DESIGN OF URBAN STORM WATER DRAINAGE SYSTEMS S D Chawathe

URBAN STORM WATER DRAINAGE SYSTEMS ... Hon. Director (Technical) Indian Water Works Association. COEFFICIENT OF ... The design of a storm drainage sys...

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DESIGN OF URBAN STORM WATER DRAINAGE SYSTEMS S D Chawathe Hon. Director (Technical) Indian Water Works Association

COEFFICIENT OF RUN OFF • As Per CPHEEO Manual Commercial Area Residential Area High density Low density Parks and Undeveloped

0.7 to 0.9 0.6 to 0.75 0.35 to 0.6 0.1 to 0.2

CPHEEO MANUAL Type of Area Residential Peripheral Central (high value) Commercial

Frequency

Twice in a year Once in a year Once in 2 years

ASCE MANUALNo 37 Type of Area Residential

Frequency Once in 2 to 15 years

Commercial (High value)

Once in 10 to 15 Years

COST COMPARISON Inclusive of CD Works Costs would be roughly 25% and 35% Higher for once in 5 years and once in 10 years frequencies respectively as Compared to once in one year frequency.

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