Overland Flow Requirement for subdivisions

[CivilG]

To whom it may concern,

What is overland flow requirements for new deveopments?

The standard specifications for a city in California require an overland flow requirement when designing grading and storm water requirements for new developments such as subdivisions. Is overland flow requirement the requirement that flooding of house pads won't occure until there is a release point for flood waters to leave the area on top of the ground via streets or some other lower channel?


Thanks,
Civil G

 

[Twinkie]

This will vary by municipality, but you have the gist of it. It's typically going to say for XX 24 hour storm event that overland flow must be contained within the cartway, or a minimum 1' below the first floor elevation, or something else similar.

 

[GeoEnvGuy]

Municipalities have different specifications for storm size to road traffic size. Cul de sacs not as important as main roads.

Overland flow directs water to the perimeter lot swales then to the road and then to the storm sewer. Requirements come in on how far the nearest storm sewer and spacing between catch basins.

 

[beej67]

In this area of the country, an overland flow requirement would mean basically "You can't connect your gutter downspouts directly to the storm drain. We want it to flow over the grass first."

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com