The Drainage Concept / Hydrology / Standard Urban Storm Water Mitigation Plan (S.U.S.M.P.) Plan is a complex study involving obtaining existing and proposed surface data, analysis of how your project will affect the existing flow of water over your site.
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||Sample Hydrology Study
Here's a small "on-site" hydrology plan I've prepared. I have the ability to obtain 2' contour LIDAR topography within Los Angeles County so there is no need to perform a large-scale site survey for this study -especially when the areas of survey would need to extend to all the watersheds that flow onto the site in question.