Research On Variations Of Precipitation And Runoff In Jinjing River Basin

Jin Jinghe river-basin is an area with quite big shortage of water resource. Influenced by natural and man-made factors, Jin Jinghe river-basin has a serious problem of water resources at present. In this thesis, according to the average rate of flow in the past years of Luoling Bridge station which is a representative station for Jin Jinghe river-basin, we will study the evolving regulations of run-off of this river-basin, so as to supply data and basis for the sustainable development for the whole jin Jinghe river-basin.Nonparameter Mann-Kendall Inspection Methods, Segmented Regression System over Time and Accumulated Anomaly curve combined Moving T Test and other methods have been applied in this thesis to study the evolving regulations of run-off of Jin Jinghe river-basin, and conclusions are summarized as following:(1) Evolving regulation of monthly average rate of run-off: by variability analysis, it's found that there is no mutation of average rate in the order of monthly average flow rate of February, March, April, May, January and November at the Luoling Bridge station.At Luoling Bridge station, Mutations of average rate occur to the order of monthly average flow rate in January, July, August, September, Ocotomber, December respectively in the year of 1987, 1991, 1992, 1987, 1992, 1992. Through analysis of trend pattern, we see that at Luoling Bridge station the monthly average flow rate of March, April, May, June is on a declining curve; while that of January, February, July, August, September, October, November and December is on the rising. October past 90% of the reliability test; August, November and December past 95% while January and September past 99% of that.(2)Evolving regulation of yearly average rate of run-off: by variability analysis, it's found that order of yearly average rate of run-off at Luoling Bridge station has mutation in 1990; by analysis of trend pattern, the yearly average rate of flow declines on an inverted"V"pattern before mutation, and rises on a"V"pattern after the mutation.(3) Maximum and minimum daily flow in a year: through variability analysis, maximum daily flow in a year had mutation in 1992 and minimum daily flow in a year had mutation respectively in 1972 and 1992. By the analysis of trend pattern, the maximum daily flow in a year at Luoling Bridge station rises at a"V"pattern before mutation and declines at an inverted"V"pattern after mustation; the minimum daily flow in a year declines on an inverted V pattern before mutation and rises at a"V"pattern between the first and second mutations.