Relationship between wadi drainage characteristics and peak-flood flows in arid northern oman

Relationships between watershed characteristics and mean wadi flood peaks in arid regions are investi- gated. Mean flood peak discharge was derived for 12 watersheds ranging from 64 to 1730 km ² in Oman using 270 flood events from 10 years of record. Fourteen watershed characteristics were automatically extracted from a digital elevation model, and multiple regression was used to investigate the effect of these characteristics on wadi mean peak flow (Q _MPF) and 5-, 10-, 20-, 50- and 100-year return period flood peaks. Drainage area (DA), wadi slope (WS), watershed mean elevation (BE) and agricultural/farm area (FR) were found to be the key variables affecting flood flows. As return period increased, the influence of BE on flood-peak estimation decreased. In addition, urbanization is increasing alongside increasing agricultural areas, and the inclusion of FR in the relationship improved the variance explanation by 11% over models using only traditional variables such as DA and BE.