HomeMy WebLinkAboutStormwater Management Report dated 4/4/18 APR 18 2018
Southo!d Town
Mannino Bo?rd
STORMWATER MANAGEMENT REPORT
FOR
PROPOSED SITE IMPROVEMENTS
TRANSFER STATION
WHISTLER AVENUE
PREPARED FOR
FISHERS ISLAND
WASTE MANAGEMENT DISTRICT
APRIL 4, 2018
ANCHOR
ENGINEERING SERVICES, INC.
41 Sequin Drive
Glastonbury, CT 06033
T: 860.633.8770
F: 860.633.5971
Anchor Engineering Services, Inc. Proposed Site Improvements —Transfer Station
Whistler Avenue, Fishers Island,N.Y.
TABLE OF CONTENTS
ProjectDescription............................................................................................................................... 1
ExistingDrainage.................................................................................................................................. l
ProposedDrainage............................................................................................................................... l
Summary& Conclusion......................................................................................................................3
StormwaterTreatment........................................................................................................................3
Erosion and Sedimentation Control.................................................................................................4
APPENDICES
Appendix A. Drainage Area Mapping
Appendix B. Pipe Flow Calculations
Appendix C. PondPack Results (Existing and Proposed)
Appendix D. Miscellaneous
TABLES
Table No. 1. Total Flows — Using Flows Into Basin
Table No.2. Total Flows — Using Flows Out of Basin
TC
Anchor Engineering Services, Inc. Proposed Site Improvements —Transfer Station
Whistler Avenue, Fishers Island, N.Y.
PROTECT DESCRIPTION
The project includes site improvements to the existing transfer station to provide a safe and organized
layout for efficient operations. Improvements include a new paved perimeter access drive, a truck scale,
new retaining walls to accommodate the required compactors and material rolloff containers. A new
2400 square foot maintenance building will be installed to the west of the existing garage which will be
renovated for meeting space and a composting area will be established to the southwest of the transfer
station area.
Also included is the installation of electric, communication and water utility services for the site and a
new storm drainage collection system that outlets to a stormwater basin.
EXISTING DRAINAGE
The existing drainage area analyzed includes 1.03 acres. The existing watershed is divided into three
different sub areas. The majority of the area, 0.64 acres currently drains to two existing catch basins on
site that drain into an underground tunnel system beneath the site without any treatment or known
outlet. The other two areas include current sheet flow to the west and north (0.17 acres) and a
primarily pervious lawn area that drain towards the existing entrance drive and Whistler Avenue (0.22
acres).
In order to analyze the existing stormwater flows from the subject property, these three areas were
delineated. The existing soils are mapped as RhB (Riverhead and Haven) and CuC (Cut and fill land
sloping) in the area. Type "B" soils was used in the drainage calculations. A map showing the
watershed for existing conditions is provided in Appendix A.
PROPOSED DRAINAGE
The proposed drainage area analyzed includes 1.03 acres. The proposed watershed is divided into two
different sub areas. The majority of the area, 0.93 acres drains to the proposed stormwater basin in the
northeast corner of the site between the existing garage building and the access driveway. The majority
of this area will drain to the new storm drainage system which includes a stormwater treatement
structure prior to outletting into the basin. The stormwater treatment structure will be sized to treat
the receiving Water Quality Flow. The remaining 0.10 acres currently drains toward the existing catch
basins on site but with the proposal, will be on the high side of the new retaining wall and will now
drain toward the south.
The proposed stormwater from the project site will be treated and then collected in the stormwater
basin in the northeast corner of the site. Some of this water will infiltrate through the bottom and sides
of the basin to recharge groundwater. The remainder that is collected will be used on the site at the
composting facility, to spray piles. A riprap overflow spillway will be installed at the northern end of
the basin to control emergency flows from the basin.
A watershed map for proposed conditions are provided in Appendix A.
1
Anchor Engineering Services, Inc. Proposed Site Improvements —Transfer Station
Whistler Avenue, Fishers Island,N.Y.
PEAK FLOWS
Peak flows for the site were calculated using the Rational Formula and/or the TR-55 method.
Runoff coefficients, curve numbers are based on values given in the Connecticut Department of
Transportation (CTDOT) Drainage Manual. The rainfall frequencies used are the NOAA Point
Precipitation Frequency Estimates for this area of Fishers island. The rates are attached in
Appendix D. A time of concentration of 5 minutes (0.083 hour) was used for the existing and
proposed analyses. The drainage areas for the project site were determined through analysis of
topographic mapping.
PIPE FLOW ANALYSIS
A combination of the rational method and the Hydraflow software program was utilized in order to
analyze and design the pipe collection system. All drainage pipes were designed to collect and
distribute the 10-year storm event prior to discharging. The results generated by the Hydraflow
software program are attached in Appendix B.
The hydraulic design of the pipes within the proposed drainage system was based on the Mannings
Equation. A minimum pipe size of 18 inches and RC pipe is proposed to meet Chapter 161 of the
Town of Southold Code of Ordinances. The minimum slope of all pipes.in the proposed system is
0.005 ft/ft.
STORMWATER BASIN ANALYSIS
To properly analyze the impact of the proposed improvements on stormwater runoff conditions, a
pre-development and post-development analysis of the site was performed in the Pondpack
software program. This program utilizes the TR-55 method to analyze peak runoff flows and
volumes.
The stormwater collected in the basin will be stored, infiltrated into the ground and used on site as
needed. Therefore, no direct runoff from the basin should occur over the spillway unless multiple
storms occur with volumes that are in excess of the pump capacity for re-use of the water on site.
The calculations for the stormwater basin have modelled the flow from the basin using the 4 foot
wide riprap spillway acting as a weir outlet. Any calculated increase in peak flows for storm events
up to the 50-year as a result of the development have been attenuated through the proposed
stormwater basin. Details are provided on the plans for the spillway and basin section.
2
Anchor Engineering Services, Inc. Proposed Site Improvements—Transfer Station
Whistler Avenue, Fishers Island, N.Y.
SUMMARY AND CONCLUSION
A summary of peak flows for existing and proposed conditions is provided below.
STORM EXISTING PROPOSED
EVENT CONDITIONS CONDITIONS DIFFERENCE
(CFS) (CFS)
10-yr 3.79 4.06 0.27
25-yr 4.76 5.03 0.27
50-yr 5.52 5.78 0.26
TABLE NO.1: TOTAL FLOWS-USING FLOWS INTO BASIN
STORM EXISTING PROPOSED
EVENT CONDITIONS CONDITIONS DIFFERENCE
(CFS) (CFS)
10-yr 3.79 0.79 -3.0
25-yr 4.76 2.19 -2.57
50-yr 5.52 3.56 -1.96
TABLE NO.2: TOTAL FLOWS-USING FLOWS OUT OF BASIN
As shown in the Table No. 1 above, there is only a slight increase in the total flow generated over the
project site with the proposed conditions. However, any increase will be stored in the basin and
infiltrated or reused on site therefore not creating an increase to flow off the site. The storage volume
provided by the proposed detention basin adequately attenuates stormwater flows generated by the
proposed site(see Table No. 2) for any situations that the emergency spillway is used.
STORMWATER TREATMENT
Provisions have been made in the design of the drainage systems for the removal of both particulate and
soluble pollutants during storm events so as to improve the quality of stormwater runoff discharged to
receiving waters both during and after construction. These provisions include the use of Site Design
Best Management Practices, Pretreatment, and Primary Treatment.
BEST MANAGEMENT PRACTICES:
Unnecessary impervious surfaces are minimized in the proposed design through the creation of
orderly traffic flow through the site, designated travel lanes and a review of operational procedures
to limit excess impervious surfaces.
PRETREATMENT:
All catch basins installed on the proposed site will be constructed with a 2-foot sump. In addition,
landscaped buffers and lawn areas are proposed to reduce runoff onto the impervious access drive.
PRIMARY TREATMENT:
Primary treatment will be provided through the placement of a hydrodynamic separator prior to
discharge into the stormwater basin. This structure will remove oil, sediment and debris prior to
storage and infiltration.
3
Anchor Engineering Services, Inc. Proposed Site Improvements —Transfer Station
Whistler Avenue, Fishers Island,N.Y.
All stormwater collection systems on the site have been designed in accordance with-the "2004
Connecticut Stormwater Quality Manual". All treatment structures have been sized to treat a
minimum of the first inch of stormwater runoff and shall be constructed with an internal bypass in
order to allow high flows to bypass. As recommended, the proposed plan specifies a required treatment
flow and bypass flow that the treatment structure needs to accommodate. The water quality flow
calculations are attached in Appendix D.
EROSION & SEDIMENTATION CONTROL PLAN
The potential impact of the project on the surrounding areas is related to the temporary transport of
soils and sediments associated with the construction phases of the project. The impact of the project on
the surrounding areas will be controlled as specified in the plan set or as required to meet field
conditions.
4
APPENDIX A
DRAINAGE AREA MAPS
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PROPOSED WATERSHED
40 0 40 80 WHISTLER AVENUE FISHERS ISLAND NY
TOTAL AREA = 1.03 ACRESSCALE: 1PROJECT DATE SHEET NO. 1 OF
40 SCALE: 1"=40' 013-32 oaro<i,a
APPENDIX B
PIPE FLOW CALCULATIONS
Hydraflow Plan View
103-
5-
--
100^
,102
I 4 3
i,.
i
i�
.10 Year Storm
r
Project File: 20180402 HYDRAFLOW Fishers Island.stm No. Lines: S O4-04-2018
Hydreflow Storm Sewers 2005
i
Storm Sewer Inventory Report Page 1
Line Alignment Flow Data Physical Data Line ID
No.
Dnstr Line DO Junc Known Dmg Runoff Inlet Invert Line Invert Line Line N J-loss Inlet/
line length angle type Q area coeff time EI Dn slope EI Up size type value coeff Rim EI
No. (ft) (deg) (cfs) (ac) (C) (min) (ft) M (ft) (In) (n) (K) (ft)
1 End 20.0 160.2 MH 0.00 0.00 0.00 0.0 10.00 7.00 11.40 18 Cir 0.013 0.15 16.10 FES-TU
2 1 16.0 -4.6 Grate 0.00 027 0.90 5.0 11.40 0.63 11.50 18 Or 0.013 1.11 1620 TU-100
3 2 14.0 -44.1 Grate 0.00 0.17 0.90 5.0 11.50 4.29 12.10 18 Cir 0.013 1.50 1620 100-101
4 3 40.0 88.0 Grate 0.00 0.13 0.41 5.0 12.10 2.00 12.90 18 Or 0.013 0.50 16.70 101-102
5 4 75.0 3.6 Grate 0.00 020 0.60 5.0 12.90 1.47 14.00 18 Cir 0.013 1.00 18.00 102-103
Project File: 20180402_HYDRAFLOW Fishers Island.stm Number of lines:5 Date: 04-04-2018
Hydraflow Storm Sewers 2005
J
Storm Sewer Summary Report Page 1
Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor HGL Dns
No. rate size length EL Dn EL Up slope down up loss Junct line
(cfs) (in) (ft) (ft) (ft) N (ft) (ft) (ft) (ft) No.
1 FES-TU 2.78 18 c 20.0 10.00 11.40 7.000 10.35 12.04 n/a 12.04 End
2 TU-100 2.80 18 c 16.0 11.40 11.50 0.625 12.90 12.91 0.05 12.95 1
3 100-101 1.62 18 c 14.0 11.50 12.10 4.286 13.00 12.98 0.05 13.04 2
4 101-102 0.90 18 c 40.0 12.10 12.90 2.000 13.60 13.59 0.01 13.60 3
5 102-103 0.72 18 c 75.0 12.90 14.00 1.467 14.40 14.42 0.05 14.47 4
Project File: 20180402_HYDRAFLOW_Flshers Island.stm Number of lines:5 Run Date:04-04-2018
NOTES: c=cir; e=ellip; b=box; Return period=10 Yrs.
Hydrallow storm Sewers 2005
Storm Sewer Tabulation Page 1
Station Len Drng Area Rnoff Area x C Tc Rain Total Cap Vel Pipe Invert Elev HGL Elev Gmd 1 Rim Elev Line ID
coeff (1) flow full
Line To Incr Total -Incr Total Inlet Syst Size Slope Up Dn Up Dn Up Dn
Line
(ft) (ac) (ac) (C) (min) (min) (in/hr) (cfs) (cfs) (ft/s) (In) (%) (ft) (ft) (ft) (ft) (ft) (ft)
1 End 20.0 0.00 0.77 0.00 0.00 0.57 0.0 9.6 4.9 2.78 27.78 6.42 18 7.00 11.40 10.00 12.04 10.35 16.10 11.25 FES-TU
2 1 16.0 0.27 0.77 0.90 0.24 0.57 5.0 9.4 4.9 2.80 8.30 1.60 18 0.63 11.50 11.40 12.91 12.90 16.20 16.10 TU-100
3 2 14.0 0.17 0.50 0.90 0.15 0.33 5.0 9.2 5.0 1.62 21.74 120 18 4.29 12.10 11.50 12.98 13.00 16.20 16.20 100-101
4 3 40.0 0.13 0.33 0.41 0.05 0.17 5.0 8.1 5.2 0.90 14.85 0.82 18 2.00 12.90 12.10 13.59 13.60 16.70 16.20 101-102
5 4 75.0 0.20 020 0.60 0.12 0.12 5.0 5.0 6.0 0.72 12.72 1.10 18 1.47 14.00 12.90 14.42 14.40 18.00 16.70 102-103
Project File: 20180402_HYDRAFLOW_Fishers Island.stm Number of lines:5 Run Date: 04-04-2018
NOTES:Intensity=54.74/(Inlet time+10.80)A 0.80; Return period= 10 Yrs.
HydraBow srorm segs 2005
Inlet Report page 1
Line Inlet ID Q Q Q Q Junc Curb Inlet Grate Inlet Gutter Inlet Byp
No CIA carry Capt byp We line
Ht L area L W So W Sw Sx n Depth Spread Depth Spread Depr No
(cfs) (Cfs) (mss) (mss) (in) (ft) (gift) (ft) (ft) (ftHt) (ft) (ft/ft) (ft/ft) (ft) (ft) (ft) (ft) (in)
1 Tu 0.00 0.00 0.00 0.00 MH 0.0 0.00 0.00 0.00 0.00 Sag 0.00 0.000 0.000 0.000 0.00 0.00 0.00 0.00 0.00 Off
2 100 1.46 0.00 1.46 0.00 Grate 0.0 0.00 3.13 3.14 1.63 Sag 2.00 0.080 0.050 0.000 0.18 2.38 0.18 2.38 0.00 Off
3 101 0.92 0.00 0.92 0.00 Grate 0.0 0.00 3.13 3.14 1.63 Sag 2.00 0.080 0.050 0.000 0.13 1.64 0.13 1.64 0.00 Off
4 102 0.32 0.00 0.32 0.00 Grate 0.0 0.00 0.00 3.14 1.63 0.019 2.00 0.080 0.050 0.013 0.14 1.75 0.13 1.64 0.00 3
5 103 0.72 0.00 0.72 0.00 Grate 0.0 0.00 0.00 3.14 1.63 0.013 2.00 0.080 0.050 0.013 0.19 2.60 0.19 2.58 0.00 4
Project File: 20180402_HYDRAFLOW_Flshers Island.stm Number of lines:5 Run Date: 04-04-2018
NOTES: Inlet N-Values= 0.016;Intensity=54.74/(inlet time+10.80)^0.80; Retum period= 10 Yrs.: `Indicates Known Q added
Hydraflow Stam Sewers 2005
APPENDIX C
PONDPACK RESULTS
EXISTING CONDITIONS
Fishers Island Transfer Station
Project Summary
Title Fishers Island
Transfer Station
Engineer Denise P. Lord,
P.E.
Anchor
Company Engineering
Services,Inc.
Date 4/3/2018
Notes
20180403_Fishers Island Transfer Station Bentley Systems,Inc. Haestad Methods Solution Bentley PondPack V8i
EXISTING.ppc Center [08.11.01.54]
4/4/2018 27 Siemon Company Drive Suite 200 W Page 1 of 12
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Table of Contents
Master Network Summary 2
Fishers Island 10
Time-Depth Curve 3
Time-Depth Curve 5
Time-Depth Curve 7
IX to IX Catch Basins 10
Runoff CN-Area 9
DC to West 10
Runoff CN-Area 10
IX to Whistler 10
Runoff CN-Area 11
Fishers Island Transfer Station
Subsection: Master Network Summary
Catchments Summary
Label Scenario Return Hydrograph Time to Peak Peak Flow
Event Volume (hours) (ft3/s)
(years) (ac-ft)
EX to West Pre-Development 10 10 0.046 12.100 0.57
EX to West Pre-Development 25 25 0.060 12.100 0.73
EX to West Pre-Development 50 50 0.071 12.100 0.86
EX to EX Catch Basins Pre-Development 10 10 0.213 12.100 2.50
EX to EX Catch Basins Pre-Development 25 25 0.268 12.100 3.10
EX to EX Catch Basins Pre-Development 50 50 0.311 12.100 3.57
EX to Whistler Pre-Development 10 10 0.058 12.100 0.72
EX to Whistler Pre-Development 25 25 0.076 12.100 0.93
EX to Whistler Pre-Development 50 1 501 0.0901 12.1001 1.09
Node Summary
Label Scenario Return Hydrograph Time to Peak Peak Flow
Event Volume (hours) (ft3/s)
I (years) (ac-ft)
OUT west Pre-Development 10 10 0.046 12.100 0.57
OUT west Pre-Development 25 25 0.060 12.100 0.73
OUT west Pre-Development 50 50 0.071 12.100 0.86
OUT CBs Pre-Development 10 10 0.213 12.100 2.50
OUT CBs Pre-Development 25 25 0.268 12.100 3.10
OUT CBs Pre-Development 50 50 0.311 12.100 3.57
OUT Whistler Pre-Development 10 10 0.058 12.100 0.72
OUT Whistler Pre-Development 25 25 0.076 12.100 0.93
OUT Whistler I Pre-Development 50 1 501 0.0901 12.1001 1.09
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 10 years
Label: Fishers Island Storm Event: 10
Time-Depth Curve- 10
Label 10
Start Time 0.000 hours
Increment 0.100 hours
End Time 24.000 hours
Return Event 10 years
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
_T1-me Depth Depth Depth Depth Depth
(hours) (in) (in) (in) (in) - (in)
0.000 0.0 0.0 0.0 0.0 0.0
0.500 0.0 0.0 0.0 0.0 0.0
1.000 0.1 0.1 0.1 0.1 0.1
1.500 0.1 0.1 0.1 0.1 0.1
2.000 0.1 0.1 0.1 0.1 0.1
2.500 0.1 0.1 0.1 0.1 0.2
3.000 0.2 0.2 0.2 0.2 0.2
3.500 0.2 0.2 0.2 0.2 0.2
4.000 0.2 0.2 0.2 0.2 0.2
4.500 0.3 0.3 0.3 0.3 0.3
5.000 0.3 0.3 0.3 0.3 0.3
5.500 0.3 0.3 0.3 0.4 0.4
6.000 0.4 0.4 0.4 0.4 0.4
6.500 0.4 0.4 0.4 0.4 0.5
7.000 0.5 0.5 0.5 0.5 0.5
7.500 0.5 0.5 0.5 0.6 0.6
8.000 0.6 0.6 0.6 0.6 0.6
8.500 0.7 0.7 0.7 0.7 0.7
9.000 0.7 0.8 0.8 0.8 0.8
9.500 0.8 0.9 0.9 0.9 0.9
10.000 1.0 1.0 1.0 1.0 1.1
10.500 1.1 1.1 1.2 1.2 1.2
11.000 1.3 1.3 1.4 1.4 1.5
11.500 1.5 1.6 1.7 1.9 2.1
12.000 2.6 3.0 3.2 3.4 3.5
12.500 3.6 3.7 3.7 3.8 3.8
13.000 3.8 3.9 3.9 3.9 4.0
13.500 4.0 4.0 4.1 4.1 4.1
14.000 4.2 4.2 4.2 4.2 4.2
14.500 4.3 4.3 4.3 4.3 4.4
15.000 4.4 4.4 4.4 4.4 4.4
15.500 4.5 4.5 4.5 4.5 4.5
16.000 4.5 4.5 4.6 4.6 4.6
16.500 4.6 4.6 4.6 4.6 4.6
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 10 years
Label: Fishers Island Storm Event: 10
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth Depth Depth Depth
i (hours] (in) (in) (in) (in)
17.000 4.7 4.7 4.7 4.7 4.7
17.500 4.7 4.7 4.7 4.7 4.7
18.000 4.8 4.8 4.8 4.8 4.8
18.500 4.8 4.8 4.8 4.8 4.8
19.000 4.8 4.8 4.8 4.9 4.9
19.500 4.9 4.9 4.9 4.9 4.9
20.000 4.9 4.9 4.9 4.9 4.9
20.500 4.9 4.9 4.9 5.0 5.0
21.000 5.0 5.0 5.0 5.0 5.0
21.500 5.0 5.0 5.0 5.0 5.0
22.000 5.0 5.0 5.0 5.0 5.0
22.500 5.0 5.1 5.1 5.1 5.1
23.000 5.1 5.1 5.1 5.1 5.1
23.500 5.1 5.1 5.1 5.1 5.1
24.000 5.1 (N/A) I (N/A) I (N/A) I (N/A)
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 25 years
Label: Fishers Island Storm Event: 25
Time-Depth Curve: 25
Label 25
Start Time 0.000 hours
Increment 0.100 hours
End Time 24.000 hours
Return Event. 25 years
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth Depth
Depth y Depth
j (hours) (in) (in) (in) (in) (in)
0.000 0.0 0.0 0.0 0.0 0.0
0.500 0.0 0.0 0.0 0.0 0.1
1.000 0.1 0.1 0.1 0.1 0.1
1.500 0.1 0.1 0.1 0.1 0.1
2.000 0.1 0.1 0.1 0.1 0.1
2.500 0.2 0.2 0.2 0.2 0.2
3.000 0.2 0.2 0.2 0.2 0.2
3.500 0.2 0.2 0.2 0.3 0.3
4.000 0.3 0.3 0.3 0.3 0.3
4.500 0.3 0.3 0.3 0.3 0.3
5.000 0.4 0.4 0.4 0.4 0.4
5.500 0.4 0.4 0.4 0.4 0.4
6.000 0.4 0.5 0.5 0.5 0.5
6.500 0.5 0.5 0.5 0.5 0.5
7.000 0.6 0.6 0.6 0.6 0.6
7.500 0.6 0.6 0.7 0.7 0.7
8.000 0.7 0.7 0.7 0.8 0.8
8.500 0.8 0.8 0.8 0.9 0.9
9.000 0.9 0.9 1.0 1.0 1.0
9.500 1.0 1.1 1.1 1.1 1.1
10.000 1.2 1.2 1.2 1.3 1.3
10.500 1.3 1.4 1.4 1.5 1.5
11.000 1.5 1.6 1.6 1.7 1.8
11.500 1.8 1.9 2.1 2.3 2.6
12.000 3.1 3.6 3.9 4.1 4.2
12.500 4.3 4.4 4.5 4.5 4.6
13.000 4.6 4.7 4.7 4.8 4.8
13.500 4.8 4.9 4.9 5.0 5.0
14.000 5.0 5.1 5.1 5.1 5.1
14.500 5.2 5.2 5.2 5.2 5.3
15.000 5.3 5.3 5.3 5.4 5.4
15.500 5.4 5.4 5.4 5.5 5.5
16.000 5.5 5.5 5.5 5.5 5.5
16.500 5.6 5.6 5.6 5.6 5.6
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 25 years
Label: Fishers Island Storm Event: 25
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth �� Depth Depth __ Depth
{� (hours) (in) (in) (in) _ (in) -Jin)
17.000 5.6 5.6 5.7 5.7 5.7
17.500 5.7 5.7 5.7 5.7 5.7
18.000 5.7 5.8 5.8 5.8 5.8
18.500 5.8 5.8 5.8 5.8 5.8
19.000 5.8 5.8 5.9 5.9 5.9
19.500 5.9 5.9 5.9 5.9 5.9
20.000 5.9 5.9 5.9 5.9 6.0
20.500 6.0 6.0 6.0 6.0 6.0
21.000 6.0 6.0 6.0 6.0 6.0
21.500 6.0 6.0 6.1 6.1 6.1
22.000 6.1 6.1 6.1 6.1 6.1
22.500 6.1 6.1 6.1 6.1 6.1
23.000 6.1 6.1 6.1 6.2 6.2
23.500 6.2 6.2 6.2 6.2 6.2
24.000 6.2 (N/A) I (N/A) I (N/A) I (N/A)
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 50 years
Label: Fishers Island Storm Event: 50
Time-Depth Curve: 50
Label 50
Start Time 0.000 hours
Increment 0.100 hours
End Time 24.000 hours
Return Event 50 years
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth Depth Depth Depth
i (hours) (in) ' (in) (in) (in) (in)
0.000 0.0 0.0 0.0 0.0 0.0
0.500 0.0 0.0 0.0 0.1 0.1
1.000 0.1 0.1 0.1 0.1 0.1
1.500 0.1 0.1 0.1 0.1 0.1
2.000 0.1 0.1 0.2 0.2 0.2
2.500 0.2 0.2 0.2 0.2 0.2
3.000 0.2 0.2 0.2 0.2 0.2
3.500 0.3 0.3 0.3 0.3 0.3
4.000 0.3 0.3 0.3 0.3 0.3
4.500 0.3 0.4 0.4 0.4 0.4
5.000 0.4 0.4 0.4 0.4 0.4
5.500 0.5 0.5 0.5 0.5 0.5
6.000 0.5 0.5 0.5 0.5 0.6
6.500 0.6 0.6 0.6 0.6 0.6
7.000 0.6 0.7 0.7 0.7 0.7
7.500 0.7 0.7 0.7 0.8 0.8
8.000 0.8 0.8 0.8 0.9 0.9
8.500 0.9 0.9 0.9 1.0 1.0
9.000 1.0 1.0 1.1 1.1 1.1
9.500 1.2 1.2 1.2 1.3 1.3
10.000 1.3 1.4 1.4 1.4 1.5
10.500 1.5 1.6 1.6 1.7 1.7
11.000 1.8 1.8 1.9 1.9 2.0
11.500 2.1 2.2 2.4 2.6 2.9
12.000 3.5 4.1 4.4 4.6 4.8
12.500 4.9 5.0 5.1 5.1 5.2
13.000 5.3 5.3 5.4 5.4 5.5
13.500 5.5 5.5 5.6 5.6 5.7
14.000 5.7 5.7 5.8 5.8 5.8
14.500 5.9 5.9 5.9 5.9 6.0
15.000 6.0 6.0 6.0 6.1 6.1
15.500 6.1 6.1 6.2 6.2 6.2
16.000 6.2 6.2 6.3 6.3 6.3
16.500 6.3 6.3 6.3 6.4 6.4
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 50 years
Label: Fishers Island Storm Event: 50
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth Depth Depth _. Depth
i (hours) (in) (in) (in) (in) (in) _
17.000 6.4 6.4 6.4 6.4 6.4
17.500 6.5 6.5 6.5 6.5 6.5
18.000 6.5 6.5 6.5 6.5 6.6
18.500 6.6 6.6 6.6 6.6 6.6
19.000 6.6 6.6 6.6 6.7 6.7
19.500 6.7 6.7 6.7 6.7 6.7
20.000 6.7 6.7 6.7 6.7 6.8
20.500 6.8 6.8 6.8 6.8 6.8
21.000 6.8 6.8 6.8 6.8 6.8
21.500 6.8 6.9 6.9 6.9 6.9
22.000 6.9 6.9 6.9 6.9 6.9
22.500 6.9 6.9 6.9 6.9 6.9
23.000 7.0 7.0 7.0 7.0 7.0
23.500 7.0 7.0 7.0 7.0 7.0
24.000 7.0 (N/A) I (N/A) I (N/A) I (N/A)
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Fishers Island Transfer Station
Subsection: Runoff CN-Area Return Event: 10 years
Label: EX to EX Catch Basins Storm Event: 10
Runoff Curve Number Data
Soil/Surface Description CN Area C UC Adjusted CN
(acres) (%) (%)
Impervious Areas-Paved parking lots,
roofs,driveways,Streets and roads-Soil 98.000 0.330 0.0 0.0 98.000
B
Impervious Areas-Gravel(w/right-of- 85.000 0.150 0.0 0.0 85.000
way)-Soil B
Open space(Lawns,parks etc.)-Poor 79.000 0.160 0.0 0.0 79.000
condition; grass cover< 50%-Soil B
COMPOSITE AREA&WEIGHTED CN---> (N/A) 0.640 (N/A) (N/A) 90.203
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Fishers Island Transfer Station
Subsection: Runoff CN-Area Return Event: 10 years
Label: EX to West Storm Event: 10
Runoff Curve Number Data
Soil/Surface Description CN Area C UC Adjusted CN
I (acres) (%) (%)
Impervious Areas-Gravel(w/right-of- 85.000 0.110 0.0 0.0 85.000
way)-Soil B
Open space(Lawns,parks etc.)-Poor 79.000 0.060 0.0 0.0 79.000
condition; grass cover< 50%-Soil B
COMPOSITE AREA&WEIGHTED CN---> (N/A) 0.170 (N/A) (N/A) 82.882
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Fishers Island Transfer Station
Subsection: Runoff CN-Area Return Event: 10 years
Label: EX to Whistler Storm Event: 10
Runoff Curve Number Data
Soil/Surface Description CN Area C UC Adjusted CN
(acres)
Impervious Areas-Paved parking lots,
roofs,driveways,Streets and roads-Soil 98.000 0.040 0.0 0.0 98.000
B
Open space(Lawns,parks etc.)-Poor 79,000 0.180 0.0 0.0 79.000
condition; grass cover< 50%-Soil B
COMPOSITE AREA&WEIGHTED CN---> I (N/A) 1 0.220 (N/A) I (N/A) 1 82.455
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Fishers Island Transfer Station
Index
E
EX to EX Catch Basins(Runoff CN-Area, 10 years)...9
EX to West(Runoff CN-Area, 10 years)...10
EX to Whistler(Runoff CN-Area, 10 years)...11
F
Fishers Island(Time-Depth Curve, 10 years)...3,4
Fishers Island(Time-Depth Curve,25 years)...5,6
Fishers Island(Time-Depth Curve,50 years)...7,8
M
Master Network Summary...2
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PROPOSED CONDITIONS
Fishers Island Transfer Station
Project Summary
Title Fishers Island
Transfer Station
Engineer Denise P. Lord,
P.E.
Anchor
Company Engineering
Services,Inc.
Date 4/3/2018
Notes Proposed Conditions
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Table of Contents
Master Network Summary 2
Fishers Island 10
Time-Depth Curve 3
Time-Depth Curve 5
Time-Depth Curve 7
Prop Area to Basin 10
Runoff CN-Area 9
Prop Area to South 10
Runoff CN-Area 10
Stormwater Basin Elevation-Area Volume 11
Curve
Composite Outlet Composite Rating Curve 12
Structure- 1
Stormwater Basin Elevation-Volume-Flow 13
Table(Pond)
Fishers Island Transfer Station
Subsection: Master Network Summary
Catchments Summary
i Label Scenario Return_ Hydrograph _ Time to Peak Peak Flow
Event Volume (hours) (ft3/s)
! (years). (ac-ft)
Prop Area to Basin Post-Development 10 10 0.309 12.100 3.63
Prop Area to Basin Post-Development 25 25 0.390 12.100 4.51
Prop Area to Basin Post-Development 50 50 0.453 12.100 5.19
Prop Area to South Post-Development 10 10 0.041 12.100 0.43
Prop Area to South Post-Development 25 25 0.050 12.100 0.52
Prop Area to South Post-Development 50 50 0.056 12.100 0.59
Node Summary
Label Scenario Return Hydrograph Time to Peak Peak Flow
Event Volume (hours) (ft3/s)
I (years) (ac-ft)
OUT from Basin Post-Development 10 10 0.103 13.000 0.36
OUT from Basin Post-Development 25 25 0.183 12.350 1.67
OUT from Basin Post-Development 50 50 0.246 12.200 2.97
OUT to South Post-Development 10 10 0.041 12.100 0.43
OUT to South Post-Development 25 25 0.050 12.100 0.52
OUT to South Post-Development 50 50 0.056 12.1001 0.59
Pond Summary
Label Scenario Return Hydrograph Time to Peak Peak Flow Maximum Maximum
I Event Volume. (hours) (ft3/s) Water Pond Storage
(years) (ac-ft) Surface (ac-ft)
Elevation
i (ft)
Stormwater Post-
Basin
oiBasin(IN) Development 10 0.309 12.100 3.63 (N/A) (N/A)
10
Stormwater Post-
Basin
owBasin(OUT) Development 10 0.103 13.000 0.36 13.04 0.208
10
Stormwater Post-
Basin
owBasin(IN) Development 25 0.390 12.100 4.51 (N/A) (N/A)
25
Stormwater Post
Basin(OUT) Development 25 0.183 12.350 1.67 13.17 0.216
25
Stormwater Post
Basin(IN) Development 50 0.453 12.100 5.19 (N/A) (N/A)
50
Stormwater Post-
Basin
owBasin(OUT) Development 50 0.246 12.200 2.97 33.30 0.224
50
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 10 years
Label: Fishers Island Storm Event: 10
Time-Depth Curve: 10
Label 10
Start Time 0.000 hours
Increment 0.100 hours
End Time 24.000 hours
Return Event 10 years
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth ^Depth Depth Depth
(hours) (in) (in) (in) (in) (in)
0.000 0.0 0.0 0.0 0.0 0.0
0.500 0.0 0.0 0.0 0.0 0.0
1.000 0.1 0.1 0.1 0.1 0.1
1.500 0.1 0.1 0.1 0.1 0.1
2.000 0.1 0.1 0.1 0.1 0.1
2.500 0.1 0.1 0.1 0.1 0.2
3.000 0.2 0.2 0.2 0.2 0.2
3.500 0.2 0.2 0.2 0.2 0.2
4.000 0.2 0.2 0.2 0.2 0.2
4.500 0.3 0.3 0.3 0.3 0.3
5.000 0.3 0.3 0.3 0.3 0.3
5.500 0.3 0.3 0.3 0.4 0.4
6.000 0.4 0.4 0.4 0.4 0.4
6.500 0.4 0.4 0.4 0:4 0.5
7.000 0.5 0.5 0.5 0.5 0.5
7.500 0.5 0.5 0.5 0.6 0.6
8.000 0.6 0.6 0.6 0.6 0.6
8.500 0.7 0.7 0.7 0.7 0.7
9.000 0.7 0.8 0.8 0.8 0.8
9.500 0.8 0.9 0.9 0.9 0.9
10,000 1.0 1.0 1.0 1.0 1.1
10.500 1.1 1.1 1.2 1.2 1.2
11.000 1.3 1.3 1.4 1.4 1.5
11.500 1.5 1.6 1.7 1.9 2.1
12.000 2.6 3.0 3.2 3.4 3.5
12.500 3.6 3.7 3.7 3.8 3.8
13.000 3.8 3.9 3.9 3.9 4.0
13.500 4.0 4.0 4.1 4.1 4.1
14.000 4.2 4.2 4.2 4.2 4.2
14.500 4.3 4.3 4.3 4.3 4.4
15.000 4.4 4.4 4.4 4.4 4.4
15.500 4.5 4.5 4.5 4.5 4.5
16.000 4.5 4.5 4.6 4.6 4.6
16.500 4.6 4.6 4.6 4.6 4.6
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 10 years
Label: Fishers Island Storm Event: 10
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth ^- Depth Depth Depth
I (hours)_ (in) _ (in) (in) (in) _ (in) '
17.000 4.7 4.7 4.7 4.7 4.7
17.500 4.7 4.7 4.7 4.7 4.7
18.000 4.8 4.8 4.8 4.8 4.8
18.500 4.8 4.8 4.8 4.8 4.8
19.000 4.8 4.8 4.8 4.9 4.9
19.500 4.9 4.9 4.9 4.9 4.9
20.000 4.9 4.9 4.9 4.9 4.9
20.500 4.9 4.9 4.9 5.0 5.0
21.000 5.0 5.0 5.0 5.0 5.0
21.500 5.0 5.0 5.0 5.0 5.0
22.000 5.0 5.0 5.0 5.0 5.0
22.500 5.0 5.1 5.1 5.1 5.1
23.000 5.1 5.1 5.1 5.1 5.1
23.500 5.1 5.1 5.1 5.1 5.1
24.000 5.1 (N/A) I (N/A) I (N/A) I (N/A)
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 25 years
Label: Fishers Island Storm Event: 25
Time-Depth Curve: 25
Label 25
Start Time 0.000 hours
Increment 0.100 hours
End Time 24.000 hours
Return Event 25 years
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth .Depth Depth Depth
4 (hours) (in) (in) (in) (in) (in)
0.000 0.0 0.0 0.0 0.0 0.0
0.500 0.0 0.0 0.0 0.0 0.1
1.000 0.1 0.1 0.1 0.1 0.1
1.500 0.1 0.1 0.1 0.1 0.1
2.000 0.1 0.1 0.1 0.1 0.1
2.500 0.2 0.2 0.2 0.2 0.2
3.000 0.2 0.2 0.2 0.2 0.2
3.500 0.2 0.2 0.2 0.3 0.3
4.000 0.3 0.3 0.3 0.3 0.3
4.500 0.3 0.3 0.3 0.3 0.3
5.000 0.4 0.4 0.4 0.4 0.4
5.500 0.4 0.4 0.4 0.4 0.4
6.000 0.4 0.5 0.5 0.5 0.5
6.500 0.5 0.5 0.5 0.5 0.5
7.000 0.6 0.6 0.6 0.6 0.6
7.500 0.6 0.6 0.7 0.7 0.7
8.000 0.7 0.7 0.7 0.8 0.8
8.500 0.8 0.8 0.8 0.9 0.9
9.000 0.9 0.9 1.0 1.0 1.0
9.500 1.0 1.1 1.1 1.1 1.1
10.000 1.2 1.2 1.2 1.3 1.3
10.500 1.3 1.4 1.4 1.5 1.5
11.000 1.5 1.6 1.6 1.7 1.8
11.500 1.8 1.9 2.1 2.3 2.6
12.000 3.1 3.6 3.9 4.1 4.2
12.500 4.3 4.4 4.5 4.5 4.6
13.000 4.6 4.7 4.7 4.8 4.8
13.500 4.8 4.9 4.9 5.0 5.0
14.000 5.0 5.1 5.1 5.1 5.1
14.500 5.2 5.2 5.2 5.2 5.3
15.000 5.3 5.3 5.3 5.4 5.4
15.500 5.4 5.4 5.4 5.5 5.5
16.000 5.5 5.5 5.5 5.5 5.5
16.500 5.6 5.6 5.6 5.6 5.6
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 25 years
Label: Fishers Island Storm Event: 25
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth Depth Depth Depth
(hours) _ (in) .(in) _ (in) (in) (in)
17.000 5.6 5.6 5.7 5.7 5.7
17.500 5.7 5.7 5.7 5.7 5.7
18.000 5.7 5.8 5.8 5.8 5.8
18.500 5.8 5.8 5.8 5.8 5.8
19.000 5.8 5.8 5.9 5.9 5.9
19.500 5.9 5.9 5.9 5.9 5.9
20.000 5.9 5.9 5.9 5.9 6.0
20.500 6.0 6.0 6.0 6.0 6.0
21.000 6.0 6.0 6.0 6.0 6.0
21.500 6.0 6.0 6.1 6.1 6.1
22.000 6.1 6.1 6.1 6.1 6.1
22.500 6.1 6.1 6.1 6.1 6.1
23.000 6.1 6.1 6.1 6.2 6.2
23.500 6.2 6.2 6.2 6.2 6.2
24.000 6.2 (N/A) I (N/A) I (N/A) I (N/A)
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 50 years
Label: Fishers Island Storm Event: 50
Time-Depth Curve: 50
Label 50
Start Time 0.000 hours
Increment 0.100 hours
End Time 24.000 hours
Return Event 50 years
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth Depth Depth Depth
j (hours) (in) (in) (in) (in) (in)
0.000 0.0 0.0 0.0 0.0 0.0
0.500 0.0 0.0 0.0 0.1 0.1
1.000 0.1 0.1 0.1 0.1 0.1
1.500 0.1 0.1 0.1 0.1 0.1
2.000 0.1 0.1 0.2 0.2 0.2
2.500 0.2 0.2 0.2 0.2 0.2
3.000 0.2 0.2 0.2 0.2 0.2
3.500 0.3 0.3 0.3 0.3 0.3
4.000 0.3 0.3 0.3 0.3 0.3
4.500 0.3 0.4 0.4 0.4 0.4
5.000 0.4 0.4 0.4 0.4 0.4
5.500 0.5 0.5 0.5 0.5 0.5
6.000 0.5 0.5 0.5 0.5 0.6
6.500 0.6 0.6 0.6 0.6 0.6
7.000 0.6 0.7 0.7 0.7 0.7
7.500 0.7 0.7 0.7 0.8 0.8
8.000 0.8 0.8 0.8 0.9 0.9
8.500 0.9 0.9 0.9 1.0 1.0
9.000 1.0 1.0 1.1 1.1 1.1
9.500 1.2 1.2 1.2 1.3 1.3
10.000 1.3 1.4 1.4 1.4 1.5
10.500 1.5 1.6 1.6 1.7 1.7
11.000 1.8 1.8 1.9 1.9 2.0
11.500 2.1 2.2 2.4 2.6 2.9
12.000 3.5 4.1 4.4 4.6 4.8
12.500 4.9 5.0 5.1 5.1 5.2
13.000 5.3 5.3 5.4 5.4 5.5
13.500 5.5 5.5 5.6 5.6 5.7
14.000 5.7 5.7 5.8 5.8 5.8
14.500 5.9 5.9 5.9 5.9 6.0
15.000 6.0 6.0 6.0 6.1 6.1
15.500 6.1 6.1 6.2 6.2 6.2
16.000 6.2 6.2 6.3 6.3 6.3
16.500 6.3 6.3 6.3 6.4 6.4
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Fishers Island Transfer Station
Subsection: Time-Depth Curve Return Event: 50 years
Label: Fishers Island Storm Event: 50
CUMULATIVE RAINFALL(in)
Output Time Increment = 0.100 hours
Time on left represents time for first value in each row.
Time Depth Depth Depth Depth Depth
(hours) (in) (in) (in) (in) (in)
17.000 6.4 6.4 6.4 6.4 6.4
17.500 6.5 6.5 6.5 6.5 6.5
18.000 6.5 6.5 6.5 6.5 6.6
18.500 6.6 6.6 6.6 6.6 6.6
19.000 6.6 6.6 - 6.6 6.7 6.7
19.500 6.7 6.7 6.7 6.7 6.7
20.000 6.7 6.7 6.7 6.7 6.8
20.500 6.8 6.8 6.8 6.8 6.8
21.000 6.8 6.8 6.8 6.8 6.8
21.500 6.8 6.9 6.9 6.9 6.9
22.000 6.9 6.9 6.9 6.9 6.9
22.500 6.9 6.9 6.9 6.9 6.9
23.000 7.0 7.0 7.0 7.0 7.0
23.500 7.0 7.0 7.0 7.0 7.0
24.000 7.0 (N/A) I (N/A) I (N/A) I (N/A)
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Fishers Island Transfer Station
Subsection: Runoff CN-Area Return Event: 10 years
Label: Prop Area to Basin Storm Event: 10
Runoff Curve Number Data
E Soil/Surface Description CN Area' -~ C uc Adjusted CN�
1 (acres) (%) M
Impervious Areas-Paved parking lots,
roofs,driveways,Streets and roads-Soil 98.000 0.620 0.0 0.0 98.000
B
Impervious Areas-Gravel(w/right-of- 85.000 0.080 0.0 0.0 85.000
way)-Soil B
Open space(Lawns,parks etc.)-Fair
condition;grass cover 50%to 75%-Soil 69.000 0.230 0.0 0.0 69.000
B
COMPOSITE AREA&WEIGHTED CN---> (N/A) 0.930 (N/A) (N/A) 89.710
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Fishers Island Transfer Station
Subsection: Runoff CN-Area Return Event: 10 years
Label: Prop Area to South Storm Event: 10
Runoff Curve Number Data
Soil/Surface Description CN Area Adjusted CNS
j (acres)
Impervious Areas-Paved parking lots,
roofs,driveways,Streets and roads-Soil 98.000 0.100 0.0 0.0 98.000
B
COMPOSITE AREA&WEIGHTED CN---> (N/A) 0.100 (N/A) (N/A) 98.000
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Fishers Island Transfer Station
Subsection: Elevation-Area Volume Curve Return Event: 10 years
Label: Stormwater Basin Storm Event: 10
f-Elevation Planimeter Area A1+A2+sqrVolume Volume(Total)
(ft) (ftz) (acres) (Al*A2) (ac-ft) - (ac-ft)
.(acres)
7.00 0.0 0.009 0.000 0.000 0.000
8.00 0.0 0.020 0.043 0.014 0.014
10.00 0.0 0.034 0.081 0.054 0.068
12.00 0.0 0.050 0.125 0.084 0.152
14.00 0.0 0.069 0.177 0.118 0.270
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Fishers Island Transfer Station
Subsection: Composite Rating Curve Return Event: 10 years
Label: Composite Outlet Structure - 1 Storm Event: 10
Composite Outflow Summary
Water Surface Flow = Tailwater Elevation, Convergence Error
Elevation (ft3/s) - (ft) (ft)
(ft)
7.00 0.00 (N/A) 0.00
7.50 0.00 (N/A) 0.00
8.00 0.00 (N/A) 0.00
8.50 0.00 (N/A) 0.00
9.00 0.00 (N/A) 0.00
9.50 0.00 (N/A) 0.00
10.00 0.00 (N/A) 0.00
10.50 0.00 (N/A) 0.00
11.00 0.00 (N/A) 0.00
11.50 0.00 (N/A) 0.00
12.00 0.00 (N/A) 0.00
12.50 0.00 (N/A) 0.00
13.00 0.00 (N/A) 0.00
13.50 4.99 (N/A) 0.00
14.001 16.24 (N/A) 1 0.00
Contributing Structures
None Contributing
None Contributing
None Contributing
None Contributing
None Contributing
None Contributing
None Contributing
None Contributing
None Contributing
None Contributing
None Contributing
None Contributing
Weir- 1
Weir- 1
Weir- 1
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Fishers Island Transfer Station
Subsection: Elevation-Volume-Flow Table(Pond) Return Event: 10 years
Label: Stormwater Basin Storm Event: 10
Infiltration
Infiltration Method No Infiltration
(Computed)
Initial Conditions
Elevation(Water Surface, 7.00 ft
Initial)
Volume(Initial) 0.000 ac-ft
Flow(Initial Outlet) 0.00 ft3/s
Flow(Initial Infiltration) 0.00 ft3/s
Flow(Initial,Total) 0.00 ft3/s
Time Increment 0.050 hours
Elevation Outflow Storage Area Infiltration Flow(Total) 2S/t+0
(ft) (ft3/s) (ac-ft) (acres) (ft3/s) (ft3/s) (ft3/s)
7.00 0.00 0.000 0.009 0.00 0.00 0.00
7.50 0.00 0.006 0.014 0.00 0.00 2.77
8.00 0.00 0.014 0.020 0.00 0.00 6.91
8.50 0.00 0.025 0.023 0.00 0.00 12.19
9.00 0.00 0.038 0.027 0.00 0.00 18.25
9.50 0.00 0.052 0.030 0.00 0.00 25.14
10.00 0.00 0.068 0.034 0.00 0.00 32.91
10.50 0.00 0.086 0.038 0.00 0.00 41.58
11.00 0.00 0.106 0.042 0.00 0.00 51.19
11.50 0.00 0.128 0.046 0.00 0.00 61.78
12.00 0.00 0.152 0.050 0.00 0.00 73.39
12.50 0.00 0.178 0.054 0.00 0.00 86.04
13.00 0.00 0.206 0.059 0.00 0.00 99.77
13.50 4.99 0.237 0.064 0.00 4.99 119.59
14.001 16.241 0.2701 0.0681 0.001 16.241 146.83
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Fishers Island Transfer Station
Index
C
Composite Outlet Structure- 1(Composite Rating Curve, 10 years)...12
F
Fishers Island(Time-Depth Curve, 10 years)...3,4
Fishers Island(Time-Depth Curve,25 years)...5,6
Fishers Island(Time-Depth Curve,50 years)...7,8
M
Master Network Summary...2
P
Prop Area to Basin(Runoff CN-Area, 10 years)...9
Prop Area to South(Runoff CN-Area, 10 years)...10
S
Stormwater Basin(Elevation-Area Volume Curve, 10 years)...11
Stormwater Basin(Elevation-Volume-Flow Table(Pond), 10 years)...13
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APPENDIX D
MISCELLANEOUS
NOAA Atlas 14, Volume 10, Version 2
Location name: Fishers Island, New
- - York, USA* �
Latitude: 41.25450
,
Longitude:-72.034
Elevation: 22.24 ft**
*source: ESRI Maps
**source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Sandra Pavlovic, Michael St. Laurent, Carl Trypaluk,
Dale Unruh, Orlan Wilhite
NOAH, National Weather Service, Silver Spring, Maryland
PF-Jabular I PF gra hg ical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Average recurrence Interval(years)
1 2 5 10 25 50 100 200 500 1000
5�nin 0.333 0.400 0.509 0.600 0.725 0.822 -0.91-8-]F-15-51F-1-21 1.34
(0.253-0.436) (0.303-0.524) (0.385-0.669) (0.452-0.791) (0.532-0.985) (0.592-1.13) (0.646-1.30) (0.698-1.49) (0.783-1.76) (0.847-1.97)
10-min 0.472 -O-.5-67-7F-O.-7-2-2--]F-O.-85-0 1.03 F-1.4-87-1372-7F-1590-
1(0.358-0.618)1(0.430-0.742)11(0.546-0.947)1(0.640-1.12) (0.753-1.40) (0.8391.60) (0.9161.84)1(0.989-2.11)11(1.11-2.50) (1.20-2.79)
15-min 0.555 0.667 0.849 1.00 1.21 1.37 1.53 1.74 2.02 2.23
1(0.421-0.726)11(0.506-0.873)11(0.642-112) (0.753 1.32) (0.886-1.64) (0.987-1.89) (1.08 2.16) (1 16 2.48) (1.31-2.94) (1.41-3.29)
30-min 0.785 0.941 1.20 1.41 1.70 1.93 2.15 2.45 2.84 3.13
(0.596-1.03) (0.714-1.23) (0.905-1.57) 1 (1.25-2.31) (1.39-2.65) (1.52 3.04) (1.64 3.48) (1.83-4.13) (1.98-4.61)
60-min 1.01 1.22 1.55 1.82 2.19 2.49 2.78 3.15 3.65 4.03
(0.770-1.33)1 1 (1.37-2.40) (1.61 2.98) (1.79-3.42) (1.95 3.92) (2.11 4 49) 1(2.36-5.31)11(2.55-5.94)
2-hr1.33 1.60 2.03 2.39 2.89 3.27 3.66 4.16 .8
42 5.32
(1.02-1.72) 11 (1.23-2.07) 1 (1.56-2.64) 1 (1.82-3.12) 1 (2.14-3.88) (2.38-4.46) (2.60 5.12) 1(2.80-5.86)11(3.13-6.95) (3.38-7.77)
3-hr1.55 1.86 2.36 2.78 -3.-36---]F-3.8-0 4.25 4.83 5.59 6.18
(1.20-1.99) (1.43-2.39) (1.82-3.04) (2.13-3.60) (2.50-4.48) 1(2.78-5.15)
(3.03 5.91) (3.26-6.77) (3.65-8.03) (3.94-8.98)
6-hr1.97 2.35 7 F 2.99 3.52 4.25 F 5.37 F 6.10 7.07 7.80
(1.54-2.50) 11 (1.84-2.99) 11 (2.33-3.81) 1 (2.73-4.50) 1 (3.20-5.60) (3.556.44) (3.86-7.40) 1(4.15-8.48)11(4.64-10.1) (5.01-11.3)
12-hr 2'43 2.91 3.69 4.33 5.23 5.91 6.60 7.51 8.71 9.62
(1.92-3.05) 11 (2.30-3.65) 1 (2.91-4.64) 1 (3.40-5.48) 1 (3.98-6.82) (4417.84) (4.79-9.01) (5.15-10.3) (5.75-12.3) (6.21-13.8)
24-hr 2.83 3.41 4.34 5.12 6.19 7.02 7.84 8.98 10.5 11.6
(2.27-3.51) 1 1 (3.47-5.40) 1 (4 76-8.01) (5.30-9.23) (5.76 10.6) 1(6.20-12.2)11(6.96-14.7)
2-day 3.14F-358-177-4--967F- 5-.8l-7F-7-.O6-7F-8-.0-27F-8.9-97F-1-0-.4-7F--12-.2--]F 13.6
(2.55 3.85) 1 (3.09-4.67) 11 (3.96-6.02) 1 (4.67-7.17) 1 (5.50-9.04) (6.13-10.5) (6.68-12.1) (7.22-14.0) (8.16-16.9) (8.87-19.1)
3�ay3.39 4.10 5.26 6.23 7.55 8.57 9.60 11.1 13.0
(2.77-4.12) 11 (3.35-4.99) 1 (4.28-6.42) 1 (5.04-7.62) 1(6.58-11.1) 1(7.17-12.9) (7.73 14.9) (8.73-17.9) (9.48 20.3
4-day3.63 4.37 5.57 6.56 7.83 ) 8.99 10.0 11.5 13.5 15.0
(2.99-4.39) (3.58-5.28) (4.55-6.75) (5.34-7.99) (6.24 10.0 1 (6.93-11.6)
1(7.53-13.4) (8.09 15.4) (9.10-18.6) (9.86-21.0)
7-day 4.31 5.09 6.36 7.42 8.87 9.99 11.1 12.6 14.6 16.1
(3.58-5.16) 11 (4.22-6.10) 11 (5.26-7.64) 1 (6.09-8.94) (7.0311.1) (7.75-12.7) (8.3514.6) (8.90-16.7)11(9.88-19.9) (10.6-22.3)
10-day 4.98 5.79 7.11 8.20 9.70 -10-.-97F-12.0--jr-13.5 15.5 16.9
(4.17-5.92) 11 (4.83-6.89) 1 (5.91-8.48) 1 (6.78-9.82) 1 (7.73-12.0) (8.46-13.7) (9.05-15.6) (9.57-17.8) (10.5 21.0) (11.2-23.3)
20-day 7.04 7.91 9.34 10.5 12.1 13.4 14.7 16.0 17.8 19.2
I I (5.96-8.26) 11 (6.69-9.30) (7.87-11.0) 1 (8.81-12.4) 1 (9.78-14.8) 1(10.5-16.6)11(11.1-18.6) (11.5-20.9) (12.2-23.9) (12.7-262)
30�1ay 8.76 9.69 112 12.5 142 ) 15.5 16.9 ) ( 18.1 19.8 21.1 )
(7.48-10.2) (826-11.3) (9.51 13.1) (10.5-14.6) (11.5-17.1 (12.2-19.0) (12.7 21.2 13.0 23.5) (13.6-26.4) (14.0-28.6
45�ay 10.9 11.9 13.5 14.9 16.8 18.2 19.6 20.8 22.4 23.5
(9.38-12.6) (102 13.8) (11.6-15.7) 1 (12.7-17.4) 1 (13.7-20.0) (14.4-22.1) (14.9-24.4) 1(15.1-26.8)11(15.4-29.6) (15.7-31.8)
60�ay 15.5 17.0 18.9 20.5 22.0 23.1 24.6 25.7
[��F-13.8
(11.9-15.8) (13.3 17.9) (14.5-19.6) (15.5 22.5) (16.3 24.7) (16.7 27.1) (16.8 29.6) (17.0 32.5) (17.2 34.6)
Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency
estimates(for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at
upper bounds are not checked against probable ma)dmum precipitation(PMP)estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Anchor Engineering Services,Inc. 1096 West Street(RT 229)
Southington,CT
PROPOSED TREATMENT STRUCTURE SIZING
Compute Water Quality Volume
WQV=Water Quality Volume(acre-feet)
R=Volumetric Runoff Coefficient,0.050+0.009(I)
KQv _ (1"xR x A) I=Percent Impervious Cover,Impervious Area/Total Area
12 DA=Drainage Area(Acres) DA= 0.770 acres
IA=Impervious Area(Acres) IA= 0.570 acres
Determine Percent Impervious Cover(I) Calculate Volumetric Runoff Coefficient(R)
I= 74% R= 0.72
Calculate Water Quality Volume
WQV= 0.046 acre-feet
Compute Runoff Depth
(WQV x 12) Q=Runoff Depth(in watershed inches)
Q(N) = DA WQV=Water Quality Volume(acre-feet)
DA=Drainage Area(acres)
Q(;,,)= 0.72 watershed inches
Determine NCRS Curve Number(CN)
Q(;,,)= 0.72 watershed inches P= 1 in
From Appendix B.Figure 2-1 of the 2004 Connecticut Stormwarer Manual
CN= 96
Determine Initial Abstraction(I,)
From Appendix B.Table 4-1 of the 2004 Connecticut Stormwarer Manual
I,= 0.083 inches
Determine Unit Peak Discharge(q„)
Time of Concentration(T,),referenced from Pipe Flow Calculation Worksheet
Tc= 0.16 hours
I,/P= 0.083
From Appendix B.Exhibit 4-111 of the 2004 Connecticut Stormwater Manual
q„= 610 csm/in
Compute Water Quality Flow
WQF=Water Quality Flow(cfs)
WQF=q.x DAxQ(in) qu=unit peak discharge(cfs/mit/inch)
DA=drainage area(mit)
Q(in)=runoff depth(watershed inches)
Hydroworks Hydroguard model or approved equal shall be substituted for
WQF= 0.526 cfs Use Vortechs Model 1000 vortechnics model
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