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STORM SEWER STORM SEWER DESIGNDESIGN

STORM SEWER STORM SEWER DESIGNDESIGN

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WHAT CAN HAPPEN

• http://www.youtube.com/watch?v=tHWwvMrOj5E

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HYDRAULIC DESIGN CHARTS

– http://www.fhwa.dot.gov/engineering/hydraulics/pubs/hds3.pdf

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INLET CAPACITY

• http://www.neenahfoundry.com/content/Inlet%20Grate%20Capacities/weir%20and%20orifice%20equation/default.aspx

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SPREAD VS. ENCROACHMENT

• http://www.iowadot.gov/design/dmanual/04a-05.pdf

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EXAMPLE• Sx = 0.03 (cross-slope of gutter)

• n = 0.016 (Manning’s “n” for PCC)• Q = 1.6 cfs

• SL = 0.02 (longitudinal gutter slope)

• Z = 1/Sx = 1/0.03 = 33.33

• Z/n = 33.33/0.016 = 2083

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EXAMPLE

Z/n = 2083

Connect to SL = 0.02

Turning line through Q = 1.6 to depth of 0.18 feet

Spread “w”

w = d * Z = 0.18 * 33.33

w = 6 feet

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