Study of 10 year-24 hour rainfall distribution Warrior Coal Basin

The use of computer models to predict storm runoff and sediment basin response has greatly increased in recent years, due largely to increased sophistication of regulatory performance requirements. This study has been conducted to develop an accurate estimate of Warrior Coal Basin (WCB) rainfall distribution for a 10 year-24 hour event. Time distribution relations have been developed for heavy storms and presented in probability terms to show extreme and average distributions with respect to time. Relations were best represented by relating percent of storm rainfall to percent of storm duration. The data was then grouped according to the quartile in which rainfall was the heaviest. The most extreme relations derived were then used to predict the effluent from a watershed with a sediment basin. In comparison to the US Soils Conservation Service (SCS) Type II storm distribution the WCB storm distributions showed the predicted effluent to be significantly less. The derived relations are applicable to all of the Warrior Coal Basin in Alabama and other areas of similar climate.