Post development storm EmpireEng FINAL REPORT

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Post-Development Memo

Empire Engineering, Inc.555 Five St.Over there, Florida 77777 Phone: (407) 555-5555

To: Larry Wray, P.E.Jeremy Morton, P.E.

CC:

From: Empire Engineering, Inc.

Date: 6/16/2015

RE: POST-DEVELOPMENT STORMWATER REPORTCapstone Senior Design

1. Post-Development Basin Map

a. Basin Divide Lines and Names

i. The basins were divided up based on the two dry retention ponds placed

on our site. Basin 1 flows into pond 1 which is our larger pond by

volume located at the south east portion of our property while basin 2

flows to pond 2 which is located on the north portion of our property by

the apartment complex.

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b. Node Names

i. Each of the basins led to a node which was a pond. Basin 1 leads to pond 1

and basin 2 leads to pond 2. Each pond then leads to its boundary node with

Pond 1 going to OBT 1 and Pond 2 going to OBT 2.

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c. Tc Paths

i. For the Tc paths we just had the flow of rainfall to drain towards our ponds

split at the basin divide line.

*Flow example for pond 1

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2. Nodal Diagram

a. A nodal diagram was generated in Microsoft paint to help visualize the basin

and node paths and this also was helpful as a reference for developing nodes

and basins in the ICPR program.

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3. Basin Composite CN Calculation Tables

a. We had to calculate the DCIA% and change our composite curve number using

developed area curve numbers and good soil for open space for what we called

our “pre-post” development. This means the property had impervious and

changed basin divides all in order to size our pond correctly. As stated in table

2-2a of the TR-55 for open space and an A hydrologic soil group in good

condition there were 3 different curve numbers that were applicable. We

chose good under the assumption that most of the property was grass and that

had a curve # of 39 (this included the pond area because we chose dry retention

ponds) and our developed area (impervious) had a curve number of 98.

Area IA DCIA %DCIA Sq. Ft AcresBasin 1 40.27 13.75 10.04 24.9 Apt. 19224.1

40.441

Basin 2 21.05 10.57 3.65 17.3 Office 39025 0.896retail 45796 1.05Pond 1 262934.

83.21

Pond 2 76000 1.41

Basin 1 Basin 2Open Space Impervious Non-DCIA Open

SpaceImperviou

sNon-DCIA

CN 39 98 98 CN 39 98 98Acres 26.52 13.75 3.71 Acres 10.48 10.57 6.92CN-Acre

1034.28 363.58 CN-Acre

408.72 678.16

Composite CN 46.24 Composite CN 62.46

4. Time of Concentration Calculations

a. The Tc calculations (time of concentration) were assumed to be 10 minutes

for a developed area.

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5. Water Quality Calculations

a. SJRWMD Applicant’s Handbook Requirement

i. Based off the applicant’s handbook for the St. John’s River Water Management District the treatment volume is retention of the first one-half inch of runoff or 1.25 inches of runoff from the impervious area, whichever is greater for an offline system and additional one half inch of runoff from the drainage area over that volume specified for off-line treatment for an online system which is what we have.

Basin 1

Treatment Volume 1" of runoff over drainage area = 3.36 acre-ft1.25" runoff over impervious area = 1.43 acre-ft

Basin 2Treatment Volume 1" of runoff over drainage area = 1.75 acre-ft

1.25" runoff over impervious area = 1.10 acre-ft

b. Pond Stage, Area and Volume

i. For each pond we ran an ICPR report known as “pre-post” before the ponds were “developed” to get a flow to size our ponds to a correct depth.

Runoff (in) Area (acre) V (acre-ft)Basin 1 3.637 40.27 12.21Basin 2 4.669 21.05 8.19

ii. It was then decided that 40% of our runoff would be retained with the rest being sent to the boundary and this was to help stage the pond and set the peak warning stage.

40% Runoff RetentionRunoff (in) Area (acre) V (acre-ft)

Basin 1 1.4548 40.27 4.88Basin 2 1.8676 21.05 3.28

This gave us a way to set a proper stage for each pond using a 4:1 sloping ratio in each basin and allowed us to see if our depth would be allowable given the bore samples water table

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levels.

Pond 1

Stage (ft) Length (ft) Width (ft) Area (sq ft)

Volume (per 1 ft h)

Cumulative Volume (cubic

ft)

Cumulative Volume (Acre-

ft)

94 350 200 70000 67832 297720 6.835

93 342 192 65664 63560 229888 5.278

92 334 184 61456 59416 166328 3.818

91 326 176 57376 55400 106912 2.454

90 318 168 53424 51512 51512 1.183

89 310 160 49600 0 0 0.000

Peak Stage (WQV is provided here)92.73 4.88

Pond 2

Stage (ft) Length (ft) Width (ft) Area (sq ft)

Volume (per 1 ft h)

Cumulative Volume (cubic

ft)

Cumulative Volume (Acre-ft)

126 350 250 87500 85132 380220 8.729125 342 242 82764 80460 295088 6.774124 334 234 78156 75916 214628 4.927123 326 226 73676 71500 138712 3.184122 318 218 69324 67212 67212 1.543121 310 210 65100 0 0 0.000

Peak Stage (WQV is provided here)123.11 3.28

6. Pond Design

7. Stormwater Pipe Network Design (2 pipes and 2 inlets)

Pipe Sizing Calculations

Inlet 1)Q=ciA

Q1=(0.9 )(8.5 ¿hr ) (0.551ac )=4.22cfs

Inlet 2)

Q= (0.9 )(8.5 ¿hr ) (0.574 ac )=4.39cfs

Q2=4.22+4.39=8.61 cfsPipe 1)

Q=1.49nA R

23 √S

4.22=( 1.490.013 )( π d

2

4 )( d4 )23 √0.02

d1=0.94 ft=11.2∈¿

Use 12” RCPPipe 2)

8.61=( 1.490.013 )( π d

2

4 )( d4 )23 √0.02

d2=1.22 ft=14.7∈¿

Use 15” RCP

8. ICPR Input Report========================================================================================== ==== Basins ========================================================================================================================================================================

Name: Basin 1 Node: Pond 1 Status: Onsite Group: BASE Type: SCS Unit Hydrograph CN

Unit Hydrograph: Uh256 Peaking Factor: 256.0 Rainfall File: Storm Duration(hrs): 0.00 Rainfall Amount(in): 0.000 Time of Conc(min): 10.00 Area(ac): 40.270 Time Shift(hrs): 0.00 Curve Number: 46.24 Max Allowable Q(cfs): 999999.000 DCIA(%): 25.00

---------------------------------------------------------------------------------------------------- Name: Basin 2 Node: Pond 2 Status: Onsite Group: BASE Type: SCS Unit Hydrograph CN

Unit Hydrograph: Uh256 Peaking Factor: 256.0 Rainfall File: Storm Duration(hrs): 0.00 Rainfall Amount(in): 0.000 Time of Conc(min): 10.00 Area(ac): 21.050 Time Shift(hrs): 0.00 Curve Number: 62.50 Max Allowable Q(cfs): 999999.000 DCIA(%): 17.00

============================================================================================== Nodes =========================================================================================================================================================================

Name: OBT 1 Base Flow(cfs): 0.000 Init Stage(ft): 89.000 Group: BASE Warn Stage(ft): 104.000 Type: Time/Stage

Time(hrs) Stage(ft)--------------- --------------- 0.00 89.000 12.00 89.700 24.00 89.400

------------------------------------------------------------------------------------------

Name: OBT 2 Base Flow(cfs): 0.000 Init Stage(ft): 89.000 Group: BASE Warn Stage(ft): 104.000 Type: Time/Stage

Time(hrs) Stage(ft)--------------- --------------- 0.00 89.000 12.00 89.700 24.00 89.400

------------------------------------------------------------------------------------------ Name: Pond 1 Base Flow(cfs): 0.000 Init Stage(ft): 89.000 Group: BASE Warn Stage(ft): 93.000 Type: Stage/Area

Stage(ft) Area(ac)--------------- --------------- 89.000 1.1400 90.000 1.2300 91.000 1.3200 92.000 1.4100 93.000 1.5100 94.000 1.6100

------------------------------------------------------------------------------------------ Name: Pond 2 Base Flow(cfs): 0.000 Init Stage(ft): 121.000 Group: BASE Warn Stage(ft): 125.000 Type: Stage/Area

Stage(ft) Area(ac)--------------- --------------- 121.000 1.4900 122.000 1.5900 123.000 1.6900 124.000 1.7900 125.000 1.9000 126.000 2.0100

============================================================================================== Drop Structures ===============================================================================================================================================================

Name: Drop 1 From Node: Pond 1 Length(ft): 160.00 Group: BASE To Node: OBT 1 Count: 1

UPSTREAM DOWNSTREAM Friction Equation: Automatic Geometry: Circular Circular Solution Algorithm: Most Restrictive Span(in): 24.00 24.00 Flow: Both Rise(in): 24.00 24.00 Entrance Loss Coef: 0.000 Invert(ft): 92.730 88.000 Exit Loss Coef: 1.000 Manning's N: 0.013000 0.013000 Outlet Ctrl Spec: Use dc or tw Top Clip(in): 0.000 0.000 Inlet Ctrl Spec: Use dc Bot Clip(in): 0.000 0.000 Solution Incs: 10

Upstream FHWA Inlet Edge Description:Circular Concrete: Square edge w/ headwall

Downstream FHWA Inlet Edge Description:Circular Concrete: Square edge w/ headwall

*** Weir 1 of 2 for Drop Structure Drop 1 *** TABLE Count: 1 Bottom Clip(in): 0.000 Type: Vertical: Mavis Top Clip(in): 0.000 Flow: Both Weir Disc Coef: 3.200 Geometry: Rectangular Orifice Disc Coef: 0.600

Span(in): 10.00 Invert(ft): 92.730 Rise(in): 12.00 Control Elev(ft): 92.730

*** Weir 2 of 2 for Drop Structure Drop 1 *** TABLE Count: 1 Bottom Clip(in): 0.000 Type: Horizontal Top Clip(in): 0.000 Flow: Both Weir Disc Coef: 3.200 Geometry: Rectangular Orifice Disc Coef: 0.600


---------------------------------------------------------------------------------------------------- Name: Drop 2 From Node: Pond 2 Length(ft): 400.00 Group: BASE To Node: OBT 2 Count: 1

UPSTREAM DOWNSTREAM Friction Equation: Automatic Geometry: Circular Circular Solution Algorithm: Most Restrictive Span(in): 24.00 24.00 Flow: Both Rise(in): 24.00 24.00 Entrance Loss Coef: 0.000 Invert(ft): 124.040 122.000 Exit Loss Coef: 1.000 Manning's N: 0.013000 0.013000 Outlet Ctrl Spec: Use dc or tw Top Clip(in): 0.000 0.000 Inlet Ctrl Spec: Use dc

Bot Clip(in): 0.000 0.000 Solution Incs: 10

Upstream FHWA Inlet Edge Description:Circular Concrete: Square edge w/ headwall

Downstream FHWA Inlet Edge Description:Circular Concrete: Square edge w/ headwall

*** Weir 1 of 2 for Drop Structure Drop 2 *** TABLE Count: 1 Bottom Clip(in): 0.000 Type: Vertical: Mavis Top Clip(in): 0.000 Flow: Both Weir Disc Coef: 3.200 Geometry: Rectangular Orifice Disc Coef: 0.600


*** Weir 2 of 2 for Drop Structure Drop 2 *** TABLE Count: 1 Bottom Clip(in): 0.000 Type: Horizontal Top Clip(in): 0.000 Flow: Both Weir Disc Coef: 3.200 Geometry: Rectangular Orifice Disc Coef: 0.600


============================================================================================== Hydrology Simulations =========================================================================================================================================================

Name: 2.3yr24hrFLMOD Filename: D:\Icpr post\2.3yr24hrFLMOD.R32

Override Defaults: Yes Storm Duration(hrs): 24.00 Rainfall File: Flmod Rainfall Amount(in): 4.55

Time(hrs) Print Inc(min) --------------- ---------------24.000 5.00

---------------------------------------------------------------------------------------------------- Name: 25yr24hrFLMOD Filename: D:\Icpr post\25yr24hrFLMOD.R32

Override Defaults: Yes Storm Duration(hrs): 24.00 Rainfall File: Flmod Rainfall Amount(in): 8.40


---------------------------------------------------------------------------------------------------- Name: 25yr24hrOrange Filename: D:\Icpr post\25yr24hrOrange.R32

Override Defaults: Yes Storm Duration(hrs): 24.00 Rainfall File: Orange Rainfall Amount(in): 8.40


============================================================================================== Routing Simulations ===========================================================================================================================================================

Name: 2.3yr24hrFLMOD Hydrology Sim: 2.3yr24hrFLMOD Filename: D:\Icpr post\2.3yr24hrFLMOD.I32

Execute: Yes Restart: No Patch: No Alternative: No

Max Delta Z(ft): 1.00 Delta Z Factor: 0.00500 Time Step Optimizer: 10.000 Start Time(hrs): 0.000 End Time(hrs): 24.00 Min Calc Time(sec): 0.5000 Max Calc Time(sec): 60.0000 Boundary Stages: Boundary Flows:


Group Run --------------- -----BASE Yes

---------------------------------------------------------------------------------------------------- Name: 25yr24hrFLMOD Hydrology Sim: 25yr24hrFLMOD Filename: D:\Icpr post\25yr24hrFLMOD.I32





---------------------------------------------------------------------------------------------------- Name: 25yr24hrOrange Hydrology Sim: 25yr24hrOrange Filename: D:\Icpr post\25yr24hrOrange.I32





9. ICPR Hydrology Basin Summary Report

Basin Name: Basin 1 Group Name: BASE Simulation: 2.3yr24hrFLMOD Node Name: Pond 1 Basin Type: SCS Unit Hydrograph

Unit Hydrograph: Uh256 Peaking Fator: 256.0 Spec Time Inc (min): 1.33 Comp Time Inc (min): 1.33 Rainfall File: Flmod Rainfall Amount (in): 4.550 Storm Duration (hrs): 24.00 Status: Onsite Time of Conc (min): 10.00 Time Shift (hrs): 0.00 Area (ac): 40.270 Vol of Unit Hyd (in): 1.000 Curve Number: 46.240 DCIA (%): 25.000

Time Max (hrs): 12.04 Flow Max (cfs): 29.08 Runoff Volume (in): 1.380 Runoff Volume (ft3): 201733

--------------------------------------------------------------------------------

Basin Name: Basin 2 Group Name: BASE Simulation: 2.3yr24hrFLMOD Node Name: Pond 2 Basin Type: SCS Unit Hydrograph

Unit Hydrograph: Uh256 Peaking Fator: 256.0 Spec Time Inc (min): 1.33 Comp Time Inc (min): 1.33 Rainfall File: Flmod Rainfall Amount (in): 4.550 Storm Duration (hrs): 24.00 Status: Onsite Time of Conc (min): 10.00 Time Shift (hrs): 0.00 Area (ac): 21.050

Vol of Unit Hyd (in): 1.000 Curve Number: 62.500 DCIA (%): 17.000


--------------------------------------------------------------------------------

Basin Name: Basin 1 Group Name: BASE Simulation: 25yr24hrFLMOD Node Name: Pond 1 Basin Type: SCS Unit Hydrograph



--------------------------------------------------------------------------------

Basin Name: Basin 2 Group Name: BASE Simulation: 25yr24hrFLMOD Node Name: Pond 2 Basin Type: SCS Unit Hydrograph



--------------------------------------------------------------------------------

Basin Name: Basin 1 Group Name: BASE Simulation: 25yr24hrOrange Node Name: Pond 1 Basin Type: SCS Unit Hydrograph

Unit Hydrograph: Uh256 Peaking Fator: 256.0 Spec Time Inc (min): 1.33 Comp Time Inc (min): 1.33 Rainfall File: Orange Rainfall Amount (in): 8.400 Storm Duration (hrs): 24.00 Status: Onsite Time of Conc (min): 10.00 Time Shift (hrs): 0.00 Area (ac): 40.270 Vol of Unit Hyd (in): 1.000 Curve Number: 46.240 DCIA (%): 25.000

Time Max (hrs): 9.02

Flow Max (cfs): 32.81 Runoff Volume (in): 3.637 Runoff Volume (ft3): 531710

--------------------------------------------------------------------------------

Basin Name: Basin 2 Group Name: BASE Simulation: 25yr24hrOrange Node Name: Pond 2 Basin Type: SCS Unit Hydrograph

Unit Hydrograph: Uh256 Peaking Fator: 256.0 Spec Time Inc (min): 1.33 Comp Time Inc (min): 1.33 Rainfall File: Orange Rainfall Amount (in): 8.400 Storm Duration (hrs): 24.00 Status: Onsite Time of Conc (min): 10.00 Time Shift (hrs): 0.00 Area (ac): 21.050 Vol of Unit Hyd (in): 1.000 Curve Number: 62.500 DCIA (%): 17.000


10. ICPR Nodes Max/Min Report

11. Pre-Development vs Post-Development

Pre Development Post DevelopmentNode Name

Hydrology Simulation

Max Inflow (Cfs)

Node Name

Hydrology Simulation

Max Inflow (Cfs)

OBT 1 2.3yr24hrFLMOD 1.05 OBT 1 2.3yr24hrFLMOD 0.00OBT 2 2.3yr24hrFLMOD 0.21 OBT 2 2.3yr24hrFLMOD 0.00OBT 1 25yr24hrFLMOD 18.12 OBT 1 25yr24hrFLMOD 9.19OBT 2 25yr24hrFLMOD 3.62 OBT 2 25yr24hrFLMOD 1.95OBT 1 25yr24hrOrange 12.58 OBT 1 25yr24hrOrange 10.21OBT 2 25yr24hrOrange 3.71 OBT 2 25yr24hrOrange 2.25

All post values are less than or equal to pre values

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Post development storm EmpireEng FINAL REPORT