TRANSFORMATION OF GROUND WATER AND SURFACE WATER IN CHINESE ARID LANDS
中国干旱区地表水与地下水的转化

In Chinese arid lands (not including the semi-arid land) , the plain, where the annuel precipition is less than 200 mm and the surface runoff can't be formed, is called runoff scattering and disappearing region, and the mountain area where much precipitation can be caught to form many rivers, is called runoff forming region.The ground water in the mountain area mainly recharges rivers. In primary estimation, the ground water recharge is about 30 percent of the annual runoff of the nain rivers in arid lands, which is a little more than the average of the country.In the piedmont plain, the ground water is mainly formed by seepage in many different ways. That formed hy the river seepage is about 80 percent of the total ground water recharge in primary estimation.At the place where the terrain is getting down to the fine mud plain, there is generally ground water overflowing belt, ground water transforming into surface water. The spring concentrated to the river and the ground water drained off to the river are the main sources of the river water in the plain.For the mutual transformation of ground water and surface water in arid lands, we must avoid repetition when cacutating the amount of the water re-soures in arid lands, but under certain conditions, the water resoures can be used repeatedly.