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HomeMy WebLinkAboutStormwater Report - 33 JOHNSON STREET 7/2/1998 CHRISTIANSEN & SERGI, INC. F"'ROFESSIONAL ENGINEERS AND LAND SURVEYORS 160SO111MER uREE'l flAVE& l-Ill..I,, kAASSA(.,'hILJSEI'-['SO1830 6318 (97 3)373-0310 FAX: (M)372, 3960 DRAINAGE ANALYSIS and STORMWATER MANAGEMENT JOSEPH H HERMANN YOUTH CENTER NORTH ANDOVER MA JULY 21998 DRAINAGE ANALYSIS We have performed a drainage analysis to determine the effect the proposed improvements to the North Andover Youth Center will have on the local drainage patterns. We analyzed the site for existing and proposed conditions for the 2 year and the 100 yr storm. The results which appear below show that there isn't any substantial increase in the flow caused by the 100 yr storm and a small increase in the 2 yr storm. STORM FREQUENCY 2yr 100yr EXISTING 5.3CFS 24.40 CFS PROPOSED 5.53CFS 24.90 CFS To mitigate the increase in the 2 yr. storm we have designed a stormwater infiltration system that consists of twenty 500 gallon leach chambers,that have a total capacity of 1350 cubic feet. This is approximately equivalent to the total increase in volume of the 2 year storm. This volume reflects only storage and not any volume lost to infiltration. STORMWATER MANAGEMENT The proposed project is redevelopment of a previously developed site and as such falls under Stormwater Management Standard 7. Oil and gas hoods will be added to the existing catch basins. The new basins will have 4 foot sumps and gas hoods. Water will be infiltrated from the roof of the new building. The use of the hoods, the 4 foot sumps and infiltration are all stormwater management techniques that are practicable to add to the project. WORKSHEET: RUNOFF CURVE NUMBER AND RUNOFF PROJECT: NORTH ANDOVER YOUTH CENTER CONDITION: EXISTING DRAINAGE AREA: E-1 1 RUNOFF CURVE NUMBER SOIL TYPE H.S.GROUP SOIL COVER DESCRIPTION C11 AR PRODUCT ACRES N X AREA SCANTIC C LAWN/OPEN SPACE 79 5.13 405.27 IMPERVIOUS 98 0.32 31.36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 TOTALS 5.45 436.63 CN = PRODUCT/AREA= 80.1 2. RUNOFF RUNOFF, Q= (P-O,2S)2 1(P+0.8S) WHERE: P= 24 HOUR RAINFALL IN INCHES S= (1000/CN) - 10 = 2.48 STORM 1 STORM 2 FREQUENCY EARS 2 100 24 HOUR RAINFALL, P INCHES 2.4 6.4 RUNOFF, Q INCHES 0.83 4.16 FILE NAME E1A-2 E1A-100 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= 900 FEET Y=AVERAGE SLOPE ALONG LONGEST FLOW PATH = 3.0 % L = 0.17 HOURS L= 10.1 MINUTES Tc= 16.8 MINUTES CLIENT - NORTH ANDOVER YOUTH CENTER DATE - 7/5/98 CONDITION - EXISTING FILE NAME - NAE-1 PERIOD STORM - 100 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 . 00 0 . 15 12 . 00 21 .39 9 . 10 0 .42 12 . 10 19 .29 9 .20 0 . 84 12 .20 11 .33 9 .30 0 . 84 12 .30 4 . 61 9 .40 0 . 84 12 .40 2 . 94 9 .50 0 . 84 12 . 50 2 .10 9 . 60 0 . 84 12 . 60 2 . 10 9 . 70 0 . 84 12 . 70 2 . 10 9 . 80 0 . 84 12 . 80 2 . 10 9 .90 0 . 84 12 .90 2 .10 10 . 00 0 . 84 13 . 00 2 .10 10 . 10 0 . 84 13 . 10 2 .10 10 .20 1 . 26 13 .20 1 . 68 10 .30 1 .26 13 .30 1 .26 10 .40 1 .26 13 .40 1 .26 10 .50 1 .26 13 .50 1 .26 10 . 60 1 .26 13 . 60 1 .26 10 .70 1 .26 13 .70 1 .26 10 . 80 1 .26 13 .80 1 .26 10 . 90 1 .26 13 . 90 1 .26 11 .00 1 .26 14 . 00 1 .26 11 .10 1 . 68 14 . 10 0 . 84 11 .20 2 .10 14 .20 0 . 84 11 .30 2 . 10 14 .30 0 .42 11 .40 2 . 10 14 .40 0 .42 11 .50 2 .52 14 . 50 0 .42 11 . 60 3 . 78 14 .60 0 .42 11 . 70 6 . 71 14 . 70 0 .42 11 . 80 10 .49 14 . 80 0 .42 11 . 90 17 . 62 14 . 90 0 .42 DIRECT RUNOFF - 4 . 16 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = 1 . 82 AREA IN ACRES FOR TIME SEGMENT 2 = 1 . 82 AREA IN ACRES FOR TIME SEGMENT 3 = 1 . 82 CLIENT - NORTH ANDOVER YOUTH CENTER DATE - 7/7/98 CONDITION - EXISTING FILE NAME - NAE2-1 PERIOD STORM - 2 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 . 00 0 . 03 12 . 00 4 . 27 9 . 10 0 . 08 12 . 10 3 . 85 9 .20 0 . 17 12 .20 2 .26 9 .30 0 . 17 12 .30 0 . 92 9 .40 0 . 17 12 .40 0 . 59 9 . 50 0 . 17 12 . 50 0 .42 9 . 60 0 . 17 12 .60 0 .42 9 . 70 0 . 17 12 . 70 0 .42 9 . 80 0 . 17 12 . 80 0 .42 9 . 90 0 .17 12 . 90 0 .42 10 . 00 0 .17 13 . 00 0 .42 10 . 10 0 . 17 13 .10 0 .42 10 .20 0 .25 13 .20 0 . 33 10 .30 0 .25 13 .30 0 . 25 10 .40 0 .25 13 .40 0 . 25 10 .50 0 .25 13 .50 0 .25 10 . 60 0 .25 13 . 60 0 . 25 10 . 70 0 .25 13 .70 0 .25 10 . 80 0 .25 13 .80 0 .25 10 .90 0 .25 13 . 90 0 . 25 11 . 00 0 . 25 14 . 00 0 . 25 11 . 10 0 .33 14 .10 0 . 17 11 .20 0 .42 14 .20 0 . 17 11 .30 0 .42 14 .30 0 . 08 11 .40 0 .42 14 .40 0 . 08 11 .50 0 . 50 14 .50 0 . 08 11 . 60 0 . 75 14 . 60 0 . 08 11 .70 1 .34 14 .70 0 . 08 11 . 80 2 . 09 14 . 80 0 . 08 11 . 90 3 .51 14 . 90 0 . 08 DIRECT RUNOFF - . 83 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = 1 . 82 AREA IN ACRES FOR TIME SEGMENT 2 = 1 . 82 AREA IN ACRES FOR TIME SEGMENT 3 = 1 . 82 WORKSHEET: RUNOFF CURVE NUMBER oND RUNOFF PROJECT: NORTH ANDOVER YOUTH CENTER CONDITION: EXISTING DRAINAGE AREA: E-2 1. RUNOFF CURVE NUMBER SOIL TYPE�H.S.GR SOIL COVER DESCRIPTION C�1I � PRODUCT ACRES N X AREA PAXTON C LAWN/OPEN SPACE 79 0.03 2.37 IMPERVIOUS 98 0.43 42.14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 TOTALS 0.46 44.51 CN = PRODUCT/AREA= 96.8 2. RUNOFF RUNOFF, Q = (P-0.2S)2/(P+0.8S) WHERE: P = 24 HOUR RAINFALL IN INCHES S= (1000/CN) - 10= 0.33 S O S O FREQUENCY EARS 2 100 4 HOUR RAINFALL, P INCHES 2.4 6.4 RUNOFF, Q INCHES 2.04 6.02 FILE NAME E1 B-2 E1 B-100 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= 350 FEET Y=AVERAGE SLOPE ALONG LONGEST FLOW PATH = 2.0 % L= 0.05 HOURS L= 3.0 MINUTES Tc= 4.9 MINUTES CLIENT - NORTH ANDOVER YOUTH CENTER DATE - 7/7/98 CONDITION - EXISTING FILE NAME - NAE2-2 PERIOD STORM - 2 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 .00 0 . 02 12 . 00 1 . 03 9 .10 0 . 00 12 . 10 0 .21 9 .20 0 . 00 12 .20 0 .21 9 .30 0 . 00 12 . 30 0 . 00 9 .40 0 .00 12 .40 0 . 00 9 .50 0 . 00 12 .50 0 . 00 9 .60 0 . 00 12 . 60 0 . 00 9 .70 0 . 00 12 . 70 0 . 00 9 .80 0 . 00 12 . 80 0 . 00 9 . 90 0 . 00 12 . 90 0 . 00 10 . 00 0 . 00 13 . 00 0 . 00 10 . 10 0 . 00 13 . 10 0 . 00 10 .20 0 . 00 13 .20 0 . 00 10 .30 0 . 00 13 . 30 0 . 00 10 .40 0 . 00 13 .40 0 . 00 10 .50 0 .00 13 .50 0 . 00 10 .60 0 .00 13 . 60 0 . 00 10 . 70 0 . 00 13 . 70 0 . 00 10 . 80 0 .00 13 . 80 0 . 00 10 .90 0 . 00 13 . 90 0 . 00 11 . 00 0 . 00 14 . 00 0 . 00 11 . 10 0 . 00 14 . 10 0 . 00 11 .20 0 . 00 14 . 20 0 . 00 11 .30 0 . 00 14 . 30 0 . 00 11 .40 0 . 00 14 .40 0 . 00 11 .50 0 .21 14 .50 0 . 00 11 .60 0 .21 14 . 60 0 . 00 11 .70 0 .41 14 . 70 0 . 00 11 . 80 0 . 62 14 . 80 0 . 00 11 . 90 1 .23 14 . 90 0 . 00 DIRECT RUNOFF - 2 . 04 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = .46 CLIENT - NORTH ANDOVER YOUTH CENTER DATE - 7/5/98 CONDITION - EXISTING FILE NAME - NAE-2 PERIOD STORM - 100 YEARS TIME, FLOW, TIME, FLOW, . HOURS CFS HOURS CFS 9 . 00 0 . 06 12 . 00 3 . 03 9 . 10 0 .00 12 . 10 0 .61 9 .20 0 .00 12 . 20 0 . 61 9 . 30 0 . 00 12 . 30 0 .00 9 .40 0 . 00 12 .40 0 . 00 9 .50 0 . 00 12 . 50 0 . 00 9 . 60 0 . 00 12 . 60 0 .00 9 . 70 0 .00 12 . 70 0 . 00 9 . 80 0 . 00 12 . 80 0 .00 9 . 90 0 . 00 12 . 90 0 .00 10 . 00 0 . 00 13 . 00 0 . 00 10 . 10 0 . 00 13 . 10 0 . 00 10 .20 0 . 00 13 . 20 0 .00 10 . 30 0 .00 13 .30 0 . 00 10 .40 0 .00 13 .40 0 . 00 10 .50 0 . 00 13 . 50 0 .00 10 . 60 0 . 00 13 . 60 0 . 00 10 .70 0 .00 13 . 70 0 .00 10 . 80 0 .00 13 . 80 0 .00 10 .90 0 . 00 13 . 90 0 .00 11 .00 0 . 00 14 .00 0 .00 11 . 10 0 . 00 14 . 10 0 . 00 11 .20 0 .00 14 .20 0 . 00 11 .30 0 .00 14 . 30 0 . 00 11 .40 0 .00 14 .40 0 . 00 11 . 50 0 . 61 14 . 50 0 .00 11 . 60 0 . 61 14 . 60 0 .00 11 . 70 1 .21 14 . 70 0 . 00 11 . 80 1 . 82 14 . 80 0 .00 11 . 90 3 . 64 14 . 90 0 . 00 DIRECT RUNOFF - 6 . 02 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = .46 NORTH ANDOVER YOUTH CENTER 7/7/98 d OFFSET IN 0 . 1 HOUR INCREMENTS : 0 . 0 0 . 0 0 . 0 0 . 0 TIME: INPUT FILE NAME: TOTAL NAE2-1 NAE2-2 NAE2T 9 0 .00 0 . 00 0 . 00 0 . 00 0 . 00 9 . 1 0 . 08 0 . 00 0 .00 0 .00 0 . 08 9 . 2 0 .17 0 . 00 0 . 00 0 .00 0 . 17 9 . 3 0 . 17 0 . 00 0 .00 0 . 00 0 . 17 9 .4 0 . 17 0 . 00 0 .00 0 . 00 0 . 17 9 .5 0 . 17 0 . 00 0 . 00 0 . 00 0 . 17 9 . 6 0 .17 0 . 00 0 . 00 0 . 00 0 . 17 9 . 7 0 . 17 0 . 00 0 . 00 0 .00 0 .17 9 . 8 0 . 17 0 . 00 0 . 00 0 . 00 0 . 17 9 . 9 0 .17 0 . 00 0 .00 0 . 00 0 . 17 10 0 .17 0 . 00 0 .00 0 .00 0 . 17 10 .1 0 . 17 0 . 00 0 . 00 0 . 00 0 . 17 10 .2 0 .25 0 . 00 0 . 00 0 . 00 0 .25 10 .3 0 .25 0 . 00 0 . 00 0 .00 0 . 25 10 .4 0 .25 0 . 00 0 . 00 0 .00 0 .25 10 .5 0 .25 0 . 00 0 .00 0 .00 0 .25 10 . 6 0 . 25 0 . 00 0 .00 0 .00 0 .25 10 .7 0 .25 0 . 00 0 . 00 0 . 00 0 .25 10 .8 0 .25 0 . 00 0 .00 0 . 00 0 .25 10 .9 0 .25 0 . 00 0 . 00 0 . 00 0 .25 11 0 .25 0 . 00 0 . 00 0 . 00 0 .25 11 .1 0 .33 0 . 00 0 .00 0 . 00 0 .33 11 .2 0 .42 0 . 00 0 .00 0 .00 0 .42 11 .3 0 .42 0 . 00 0 .00 0 .00 0 .42 11 .4 0 .42 0 . 00 0 .00 0 .00 0 .42 11 .5 0 .50 0 . 21 0 . 00 0 . 00 0 . 71 11 .6 0 .75 0 . 21 0 . 00 0 .00 0 . 96 11 .7 1 .34 0 .41 0 . 00 0 . 00 1 . 75 11 . 8 2 . 09 0 . 62 0 . 00 0 . 00 2 . 71 11 . 9 3 .51 1 . 23 0 . 00 0 . 00 4 . 74 12 4 .27 1 . 03 0 .00 0 .00 5 .30 <- 12 .1 3 .85 0 . 21 0 .00 0 .00 4 . 06 12 .2 2 .26 0 . 21 0 . 00 0 .00 2 .47 12 .3 0 .92 0 . 00 0 . 00 0 .00 0 . 92 12 .4 0 .59 0 . 00 0 .00 0 . 00 0 .59 12 .5 0 .42 0 . 00 0 .00 0 . 00 0 .42 12 . 6 0 .42 0 . 00 0 .00 0 . 00 0 .42 12 . 7 0 .42 0 . 00 0 .00 0 . 00 0 .42 12 .8 0 .42 0 . 00 0 .00 0 .00 0 .42 12 . 9 0 .42 0 . 00 0 . 00 0 .00 0 .42 13 0 .42 0 . 00 0 .00 0 .00 0 .42 13 .1 0 .42 0 . 00 0 .00 0 . 00 0 .42 13 .2 0 .33 0 .00 0 .00 0 .00 0 .33 13 .3 0 .25 0 . 00 0 .00 0 .00 0 .25 13 .4 0 .25 0 . 00 0 .00 0 . 00 0 .25 13 . 5 0 .25 0 . 00 0 . 00 0 .00 0 .25 13 . 6 0 .25 0 . 0.0 0 . 00 0 .00 0 .25 NORTH ANDOVER YOUTH CENTER 7/5/98 OFFSET IN 0 . 1 HOUR INCREMENTS : 0 . 0 0 . 0 0 . 0 0 . 0 TIME : INPUT FILE NAME : TOTAL NAE-1 NAE-2 NAET 9 0 . 00 0 . 00 0 . 00 0 . 00 0 . 00 9 .1 0 .42 0 . 00 0 . 00 0 . 00 0 .42 9 .2 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 .3 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 .4 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 .5 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 . 6 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 .7 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 . 8 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 . 9 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 10 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 10 . 1 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 10 .2 1 .26 0 . 00 0 . 00 0 . 00 1 .26 10 .3 1 .26 0 . 00 0 . 00 0 . 00 1 .26 10 .4 1 .26 0 . 00 0 . 00 0 . 00 1 .26 10 . 5 1 .26 0 . 00 0 . 00 0 . 00 1 . 26 10 . 6 1.26 0 . 00 0 . 00 0 . 00 1 .26 10 . 7 1 .26 0 . 00 0 . 00 0 . 00 1 .26 10 . 8 1 .26 0 . 00 0 . 00 0 . 00 1 . 26 10 .9 1 .26 0 . 00 0 . 00 0 . 00 1 .26 11 1 .26 0 . 00 0 . 00 0 . 00 .1 .26 11 . 1 1 . 68 0 . 00 0 . 00 0 . 00 1 . 68 11 .2 2 .10 0 . 00 0 . 00 0 . 00 2 . 10 11 . 3 2 . 10 0 . 00 0 . 00 0 . 00 2 . 10 11 . 4 2 . 10 0 . 00 0 . 00 0 . 00 2 . 10 11 . 5 2 .52 0 . 61 0 . 00 0 . 00 3 . 13 11 . 6 3 . 78 0 . 61 0 . 00 0 . 00 4 . 39 11 . 7 6 .71 1 .21 0 . 00 0 . 00 7 . 92 11 . 8 10 .49 1 . 82 0 . 00 0 . 00 12 . 30 11 . 9 17 . 62 3 . 64 0 . 00 0 . 00 21 . 20 12 21.39 3 . 03 0 . 00 0 . 00 24 .40 - 12 . 1 19 .29 0 . 61 0 . 00 0 . 00 19 . 90 12 . 2 11 .33 0 . 61 0 . 00 0 . 00 11 . 90 12 .3 4 . 61 0 . 00 0 . 00 0 . 00 4 . 61 12 .4 2 . 94 0 . 00 0 . 00 0 . 00 2 . 94 12 . 5 2 .10 0 . 00 0 . 00 0 . 00 2 . 10 12 . 6 2 .10 0 . 00 0 . 00 0 . 00 2 . 10 12 . 7 2 . 10 0 . 00 0 . 00 0 . 00 2 .10 12 . 8 2 .10 0 .00 0 . 00 0 . 00 2 .10 12 . 9 2 . 10 0 . 00 0 . 00 0 . 00 2 . 10 13 2 . 10 0 . 00 0 . 00 0 . 00 2 . 10 13 .1 2 . 10 0 . 00 0 . 00 0 . 00 2 . 10 13 .2 1. 68 0 . 00 0 . 00 0 . 00 1. 68 13 . 3 1.26 0 . 00 0 . 00 0 . 00 1 .26 13 .4 1.26 0 . 00 0 . 00 0 . 00 1 .26 13 .5 1.26 0 . 00 0 . 00 0 .00 1 .26 13 . 6 1 .26 0 . 00 0 . 00 0 . 00 1 .26 13 . 7 1 . 26 0 . 00 0 . 00 0 .00 1 .26 RORU EE RUNOFF CURVE R �MRFR AND RUNOFF PROJECT: NORTH ANDOVER YOUTH CENTER CONDITION: PROPOSED DRAINAGE AREA: P-1 1. RUNOFF RVE NUMBER SOIL TYPE !-LS.GROUP SOIL COVER QESCRIPTION CL ACRE) N X AREA PAXTON C LAWN/OPEN 79 4.69 370.51 IMPERVIOUS 98 0.38 37.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 TOTALS 5.07 407.75 CN = PRODUCT/AREA= 80.4 RUNOFF RUNOFF, Q = (P-0.2S)2/(P+0.8S) WHERE: P= 24 HOUR RAINFALL IN INCHES S = (1000/CN) - 10 = 2.43 "PIA-2PlA-100 FREQUENCY EARS 24 HOUR RAINFALL, P INCHES RUNOFF, Q INCHES FILE NAME CONCENTBATJ9N 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 = 900 FEET Y=AVERAGE SLOPE ALONG LONGEST FLOW PATH = 3.0 % L= 0.17 HOURS L= 10.0 MINUTES Tc= 16.6 MINUTES CLIENT - NORTH ANDOVER YOUTH CENTER DATE - 7/5/98 CONDITION - PROPOSED FILE NAME - NAP-1 PERIOD STORM - 100 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 . 00 0 . 14 12 . 00 19 . 86 9 .10 0 .42 12 . 10 17 . 74 9 .20 0 .84 12 .20 10 . 56 9 .30 0 . 84 12 .30 4 .22 9 .40 0 . 84 12 .40 2 .96 9 .50 0 .84 12 .50 2 . 11 9 .60 0 .84 12 . 60 2 . 11 9 .70 0 . 84 12 .70 2 .11 9 . 80 0 . 84 12 . 80 2 . 11 9 . 90 0 .84 12 . 90 2 . 11 10 .00 0 .84 13 . 00 2 . 11 10 .10 0 . 84 13 .10 1 . 69 10 .20 0 . 84 13 .20 1 .27 10 .30 1 .27 13 .30 1 .27 10 .40 1 .27 13 .40 1 .27 10 .50 1 .27 13 .50 1 .27 10 .60 1 .27 13 . 60 1 .27 10 .70 1 .27 13 . 70 1 .27 10 . 80 1 .27 13 . 80 1 .27 10 .90 1 .27 13 .90 1 .27 11 .00 1 .27 14 .00 1 .27 11 .10 1 .27 14 .10 0 .84 11 .20 1 .69 14 .20 0 . 84 11 .30 2 .11 14 .30 0 .42 11 .40 2 .11 14 .40 0 .42 11 .50 2 .53 14 .50 0 .42 11 . 60 3 .38 14 . 60 0 .42 11 .70 6 .34 14 . 70 0 .42 11 . 80 9 .72 14 .80 0 .42 11 .90 16 .48 14 . 90 0 .42 DIRECT RUNOFF - 4 . 19 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = 1 . 69 AREA IN ACRES FOR TIME SEGMENT 2 = 1 . 69 AREA IN ACRES FOR TIME SEGMENT 3 = 1 . 69 CLIENT - NORTH ANDOVER YOUTH CENTER DATE - 7/7/98 CONDITION - PROPOSED FILE NAME - NAP2-1 PERIOD STORM - 2 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 .00 0 . 03 12 . 00 3 .98 9 .10 0 . 08 12 . 10 3 .56 9 .20 0 . 17 12 .20 2 . 12 9 . 30 0 .17 12 .30 0 . 85 9 .40 0 .17 12 .40 0 .59 9 .50 0 .17 12 . 50 0 .42 9 . 60 0 . 17 12 . 60 0 .42 9 . 70 0 . 17 12 . 70 0 .42 9 . 80 0 . 17 12 . 80 0 .42 9 .90 0 . 17 12 . 90 0 .42 10 .00 0 .17 13 . 00 0 .42 10 .10 0 . 17 13 .10 0 .34 10 .20 0 .17 13 .20 0 .25 10 .30 0 .25 13 .30 0 .25 10 .40 0 .25 13 .40 0 .25 10 .50 0 .25 13 .50 0 .25 10 .60 0 .25 13 . 60 0 .25 10 .70 0 .25 13 . 70 0 .25 10 . 80 0 .25 13 . 80 0 .25 10 . 90 0 .25 13 . 90 0 .25 11 . 00 0 .25 14 . 00 0 .25 11 .10 0 .25 14 . 10 0 . 17 11 .20 0 .34 14 .20 0 . 17 11 . 30 0 .42 14 .30 0 . 08 11 .40 0 .42 14 .40 0 . 08 11 .50 0 .51 14 .50 0 . 08 11 . 60 0 . 68 14 . 60 0 . 08 11 .70 1 . 27 14 . 70 0 .08 11 . 80 1 . 95 14 . 80 0 . 08 11 . 90 3 .30 14 . 90 0 . 08 DIRECT RUNOFF - . 84 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = 1 . 69 AREA IN ACRES FOR TIME SEGMENT 2 = 1 . 69 AREA IN ACRES FOR TIME SEGMENT 3 = 1 . 69 WORKSHEET: RUNOFF CURVE NUMBER AND RUNOFF PROJECT: NORTH ANDOVER YOUTH CENTER CONDITION: PROPOSED DRAINAGE AREA: P-2 1. R NOFF CURVE NUMBER 7SCANTIC H.S.GROUP SOIL COVER DESCRIPTION ACRE)TXAREA C LAWN/OP EN 79 0.23 IMPERVIOUS 98 0.70 0.00 0.00 0.00 0.00 EE 0.00 0.00 TOTALS 0.93 86.77 CN = PRODUCT/AREA= 93.3 2 RUNOFF RUNOFF, Q = (P-0.2S)2/(P+0.8S) WHERE: P = 24 HOUR RAINFALL IN INCHES S = (1000/CN) - 10 = 0.72 STORM 1 STORM FREQUENCY EARS 2 100 24 HOUR RAINFALL, P INCHES 2.4 6.4 RUNOFF, Q INCHES 1.71 5.61 FILE NAME P1 B-2 P1 B-100 I 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 = 350 FEET Y= AVERAGE SLOPE ALONG LONGEST FLOW PATH = 2.0 L= 0.06 HOURS L= 3.5 MINUTES Tc= 5.9 MINUTES CLIENT - NORTH ANDOVER YOUTH CENTER DATE - 7/7/98 CONDITION - PROPOSED FILE NAME - NAP2-2 PERIOD STORM - 2 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 . 00 0 . 03 12 . 00 1 .55 9 . 10 0 . 00 12 .10 0 . 52 9 .20 0 . 00 12 . 20 0 . 34 9 .30 0 .00 12 .30 0 . 17 9 .40 0 .00 12 .40 0 . 17 9 .50 0 . 00 12 .50 0 . 17 9 . 60 0 . 00 12 . 60 0 . 17 9 . 70 0 .00 12 .70 0 . 17 9 . 80 0 . 00 12 . 80 0 . 17 9 . 90 0 .00 12 . 90 0 . 17 10 . 00 0 . 00 13 . 00 0 . 17 10 .10 0 .00 13 . 10 0 . 00 10 .20 0 . 00 13 .20 0 . 00 10 .30 0 . 00 13 .30 0 . 00 10 .40 0 . 00 13 .40 0 . 00 10 .50 0 .00 13 .50 0 . 00 10 . 60 0 .00 13 . 60 0 . 00 10 .70 0 . 00 13 . 70 0 . 00 10 . 80 0 . 00 13 . 80 0 . 00 10 .90 0 . 00 13 . 90 0 . 00 11 . 00 0 . 00 14 . 00 0 . 00 11 . 10 0 .17 14 . 10 0 . 00 11 .20 0 .17 14 .20 0 . 00 11 .30 0 . 17 14 .30 0 .00 11 .40 0 . 17 14 .40 0 . 00 11 .50 0 .17 14 .50 0 . 00 11 . 60 0 . 34 14 . 60 0 . 00 11 . 70 0 . 86 14 . 70 0 . 00 11 . 80 1 . 03 14 . 80 0 . 00 11 .90 1 . 90 14 . 90 0 . 00 DIRECT RUNOFF - 1 . 71 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = . 93 CLIENT - NORTH ANDOVER YOUTH CENTER DATE - 7/6/98 CONDITION - PROPOSED FILE NAME - NAP-2 PERIOD STORM - 100 YEARS TIME, FLOW, TIME, FLOW, HOURS CFS HOURS CFS 9 . 00 0 .11 12 . 00 5 . 09 9 . 10 0 .00 12 .10 1 . 70 9 .20 0 .00 12 . 20 1 . 13 9 .30 0 .00 12 . 30 0 . 57 9 .40 0 .00 12 .40 0 . 57 9 . 50 0 .00 12 .50 0 . 57 9 .60 0 .00 12 . 60 0 . 57 9 . 70 0 . 00 12 . 70 0 . 57 9 . 80 0 .00 12 . 80 0 . 57 9 .90 0 .00 12 .90 0 . 57 10 . 00 0 .00 13 . 00 0 . 57 10 .10 0 .00 13 . 10 0 . 00 10 .20 0 .00 13 .20 0 . 00 10 .30 0 .00 13 .30 0 . 00 10 .40 0 . 00 13 .40 0 . 00 10 .50 0 . 00 13 . 50 0 . 00 10 . 60 0 .00 13 . 60 0 . 00 10 .70 0 .00 13 . 70 0 . 00 10 . 80 0 . 00 13 . 80 0 . 00 10 . 90 0 . 00 13 . 90 0 . 00 11 . 00 0 . 00 14 . 00 0 . 00 11 .10 0 .57 14 . 10 0 . 00 11 .20 0 .57 14 .20 0 . 00 11 . 30 0 .57 14 .30 0 . 00 11 .40 0 .57 14 .40 0 . 00 11 .50 0 .57 14 .50 0 . 00 11 . 60 1 .13 14 . 60 0 . 00 11 . 70 2 . 83 14 .70 0 . 00 11 . 80 3 .39 14 . 80 0 . 00 11 . 90 6 .22 14 . 90 0 . 00 DIRECT RUNOFF - 5 . 61 INCHES AREA IN ACRES FOR TIME SEGMENT 1 = . 93 NORTH ANDOVER YOUTH CENTER 7/7/98 OFFSET IN 0 . 1 HOUR INCREMENTS : 0 . 0 0 . 0 0 . 0 0 . 0 TIME : INPUT FILE NAME : TOTAL NAP2-1 NAP2-2 NAP2T 9 0 . 00 0 . 00 0 . 00 0 . 00 0 .00 9 . 1 0 .08 0 . 00 0 . 00 0 . 00 0 . 08 9 . 2 0 . 17 0 . 00 0 . 00 0 . 00 0 .17 9 . 3 0 . 17 0 . 00 0 . 00 0 . 00 0 .17 9 .4 0 . 17 0 . 00 0 . 00 0 . 00 0 .17 9 .5 0 . 17 0 . 00 0 . 00 0 . 00 0 . 17 9 . 6 0 . 17 0 . 00 0 . 00 0 . 00 0 .17 9 . 7 0 . 17 0 . 00 0 . 00 0 . 00 0 .17 9 . 8 0 . 17 0 . 00 0 . 00 0 . 00 0 .17 9 . 9 0 . 17 0 . 00 0 . 00 0 . 00 0 .17 10 0 . 17 0 . 00 0 . 00 0 . 00 0 . 17 10 . 1 0 .17 0 . 00 0 . 00 0 .00 0 .17 10 .2 0 . 17 0 . 00 0 . 00 0 . 00 0 .17 10 . 3 0 .25 0 . 00 0 . 00 0 .00 0 .25 10 .4 0 .25 0 . 00 0 . 00 0 . 00 0 .25 10 . 5 0 .25 0 . 00 0 . 00 0 .00 0 .25 10 . 6 0 .25 0 . 00 0 . 00 0 . 00 0 .25 10 . 7 0 .25 0 . 00 0 . 00 0 . 00 0 .25 10 . 8 0 .25 0 . 00 0 . 00 0 . 00 0 .25 10 . 9 0 .25 0 . 00 0 . 00 0 . 00 0 .25 11 0 .25 0 . 00 0 . 00 0 . 00 0 .25 11 . 1 0 .25 0 . 17 0 . 00 0 . 00 0 .42 11 . 2 0 .34 0 . 17 0 . 00 0 . 00 0 .51 11 . 3 0 .42 0 . 17 0 . 00 0 .00 0 .59 11 .4 0 .42 0 . 17 0 . 00 0 . 00 0 .59 11 . 5 0 .51 0 . 17 0 . 00 0 . 00 0 . 68 11 . 6 0 . 68 0 .34 0 . 00 0 . 00 1 . 02 11 . 7 1 .27 0 . 86 0 . 00 0 . 00 2 .13 11 . 8 1 . 95 1 . 03 0 . 00 0 . 00 2 .98 11 . 9 3 .30 1 . 90 0 . 00 0 . 00 5 .20 12 3 . 98 1 .55 0 . 00 0 . 00 5 .53 •t" 12 .1 3 .56 0 .52 0 . 00 0 . 00 4 . 08 12 .2 2 . 12 0 .34 0 . 00 0 . 00 2 .46 12 .3 0 . 85 0 . 17 0 . 00 0 . 00 1 . 02 12 .4 0 . 59 0 . 17 0 . 00 0 . 00 0 . 76 12 .5 0 .42 0 . 17 0 .00 0 . 00 0 .59 12 . 6 0 .42 0 . 17 0 . 00 0 . 00 0 .59 12 . 7 0 .42 0 .17 0 . 00 0 . 00 0 .59 12 . 8 0 .42 0 .17 0 . 00 0 . 00 0 .59 12 . 9 0 .42 0 . 17 0 . 00 0 . 00 0 .59 13 0 .42 0 .17 0 .00 0 .00 0 .59 13 .1 0 .34 0 . 00 0 . 00 0 . 00 0 .34 13 . 2 0 .25 0 . 00 0 . 00 0 . 00 0 .25 13 .3 0 .25 0 . 00 0 . 00 0 . 00 0 .25 13 .4 0 .25 0 . 0,0 0 . 00 0 . 00 0 .25 13 .5 0 .25 0 . 00 0 . 00 0 . 00 0 .25 NORTH ANDOVER YOUTH CENTER 7/6/98 OFFSET IN 0 . 1 HOUR INCREMENTS : 0 . 0 0 . 0 0 . 0 0 . 0 TIME: INPUT FILE NAME : TOTAL NAP-1 NAP-2 NAPT 9 0 . 00 0 . 00 0 .00 0 . 00 0 . 00 9 . 1 0 .42 0 . 00 0 . 00 0 . 00 0 .42 9 . 2 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 . 3 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 . 4 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 . 5 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 . 6 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 . 7 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 9 . 8 0 . 84 0 . 00 0 .00 0 . 00 0 . 84 9 . 9 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 10 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 10 .1 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 10 .2 0 . 84 0 . 00 0 . 00 0 . 00 0 . 84 10 .3 1 .27 0 . 00 0 . 00 0 . 00 1 .27 10 .4 1 .27 0 . 00 0 .00 0 . 00 1 .27 10 .5 1 .27 0 . 00 0 .00 0 . 00 1 .27 10 . 6 1 .27 0 . 00 0 .00 0 . 00 1 .27 10 .7 1 .27 0 . 00 0 . 00 0 . 00 1 .27 10 .8 1 . 27 0 . 00 0 .00 0 . 00 1 .27 10 .9 1 . 27 0 . 00 0 . 00 0 . 00 1 .27 11 1 .27 0 . 00 0 . 00 0 . 00 1 .27 11 .1 1 .27 0 .57 0 . 00 0 . 00 1 . 84 11 .2 1 . 69 0 .57 0 .00 0 . 00 2 .26 11 .3 2 . 11 0 .57 0 . 00 0 . 00 2 . 68 11 .4 2 . 11 0 . 57 0 .00 0 . 00 2 . 68 11 .5 2 . 53 0 .57 0 . 00 0 . 00 3 .10 11 . 6 3 . 38 1 . 13 0 .00 0 . 00 4 . 51 11 .7 6 .34 2 . 83 0 .00 0 . 00 9 . 17 11 .8 9 . 72 3 .39 0 . 00 0 . 00 13 . 10 11 .9 16 .48 6 .22 0 . 00 0 . 00 22 . 70 12 19 . 86 5 . 09 0 . 00 0 . 00 24 .904- 12 .1 17 . 74 1 . 70 0 . 00 0 . 00 19 .40 12 .2 10 . 56 1 . 13 0 . 00 0 . 00 11 . 60 12 .3 4 .22 0 .57 0 . 00 0 . 00 4 . 79 12 .4 2 . 96 0 . 57 0 . 00 0 . 00 3 . 53 12 .5 2 . 11 0 . 57 0 . 00 0 . 00 2 . 68 12 . 6 2 . 11 0 .57 0 . 00 0 . 00 2 . 68 12 .7 2 . 11 0 . 57 0 . 00 0 . 00 2 . 68 12 . 8 2 . 11 0 .57 0 . 00 0 . 00 2 . 68 12 .9 2 . 11 0 . 57 0 . 00 0 . 00 2 . 68 13 2 . 11 0 . 57 0 .00 0 . 00 2 . 68 13 .1 1 . 69 0 . 00 0 . 00 0 . 00 1 . 69 13 .2 1 .27 0 . 00 0 . 00 0 . 00 1 .27 13 .3 1 .27 0 . 00 0 . 00 0 . 00 1 .27 13 .4 1 .27 0 . 00 0 . 00 0 . 00 1 .27 13 .5 1 .27 0 . 00 0 . 00 0 . 00 1 .27 13 .6 1 . 27 0 . 00 0 .00 0 . 00 1 .27