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Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

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Page 1: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Integrating Simulation and Design

for Stormwater Management

by

Alan A. Smith

Alan A. Smith Inc.Dundas, Ontario, Canada

Page 2: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

A SWMM Program Classification Scheme

Page 3: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Representing a Drainage Network as a Tree

11 Nodes

10 Links

Page 4: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

A node numbering convention

Page 5: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

A time-wise marching solution

UpstreamboundaryQ = Q(t)

DownstreamboundaryH = f(Q,t)

Intermediateinflow Q(j)

Page 6: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

A downstream marching solution

UpstreamboundaryQ = Q(t)

Intermediateinflow Q(j)

Page 7: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Hydrology options in MIDUSS 98

Storms RainfallLoss

Overland flowmethod

Chicago SCS CurveNumber

Triangular response

Huff quartile Runoffcoefficient

Rectangular response

Mass RainfallDistribution

Horton (movingcurve)

Linear reservoirresponse

CanadianAES

Green & Ampt SWMM RUNOFFalgorithm

Historic

Storms Infiltration Overland

Page 8: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Design options in MIDUSS 98

Pipes - part-full uniform flow - surcharged HGL Channels - simple trapezoidal - complex (50 points) Pond - detention, rooftop, parking lot, super-

pipe Exfiltration trench - split inflow between

outflow and exfiltration Diversion - split major and minor flows Route - modified Muskingum-Cunge method

Channel

Pipe

Pond

Trench

Diversion

Route

Page 9: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Benefits of On-Site Detention(for commercial developments)

(1) Should be explored before end-of-pipe BMP

(2) Runoff should be attenuated locally when possible

(3) Local control of peak flow reduces hydraulic load on centralized quality control

(4) Peak flow reduction reduces re-suspension of settled solids

(5) Reduce cost of centralized SWM facility

(6) Facilitates cost-sharing between benefiting parties.

Page 10: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Idealized discretization ofa commercial development

Page 11: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Define catchment 100% imperviousFor 450 sq.m./RD set L = 10 m @ 0.5%Generate runoff hydrographAdd to Inflow hydrographDesign pond - use Rooftop optionConfirm/edit parameters 24

litres/min/25mmRoute hydrograph

Rooftop storage

Rooftop

Page 12: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Rooftop storage - Q,V = f(H)

Discharge

Volume

Page 13: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Rooftop storage - Results

Page 14: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Parking lot storage (1)

Page 15: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Parking lot storage (2)

Rim elevation

Catch basinInvert level

Volume

Discharge

Rim capacity

Page 16: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Parking lot storage (3)

Rim Elevation

Page 17: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Flood routing

Ti+1

Ti

Xj+1Xj

Time T

Distance X

tt

xx

Cr=ct/x=2

Nucleus

Unstable

Page 18: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Muskingum-Cunge method

2

21

x

QD

t

Q

cx

Q

x

tcx

dhdQS

QD

f

122122

1

1

x

tc

Diffusion equation is

where D can be defined by:

subject to stability criteria

Page 19: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Running in Automatic mode

Created in previous manual run

Page 20: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Running in Automatic mode

•Test previous design for more severe storm

•Complete design in 2 or more sessions

•Add extra commands

•Modify design for more severe storm

Page 21: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Edit Paneland Control Panel

Page 22: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Applications of MIDUSS 98

Program functionality has been developed over many years of professional practice.

Has proved valuable in ‘fleshing out’ Master Drainage Plans to separate local and centralized SWM facilities

Most recent application in Belleville, Ontario to 400 ha catchment to assign cost sharing among two municipalities, 8 to 10 new developments and many existing developments.

Page 23: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Conclusions

Drainage design cannot easily separate simulation and design

Page 24: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Conclusions

Drainage design cannot easily separate simulation and design

Design process needs a highly interactive decision support system

Page 25: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Conclusions

Drainage design cannot easily separate simulation and design

Design process needs a highly interactive decision support system

Automatic mode allows sensitivity of design to storm magnitude to be tested incrementally.

Page 26: Integrating Simulation and Design for Stormwater Management by Alan A. Smith Alan A. Smith Inc. Dundas, Ontario, Canada

Conclusions

Drainage design cannot easily separate simulation and design

Design process needs a highly interactive decision support system

Automatic mode allows sensitivity of design to storm magnitude to tested be incrementally.

Versatile hydrology simulation and flexible, interactive design provides a training tool for professional and student.