The Saudi Geological Survey (SGS) conducted a flood hazard assessment study for the entire country. Detailed precipitation data until 2020 were collected, and flood discharges of 5216 basins ranging from small basins ( 10,000 km(2)) were calculated using a precipitation-based hydrological model with a return period of 100 years. This study aims to understand the relationships between peak flood discharges, volumes and catchment areas for the Kingdom of Saudi Arabia and to extract flood peak discharge envelopes over a 100-year return period. The results show that an envelope for peak flow and flow volume versus catchment area is not suitable for all of Saudi Arabia, due to many uncertainties such as precipitation and geological variability. For this reason, the study area is divided into seven regions according to the main basin boundaries and different physiographic features. Seven envelopes are developed on the basis of different geological units and precipitation distributions in each hydrologic zone. They are also validated based on several studies that showed good agreement. These envelopes can help engineers and planners to predict peak flows and flow volumes for watersheds with great accuracy.
展开▼
