El Paso County
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Cheat Sheet - Storm
HGL
Slope/Gradient
Velocity
MH Loss Coefficient
HGL
Drainage Criteria Manual V1: Chapter 8.3
The hydraulic grade line shall in no case be closer than one (1) foot to the ground or street surface unless otherwise approved by the City/County.
Slope/Gradient
Engineering Criteria Manual: Chapter 3.3
The minimum gradient shall be 0.5% or a minimum velocity of 4 feet per second (fps) with the pipe flowing one quarter full.
Velocity
Drainage Criteria Manual: Chapter 6.3
Storm drains shall be designed to have a minimum mean velocity of 2.5 fps.
Engineering Criteria Manual: Chapter 3.3
The maximum storm sewer velocity shall be 18 fps.
MH Loss Coefficient
Drainage Criteria Manual: Chapter 8.4
