•Designed a minor system to meet City of London design guidelines for a 2 year storm by XPSWMM. •Dealt with the layout of most economical Conduit Network for 4.6 ha of total drainage area.

1. Design of a Minor System Using XPSWMM
Software
Prepared for
Dr. Imtiaz Shah, CEE 9632 Advanced Storm Water Management
Prepared By:
Fatima Elkhair
Aronne De Souza
Muhammad Umar
Stewart Handrahan
Rongtian Feng
JM Rakibul Hasan
December 2, 2014

2. Content
• Introduction
• Advantages of XPSWMM
• Site Plan
• Objectives
• Design Requirements
• Design Methodology
• Layout and Design of Conduit Network
• Modelling Details
• Results & Discussion
• Alternatives & Value Engineering
• Conclusion

3. Introduction
• The Site
– Next Phase of a residential subdivision in London Ontario.
– Approx. 4.6 ha of total drainage area
• Scope of Work
– Design of a minor system to meet City of London design guidelines for a 2
year storm
– Briefly discuss some value engineering/LID alternatives (concept level only)
– End of pipe is a wet pond designed for 250 year storm
– Flows greater than 2 year storm event will be carried by the major system

4. Introduction
• Minor System
• Collects Stormwater runoff of 2 to 10 years return period
– Urban minor system consists of
• curbs, gutters, catch basin inlets, storm sewer, swales, ditches
– Rural minor system consists of
• roadside ditches, minor drainage swales

5. Introduction
• XPSWMM
– Comprehensive strorm, sewer and flood modeling software
– Create dynamic hydrologic or hydraulic modeling
– Calculates 1D and 2D hydraulic performances
– Simulates natural runoff to design drainage system
– Does water quality analysis

6. Advantages of XPSWMM
• Physical reality
• Regulator approval
• Easy sharing of model
• Integration of GIS systems
• Time Saving
• Economical Solution

7. Site Plan
Area No. Area (ha) c
A1 0.514 0.55
A2 0.928 0.55
A3 0.341 0.55
A4 0.109 0.55
A5 0.29 0.55
A6 1.073 0.75
A7 0.767 0.75
A8 0.62 0.55
A9 0.022 0.55

8. Objectives
• Determine the most economical and sustainable design of the
minor system
• Meet requirements given by regulatory authorities for the site

9. Design Requirements
• From City of London SWM Guidelines :
– Manholes must not flood during a 2-year storm event.
– Capacity > Flow
– Velocity of flow must be between min & max
• Vmin 1.0 m/s
• Vmax
– 4.5 m/s (300 mm to 825 mm)
– 6.0 m/s (> 825 mm)
– Minimum slope
• 0.54% (300 mm)
• Slope based on velocity (>300mm)
– Min embedment depth = 1.5m
– Wet pond permanent pool elevation = 314.75m
• Standard OPSS conduit and catch basins must be used

10. Design Methodology
• 2 Year Storm, City of London parameters
• Catchment Areas based on economical grading, provided by others
• Run-off for each catchment area generated by Rational Method
– Q = 0.0028*C*I*A
– C: runoff coefficient ranges from 0.55 to 0.75 (provided by others)
– I: generated from IDF parameters provided by City of London SWM
Guidelines
– A: catchment area (provided by others)
• Standard OPSS concrete CB/CBMH/MH and circular conduit

11. Layout of Conduit Network

12. Design of Conduit Network
• Layout based on grading plan (lengths and routing provided)
• Network input into XPSWMM model (nodes & links)
• Flows manually input into catch basins (nodes) in XPSWMM model
• Flow simulation performed by software, given initial conduit sizes and
inverts. Size and slope (inverts) adjusted downstream if upstream
manholes flooding during a given simulation. (iterative process)
• Capacity of each conduit based on Manning’s Equation for flow
– Q = (1/n)*A*Rh2/3*S1/2
• Once the system is not flooding, velocity for each conduit section is
checked against min/max velocity requirements. Conduit size and/or slope
adjusted accordingly by iterative process

13. Defining Nodes and Conduit Profile

14. Flow Route 1

15. Dynamic Long Section 1

16. Flow Route 2

17. Dynamic Long Section 2

18. Flow Route 3

19. Dynamic Long Section 3

20. Results (Running The Model)

21. Results
Area No. Q (m3/s)
A1 0.051196
A2 0.092431
A3 0.033964
A4 0.010857
A5 0.028885
A6 0.145736
A7 0.104175
A8 0.061754
A9 0.002191

22. Discussion of Results
• Manholes do not flood during 2 yr storm event
• Capacity > Flow
• Velocity between min. & max. guidelines
• Min. slope achieved on all but one conduit section
• Min. ground cover (1.5m) could not be achieved for
– 0810, 2010, 30PD
– Grading should be altered to achieve min. cover over these conduit
sections, or alternatively provide insulation

23. Design Alternatives / Value Engineering
• Conduit 1232 & 3230 require 500mm conduit size
– The minimum size is 300mm
– Q = CIA; therefore Q is directly proportional to C
– LID methods should be evaluated to attempt a reduction in the 2 yr
run-off so that 300mm conduit sizes can be used
– Possible LID options include lot-level conveyance (roof water barrels
or cisterns), permeable pavements, bio-swales, infiltration trenches,
etc.
– Cost benefit analysis should be performed

24. Conclusion
• An effective design of the minor system is presented, from the
XPSWMM modelling.
• The design presented meets the objectives required by the
City of London SWM Guidelines.
• Alternatives should be evaluated to reduce cost of the minor
system while leading to an overall system that better
resembles the natural hydrologic cycle.

25. THANK YOU
Questions?