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Home My WebLink About02-00500168- 00074718AUTUMN CHASE SUBDIVISION 8.35 ACRE TRACT 1. STORM WATER DETENTION BASIN SIZING: Rational Method (Q = CIA) Pre-Development, Ac.: 6.43 1.92 8.35 Area Description (acres) C C(area) Grassland 8.35 0.35 2.92 Post-Development Area Description (acres) C C(area) Landscaping 0.75 0.35 0.26 Impervious Area 7.60 0.90 6.84 8.35 7.10 C(avg) = 7.10 = 8.35 0.85 Frequency Intensity Qpost Vpre Vpost Required (Years) (in/in) (Tc=10 Cpre Cpost Qpre (cfs) (cfs) (cf) (c Storage min) Volume 100 12.6 0.35 0.85 36.82 89.43 33,141 80,486 47,345 50 11.1 0.35 0.85 32.44 78.78 29,196 70,904 41,708 25 9.9 0.35 0.85 28.93 70.27 26,039 63,239 37,199 10 8.6 0.35 0.85 25.13 61.04 22,620 54,935 32,315 5 7.7 0.35 0.85 22.50 54.65 20,253 49,186 28,933 Vol_ (cfl = 1 /3(Aton + Abottom + SORT(Aton x Abottom)) x Depth Atop (sf) Abot. (sf) At x Ab (sf) Depth (ft) Volume (cf) Detention Volume Res B 10913 4760 51945880 4 30,477 Res A 4528 440 1992320 3.5 7,435 Total 37,912 O.K. Rational Method 8.37Rev2 Page 1 of 2 AUTUMN CHASE SUBDIVISION 8.35 ACRE TRACT II. STORM SEWER OUTFALL: 1. ASSUME 30" F.L. IN ON W. SIDE OF CORNELL DRIVE _ 2. FALL UNDER STREET: 60 LF @ 0.5% _ 3. F.L. OF 30" INTO DETENTION BASIN = 4. FALL ACROSS DET. BASIN: 80 LF @ 0.76% = 5. F.L. OF OUTFALL OUT OF DETENTION BASIN = 6. F.L. OF 36" @ CREEK FOR JACKSON RIDGE _ 7. FALL FROM DETION BASIN TO CREEK= 8. DISTANCE FROM DETENTION BASIN TO CREEK = 9. SLOPE FROM DETION BASIN TO CREEK= III. SIZE OF OUTFALL: 1. ASSUME "n" = 0.014 A. 42" diameter @ 0.096% grade = B. 48" diameter @ .05% grade= 2. EQUIVALENT RECTANGLES FOR 29 CFS (QPRE) A. 42" = 9.6 S.F. = 2 FT. x 5 FT. WIDE @ 0.096% B. 48" =12.6 S.F. = 2 FT. x 6.5 FT. WIDE @ 0.05% 290.20 FT. -0.30 FT. 289.90 FT. -0.61 FT. 289.29 FT. 289.00 FT. 0.29 FT. 360 FT. 0.08% C 0.35 FT. 0.18 FT. O.K. USE ~as> Rational Method 8.37Rev2 Page 2 of 2 AUTUMN CHASE SUBDIVISION 8.35 ACRE TRACT WATER AND SANITARY SEWER USEAGES 1. LAND FOR R2 ZONING: R2 = 540ft. x 100ft./43,560ft.2/ac. = 1.24ac. Water Demands: AVER = 1.24ac. x 2,500gpd/ac. = 3,100gpd MAXD = 3,100 x 1.7 = 5,300gpd MAXp = 3,100 x 3.77 = 11,700gpd Sanitary Sewer: AVER = 1.24ac. x 2,000gpd/ac. = 2,500gpd MAXp = 3.0 x 2,500 = 7,500gpd INF = 0.1 x 2,500 = 300gpd Total Peak = 7,800gpd 2. LAND FOR R5 ZONING: R5 = 8.35ac. -(1.24ac. + 0.74ac.) - 0.57ac. (ft. x 60 ft. ROW/ 43,560 ft.2) R5 = 8.35ac. - 1.92ac. - 0.57ac. = 5.86ac. Water Demands: AVER = 5.86ac. x 2,500gpd/ac. = 14,600gpd MAXD = 14,600 x 1.7 = 24,800gpd MAXp = 14,600 x 3.77 = 55,000gpd Sanitary Sewer: AVER = 5.86ac. x 2,000gpd/ac. = 11,600gpd MAXp = 3.0 x 11,600 = 34,800gpd INF = 0.1 X 11,600 = 1,200gpd Total Peak = 36,000gpd 3. TOTALS FOR 8.35ac. Water Demands: AVER = 3,100 + 14,600 = 17,700gpd MAXD = 5,300 + 24,800 = 30,100gpd MAXp = 11,700 + 55,000 = 66,700gpd 6"d @ 2fps = 260,000gpd 66,700gpd water&sewer 1 of 1 i PARKLAND DEDICATION PROJECT REVIEW CHECKLIST Please provide the following information in order for the Parks and Recreation Board to process your request: Minimum Submittal Requirements The proposed street layout of the subdivision; The location of proposed parkland; Delineated floodplain; The location and design of any detention in proposed parkland; and, The location of any greenway that is part of the approved City of College Station Greenway Master Plan on proposed parkland dedication. REQUIREMENT COMPLIANCE SECTION 10-8.1: Land Dedication Single-family Dwelling Units: 0 Multi-family Dwelling Units: Total Land Dedication Requirement: 0.672 Acres (Single-family: 1 acre per 101 DUs; Multi-family: 1 acre per 125 DUs) Proposed Dedication: 0.350 Acres SECTION 10-B.2: Fee in Lieu of Land Park Acquisition Fee: Single-family Fee ($198/dwelling unit): $0 Multi-family Fee ($160/dwelling unit): $6,400 Total Acquisition Fee: $6,400 SECTION 10-B.3: Park Development Fee Park Development Costs: Single-family Fee ($358/dwelling unit): $0 Multi-family Fee ($292/dwelling unit): $11,680 TOTAL PARKLAND DEDICATION FEE REQUIRED Acquisition and Development Fee: Single-family Fee: ($556/dwelling unit): $0 Multi-family Fee ($452/dwelling unit): $18,080 SECTION 10-F: Additional Requirements: Is land in the 100-year floodplain? No Percentage: Acreage in floodplain: 0 Percentage: Acreage in detention: 0.350 Percentage: Acreage in greenways: 0 Percentage: Comments: AUTUMN CHASE SUBDIVISION 8.37 ACRE TRACT WATER AND SANITARY SEWER USEAGES 1. LAND FOR R2 ZONING: R2 = 540ft. x 100ft./43,560ft.2/ac. = 1.24ac. Water Demands: AVER = 1.24ac. x 2,500gpd/ac. = 3,100gpd MAXD = 3,100 x 1.7 = 5,300gpd MAXp = 3,100 x 3.77 = 11,700gpd Sanitary Sewer: AVER = 1.24ac. x 2,000gpd/ac. = 2,500gpd MAXp = 3.0 x 2,500 = 7,500gpd INF = 0.1 x 2,500 = 300gpd Total Peak = 7,800gpd 2. LAND FOR R5 ZONING: R5 = 8.37ac. -(1.24ac. + 0.74ac.) - 0.57ac. (ft. x 60 ft. ROW/ 43,560 ft.2) R5 = 8.37ac. - 1.98ac. - 0.57ac. = 5.82ac. Water Demands: AVER = 5.82ac. x 2,500gpd/ac. = 14,600gpd MAXD = 14,600 x 1.7 = 24,800gpd MAXp = 14,600 x 3.77 = 55,000gpd Sanitary Sewer: AVER = 5.82ac. x 2,000gpd/ac. = 11,600gpd MAXp = 3.0 x 11,600 = 34,800gpd INF = 0.1 X 11,600 = 1,200gpd Total Peak = 36,000gpd 3. TOTALS FOR 8.37ac. Water Demands: AVER = 3,100 + 14,600 = 17,700gpd MAXD = 5,300 + 24,800 = 30,100gpd MAXp = 11,700 + 55,000 = 66,700gpd 6"d @ 2fps = 260,000gpd 66,700gpd . -e water&sewer.xls Page 1 of 1 AUTUMN CHASE SUBDIVISION 8.37 ACRE TRACT 1. STORM WATER DETENTION BASIN SIZING: Rational Method (Q = CIA) Pre-Development, Ac.: 6.43 1.94 8.37 Area Description (acres) C C(area) Grassland 8.37 0.35 2.9295 Post-Development Area Description (acres) C C(area) Landscaping 0.75 0.35 0.2637 Impervious Area 7.62 0.9 6.8550 8.37 7.1187 C(avg) = 7.1187 0.85 8.37 i d Frequency (years) Intensity in/in) ( (Tc=10min) Cpre Cpost Qpre (cfs) Qpost (cfs) Vpre (c~ Vpost (cfl re Requ Storage Volume 100 12.6 0.35 0.85 36.91 89.64 33,221 80,678 47,458 808 41 50 11.1 0.35 0.85 32.52 78.97 29,266 71,074 , 25 9.9 0.35 0.85 29.00 70.43 26,102 63,390 37,288 392 32 10 8.6 0.35 0.85 25.19 61.18 22,674 55,066 , 002 29 5 7.7 0.35 0.85 22.56 54.78 20,301 49,303 , Vol. (cf) = 1/3(Atop + Abottom + SQRT(Atop x Abottom)) x Depth Atop (sf) Abot. (sf) At x Ab (sf) Depth (ft) Volume (cf) Detention Volume 13324 6394 85193656 Rational Method 8.37Revl.xls 4 38,559 O.K. Page 1 of 2 AUTUMN CHASE SUBDIVISION 8.37 ACRE TRACT H. STORM SEWER OUTFALL: 1. ASSUME 30" F.L. IN ON W. SIDE OF CORNELL DRIVE = 290.20 FT. 2. FALL UNDER STREET: 60 LF @ 0.5% _ -0.30 FT. 3. F.L. OF 30" INTO DETENTION BASIN = 289.90 FT. 4. FALL ACROSS DET. BASIN: 80 LF @ 0.76% _ -0.61 FT. 5. F.L. OF OUTFALL OUT OF DETENTION BASIN = 289.29 FT. 6. F.L. OF 36" @ CREEK FOR JACKSON RIDGE = 289.00 FT. 7. FALL FROM DETION BASIN TO CREEK: 0.29 FT. 8. DISTANCE FROM DETENTION BASIN TO CREEK = 360 FT. 9. SLOPE FROM DETION BASIN TO CREEK: 0.08% III. SIZE OF OUTFALL: 1. ASSUME "n" = 0.014 A. 42" diameter @ 0.096% grade = 0.35 FT. B. 48" diameter @.05% grade = 0.18 FT. 2. EQUIVALENT RECTANGLES FOR 29 CFS (QPRE) A. 42" = 9.6 S.F. = 2 FT. x 5 FT. WIDE @ 0.096% B. 48" = 12.6 S.F. = 2 FT. x 6.5 FT. WIDE @ 0.05% USE O.K. °~SPi!®00~•4p 4. x r'°G~4N JR. r.: F~ra_sS..feve• gJ 0- Rational Method 8.37Revl.xls Page 2 of 2