خصائص الشبكة الهيدرولوجية الحوض وادي الرشاء

الملخص EN

abstract.

recently the interest has increased in the study of water basins in Saudi Arabia because of the environmental hazards caused by the flow of these basins and increasing potentials for flash floods occurrence in various public areas of the kingdom and the region Qassim in particular.

in this context the study in Handi reflects such a trend.

wadi al-Risha is one of the southern tributaries of the wadi al-Rumah.

the northwestern headwaters of wadi al-Risha start from al-Niir mountains (595m-1133m) and its mainstream extends for a about 150 km northeaster ward where it disappears due deposits of Nafud ashuqayyiqah.

wadi al-Rasha basin covers an area of 15-940 km2 representing about 11.1 % of wadi al-Rumah total area.

in order to extract the hydrological network of wadi al-Risha remote sensing techniques were employed.

also, geographical information systems were applied to calculate all morphometric variables of the basin.

the results revealed varied dimensions of the main tributaries basin of wadi al-Risha.

such varied dimensions can be attributed mainly to geological structure of the basin.

also, the basin generally, tends to have longitudinal shape.

this in tum means that the basin has an intermediate level of risk in case of flash floods due to heavy rains.

moreover, it was found that wadi al-Risha is in mature stage according to hypsometric integral value and the Strahler classification which means it will take more time to complete its erosion cycle.