Flood-frequency studies for urban areas in several parts of the United States and flood-frequency relations for natural streams of Oklahoma were used to develop a set of flood-frequency equations for urban areas of Oklahoma. Equations are
presented for estimating the 2-, 5-, 10-, 25-, 50-, and 100-year flood-peak discharges for basins of 0.5 to 100 mil (1.3 to 260 km2).