.40 1448.56 1577.16 1468.25 1260.98 1341.32 1279.83 1346.55 1208.11 1237.47 1372.16 1296.73 1414.18 1250.89 978.29 887.73 1040.25 1195.16 994.73 1016.94 608.51 996.12 1261.38 1234.35 757.00 818.81 1003.26 487.78 935.99 865.38 837.30 1448.75 1114.08 1087.37 979.08 963.88 900.46 791.31 Top Width (ft) 80.18 80.20 163.34 163.98 179.11 195.92 173.62 191.62 162.07 168.50 178.22 199.28 190.20 154.44 186.88 195.05 168.43 147.40 145.88 162.47 158.87 137.71 102.50 131.64 159.43 173.52 114.64 111.80 117.45 73.82 293.63 297.57 284.80 291 .94 167.11 192.11 200.04 251.02 234.08 296.06 FroudetfChl 045 0.40 0.29 0.30 0.28 0.32 0.38 0.36 0.36 0.34 0.41 0.42 0.35 0.34 0.33 0.41 0.55 0.59 0.46 0.40 0.52 0.47 0.87 0.47 0.36 0.39 0.66 0.58 0.44 0.97 0.46 0.49 0.52 0.31 0.39 0.43 0.55 0.60 0.68 0.97 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 Legend WS 100-year Floodpl Ground 1000 2000 3000 Main Channel Distance (ft) 4000 5000 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 7014 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 6619 110 ro> _0> LJJ Legend WS 100-year Flood pi Ground •Bank Sta I 80 100 200 300 Station (ft) 400 500 70 100 200 300 Station (ft) 400 500 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 6463 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 6443 100 95- LLJ Legend WS 100-year Floodpl Ground •Bank Sta 110- 100- £• 90- LU 80 0 100 200 300 400 Station (ft) 60 500 600 0 100 200 300 400 500 600 700 Station (ft) .LU Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 6323 e.co ! LU 65 0 100 200 300 400 500 600 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5933 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 6188 95 0 100 200 300 400 500 600 700 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5598 Legend WS 100-year Floodpl Ground •Bank Sta 110-Legend WS 100-year Floodpl Ground •Bank Sta 0 100 200 300 400 500 600 700 Station (ft) 0 100 200 300 400 500 600 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5508 LOB Proposed Imps 120- 110 Legend WS 100-year Floodpl • Ground Ineff •Bank Sta 100 200 300 400 500 600 Station (ft) 700 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5250 BR Proposed College Boulevard Bridge K .035 4*— .06 —4t .035 *| Legend WS 100-year Floodpl Ground Ineff •Bank Sta 65 60 300 350 400 450 500 Station (ft) 550 600 650 3.g> LLJ 85 80 J l 75 70 65 60 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5368 Pr. College Blvd Bridge - U/S Face - LOB Proposed Imps — .035— >H—.06—*|« .035 >| Legend WS 100-year Floodpl Ground Ineff •Bank Sta 300 350 400 450 500 550 600 650 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5250 BR Proposed College Boulevard Bridge 901 85- 100 200 300 400 Station (ft) 500 600 700 4±_ co Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5218 Pr. College Blvd Bridge - D/S Face 90n Legend WS 100-year Floodpl Ground .—A Ineff •Bank Sta 0 100 200 300 400 500 600 700 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5158 Alternative 1 Legend WS 100-year Floodpl • Ground •Bank Sta 20 40 60 80 Station (ft) 100 120 140 iro JU UJ Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5188 Alternative 1 85 80 75 70 65 60 55 .06 \ V Legend WS 100-year Floodpl Ground •Bank Sta 20 40 60 80 100 120 140 160 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5106 Alternative 1 Legend WS 100-year Floodpl • Ground •Bank Sta 0 20 40 60 80 100 120 140 160 180 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5069 Alternative 1 Legend WS 100-year Floodpl • Ground •Bank Sta .3? LU 50 100 Station (ft) 150 200 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4939 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta ro ®LU 20 40 60 80 100 120 140 160 Station (ft) 72- 68 66 64- 58 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 5051 Alternative 1 — .06— —»| Legend WS 100-year Floodpl Ground •Bank Sta 0 20 40 60 80 100 120 140 160 180 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4782 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta 20 40 60 80 Station (ft) 100 120 140 .2 ro .SBLU Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4709 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta 55 100 Station (ft) 200 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4617 Alternative 1 72 70-- 68 66 64- 62- 60- 58 56- 54- -.06- Legend WS 100-year Floodpl Ground •Bank Sta 50 100 Station (ft) 150 200 LU LU Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4665 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta 50 100 150 Station (ft) 200 250 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4550 Alternative 1 Legend WS 100-year Floodpl • Ground •Bank Sta 50 100 Station (ft) 150 200 o>j) LU Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4523 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta 50 100 Station (ft) 150 200 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4290 Alternative 1 66-Legend WS 100-year Floodpl Ground •Bank Sta .3?LU 50 100 150 Station (ft) 200 250 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4397 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta 50 100 150 200 250 Station (ft) 300 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 4244 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta 50 100 150 Station (ft) 200 250 •sro Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3953 Alternative 1 Legend WS100-year Floodpl Ground •Bank Sta 100 Station (ft) 150 200 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3756 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta 48^ 50 100 150 Station (ft) 200 250 I I _ LU Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3877 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta 50 100 150 Station (ft) 200 250 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3621 Alternative 1 62 Legend WS 100-year Floodpl Ground •Bank Sta 50 100 Station (ft) 150 200 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 S.5?LU I RS = 3583 Alternative 1 -.06 50) 0 20 40 60 80 100 120 140 160 180 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3291 Alternative 1 60 Legend WS 100-year Floodpl Ground •Bank Sta 46 50 100 150 Station (ft) 200 250 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3374 Alternative 1 Legend WS 100-year Floodpl Ground •Bank Sta 48 0 20 40 60 80 100 120 140 160 180 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3236 Alternative 1 60 Legend WS 100-year Floodpl Ground •Bank Sta 50 100 150 Station (ft) 200 250 •9 LU Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3188 Alternative 1 Legend WS 100-year Floodpl • Ground •Bank Sta 48 46 50 100 150 Station (ft) 200 250 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3088 Alternative 1 60 58 56 54 52- 50 48 464 44 -.06 — Legend WS 100-year Floodpl Ground •Bank Sta 0 20 40 60 80 100 120 140 160 180 Station (ft) uu I Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3148 Alternative 1 60- 464 Legend WS 100-year Floodpl Ground •Bank Sta 100 Station (ft) 150 200 Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 3024 Alternative 1 - downstream limit Legend WS 100-year Floodpl Ground •Bank Sta 0 20 40 60 80 100 120 140 160 180 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 300.50 Rcho Carlsbad Drive U/S Face - Pr 80' Bridge b/: DO g "to I 52- UJ 4o 46- < eo^ Eft Elevation (ft)n 01 c3 N> 4AC AAJ( ^^\^ D > ^^_^S T ^~* : Legend WS 100-year Floodpl Ground Ineff Bank Sta ) 100 200 300 400 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 300.30 BR Culvert #1 (3 12' x 1 1' Boxes) ^^* 0 100 ~^^ ^ <r^ ^ Legend WS 100-year Floodpl Ground •Bank Sta 200 300 400 Station (ft) V£. 58 g c «4 QJ CA 48- ( 60 •> 58- £ c 50- 48- Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 300.30 BR Culvert #1 (3 12' x 11' Boxes) < .03o ^ ^^ k ^ T .uo ~J L_>r^U"Legend WS 100-year Floodpl Ground Ineff Bank Sta ) 100 200 300 400 Station (ft) Agua Hedionda Creek - Alternative 1_RCD 1/22/2009 RS = 300.12 Rcho Carlsbad Drive D/S Face - Pr 80' Bridge ^^\ ^n 0 100 r^ Legend WS 100-year Floodpl Ground Bank Sta 200 300 400 Station (ft) Earthwork Sections 65 - 60 0 55 " 0) UJ 50 1 45 40 - ()50 Ag K U )0 a Heid E = it XI | 1! >n 3ti >0 d ng a C S re V 2 a ek Alte n io •=; n rn — 5 at =^ 5C ve p*: 2. ti 1 -A >o o I n 3()0 3( .£ )0 3,JO 4()0 65 -Elevationgag45 - 40 ~ Agua Hedionda Creek - Section 3024 • — — ^, \ ) 20 -•—Existing • Alternative 1 _,._ \\ \s xJ X S ,s 2 I> i —f H/ -' , 40 60 80 100 120 140 160 180 Station Agua Hedionda Creek - Section 3088 60 -levation3 Ol45 - 40 - \ \ -^-Existing -^Alternative 1 s \ S \ ^^S, / £ / /:/ i? — // w /^= 0 20 40 60 80 100 120 140 160 180 Station 70 -, R^ -Elevation^ 01 O1 O)n o 01 oAgua Hedionda Creek - Section 3148 \ ! : \ 0 20 40 V "s •-Existing -»-Alte ( j 4 / // / f mative 1 s^=-*- 60 80 100 120 140 160 180 200 Station 70 -Elevation*. en ui en 01<ji o en O tnAgua Hedionda Creek - Section 3188 ~1y \ i\ [S ^ >» ) 20 40 60 -»- Existing / 7 > / ' / 7? •—Alternative 80 100 120 Station 1 - - 140 160 == =— — h - 180 200 220 65 i I I , . ! . | I, ^ S "S O 11 55- ; r in V L 50-" Agua Hedionda Creek - Section 3236 " — •— Existir* I"t 1 II / I / i'-'-'l I - tl-t- i 0 20 40 60 80 •j -*— Altemativ( LQ 100 120 140 Station s 1 • / _,^ 160 180 / / 200 220 240 60 g S UJ 50 Agua Hedionda Creek - Section 3291 i,\\v \\\' / 1, s /w\\yV y^' 1 / --J _L _L_.i -•—Existing -"—Proposed \-I-. T \ . ; C -L t / 0 20 40 60 80 100 120 140 160 180 200 220 240 Station Agua Hedionda Creek - Section 3374 65 -, —Elevation5; g a\V\ i V\ \ ;\N^ // / t I -»- Existing I/ / -~ -•— Alternative 1 =' / / / 0 20 40 60 80 100 120 140 160 180 200 Station Ac 65 60 D !\£i\\\\\y. S\v5 ,.ZSIT^ Uc If Hedionda Creek - Section 3583 — * ^~ ^-^*s — Existing * Alternative ~f i A s* s^s * t -" 0 20 40 60 80 100 120 140 160 180 200 Station 60 jj 0 I \_V_ \-3 Agua Hedionda Creek - Section 3621 s, \\; \ \, 1 i —•—Exist! "9 1 ' / ii .. •- 1 ig -• f —*• I i ! Alternative 1 . / /~7/ f T^ 20 40 60 80 100 120 140 160 180 200 220 Station 60 - •"55 50 - 651\ \ \ \\\ \\ y \ Agua Hedionda Creek - Section 3756 i i I —•—Existing • Alternative 1 \ S\ *•^s ' f /// t_ f — - .— |-;3 \ • y \\ \/ / 0 20 40 60 80 100 120 140 160 180 200 220 Station 65 Elevation3 I50 - __• P--1 =— /i t\\1 gua Hedionda Creek - Section 3877ii i i;i i \5 0 20 40 \ ••—Existing k •* rf-* /- / Alternative 1 \ / s . • / • / - p — // 60 80 100 120 140 160 180 200 220 Station 70 - 65 c 60 - UJ 55 50 - 45 Agua Hedionda Creek - Section 3953 ^-^ \ V\\\\_5A \^ -»- Existing ••••• Alternative 1 \ '. ^\\. ^ / / / / / I / / *•=^- / •" / — ) 20 40 60 80 100 120 140 160 180 200 Station Agua Hedionda Creek - Section 4244 70 , , , — i — n n 65 - 5a JO 60iui 55 - 50 - -«-£»: \\\ \ iting -*- Alternative 1 I \ \s N''^^ 2 i i / , 7 — •t-*- / — '' ) 20 40 60 80 100 120 140 160 180 200 220 Station 65 - §vn 60 1UJ 50 ( \ \s \ Ag X,"\ ua Hedionda Creek - Section \^ -•-Existing \ V\ 1^v ) 20 40 60 80 / / 1 -«-AKei Hr, \~' ' \ . 49Qn . - / / _ ' / 7 — - 100 120 140 160 180 200 220 240 Station 7f1 -Elevationji 01 en at3 m o 01| |Agua Hedionda Creek - Section 4: -•-Existing * Alternative 1 S 5 , -,, \\\\ tUt-IE___ .3T::F 0 20 40 --J ^ry\t_ j i// - i„•*=* • • — t — \ \ _» S, I97" . /' :— — / / //7 / £ 60 80 100 120 140 160 180 200 220 240 260 Ctatinn c 65^ UJ 60- 55 - 50 - -•— E i xi sting I |LA * . /\gua Hedionda Creek - Section 45 -•— Alternative 1 -- I \ \\ sS,S / v~ r 1 j 1 / / ^*~z_r \ \ \ . li ^ — 7 23 ~ / / =rz/_ / ) 20 40 60 80 100 120 140 160 180 200 Station 75 - 70 - C 65 - I W 60 55 Agua Hedionda Creek - Section 4550 -•—Existing V \ \ J ~ \V) Alternative 1 \ \N,^,/ / / 1 ^^f71 1i ^ ^ «£ / / '/ 0 20 40 60 80 100 120 140 160 180 200 Station 75 - 70 roui 60 55 50 Agua Hedionda Creek - Section 4617 \ -•—Existing » Alternative 1 ^\j i~t\ i 1 11 i rj1I \\ ^r f^ / /• // 0 20 40 60 80 100 120 140 160 180 200 Station Elevation5 360 Agua Hedionda Creek - Section 4665 -•-Existing -•- V Alternative 1 \\\\\\\l\\ \ I\ I,/I 1 1 1 f 0 20 40 60 80 100 120 140 160 180 200 220 Station 85 Elevationn & -* -i c3 Ul O U155 -M L 0 Agua Hedionda Creek - Section 4709 -»- Existing -—Alternative 1 20 40 ^ \\ I3 5 60 80 / // / /f -*- 100 Station /,x-*~ — .X px^- — / 120 140 ^// / . / 160 - / 180 200 100 - 95 - 90 85 - O 80 $ 75 UJ 70 - 65 - 60 Agua Hedionda Creek - Section 4782 -•— Existing -*-• Alternative 1 55 J 1 0 t-v -~H— 20 ^ i 40 ^-•*^- 60 ^4/ / 2! / 80 100 Station sf S" / •S" ' / / / / 120 140 160 180 Agua Hedionda Creek - Section 4939 20 40 60 80 100 120 140 160 Agua Hedionda Creek - Section 5051 7C Elevation501 ^i01 0- \\ -»— Existing « Alternative 1 i\ S\ \ \ \ -^-- / / / / A , ^ • / / / ^ / —f— 0 20 40 60 80 100 120 140 160 180 Station 70 C 'S 65 60 - -•- Existing \\ \\\\\ ,\•^^•^ Agua Hediondi Alternative 1 ^A / I f / /I / / f i Creek - Section 5069 ——=—-h— 0 20 40 60 80 100 120 140 160 180 200 Station ElevationSO> ai -4o 01 o c_ \ - Agua Hedionda Creek - Section 5106 -•—Existing -•— Alternative ^\N \ \ \ \—-« - 1 \\ \ \ \ \ ; / 2 =•*=^f 0 20 40 60 80 100 120 140 160 180 Station Elevationjt O) at -J -*jJi o 01 o uiS^ \ ^«\ A. \ ^gua Hedionda Crei -•- Existing » Alternative 1 \s \\s\s\ V -«r"' S // / i/ y / ^k * Section 5158 f~^_ / ^ /'\ // \ / 0 20 40 60 80 100 120 140 Station 85 Agua Hedionda Creek - Section 5188 80 • 75 JO 70 - UJ 65 60 =r , -<j > ^s s s I -•—Existing --«-•• Alternative 1 9 / f/ / / S -•—— ;— =^=~- 0 20 40 60 80 100 120 140 160 Station APPENDIX III: MAPS HEC/RA^ SECTIO \ \k •RvSUR VAttQN (JAN 2009)" Lyle Engineering, Inc. | Agua Hedionda Creek Job # 08-29 | HEC-RAS Workmap Existing Conditions Sheet 1 of 2 | 01/29/2009 SECTION FLOODPLAIN 100-YR WATER SURFACE ELEVATION Lyle Engineering, Inc. | Agua Hedionda Creek Job #08-29 HEC-RAS Workmap Existing Conditions Sheet 2 of 2 | 01/29/2009 * Lyle Engineering, Inc. | Agua Hedionda Creek Job # 08-29 Alternative 1 - HEC-RAS Work Map | Sheet 1 of 1 | 01/29/2009 Iciclwig Design Group, Inc L-1097 1/29/09 PROPOSED CREEK BUDGET/ESTIMATE Goal • Design and construct an enhanced Agua Hedionda Creek between Rancho Carlsbad Drive and College Blvd. that will convey the 100 year flows with no overbank spilling. Design to maintain existing creek and not an impact existing Sycamore trees (90 plus) or existing Riparian vegetation. Create an enhanced creek with varying channel bank slopes that range from 2 to 1 to 4 to 1 and incorporate a meandering creek with 5 islands. All but 0.05 acres of existing creek will be maintained (a short stretch of creek needs to be moved to protect the existing adjacent City outfall sewer line.) New creek bed to be created is 3.3 acres while maintaining the existing creek (0.5 ± acres). 3.0 acres of new creek side slopes will be created with the 2 to 1 to 4 to 1 slope ratio. The existing bridge on Rancho Carlsbad Drive is undersized and 100 year flows go over the top with potential to scour at the bridge abutments. This overtopping creates a significant backwater upstream about 800 feet. A new bridge is required to eliminate the significant backwater and carry flows under the bridge. A new bridge will be a clear span bridge designed to meet the existing downstream channel width of 60 feet. Costs • Channel grading (100,000 cy) @ $10 = $1,000,000 • New Bridge (46' x 108' = 4,968 sq. ft. X $230) $1,150,000 • Planting - slopes and wetlands (design, install and 5 year maintenance and monitoring) $ 400.500 Total Cost $2,550,500* 2234 Faraday flvenue 4 Carlsbad, California 92008 (760) 438-3182 4 FfiX (760) 438-0173 f €mail ldg@dujilsoneng.com Proposed Creek Budget/Estimate January 29, 2009 Page 2 *Cost Do Not Include • Final channel design and bridge design • Soils and structural engineering • Demolition • Reconstruction of the golf course and cart bridges • Permits and agency fees • Land cost (golf course) • Development costs for equestrian parcel or Sunny Creek Road access. • Verification of existing wetlands - wetlands impacts and area available for wetlands credit sales. *Notes 1. Current wetland creation credits sell for $300,000 per acre. This project has the potential to sell credits to the City of Carlsbad for wetland impacts from City dredging within Rancho Carlsbad with 3± acres credits being created or $900,000 of credit sales is possible in the near term. If you decide to proceed I suggest we verify total credit amount and start meeting with the City reference their purchase of the credits. 2. We will have 100,000 cubic yards of material to dispose of from the creek dredging. The equestrian pad from the edge of the creek is 8+ acres. The excess dirt could be used to fill the extension of College Blvd. south of the creek along with filling of the affordable site. The balance of the material could be put on the equestrian center. $10 per cubic yard was used for the excavation which includes trucking the material away. If it is all used on site, the cost will be significantly less, possible half. It would be easy to adjust grades in Dos Colinas to provide for the dirt in College and the affordable site from the creek dredging. 2234 Faraday flvenue * Carlsbad, California 92008 (760) 438-3182 4 FflX (760) 438-0173 4 €mail Id9@duuilsoneng.com