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TRIP GENERATION ESTIMATE
Prepared by: JRF
Project No.: 03-006
Project Name: Hockanum Townhouses(Gruber)
Project Location: Northampton,MA
Date: June 17, 2003
Reference: Institute of Transportation Engineers, Trip Generation, e Edition, Volume 1 of 3, 1997.
Land Use: Residential Condom inium/Townhouse
Average Vehicle Trip Ends vs: Dwelling Units
Trip
Number of Generation
Dwelling per Dwelling
Time Category Units Unit Total Trip Ends % Entering % Exiting
Weekday 14 5.86 82 50 50
Weekday, Peak 14 0.44 6 17 83
Hr. 7—9 A.M.
Weekday, Peak 14 0.54 8 67 33
Hr. 4—6 P.M.
Saturday 14 5.67 79 50 50
Saturday, Peak Hr. 14 0.47 7 54 46
of Generator
Sunday 14 4.84 68 50 50
L W3W067RlP GENERA770N ESTLNATE.doc
Data for 03006-Post-Construction Page 8
TYPE III 24-HOUR RAINFALL= 6.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
POND 1 SWALE AND DETENTION POND STORAGE
Qin = 8.08 CFS @ 12.02 HRS, VOLUME= .57 AF
Qout= 5.57 CFS @ 12.19 HRS, VOLUME= .51 AF, ATTEN= 310, LAG= 10.4 MIN
Qpri= 5.37 CFS @ 12.19 HRS, VOLUME= .39 AF
Qsec= .21 CFS @ 12 .19 HRS, VOLUME= .12 AF
ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD
(FT) (SF) (CF) (CF) PEAK STORAGE = 8893 CF
110.0 1 0 0 PEAK ELEVATION= 113 .6 FT
110.1 833 42 42 FLOOD ELEVATION= 114.5 FT
111.0 1578 1085 1127 START ELEVATION= 110.0 FT
112.0 2538 2058 3185 SPAN= 10-20 HRS, dt=.1 HRS
113 .0 3668 3103 6288 Tdet= 117 MIN ( .5 AF)
114.0 5021 4345 10632
114.5 5300 2580 13212
# ROUTE INVERT OUTLET DEVICES
1 3 111.5' 4" ORIFICE/GRATE
Q=.6 PI r"2 SQR(2g) SQR(H-r)
2 3 113 .5 ' 24" HORIZONTAL ORIFICE/GRATE
Q=.6 Area SQR(2gH)
3 P 109.4 ' 12" CULVERT
n=.011 L=1' S=.005'/' Ke=.S Cc=.9 Cd=.6
4 S 110.0' EXFILTRATION
V= .002778 FPM over (SURFACE AREA - 1 SF)
Primary Discharge
�-3=Culvert
�--1=Orifice/Grate
I2=Orifice/Grate
Secondary Discharge
-4=Exf iltration
Data for 03006-Post-Construction Page 7
TYPE III 24-HOUR RAINFALL= 6.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
REACH 1 RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110
Qin = .27 CFS @ 12.02 HRS, VOLUME= .02 AF
Qout= .20 CFS @ 12 .17 HRS, VOLUME= .02 AF, ATTEN= 25%, LAG= 8.9 MIN
DEPTH END AREA DISCH
(FT) (SQ-FT) (CFS) 10' x .5' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 '/' PEAK DEPTH= .01 FT
.1 .5 .75 n= .027 PEAK VELOCITY= 1.5 FPS
.1 1.0 2 .38 LENGTH= 298 FT TRAVEL TIME = 3 .4 MIN
.2 1.6 4.70 SLOPE= .04 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2 .3 8 .59
.3 3 .2 15.05
.4 4 .4 24.46
.5 5.6 35.73
REACH 2 12" DIA. PVC ACROSS HOCKANUM ROAD
Qin = 5.37 CFS @ 12.19 HRS, VOLUME= .39 AF
Qout= 5.34 CFS @ 12.20 HRS, VOLUME= .39 AF, ATTEN= 1%, LAG= .2 MIN
DEPTH END AREA DISCH
(FT) (SQ-FT) (CFS) 12" PIPE STOR-IND+TRANS METHOD
0.0 0.0 0.00 PEAK DEPTH= .75 FT
.1 0.0 .12 n= .011 PEAK VELOCITY= 8.6 FPS
.2 .1 .52 LENGTH= 70 FT TRAVEL TIME = .1 MIN
.3 .2 1.17 SLOPE= .02 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.7 .6 4.99
.8 .7 5.82
. 9 .7 6.35
. 9 .8 6.41
1. 0 .8 6 .35
1. 0 .8 5.95
Data for 03006-Post-Construction Page 6
TYPE III 24-HOUR RAINFALL= 6.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
• HYdroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= .27 CFS @ 12 .02 HRS, VOLUME= .02 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 6.40 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37' s=.26 '/'
SUBCATCHMENT 2 AREA 2
PEAK= 7.96 CFS @ 12.02 HRS, VOLUME= .54 AF
ACRES CN SCS TR-20 METHOD
.77 98 ROOF, PARKING, TENNIS, SIDEWALK TYPE III 24-HOUR
.77 74 NEW GRASS RAINFALL= 6.40 IN
1.54 86 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO DET. POND VIA SWALE 4.9
L=298 ' s=.04 ' /'
SUBCATCHMENT 3 AREA 3
PEAK= 1.33 CFS @ 12.07 HRS, VOLUME= .10 AF
ACRES CN SCS TR-20 METHOD
.23 74 NEW GRASS TYPE III 24-HOUR
.11 85 EXISTING GRASS RAINFALL= 6 .40 IN
.34 78 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO OFFSITE 7.4
L=298 ' s=.03 /'
Data for 03006-Post-Construction Page 5
TYPE III 24-HOUR RAINFALL= 6.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroC:AD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
O A, ---> o
T
1 O
Fl
T
O
OSUBCATCHMENT 1:1 REACH A POND LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> POND 1
SUBCATCHMENT 3 = AREA 3 ->
REACH 1 = RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110 -> POND 1
REACH 2 = 12" DIA. PVC ACROSS HOCKANUM ROAD ->
POND 1 = SWALE AND DETENTION POND STORAGE -> REACH 2
Data for 03006-Post-Construction Page 4
TYPE III 24-HOUR RAINFALL= 5.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
POND 1 SWALE AND DETENTION POND STORAGE
Qin = 7.27 CFS @ 12.02 HRS, VOLUME= .51 AF
Qout= 5.06 CFS @ 12.21 HRS, VOLUME= .45 AF, ATTEN= 300, LAG= 11.7 MIN
Qpri= 4 .85 CFS @ 12.21 HRS, VOLUME= .34 AF
Qsec= .21 CFS @ 12.22 HRS, VOLUME= .12 AF
ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD
(FT) (SF) (CF) (CF) PEAK STORAGE = 8843 CF
110.0 1 0 0 PEAK ELEVATION= 113.6 FT
110.1 833 42 42 FLOOD ELEVATION= 114.5 FT
111.0 1578 1085 1127 START ELEVATION= 110.0 FT
112 .0 2538 2058 3185 SPAN= 10-20 HRS, dt=.l HRS
113 .0 3668 3103 6288 Tdet= 125.6 MIN ( .45 AF)
114 . 0 5021 4345 10632
114.5 5300 2580 13212
# ROUTE INVERT OUTLET DEVICES
1 3 111.5 ' 4" ORIFICE/GRATE
Q=.6 PI r^2 SQR(2g) SQR(H-r)
2 3 113.5' 24" HORIZONTAL ORIFICE/GRATE
Q=.6 Area SQR(2gH)
3 P 109.4' 12" CULVERT
n=.011 L=1' 5=.0051 /' Ke=.5 Cc=.9 Cd=.6
4 S 110.0' EXFILTRATION
V= .002778 FPM over (SURFACE AREA - 1 SF)
Primary Discharge
�-3=Culvert
�--1=Orifice/Grate
I2=Orifice/Grate
Secondary Discharge
�4=Exfiltration
Data for 03006-Post-Construction Page 3
TYPE III 24-HOUR RAINFALL= 5.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
REACH 1 RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110
Qin = .19 CFS @ 12.03 HRS, VOLUME= .02 AF
Qout= .14 CFS @ 12.20 HRS, VOLUME= .02 AF, ATTEN= 239o, LAG= 10.3 MIN
DEPTH END AREA DISCH
_ (FT) (SO-FT) (CFS) 10' x .5 ' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 '/' PEAK DEPTH= .01 FT
.1 .5 .75 n= .027 PEAK VELOCITY= 1.5 FPS
.1 1.0 2.38 LENGTH= 298 FT TRAVEL TIME = 3.4 MIN
.2 1.6 4.70 SLOPE= .04 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2 .3 8 .59
.3 3 .2 15.05
.4 4.4 24.46
.5 5.6 35.73
REACH 2 12" DIA. PVC ACROSS HOCKANUM ROAD
Qin = 4.85 CFS @ 12.21 HRS, VOLUME= .34 AF
Qout= 4.63 CFS @ 12.22 HRS, VOLUME= .34 AF, ATTEN= 5%, LAG= .3 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 12" PIPE STOR-IND+TRANS METHOD
0.0 0.0 0.00 PEAK DEPTH= .66 FT
.1 0.0 .12 n= .011 PEAK VELOCITY= 8.4 FPS
.2 .1 .52 LENGTH= 70 FT TRAVEL TIME _ .1 MIN
.3 .2 1.17 SLOPE= .02 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.7 .6 4.99
.8 .7 5.82
. 9 .7 6.35
.9 .8 6 .41
1.0 .8 6.35
1. 0 .8 5.95
Data for 03006-Post-Construction Page 2
TYPE III 24-HOUR RAINFALL= 5.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= .19 CFS @ 12.03 HRS, VOLUME= .02 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 5.90 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37 ' s=.26 1 /1
SUBCATCHMENT 2 AREA 2
PEAK= 7.20 CFS @ 12.02 HRS, VOLUME= .49 AF
ACRES CN SCS TR-20 METHOD
.77 98 ROOF, PARKING, TENNIS, SIDEWALK TYPE III 24-HOUR
.77 74 NEW GRASS RAINFALL= 5.90 IN
1.54 86 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO DET. POND VIA SWALE 4.9
L=298 ' s=.04 ' /'
SUBCATCHMENT 3 AREA 3
PEAK= 1.19 CFS @ 12 .07 HRS, VOLUME= .09 AF
ACRES CN SCS TR-20 METHOD
.23 74 NEW GRASS TYPE III 24-HOUR
.11 85 EXISTING GRASS RAINFALL= 5.90 IN
.34 78 SPAN= 10-20 HRS, dt=.l HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO OFFSITE 7.4
L=298 ' s=.03 ' /'
Data for 03006-Post-Construction Page 1
TYPE III 24-HOUR RAINFALL= 5.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
O ono
T
Fl O
T
O
OSUBCATCHMENT 1:1 REACH Q POND I I LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> POND 1
SUBCATCHMENT 3 = AREA 3 ->
REACH 1 = RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110 -> POND 1
REACH 2 = 12" DIA. PVC ACROSS HOCKANUM ROAD ->
POND 1 = SWALE AND DETENTION POND STORAGE -> REACH 2
Data for 03006-Post-Construction Page 12
TYPE III 24-HOUR RAINFALL= 5.20 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
POND 1 SWALE AND DETENTION POND STORAGE
Qin = 6.16 CFS @ 12 .02 HRS, VOLUME= .43 AF
Qout= 2.15 CFS @ 12.38 HRS, VOLUME= .38 AF, ATTEN= 650, LAG= 21.8 MIN
Qpri= 1.95 CFS @ 12.38 HRS, VOLUME= .27 AF
Qsec= .20 CFS @ 12.38 HRS, VOLUME= .11 AF
ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD
(FT) (SF) (CF) (CF) PEAK STORAGE = 8583 CF
110.0 1 0 0 PEAK ELEVATION= 113 .5 FT
110.1 833 42 42 FLOOD ELEVATION= 114.5 FT
111.0 1578 1085 1127 START ELEVATION= 110.0 FT
112.0 2538 2058 3185 SPAN= 10-20 HRS, dt=.1 HRS
113.0 3668 3103 6288 Tdet= 137.2 MIN ( .37 AF)
114.0 5021 4345 10632
114.5 5300 2580 13212
# ROUTE INVERT OUTLET DEVICES
1 3 111.5' 4" ORIFICE/GRATE
Q=.6 PI r^2 SQR(2g) SQR(H-r)
2 3 113.5' 24" HORIZONTAL ORIFICE/GRATE
Q=.6 Area SQR(2gH)
3 P 109.4' 12" CULVERT
n=.011 L=1' 5=.0051 /' Ke=.5 Cc=.9 Cd=.6
4 S 110.0' EXFILTRATION
V= .002778 FPM over (SURFACE AREA - 1 SF)
Primary Discharge
�-3=Culvert
�--1=Orif ice/Grate
I-2=Orif ice/Grate
Secondary Discharge
�4=Exfiltration
Data for 03006-Post-Construction Page 11
TYPE III 24-HOUR RAINFALL= 5.20 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydrOCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Svstems
REACH 1 RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110
Qin = .08 CFS @ 12.15 HRS, VOLUME= .01 AF
Qout= .08 CFS @ 12.25 HRS, VOLUME= .01 AF, ATTEN= 3%, LAG= 5.8 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 10' x .5' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 '/' PEAK DEPTH= .01 FT
.1 .5 .75 n= .027 PEAK VELOCITY= 1.5 FPS
.1 1.0 2 .38 LENGTH= 298 FT TRAVEL TIME = 3.4 MIN
.2 1.6 4.70 SLOPE= .04 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2 .3 8 .59
.3 3 .2 15.05
.4 4.4 24.46
.5 5.6 35.73
REACH 2 12" DIA. PVC ACROSS HOCKANUM ROAD
Qin = 1.95 CFS @ 12.38 HRS, VOLUME= .27 AF
Qout= 1.94 CFS @ 12.39 HRS, VOLUME= .27 AF, ATTEN= Og, LAG= .3 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 12" PIPE STOR-IND+TRANS METHOD
0.0 0.0 0.00 PEAK DEPTH= .3e FT
.1 0.0 .12 n= .011 PEAK VELOCITY= 7.0 FPS
.2 .1 .52 LENGTH= 70 FT TRAVEL TIME _ .2 MIN
.3 .2 1.17 SLOPE= .02 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.7 .6 4.99
.8 .7 5.82
.9 .7 6.35
.9 .8 6.41
1.0 .8 6.35
1.0 .8 5.95
Data for 03006-Post-Construction Page 10
TYPE III 24-HOUR RAINFALL= 5.20 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= .08 CFS Q 12 .15 HRS, VOLUME= .01 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 5.20 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37 ' s=.26 ' /'
SUBCATCHMENT 2 AREA 2
PEAK= 6 .14 CFS @ 12.02 HRS, VOLUME= .42 AF
ACRES CN SCS TR-20 METHOD
.77 98 ROOF, PARKING, TENNIS, SIDEWALK TYPE III 24-HOUR
.77 74 NEW GRASS RAINFALL= 5.20 IN
1.54 86 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO DET. POND VIA SWALE 4.9
L=298 ' s=.04
SUBCATCHMENT 3 AREA 3
PEAK= .98 CFS @ 12.07 HRS, VOLUME= .07 AF
ACRES CN SCS TR-20 METHOD
.23 74 NEW GRASS TYPE III 24-HOUR
.11 85 EXISTING GRASS RAINFALL= 5.20 IN
.34 78 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO OFFSITE 7.4
L=298 ' s=.03 ' /'
Data for 03006-Post-Construction Page 9
TYPE III 24-HOUR RAINFALL= 5.20 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
T
) O
T
O
OSUBCATCHMENT ❑ REACH Q POND LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> POND 1
SUBCATCHMENT 3 = AREA 3 ->
REACH 1 = RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110 -> POND 1
REACH 2 = 12" DIA. PVC ACROSS HOCKANUM ROAD ->
POND 1 = SWALE AND DETENTION POND STORAGE -> REACH 2
Data for 03006-Post-Construction Page 8
TYPE III 24-HOUR RAINFALL= 4.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
POND 1 SWALE AND DETENTION POND STORAGE
Qin = 4.92 CFS @ 12.02 HRS, VOLUME= .34 AF
Qout= .71 CFS @ 12.61 HRS, VOLUME= .29 AF, ATTEN= 866, LAG= 35.5 MIN
Qpri= .53 CFS @ 12.61 HRS, VOLUME= .19 AF
Qsec= .18 CFS @ 12.61 HRS, VOLUME= .10 AF
ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD
(FT) (SF) (CF) (CF) PEAK STORAGE = 7323 CF
110.0 1 0 0 PEAK ELEVATION= 113 .2 FT
110.1 833 42 42 FLOOD ELEVATION= 114.5 FT
111.0 1578 1085 1127 START ELEVATION= 110.0 FT
112 .0 2538 2058 3185 SPAN= 10-20 HRS, dt=.1 HRS
113 .0 3668 3103 6288 Tdet= 139.4 MIN ( .29 AF)
114.0 5021 4345 10632
114.5 5300 2580 13212
# ROUTE INVERT OUTLET DEVICES
1 3 111.5' 4" ORIFICE/GRATE
Q=.6 PI r^2 SQR(2g) SQR(H-r)
2 3 113 .5' 24" HORIZONTAL ORIFICE/GRATE
Q=.6 Area SQR(2gH)
3 P 109.4 ' 12" CULVERT
n=.011 L=1' 5=.0051/' Ke=.S Cc=.9 Cd=.6
4 S 110.0' EXFILTRATION
V= .002778 FPM over (SURFACE AREA - 1 SF)
Primary Discharge
�3=Culvert
�--1=Orifice/Grate
I 2=Orifice/Grate
Secondary Discharge
�-4=Exfiltration
Data for 03006-Post-Construction Page 7
TYPE III 24-HOUR RAINFALL= 4.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
REACH 1 RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110
Qin = .03 CFS @ 12.26 HRS, VOLUME= .01 AF
Qout= .03 CFS @ 12 .38 HRS, VOLUME= .01 AF, ATTEN= 70, LAG= 7.6 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 10' x .5 ' CHANNEL STOR-IND+TRANS METHOD
0. 0 0.0 0.00 SIDE SLOPE= .45 '/' PEAK DEPTH= 0.00 FT
.1 .5 .75 n= .027 PEAK VELOCITY= 1.5 FPS
.1 1.0 2.38 LENGTH= 298 FT TRAVEL TIME = 3 .4 MIN
.2 1.6 4.70 SLOPE= .04 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2 .3 8.59
.3 3 .2 15.05
.4 4.4 24.46
.5 5.6 35.73
REACH 2 12" DIA. PVC ACROSS HOCKANUM ROAD
Qin = .53 CFS @ 12.61 HRS, VOLUME= .19 AF
Qout= .53 CFS @ 12 .60 HRS, VOLUME= .19 AF, ATTEN= Oo, LAG= 0.0 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 12" PIPE STOR-IND+TRANS METHOD
0.0 0.0 0.00 PEAK DEPTH= .20 FT
.1 0.0 .12 n= .011 PEAK VELOCITY= 4.7 FPS
.2 .1 .52 LENGTH= 70 FT TRAVEL TIME = .2 MIN
.3 .2 1.17 SLOPE= .02 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.7 .6 4.99
.8 .7 5.82
. 9 .7 6.35
. 9 .8 6.41
1.0 .8 6.35
1.0 .8 5.95
• Data for 03006-Post-Construction Page 6
TYPE III 24-HOUR RAINFALL= 4.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= .03 CFS ® 12.26 HRS, VOLUME= .01 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 4.40 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37 ' s=.26 ' /'
SUBCATCHMENT 2 AREA 2
PEAK= 4.92 CFS @ 12.02 HRS, VOLUME= .34 AF
ACRES CN SCS TR-20 METHOD
.77 98 ROOF, PARKING, TENNIS, SIDEWALK TYPE III 24-HOUR
.77 74 NEW GRASS RAINFALL= 4.40 IN
1.54 86 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO DET. POND VIA SWALE 4.9
L=298 ' s=.04 '/'
SUBCATCHMENT 3 AREA 3
PEAK= .75 CFS @ 12 .08 HRS, VOLUME= .06 AF
ACRES CN SCS TR-20 METHOD
.23 74 NEW GRASS TYPE III 24-HOUR
.11 85 EXISTING GRASS RAINFALL= 4.40 IN
.34 78 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO OFFSITE 7.4
L=298 ' s=. 03 '/ '
• Data for 03006-Post-Construction Page 5
TYPE III 24-HOUR RAINFALL= 4.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
O A,
T
O
O
OSUBCATCHMENT [-] REACH Q POND I I LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> POND 1
SUBCATCHMENT 3 = AREA 3 ->
REACH 1 = RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110 -> POND 1
REACH 2 = 12" DIA. PVC ACROSS HOCKANUM ROAD ->
POND 1 = SWALE AND DETENTION POND STORAGE -> REACH 2
Data for 03006-Post-Construction Page 4
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
POND 1 SWALE AND DETENTION POND STORAGE
Qin = 2.68 CFS @ 12.02 HRS, VOLUME= .19 AF
Qout= .43 CFS @ 12.57 HRS, VOLUME= .14 AF, ATTEN= 84g, LAG= 33 .1 MIN
Qpri= .30 CFS @ 12 .57 HRS, VOLUME= .07 AF
Qsec= .13 CFS @ 12.57 HRS, VOLUME= .08 AF
ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD
(FT) (SF) (CF) (CF) PEAK STORAGE = 3778 CF
110.0 1 0 0 PEAK ELEVATION= 112.2 FT
110.1 833 42 42 FLOOD ELEVATION= 114.5 FT
111.0 1578 1085 1127 START ELEVATION= 110.0 FT
112.0 2538 2058 3185 SPAN= 10-20 HRS, dt=.1 HRS
113 .0 3668 3103 6288 Tdet= 142.3 MIN ( .14 AF)
114.0 5021 4345 10632
114.5 5300 2580 13212
# ROUTE INVERT OUTLET DEVICES
1 3 111.5' 4" ORIFICE/GRATE
Q=.6 PI r-2 SQR(2g) SQR(H-r)
2 3 113 .5' 24" HORIZONTAL ORIFICE/GRATE
Q=.6 Area SQR(2gH)
3 P 109.4 ' 12" CULVERT
n=.011 L=1' S=.0051 / ' Ke=.S Cc=.9 Cd=.6
4 S 110.0' EXFILTRATION
V= .002778 FPM over (SURFACE AREA - 1 SF)
Primary Discharge
L-3=Culvert
�-1=Orifice/Grate
I2=Orifice/Grate
Secondary Discharge
L-4=Exf iltration
• Data for 03006-Post-Construction Page 3
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Svstems
i
l
Y
REACH 1 RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110 p
Qin = 0.00 CFS @ 20.00 HRS, VOLUME= 0.00 AF
Qout= 0.00 CFS @ 20.00 HRS, VOLUME= 0.00 AF, ATTEN= Ot, LAG= 0.0 MIN
DEPTH END AREA DISCH
(FT) (SQ-FT) (CFS) 10' x .5' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 ' /' PEAK DEPTH= 0.00 FT
.1 .5 .75 n= .027 PEAK VELOCITY= 1.5 FPS !
.1 1.0 2.38 LENGTH= 298 FT TRAVEL TIME = 3 .4 MIN
.2 1.6 4.70 SLOPE= .04 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2.3 8.59
.3 3.2 15.05
.4 4.4 24.46
.5 5.6 35.73
REACH 2 12" DIA. PVC ACROSS HOCKANUM ROAD
Qin = .30 CFS @ 12.57 HRS, VOLUME= .07 AF
Qout= .31 CFS @ 12.60 HRS, VOLUME= .07 AF, ATTEN= 09., LAG= 1.6 MIN
DEPTH END AREA DISCH
(FT) (SQ-FT) (CFS) 12" PIPE STOR-IND+TRANS METHOD
0.0 0.0 0.00 PEAK DEPTH= .15 FT
.1 0.0 .12 n= .011 PEAK VELOCITY= 4.2 FPS
.2 .1 .52 LENGTH= 70 FT TRAVEL TIME _ .3 MIN
.3 .2 1.17 SLOPE= .02 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.7 .6 4.99
.8 .7 5.82
.9 .7 6 .35
.9 .8 6.41
1.0 .8 6.35
1.0 .8 5.95
I
Data for 03006-Post-Construction Page 2
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= 0. 00 CFS @ 20.00 HRS, VOLUME= 0.00 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 2.90 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37' s=.26 ' /'
SUBCATCHMENT 2 AREA 2
PEAK= 2 .68 CFS @ 12.02 HRS, VOLUME= .19 AF
ACRES CN SCS TR-20 METHOD
.77 98 ROOF, PARKING, TENNIS, SIDEWALK TYPE III 24-HOUR
.77 74 NEW GRASS RAINFALL= 2.90 IN
1.54 86 SPAN= 10-20 HRS, dt=.l HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO DET. POND VIA SWALE 4 .9
L=298 ' s=.04
SUBCATCHMENT 3 AREA 3
PEAK= .35 CFS @ 12.08 HRS, VOLUME= .03 AF
ACRES CN SCS TR-20 METHOD
.23 74 NEW GRASS TYPE III 24-HOUR
.11 85 EXISTING GRASS RAINFALL= 2.90 IN
.34 78 SPAN= 10-20 HRS, dt=.l HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO OFFSITE 7.4
L=298 ' s=.03 ' /'
Data for 03006-Post-Construction Page 1
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
O A, ---> 0
T
O
Fl
T
O
OSUBCATCHMENT ❑ REACH Q POND M LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> POND 1
SUBCATCHMENT 3 = AREA 3 ->
REACH 1 = RUNOFF PATH FROM AREA 1 TO SWALE ELEV. 110 -> POND 1
REACH 2 = 12" DIA. PVC ACROSS HOCKANUM ROAD ->
POND 1 = SWALE AND DETENTION POND STORAGE -> REACH 2
Summary HydroCAD Results
51 105 251 50, 100-Year Events
(Proposed Conditions)
Data for 03006-Pre-Construction Page 15
TYPE III 24-HOUR RAINFALL= 6.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
REACH 1 RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL
Qin = .27 CFS @ 12.02 HRS, VOLUME= .02 AF
Qout= .20 CFS @ 12.15 HRS, VOLUME= .02 AF, ATTEN= 240, LAG= 8 .1 MIN
DEPTH END AREA DISCH
(FT) (SQ-FT) (CFS) 10' x .5' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 '/ ' PEAK DEPTH= .02 FT
.1 .5 .71 n= .03 PEAK VELOCITY= 1.4 FPS
.1 1.0 2.25 LENGTH= 264 FT TRAVEL TIME = 3.1 MIN
.2 1.6 4.43 SLOPE= .044 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2.3 8.11
.3 3 .2 14.20
.4 4.4 23 .09
.5 5.6 33 .73
REACH 2 Swale
Qin = 9.38 CFS @ 12 .02 HRS, VOLUME= .65 AF
Qout= 7.76 CFS @ 12 .20 HRS, VOLUME= .65 AF, ATTEN= 179o, LAG= 11.0 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 3' x 1' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .01 '/' PEAK DEPTH= .22 FT
.1 1.3 1.12 n= .018 PEAK VELOCITY= 1.4 FPS
.2 4.6 6.05 LENGTH= 500 FT TRAVEL TIME = 5.8 MIN
.3 9.9 16.83 SLOPE= .005 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.4 19.8 42.36
.6 37.8 100.48
.8 66.4 213 .00
1.0 103 .0 382.49
Data for 03006-Pre-Construction Page 14
TYPE III 24-HOUR RAINFALL= 6.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= .27 CFS @ 12.02 HRS, VOLUME= .02 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 6.40 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37 ' s=.26 '/'
SUBCATCHMENT 2 AREA 2
PEAK= 9.26 CFS @ 12.02 HRS, VOLUME= .63 AF
ACRES CN SCS TR-20 METHOD
1.54 85 DIRT/GRASS UNDER LIMERICK SOIL TYPE III 24-HOUR
.34 73 WOODED AREA WITH FAIR COVER RAINFALL= 6.40 IN
1.88 83 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO LOW POINT ON PL 4.7
L=264 ' s=.044 '/'
Data for 03006-Pre-Construction Page 13
TYPE III 24-HOUR RAINFALL= 6.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD S.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
F2]
T
O
0
T
O
OSUBCATCHMENT ❑ REACH POND LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> REACH 2
REACH 1 = RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL -> REACH 2
REACH 2 = Swale ->
Data for 03006-Pre-Construction Page 12
TYPE III 24-HOUR RAINFALL= 5.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
REACH 1 RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL
Qin = .19 CFS ® 12 .03 HRS, VOLUME= .02 AF
Qout= .14 CFS ® 12.19 HRS, VOLUME= .02 AF, ATTEN= 2311, LAG= 9.8 MIN
DEPTH END AREA DISCH
(FT) (SQ-FT) (CFS) 10' x .5' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 ' /' PEAK DEPTH= .01 FT
.1 .5 .71 n= .03 PEAK VELOCITY= 1.4 FPS
.1 1.0 2.25 LENGTH= 264 FT TRAVEL TIME = 3.1 MIN
.2 1.6 4.43 SLOPE= .044 FT/FT SPAN= 10-20 HRS, dt=.l HRS
.2 2 .3 8.11
.3 3 .2 14.20
.4 4.4 23 .09
.5 5.6 33.73
REACH 2 Swale
Qin = 8.39 CFS Q 12.02 HRS, VOLUME= .58 AF
Qout= 6.83 CFS Q 12 .20 HRS, VOLUME= .58 AF, ATTEN= 19g, LAG= 11.3 MIN
DEPTH END AREA DISCH
(FT) (SQ-FT) (CFS) 3 ' x 1' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .01 '/ ' PEAK DEPTH= .21 FT
.1 1.3 1.12 n= .018 PEAK VELOCITY= 1.4 FPS
.2 4.6 6.05 LENGTH= 500 FT TRAVEL TIME = 6.1 MIN
.3 9.9 16.83 SLOPE= .005 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.4 19.8 42.36
.6 37.8 100.48
.8 66.4 213 .00
1.0 103 . 0 382 .49
Data for 03006-Pre-Construction Page 11
TYPE III 24-HOUR RAINFALL= 5.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= .19 CFS @ 12.03 HRS, VOLUME= .02 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 5.90 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37' s=.26 ' /'
SUBCATCHMENT 2 AREA 2
PEAK= 8.32 CFS @ 12.02 HRS, VOLUME= .56 AF
ACRES CN SCS TR-20 METHOD
1.54 85 DIRT/GRASS UNDER LIMERICK SOIL TYPE III 24-HOUR
.34 73 WOODED AREA WITH FAIR COVER RAINFALL= 5.90 IN
1.88 83 SPAN= 10-20 HRS, dt=.l HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO LOW POINT ON PL 4.7
L=264 ' s=.044 '/'
Data for 03006-Pre-Construction Page 10
TYPE III 24-HOUR RAINFALL= 5.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Svstems
WATERSHED ROUTING
F2]
T �
O
T
O
OSUBCATCHMENT El REACH A POND Q1 LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> REACH 2
REACH 1 = RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL -> REACH 2
REACH 2 = Swale ->
Data for 03006-Pre-Construction Page 9
TYPE III 24-HOUR RAINFALL= 5.20 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
REACH 1 RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL
Qin = .08 CFS @ 12.15 HRS, VOLUME= .01 AF
Qout= .08 CFS @ 12.25 HRS, VOLUME= .01 AF, ATTEN= 096, LAG= 5.5 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 10' x .5' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 '/' PEAK DEPTH= .01 FT
.1 .5 .71 n= .03 PEAK VELOCITY= 1.4 FPS
.1 1.0 2.25 LENGTH= 264 FT TRAVEL TIME = 3 .1 MIN
.2 1.6 4.43 SLOPE= .044 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2 .3 8.11
.3 3 .2 14.20
.4 4.4 23 .09
.5 5.6 33 .73
REACH 2 Swale
Qin = 7.03 CFS @ 12.02 HRS, VOLUME= .49 AF
Qout= 5.55 CFS @ 12.21 HRS, VOLUME= .48 AF, ATTEN= 219o, LAG= 11.7 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 3 ' x 1' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .01 '/' PEAK DEPTH= .19 FT
.1 1.3 1.12 n= .018 PEAK VELOCITY= 1.3 FPS
.2 4.6 6.05 LENGTH= 500 FT TRAVEL TIME = 6.4 MIN
.3 9.9 16.83 SLOPE= .005 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.4 19.8 42.36
.6 37.8 100.48
.8 66.4 213.00
1.0 103 .0 382.49
Data for 03006-Pre-Construction Page 8
TYPE III 24-HOUR RAINFALL= 5.20 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= .08 CFS @ 12.15 HRS, VOLUME= .01 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 5.20 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37 ' s=.26 '/'
SUBCATCHMENT 2 AREA 2
PEAK= 7.01 CFS @ 12 .02 HRS, VOLUME= .48 AF
ACRES CN SCS TR-20 METHOD
1.54 85 DIRT/GRASS UNDER LIMERICK SOIL TYPE III 24-HOUR
.34 73 WOODED AREA WITH FAIR COVER RAINFALL= 5.20 IN
1.88 83 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO LOW POINT ON PL 4.7
L=264 ' s=.044 /'
Data for 03006-Pre-Construction Page 7
TYPE III 24-HOUR RAINFALL= 5.20 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
[2]
T �
a
O
T
O
OSUBCATCHMENT ❑ REACH A POND LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> REACH 2
REACH 1 = RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL -> REACH 2
REACH 2 = Swale ->
Data for 03006-Pre-Construction Page 6
TYPE III 24-HOUR RAINFALL= 4.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Svstems
REACH 1 RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL
Qin = .03 CFS Q 12 .26 HRS, VOLUME= .01 AF
Qout= .03 CFS Q 12 .38 HRS, VOLUME= .01 AF, ATTEN= 70, LAG= 7.1 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 10' x .5 ' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 '/' PEAK DEPTH= 0.00 FT
.1 .5 .71 n= .03 PEAK VELOCITY= 1.4 FPS
.1 1.0 2.25 LENGTH= 264 FT TRAVEL TIME = 3.1 MIN
.2 1.6 4.43 SLOPE= .044 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2 .3 8.11
.3 3 .2 14.20
.4 4.4 23.09
.5 5.6 33.73
REACH 2 Swale
Qin = 5.53 CFS Q 12.02 HRS, VOLUME= .38 AF
Qout= 4.33 CFS @ 12.22 HRS, VOLUME= .38 AF, ATTEN= 220, LAG= 11.9 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 3' x 1' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .01 '/' PEAK DEPTH= .17 FT
.1 1.3 1.12 n= .018 PEAK VELOCITY= 1.3 FPS
.2 4.6 6.05 LENGTH= 500 FT TRAVEL TIME = 6.6 MIN
.3 9.9 16.83 SLOPE= .005 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.4 19.8 42 .36
.6 37.8 100.48
.8 66.4 213.00
1.0 103 .0 382 .49
Data for 03006-Pre-Construction Page 5
TYPE III 24-HOUR RAINFALL= 4.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydrOCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Svstems
SUBCATCHMENT 1 AREA 1
PEAK= .03 CFS @ 12.26 HRS, VOLUME= .01 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 4.40 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37 ' s=.26 ' /'
SUBCATCHMENT 2 AREA 2
PEAK= 5.53 CFS @ 12 .02 HRS, VOLUME= .38 AF
ACRES CN SCS TR-20 METHOD
1.54 85 DIRT/GRASS UNDER LIMERICK SOIL TYPE III 24-HOUR
.34 73 WOODED AREA WITH FAIR COVER RAINFALL= 4.40 IN
1.88 83 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO LOW POINT ON PL 4.7
L=264' s=.044 '/'
Data for 03006-Pre-Construction Page 4
TYPE III 24-HOUR RAINFALL= 4.40 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
T �
O
F I
T
O
OSUBCATCHMENT ❑ REACH Q POND I I LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> REACH 2
REACH 1 = RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL -> REACH 2
REACH 2 = Swale ->
Data for 03006-Pre-Construction Page 3
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
REACH 1 RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL
Qin = 0.00 CFS @ 20.00 HRS, VOLUME= 0.00 AF
Qout= 0. 00 CFS @ 20.00 HRS, VOLUME= 0.00 AF, ATTEN= Oo, LAG= 0.0 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 10' x .5 ' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 '/' PEAK DEPTH= 0.00 FT
.1 .5 .71 n= .03 PEAK VELOCITY= 1.4 FPS
.1 1.0 2 .25 LENGTH= 264 FT TRAVEL TIME = 3 .1 MIN
.2 1.6 4.43 SLOPE= .044 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2 .3 8.11
.3 3 .2 14.20
.4 4.4 23 .09
.5 5.6 33.73
REACH 2 Swale
Qin = 2 .84 CFS @ 12.02 HRS, VOLUME= .20 AF
Qout= 2.07 CFS @ 12.25 HRS, VOLUME= .20 AF, ATTEN= 27%, LAG= 13 .7 MIN
DEPTH END AREA DISCH
(FT) (SO-FT) (CFS) 3 ' x 1' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .01 '/' PEAK DEPTH= .12 FT
.1 1.3 1.12 n= .018 PEAK VELOCITY= 1.1 FPS
.2 4.6 6.05 LENGTH= 500 FT TRAVEL TIME = 7.7 MIN
.3 9.9 16.83 SLOPE= .005 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.4 19.8 42.36
.6 37.8 100.48
.8 66.4 213.00
1.0 103.0 382 .49
Data for 03006-Pre-Construction Page 2
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= 0.00 CFS @ 20.00 HRS, VOLUME= 0.00 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 2.90 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37' s=.26 '/ '
SUBCATCHMENT 2 AREA 2
PEAK= 2.84 CFS @ 12.02 HRS, VOLUME= .20 AF
ACRES CN SCS TR-20 METHOD
1.54 85 DIRT/GRASS UNDER LIMERICK SOIL TYPE III 24-HOUR
.34 73 WOODED AREA WITH FAIR COVER RAINFALL= 2.90 IN
1.88 83 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO LOW POINT ON PL 4.7
L=264 ' s=.044 ' /'
Data for 03006-Pre-Construction Page 1
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
a
T �
O
0
T
O
OSUBCATCHMENT ❑ REACH APOND I I LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> REACH 2
REACH 1 = RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL -> REACH 2
REACH 2 = Swale ->
Data for 03006-Pre-Construction Page 3
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
REACH 1 RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL
Qin = 0.00 CFS @ 20.00 HRS, VOLUME= 0.00 AF
Qout= 0.00 CFS @ 20.00 HRS, VOLUME= 0.00 AF, ATTEN= 0%, LAG= 0. 0 MIN
DEPTH END AREA DISCH
_(FT) (SQ-FT) (CFS) 10' x .5 ' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .45 '/' PEAK DEPTH= 0.00 FT
.1 .5 .71 n= .03 PEAK VELOCITY= 1.4 FPS
.1 1.0 2.25 LENGTH= 264 FT TRAVEL TIME = 3 .1 MIN
.2 1.6 4.43 SLOPE= .044 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.2 2 .3 8.11
.3 3 .2 14.20
.4 4.4 23 .09
.5 5.6 33 .73
REACH 2 Swale
Qin = 2.84 CFS @ 12.02 HRS, VOLUME= .20 AF
Qout= 2. 07 CFS @ 12.25 HRS, VOLUME= .20 AF, ATTEN= 27%, LAG= 13 .7 MIN
DEPTH END AREA DISCH
(FT) (SQ-FT) (CFS) 3' x 1' CHANNEL STOR-IND+TRANS METHOD
0.0 0.0 0.00 SIDE SLOPE= .01 '/' PEAK DEPTH= .12 FT
.1 1.3 1.12 n= .018 PEAK VELOCITY= 1.1 FPS
.2 4.6 6.05 LENGTH= 500 FT TRAVEL TIME = 7.7 MIN
.3 9.9 16.83 SLOPE= .005 FT/FT SPAN= 10-20 HRS, dt=.1 HRS
.4 19.8 42.36
.6 37.8 100.48
. 8 66.4 213 .00
1.0 103 .0 382.49
Data for 03006-Pre-Construction Page 2
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
SUBCATCHMENT 1 AREA 1
PEAK= 0. 00 CFS @ 20.00 HRS, VOLUME= 0.00 AF
ACRES CN SCS TR-20 METHOD
.32 45 RAILROAD GRAVEL UNDER SAND TYPE III 24-HOUR
RAINFALL= 2.90 IN
SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF FROM TOP RAILROAD TO PL 1.1
L=37' s=.26 ' /'
SUBCATCHMENT 2 AREA 2
PEAK= 2 .84 CFS @ 12.02 HRS, VOLUME= .20 AF
ACRES CN SCS TR-20 METHOD
1.54 85 DIRT/GRASS UNDER LIMERICK SOIL TYPE III 24-HOUR
.34 73 WOODED AREA WITH FAIR COVER RAINFALL= 2 .90 IN
1.88 83 SPAN= 10-20 HRS, dt=.1 HRS
Method Comment Tc (min)
CURVE NUMBER (LAG) METHOD RUNOFF TO LOW POINT ON PL 4.7
L=264' s=.044 ' /'
Data for 03006-Pre-Construction Page 1
TYPE III 24-HOUR RAINFALL= 2.90 IN
Prepared by Huntley Associates, P.C. 17 Jun 03
HydroCAD 5.01 000451 (c) 1986-1998 Applied Microcomputer Systems
WATERSHED ROUTING
[2]
T
F 1-1
0
T
0
OSUBCATCHMENT ❑ REACH A POND I I LINK
SUBCATCHMENT 1 = AREA 1 -> REACH 1
SUBCATCHMENT 2 = AREA 2 -> REACH 2
REACH 1 = RUNOFF PATH FROM AREA 1 TO LOW POINT ON PL -> REACH 2
REACH 2 = Swale ->
Summary HydroCAD Results
51 101 25, 50, 100-Year Events
(Existing Conditions)
HUNTLEY
HUNTLEY ASSOCIATES, P.C.
SURVEYORS.ENGINEERS. LANDSCAPE ARCHITECTS
Table 2.0. Estimated Post Construction runoff routed off site.
RAIN EVENT RAINFALL TOTAL TOTAL OFFSITE TOTAL OFFSITE
(in.) SWALE/POND VOLUME (CF) RUNOFF(cfs)
STORAGE (CF)
2-year 2.9 3,778 0.10 0.66
10-year 4.4 7,323 0.25 1.28
25-year 5.2 8,583 0.34 2.91
50-year 5.9 8,843 0.43 5.82
100-year 6.4 8,893 0.49 6.67
CONCLUSIONS
From review of Table 1 and Table 2, it can be seen that runoff for post-construction conditions will
be less than existing conditions for the various modeled rain events. Upon calculation or
comparison of the total offsite runoff, it was determined that a reduction of runoff between 50% and
25% occurs for each of the modeled storms. However, it can be reasonably assumed that
groundwater recharge or infiltration occurs within the detention pond after each rain event ceases,
offsetting the reduction for the post-construction condition. In addition and more importantly, the
peak elevation of stored runoff within the detention pond for more intense rain events will not affect
or overflow into abutting properties.
The positive modeling results assume that the storm water detention system will be constructed as
shown on the proposed June 2003 Site Plan, prepared by Huntley Associates, P.C. In addition, it is
also assumed that system maintenance and cleaning or removal of leaves and other debris occurs on
an as-need basis to ensure proper operation.
LIMITATIONS
The watershed and project analyses was performed in accordance with standard civil engineering
practice, and relies on information provided by others or published information. Areas of potential
runoff analysis were limited to those areas within the bounds of property owned or believed to
impact the property of concern.
In addition, Huntley Associates, P.C. shall not be responsible for construction or installation not
conforming to the plans, nor shall Huntley Associates, P.C. be responsible for maintenance of the
proposed Stormwater Management System.
It shall also be understood that the SCS Time Lag Method of drainage analyses was originally
formulated to assist with the development of farmland and crop production. The SCS method has
become a standard method of hydrologic analysis within civil engineering community, yet may be
conservative for use on very small areas of modern development and provide runoff results that are
greater or more conservative than actual conditions (pre or post construction).
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HUNTLEY ASSOCIATES, P.C.
SURVEYORS.ENGINEERS• LANDSCAPE ARCHITECTS
surface runoff routed from Area 3 will essentially remain the same as in the Pre-Construction
Condition, by minimal grading within this area(see Sheet 1 of 2).
METHOD OF DRAINAGE ANALYISIS
The Natural Resource Conservation Service (formerly Soil Conservation Service, or SCS) method
of analysis was utilized for this project. The SCS method is based on TR-20 and is widely accepted
as standard engineering practice within the civil engineering profession for stormwater runoff or
hydrology analysis. The SCS method of hydrology analysis utilizes the drainage area, hydraulic
length, terrain slope, and soil conditions of a watershed or catchment as input to calculate peak
flows and total volume of runoff for specific synthetic rain events.
HAPC modeled the 2-year, 10-year, 25-year, 50-year, and 100-year statistical rain events for both
the pre and post construction conditions. The total rainfall per a 24-hour period for the 2, 10, 25, 50,
and 100-year statistical rain events are 2.9-inches, 4.4-inches, 5.2-inches, 5.9-inches, and 6.4-
inches, respectively.
RESULTS
Table 1 and Table 2 indicate the overall storm water model results for the pre and post construction
conditions. Currently, site rainwater or runoff flows in an easterly and southeasterly direction and
percolates or infiltrates into the ground. Runoff not infiltrating naturally into the ground exits the
sites and enters into abutting properties via a very shallow swale. The peak volume (AF) and runoff
(cfs) routed offsite for the existing conditions scenario is shown in Table 1.
Table 2 results demonstrate that all runoff generated from the site for the increased impervious area
can be routed to the detention pond via swale and eliminate runoff to abutting properties. An
overflow control structure with a 4-inch diameter orifice will regulate higher storm events. Column
3 shows storage volume within the detention/swale. Column 4 and 5 shows overflow volume and
runoff offsite.
Note that volume and runoff for Subcatchment 3 is routed offsite to its natural state and is not
incorporated into our calculations, or shown on Table 2.
Table 1.0. Estimated Pre Construction runoff routed off site.
RAIN EVENT RAINFALL(in.) OFFSITE VOLUME (AF) OFFSITE RUNOFF(cfs)
2-year 2.9 0.20 2.07
10-year 4.4 0.38 4.33
25-year 5.2 0.48 5.55
50-year 5.9 0.58 6.83
100-year 6.4 0.65 7.76
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LOCATION AND PURPOSE
The proposed site development by Mr. William Gruber consists of the construction of Townhouses
located on Hockanum Road, just east of the Boston and Maine Railroad tracks, in Northampton,
MA. The site can also be located on the Mt. Holyoke USGS quadrangle at coordinates 42° 18' 54"
N and 72° 37' 27" W. The purpose of this report is to compare computer-modeling results of storm
water runoff for existing and proposed conditions using synthetic or statistical rain events, and to
ensure that at a minimum,peak runoff does not increase for the more developed condition.
EXISTING SITE CONDITIONS
Upon review of the Soil Conservation Service (SCS) Soil Survey Manual of Hampshire County,
Central Part, soils located within the property bounds is considered Limerick silt loam (Lk), and
hydrologic group of C. Based on review of the SCS Soil Survey, the anticipated permeability rate
of the Limerick soil is 30 min/inch (0.002778 ft/min.), or very low permeability.
Existing site topography is characterized by sloping areas of very gentle, to gentle grades, and
generally steep at the railroad track embankment, that slopes to the east. There are deciduous trees,
plants, and shrubs, which account for approximately 20 percent of coverage for the lot of concern;
the remaining 80 percent is composed of exposed soil or hardpack dirt and grass areas. Based on
the topography, it appears that runoff flows generally to the center of the lot, and then in an easterly
direction to a low point or swale, while infiltrating into the ground.
Pre-Construction Subcatchment Area 1 has area of 0.32 acres and is 3/4-inch crushed stone located
along the rail roadbed. The hydraulic length and average slope for Area 1 are 37 feet and 26
percent, respectively. Subcatchment Area 2 has a total area of 1.88 acres of which 1.54 acres are
grass and dirt, and 0.34 acres is wooded or vegetative cover. The hydraulic length and slope for
Area 2 are 264 feet and 4.4 percent, respectively. See attached Pre-Construction drawing.
PROPOSED SITE PLAN MODIFICATIONS
The project consists of constructing 14-unit townhouses, parking area, tennis court, sidewalks,
drainage swale, detention pond, and associated utilities and landscape areas. All impervious surface
and roof runoff will flow over ground and be routed into a forebay and detention pond. An outlet
control structure consisting of a 4-inch diameter orfice with a 2'x2' horizontal overflow grate, and
12-inch diameter PVC outlet pipe will route excess runoff to a flared end section south of
Hockanum Road, and discharge to an existing swale..
For the Hydrocad modeling or analysis, Post-Construction Subcatchment Area 1 has the same
characteristics as the existing or Pre-Construction. Subcatchment Area 2 has a total area of 1.54
acres of which 0.77 acres are impervious (roof, parking lot, sidewalk, and tennis court) and 0.77
acres is new grass. Subcatchment Area 3 has a total of 0.34 acres of new and existing grass ground
cover without any substantial tree canopy or cover. In an effort to minimize drainage alterations,
30 INDUSTRIAL DRIVE EAST.NORTHAMPTON, MASSACHUSETTS 01060 .(413) 584-7444 .FAx(413) 586-9159
1885 STATE STREET•SCHENECTADY, NEW YORK 12304 . (518) 393-4767 .FAx(518) 393-3510
16-18 REYNOLDS AVENUE•ONEONTA, NEW YORK 13820 .(607) 432-3300 .FAx(607) 432-8313
HUNTLEY
HUNTLEY ASSOCIATES, P.C.
SURVEYORS.ENGINEERS. LANDSCAPE ARCHITECTS
DRAINAGE REPORT
for the
PROPOSED TOWNHOUSES at HOCKANUM ROAD
Prepared for:
Mr. William Gruber
7 Torrey Way
Easthampton, MA. 01027
Prepared by.-
Huntley Associates, P.C.
30 Industrial Drive East
Northampton, MA 01060yjH OF�a
sucY
(413) 584-7444 Fax (413) 586-9159
e-mail: huntleyjhuntleyassociates.com o MARK A. c '
z MXLUSKY U'Y
CML
NO.41747 v
30 INDUSTRIAL DRIVE EAST•NORTHAMPTON, MASSACHUSETTS 01060 .(413) 584-7444 .FAx(413) 586-9159
1885 STATE STREET•SCHENECTADY, NEW YORK 12304 .(518) 393-4767 .FAx(518) 393-3510
16-18 REYNOLDS AVENUE•ONEONTA, NEW YORK 13820 • (607) 432-3300 •FAx(607) 432-8313