التحليل الكمي المقارن لكثافة التصريف مع التطبيق على حوض وادي العاقول بالمدينة المنورة

الملخص EN

This study deals a comparative study of the Drainage Density using traditional methods - represented in the topographic maps - and modern methods represented in the digital elevation model (DEM) and satellite images with application to the basin of Aqoul, Madinah Munwara.

The study was based on two map scales of the topographic maps as the most important parameters used in Geomorphological studies, the first map scale is 1:250.000 .

Another map scale is the most common map scale used in most Geomorphological studies is a scale of 1:50.000.

The study relied on the digital elevation model accuracy 90×90 meter and the study also relied on the Satellite image of the type of Landsat TM.

Drainage basin network is extracted of Wadi Al-Aqoul using topographic maps of the two map scales mentioned previously as well as using modern methods, has been shown that topographic maps do not show most of the streams with 1st .and 2nd .

order ,and thus affect the Drainage Density which in turn depends at one end by the total length of streams, as shown that there are errors when using topographic maps even at the same map scale because of different accuracy of topographic mapping from a map to another.

The study concluded that the use of modern methods to extract the drainage network and calculate the Drainage density addresses many of the shortcomings in the use of topographic maps, and study also found that we must not calculate the Drainage density at the level of valleys and large basins, and major tributaries, but may be preferable to calculate the Drainage density each watercourse regardless stream Order, and then we get the Drainage Density detailed actual and reliable when analyzing the Morphometric and geomorphologic characteristics, and helps to identify general areas exposed to hazards such as torrents and landslides.