الخصائص الهيدروموفومترية و خصائص السيول في أحواض السدود المقترحة على أودية علية في محافظة الخرج

الملخص EN

This study demonstrates the analysis of rainfall frequency and hydromorphometric and flow characteristics for the suggested dam basins in Ulaya wadis, mainly the Upper basins of Mawan and AlAin in Al-Kharj province.

Annual rainfall for the return period between 2 to 100 years ranging as follows; 100.6 mm/y and 244 mm/y in Riyadh station, and between 98.1 mm/y and 246.6 mm/y in the AlKharj station, and 57.4 mm/y and 208.4 mm/y in the Huta station, and 72.3 mm/y and 178.6 mm/y in the Al-Hariq station and finally between 74.9 mm/y and 254 mm/y in Wadi Hanifa station.

Morphometric analysis shows that the drainage basin area in wadi Al-Ain is bigger than the area in Wadi Mawan by more than 77 km2.

In Wadi Al-Ain basin, streams numbers are about 1111 with total length of 728 km, the mean bifurcation ratio is around 4.18 and the drainage density is 2 km/km2.

Whereas in Wadi Mawan basin, streams numbers are about 2207 with total length of 785 km, the mean bifurcation ratio is around 4.84 and the drainage density is 2.7 km/km2.

Flow characteristics indicate that maximum discharge peak in wadi Al-Ain basin reaches 1310.4 m3/sec, the specific discharge peak is 3.59 m3/s/km2 and runoff volume is 120.8 .10 ^ m3 with depth reaches 333.4 mm.

Whereas maximum discharge peak in wadi Mawan basin reaches 1279.1 m3/sec, the specific discharge peak is 4.45 m3/s/km2 and runoff volume is 116.9 .10 m3 with depth reaches 407.1 mm.