Determination of Size of Drainage Area
Determination of Size of Drainage Area
(OP)
I would like a rough idea of how the AREA of a drainage area for water flowing from a steep slope (2 to 1 ratio) would be calculated. Are there minimum area requirements that must be met for grading plans to be approved?





RE: Determination of Size of Drainage Area
RE: Determination of Size of Drainage Area
Certainly there are any number of things related to drainage that must be met for a grading plan to be approved.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: Determination of Size of Drainage Area
For large areas one might use the USGS topographic maps. You would investigate upstream areas and draw a line delineating one drainage shed from another. Imagine where a drop of water would drain, towards your area or away from, as an example.
A customary rule of thumb is the modified rational formula can be used for determining storm run offs for 200 acres or less. Larger areas use the unit hydrograph analysis.
In urbanized areas, you might need to do a fair amount of research of as builts to determine if storm water is intercepted before reaching your site, for example.
RE: Determination of Size of Drainage Area
Start from the limits of your project and see where the flow lines lead you to determine the total drainage area.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Determination of Size of Drainage Area
RE: Determination of Size of Drainage Area
Haven't used one for 40 years now, but haven't forgotten how either. Kinda like riding a bike or using a slide rule.
Interesting how they can both add and subract, no?
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Determination of Size of Drainage Area
RE: Determination of Size of Drainage Area
It doesn't appear that every state has StreamStats but maybe you'll get luck and they'll have your state:
h
http://water.usgs.gov/osw/streamstats/ssinfo.html
RE: Determination of Size of Drainage Area
RE: Determination of Size of Drainage Area
Funny how people would steal ipods in the Engineers' drawers, but there are all of these HP48GX's and other expensive equipment (Leroy) sitting around like nothing.
B+W Engineering and Design
Los Angeles Civil Engineer and Structural Engineer
http://bwengr.com
RE: Determination of Size of Drainage Area
RE: Determination of Size of Drainage Area
Nobody's going to buy your Leroy at a pawn shop.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com