design of urban storm water drainage...
TRANSCRIPT
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 0.7 to 0.9
Residential Area
High density 0.6 to 0.75
Low density 0.35 to 0.6
Parks and Undeveloped 0.1 to 0.2
CPHEEO MANUAL
Type of Area Frequency
Residential
Peripheral Twice in a year
Central (high value) Once in a year
Commercial Once in 2 years
ASCE MANUALNo 37
Type of Area Frequency
Residential Once in 2 to 15 years
Commercial Once in 10 to 15
(High value) 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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