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HomeMy WebLinkAbout19961007 STORMWATER CALCULATIONS y PROFESSIONAL ENGINEERS AND LAND SURVEYORS 160 SUMMER STREET HAVERHILL, MASSACHUSE17S 01830 (508)373-0310 FAX: (508)372.3960 August 28, 1996 Mr. John Chessie � o i , Coler & Colantonio 101 Accord Park Drive, Suite One u , trs Norwell, Ma 02061-1685 Dear Mr Chessie: "" .. j�'`, ;t i Attached is a plan for a driveway for Michael Rullo at 1750 Great Pond Road, North Andover. The owner has filed for a special permit for construction in the water shed. Also j attached are drainage calculations and calculations for sizing the infiltration system that is proposed. The calculations show that the system will cause a minor increase in peak flow. The increase is minimal because the driveway construction causes a lengthening of the flow path and thus increasing the time of concentration. The design of the infiltration trenches is based upon discharge to the subsoil which has a permeability of 3 in/hr ( .00069 Ft/sec) according to the SCS . The peak increase in the 100 year storm is .84 cfs . Using D'Arcys Law and an assumed hydraulic gradient of 1 ft/ft the infiltration area can be sized. Q = kiA .84cfs = ( . 0069 Ft/sec) (1) (A) 1217 ft2 = A Using a 4 foot wide trench with a 1.5 foot sidewall we obtain a length of 175 feet . Three infiltration trenches are shown on the plan with a total length of 175 feet . V r r ours, Ph 'p . Christiansen PGC;ac cc K Colwell i "'ORKSHEET RUNOFF CURVE NUMBER AND RUNOFF PROJECT: GREAT POND RD CONDITION : EXISTING DRAINAGE AREA: 1 SOIL TYPE H.S.GROUP SnIL COVER DESCRIPTION CN AREA PRODUCT ACRES CN X AREA PAXTON C WOODS 70 2.15 150.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 TOTALS 2.15 150.50 CN = PRODUCT/AREA= 70.0 2 RUNOFF RUNOFF, Q = (P-0.2S)2/(P+0.8S) WHERE: P = 24 HOUR RAINFALL IN INCHES S= (1000/CN) - 10 = 4.29 STORM 1 STORM 2 STORM 3 FREQUENCY EARS 2 10 100 24 HOUR RAINFALL, P (INCHES 3.1 4.5 6.4 RUNOFF, Q INCHES 0.77 1.67 3.13 FILE NAME R-2 i R-10 R-100 j 3 TIME OF CONCENTRATION TIME OF CONCENTRATION, Tc= L/0.6 WHERE: L = LAG TIME = LFP".8 x (S+1)".7/(1900 x Y^.5) WHERE: LFP = LONGEST FLOW PATH THROUGH DRAINAGE AREA= 461 FEET Y= AVERAGE SLOPE ALONG LONGEST FLOW PATH = 18.0 % L= 0.05 HOURS L= 3.2 MINUTES Tc= 5.4 MINUTES WORKSHEET: RUNOFF CURVE F' ''hRFR AND RUNOFF PROJECT: GREAT POND RD CONDITION: PROPOSED DRAINAGE AREA: 1 1 RUNOFF CURVE NUMSER PRODUCT 7AXTON OV A9CRRFE�S CN X AREA MCLAEWN DS 70 1.23 86.10 74 0.45 33.30 PAXTON C IDRIVE 98 0.22 21.07 PAXTON G ISHOULDER 87 0.15 12.70 PAXTON C BUILDING AND TURNAROUND 98 0.10 0.00 0.00 0.00 0.00 TOTALS 2.14 162.97 ON = PRODUCT/AREA= 76.1 2 RUNOFF RUNOFF, Q = (P-0.2S)2/(P+0.8S) WHERE: P = 24 HOUR RAINFALL IN INCHES S = (1000/CN) - 10 = 3.14 S O 1 STORM 2 S O 3 ERUNOFF,UENCY EARS 2 10 100 OUR RAINFALL, P INCHES 3.1 4.5 6.4 Q INCHES 1.09 2.14 3.74 NAME R-2 R-10 R-100 3 TIME OF CONCENTRATION TIME OF CONCENTRATION, Tc= L10.6 WHERE: L = LAG TIME = LFP^.8 x(S+1)^.7/(1900 x Y^.5) WHERE: LFP = LONGEST FLOW PATH THROUGH DRAINAGE AREA = 870 FEET Y = AVERAGE SLOPE ALONG LONGEST FLOW PATH = 9.5% L= 0.10 HOURS L= 6.2 MINUTES Tc= 10.4 MINUTES CLIENT - RULLO DATE - 8/27/96 CONDITION - EXIST FILE NAME - E-2 PERIOD STORM - 2 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 . 00 0 . 03 12 . 00 1.71 9 . 10 0 . 08 12 .10 0 .47 9 .20 0 . 08 12 .20 0 .31 9 .30 0 . 08 12 .30 0 .16 9 .40 0 . 08 12 .40 0 .16 9 .50 0 . 08 12 .50 0 . 16 9 . 60 0 . 08 12 .60 0 .16 9 . 70 0 . 08 12 .70 0 . 16 9 . 80 0 . 08 12 . 80 0 . 16 9 . 90 0 . 08 12 . 90 0 .16 10 . 00 0 . 08 13 . 00 0 . 16 10 . 10 0 . 08 13 . 10 0 . 08 10 .20 0 . 08 13 .20 0 . 08 10 .30 0 . 08 13 .30 0 . 08 10 .40 0 . 08 13 .40 0 . 08 10 . 50 0 . 08 13 .50 0 . 08 10 . 60 0 . 08 13 . 60 0 . 08 10 . 70 0 . 08 13 . 70 0 . 08 10 . 80 0 . 08 13 . 80 0 . 08 10 . 90 0 . 08 13 . 90 0 . 08 11. 00 0 . 08 14 . 00 0 . 08 11 . 10 0 . 16 14 . 10 0 . 00 11.20 0 .16 14 .20 0 . 00 11. 30 0 . 16 14 . 30 0 . 00 11.40 0 . 16 14 .40 0 . 00 11.50 0 . 23 14 .50 0 . 00 11 . 60 0 .39 14 . 60 0 . 00 11 . 70 0 . 85 14 . 70 0 . 00 11. 80 1. 01 14 . 80 0 . 00 11. 90 2 . 02 14 . 90 0 . 00 DIRECT RUNOFF - .77 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = 2 .15 CLIENT - RULLO DATE - 8/27/96 CONDITION - EXIST FILE NAME - E-10 PERIOD STORM - 10 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 . 00 0 . 07 12 . 00 3 . 70 9 . 10 0 . 17 12 . 10 1. 01 9 .20 0 . 17 12 . 20 0 . 67 9 . 30 0 . 17 12 .30 0 . 34 9 .40 0 .17 12 . 40 0 .34 9 . 50 0 . 17 12 . 50 0 . 34 9 . 60 0 . 17 12 . 60 0 .34 9 . 70 0 .17 12 . 70 0 . 34 9 . 80 0 . 17 12 . 80 0 . 34 9 . 90 0 . 17 12 . 90 0 .34 10 . 00 0 . 17 13 . 00 0 .34 10 . 10 0 . 17 13 . 10 0 . 17 10 .20 0 . 17 13 . 20 0 . 17 10 .30 0 . 17 13 . 30 0 . 17 10 .40 0 . 17 13 . 40 0 . 17 10 .50 0 . 17 13 . 50 0 . 17 10 . 60 0 . 17 13 . 60 0 . 17 10 .70 0 . 17 13 . 70 0 . 17 10 .80 0 .17 13 . 80 0 .17 10 . 90 0 . 17 13 . 90 0 .17 11. 00 0 .17 14 . 00 0 . 17 11. 10 0 .34 14 . 10 0 . 00 11.20 0 .34 14 .20 0 . 00 11 .30 0 .34 14 .30 0 . 00 11 .40 0 .34 14 .40 0 . 00 11 .50 0 .51 14 . 50 0 . 00 11 . 60 0 . 84 14 . 60 0 . 00 11 . 70 1. 85 14 . 70 0 . 00 11 . 80 2 . 19 14 . 80 0 . 00 11 . 90 4 .38 14 . 90 0 . 00 DIRECT RUNOFF - 1.67 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = 2 . 15 CLIENT - RULLO DATE - 8/27/96 CONDITION - EXIST FILE NAME - E-100 PERIOD STORM - 100 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 .00 0 .14 12 . 00 6.94 9 . 10 0 .32 12 . 10 1. 89 9 .20 0 .32 12 . 20 1.26 9 .30 0 . 32 12 .30 0 . 63 9 .40 0 .32 12 .40 0 . 63 9 . 50 0 .32 12 .50 0 . 63 9 .60 0 .32 12 .60 0 .63 9 . 70 0 .32 12 . 70 0 . 63 9 . 80 0 .32 12 . 80 0 . 63 9 . 90 0 . 32 12 . 90 0 . 63 10 . 00 0 .32 13 . 00 0 . 63 10 . 10 0 .32 13 .10 0 .32 10 .20 0 .32 13 .20 0 .32 10 .30 0 .32 13 .30 0 .32 10 .40 0 .32 13 .40 0 .32 10 .50 0 .32 13 .50 0 .32 10 .60 0 .32 13 . 60 0 .32 10 .70 0 .32 13 . 70 0 .32 10 .80 0 .32 13 .80- 0 .32 10 .90 0 .32 13 .90 0 .32 11 . 00 0 .32 14 . 00 0 .32 11. 10 0 . 63 14 . 10 0 . 00 11.20 0 . 63 14 .20 0 . 00 11 .30 0 .63 14 .30 0 . 00 11.40 0 .63 14 .40 0 . 00 11 .50 0 .95 14 .50 0 . 00 11.60 1 .58 14 . 60 0 . 00 11.70 3 .47 14 . 70 0 . 00 11. 80 4 .10 14. 80 0 . 00 11.90 8 .21 14 . 90 0 . 00 DIRECT RUNOFF - 3 .13 INCHES AREA IN ACRES FOR TIME SEGMENT 1 - 2 .15 CLIENT - RULLO DATE - 8/27/96 CONDITION - PROPOSED FILE NAME - P-2 PERIOD STORM - 2 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 . 00 0 . 02 12 . 00 2 . 64 9 . 10 0 .11 12 . 10 1.54 9 . 20 0 . 11 12 . 20 0 .55 9 . 30 0 .11 12 .30 0 .33 9 .40 0 . 11 12 .40 0 .22 9 . 50 0 . 11 12 .50 0 .22 9 .60 0 .11 12 . 60 0 .22 9 .70 0 . 11 12 .70 0 .22 9 . 80 0 . 11 12 . 80 0 .22 9 .90 0 . 11 12 . 90 0 .22 10 . 00 0 .11 13 . 00 0.22 10 .10 0 . 11 13 .10 0 .22 10 .20 0 .11 13 .20 0 .11 10 .30 0 .11 13 .30 0 .11 10 .40 0 . 11 13 .40 0 . 11 10 .50 0 .11 13 .50 0 .11 10 . 60 0 .11 13 . 60 0 .11 10 . 70 0 . 11 13 .70 0 . 11 10 .80 0 . 11 13 .80 0 .11 10 . 90 0 .11 13 .90 0 .11 11 . 00 0 . 11 14 . 00 0 .11 11 . 10 0 .22 14 .10 0 .11 11.20 0 .22 14 .20 0 . 00 11 .30 0 .22 14 .30 0 . 00 11.40 0 .22 14 .40 0 . 00 11 .50 0 .33 14 .50 0 . 00 11 . 60 0 .44 14 . 60 0 : 00 11 .70 0 . 88 14 .70 0 . 00 11. 80 1.32 14 . 80 0 . 00 11 .90 2 . 09 14 .90 0 . 00 DIRECT RUNOFF - 1. 09 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = 1 . 075 AREA IN ACRES FOR TIME SEGMENT 2 = 1 . 075 CLIENT - RULLO DATE - 8/27/96 CONDITION - PROPOSED FILE NAME - P-10 PERIOD STORM - 10 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 . 00 0 . 05 12 . 00 5 .18 9 . 10 0 .22 12 . 10 3 . 02 9 .20 0 .22 12 .20 1 . 08 9 .30 0 .22 12 .30 0 . 65 9 .40 0 .22 12 .40 0 .43 9 .50 0 .22 12 . 50 0 .43 9 .60 0.22 12 . 60 0 .43 9 . 70 0 .22 12 . 70 0 .43 9 . 80 0 .22 12 . 80 0 .43 9 . 90 0 .22 12 . 90 0 .43 10 . 00 0 .22 13 . 00 0 .43 10 . 10 0 .22 13 . 10 0 .43 10 .20 0 .22 13 .20 0 .22 10 .30 0 .22 13 .30 0 .22 10 .40 0 .22 13 .40 0 .22 10 . 50 0 .22 13 .50 0 .22 10 . 60 0 .22 13 . 60 0 .22 10 . 70 0 .22 13 .70 0 .22 10 . 80 0 .22 13 . 80 0 .22 10 .90 0 .22 13 . 90 0 .22 11 . 00 0 .22 14 . 00 0 .22 11 . 10 0 .43 14 . 10 0 .22 11.20 0 .43 14 .20 0 . 00 11 .30 0 .43 14 .30 0 . 00 11 .40 0 .43 14 .40 0 . 00 11 .50 0 . 65 14 . 50 0 . 00 11 . 60 0 .86 14 . 60 0 . 00 11 . 70 1.73 14 . 70 0 . 00 11. 80 2 .59 14 . 80 0 . 00 11 . 90 4 .10 14 . 90 0. 00 DIRECT RUNOFF - 2 .14 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = 1 . 075 AREA IN ACRES FOR TIME SEGMENT 2 = 1. 075 CLIENT - RULLO DATE - 8/27/96 CONDITION - PROPOSED FILE NAME - P-100 PERIOD STORM - 100 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9. 00 0 . 08 12 . 00 9 . 05 9 .10 0 .38 12 .10 5 .28 9 .20 0 .38 12 .20 1 . 89 9 .30 0 .38 12 .30 1 . 13 9 .40 0 .38 12 .40 0 .75 9 .50 0 .38 12 .50 0 .75 9 .60 0 .38 12 .60 0 .75 9 . 70 0 .38 12 .70 0 .75 9 . 80 0 .38 12 . 80 0 .75 9 . 90 0 .38 12 .90 0 . 75 10 . 00 0 .38 13 . 00 0 .75 10 .10 0 .38 13 . 10 0 . 75 10 .20 0 .38 13 .20 0 .38 10 .30 0 .38 13 .30 0 .38 10 .40 0 .38 13 .40 0 .38 10 .50 0 .38 13 .50 0 .38 10 . 60 0 . 38 13 . 60 0 .38 10 .70 0 .38 13 . 70 0 .38 10 . 80 0 .38 13 .80 0 .38 10 . 90 0 .38 13 .90 0 .38 11. 00 0 .38 14 . 00 0 .38 11. 10 0 .75 14 .10 0 .38 11 .20 0 . 75 14 .20 0 . 00 11 .30 0 . 75 14 .30 0 . 00 11.40 0 .75 14 .40 0 . 00 11.50 1.13 14 .50 0 . 00 11 .60 1.51 14 .60 0 . 00 11. 70 3 . 02 14 . 70 0 . 00 11 . 80 4 .53 14 . 80 0 . 00 11. 90 7 . 16 14 .90 0 . 00 DIRECT RUNOFF - 3 .74 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = 1. 075 AREA IN ACRES FOR TIME SEGMENT 2 = 1. 075 �T�� OJ-4T IDAI T E5T D,,4T.A : T_` 4/21/92 DATE 4/21/92 DATE DATE J�iy�9 z \ fiATF 111//N./JY1(. RATE 7lNW.1IN. RATE RATE /1 MIN��wI i �!' r X84 f 7 E TAT 3 vvofj AbA+/l7ox�c—u b'yu,LE it w�►S Gos.rJp/�7'6rr� (�6GiUSF 0 7YFr1e ^STS zL.D I 7-E,5 T PIT- DATA TP— . -1121tV -DAZE LWTE lI-2S' Z 7i7P-� MP 4 DSO/L �901L &050IL ' 1 2Yz -4' { AVDY77LL sAA/DYTlLL IMAVY71LL LOOSE 1DASE LOQSE S4NDY774L SlI Y a4vDY` •6' -/GiG` \ MWACMD TX4 -SIA4 NDY7/LL Q�II'l4CTFD CVO.CAW.. i MP f1. IUD X3.75 193 ^wj!4 EL. mo >85T5 182.34 A?T7LW/ FL. No W2.73 182.34 CALCUL44T/DN5