Study Of Ecological Environment Evaluation And Ecological Water Requirement Based On Ziya River Basin

With the development of social economy,the problems of ecological environment and ecological system water demand in the basin got more and more attention. The ecological environment and socio-economic factors were added to basin water resources evaluation.This paper selected Ziya River Basin as the study area, and evaluated the basin ecological water resources,then studied the basin ecological system water demand with the corresponding computation models. The main research contents were as follows:The comprehensive evaluation index systems were built from the water resources subsystem aspect, social economy subsystem aspect and eco-environment subsystem aspect based on the statistical data of Ziya River Basin. Then, the water resources and ecological environment were evaluated quantitatively.The results indicated that comparing with the 1970 s, the evaluating values of eco-environment subsystem and water resources subsystem in Ziya River Basin showed an obvious downward trend in the 2000 s, while the evaluation values of the socio-economic subsystem showed a manifest upward trend, and the evaluation values of the comprehensive index showed an downward trend. The water resources environment of northwest Ziya River Basin was better than the east, and the west is better than the north.Daily vegetation evaporation capacity of the Ziya River Basin was simulated with Penman Monteith model recommended by the FAO, and the method of crop coefficient.The Ziya river basin was divided into seven different sub-regions which was tussock, meadow, grasslands, shrub, broad-leaved forest, cultivated vegetation and coniferous forest through considering the vegetation spatial diversity.Then the monthly simulated values and annual simulated values were separately calculated, and compared with the observed evaporation. The results indicated that the monthly simulated values of the 7 different sub-regions in 2011 were almost consistent with the observed monthly evaporation values, and the R2 was more than 0.8.The annual simulated values were almost consistent with the observed annual evaporation values, and the relative error was below 20%, the average relative error for five years was below 15%. The results showed that the method of P-M model combined with the crop coefficient was feasible.With the meteorological data of Ziya river basin, combined with the measured data of water surface evaporation, Dalton model was built to simulate the water surface evaporation inZiya river basin. The results indicated that the Dalton model could reflect the water surface evaporation condition of the basin, and the simulated water surface evaporation values were almost consistent with the observed values.The average relative error ? and the percent of pass ? between-20% and +20% could meet the requirements. The model was applied to Luan river basin and the water surface evaporationfrom 2007 to 2012 was calculated to verify its applicability.The results showed that the simulation in the Luanhe river basin was satisfied.