The Effect of Soil and Water Conservation on Water Cycle: A Case Study in the Mountainous Area of Southern Ningxia
水土保持措施对山区水循环的影响--以宁夏南部山区为例

Water resources have become an important factor restricting economic development. Therefore, more and more researchers focused their study on water cycle and the effect of soil and water conservation. For the purpose of preventing the loss of soil and water in the mountainous area of southern Ningxia, many engineering measures of soil and water conservation have been planned which will be certain to affect water cycle of mountainous area. The soil and water conservation measures will retain effectively the runoff and improve the water cycle of the mountainous area. The runoff is retained by the soil and water conservation project, which decreases the erosion and increases the probability of precipitation infiltrating into the soil and ground. Consequently the available water resources will be added and the environment will also be improved. This paper analyzes the influences of soil and water conservation on water cycle. By comparing the efficiency of the different soil and water conservation project, this paper chooses two schemes based on the water resources allocation and the development of economy and population. In the first scheme, the percent of retained runoff is 33.2%, 48.8% and 57.6% respectively in 2010, 2020 and 2030; in the second scheme, the percent of retained runoff is 15.6%, 27.4% and 37.8% respectively in 2010, 2020 and 2030. The results show that the differences of the integrated efficiency of soil and water conservation project between regions are vident because of the different engineering measures. But the total efficiency in each region is well. Therefore, it is very effective to prevent the loss of soil and water and improve the environment with these engineering measures.