Preliminary flood-frequency relations for urban streams, Metropolitan Atlanta, Georgia

A method is presented for estimating the magnitude and frequency of floods for urban streams in metropolitan Atlanta. The method is based on adjustments to the natural stream flood-frequency and rainfall-frequency characteristics of the local area as defined by urban flood studies in other areas.

The effects of urbanization on flood-peak runoff are estimated from the percentage of drainage basin that is impervious and the percentage of drainage area served by storm sewers. Equations are presented for estimating the 2-, 5-, 10-, 25-, 50-, and 100-year flood peak discharges for basin sizes from 0.5 to 100 square miles in the Atlanta metro area.