A STUDY ON THE RELATION BETWEEN THE VARIATION OF THE PRECIPITATION IN EASTERN JIANGHUAI WATERSHED AND SEDIMENT TRANSPORT IN CHIHE RIVER VALLEY

摘要

Rainfall resource is very important to the development of society and economy, especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records covering the period from 1957 to 1999, the characteristics of precipitation changing over eastern JiangHuai watershed and its connection to sediment discharge in Chihe River valley were studied using tendency analysis and correlation analysis. Results show that the rainfall in this area had a declining tendency in Spring at a rate of - 21. 2mm/10a, annual and Summer precipitation was increasing at the rate of 10. 6mm/10a and 14. 8mm/10a. The gray correlation analysis shows that sediment discharge correlates most closely with runoffs and the frequency of the rainstorm with a daily precipitation of 50 - 100mm, on the second place, with the rainfall and the frequency of the rainstorm of a daily precipitation no less than 100mm; and thirdly with the number of rainy days. In addition, the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.