The Change Of Water Yield In The Upstream Of Shiyang River And Its Response To Climate And Land Use Change Based On InVEST

Shiyang River Basin is one of the most densely populated rivers in China,with the most developed and utilized water resources,the most contradictory water use and the most serious ecological environment problems.The upper reaches of Shiyang River,as a water conservation area of Shiyang River Basin,is also a typical ecological fragile area,which is sensitive to climate and land use change.Under the background of global change,greater changes have taken place in the upper reaches of the Shiyang River Runoff and water conservation ability,influence the spatial configuration pattern process of hydrological cycle and water resources,a serious threat to the sustainable development in the middle and lower reaches.This paper is based on the Shiyang River Basin is a typical region and water production module based on the InVEST model.The temporal and spatial pattern of water yield in the upper reaches of Shiyang River was analyzed,quantitative assessment of the effects of climate and land use changes on water production intensity and spatial heterogeneity,to reveal the formation mechanism of water yield variation in the upper reaches of Shiyang River.The main conclusions of this paper are as follows.?1?1961-2012 years in the upper reaches of the Shiyang River annual temperature and potential evapotranspiration showed a significant increase in the volatility trend,the annual precipitation showed a slight increasing trend in fluctuation;The temperature,precipitation and potential evaporation in winter are significantly different;The trend of temperature increase in each sub basin was significant,and the trend of potential evapotranspiration and temperature was consistent in the precipitation?2?1986-2000 years of arable land,construction land and unused land increased by127.93 km²,3.22 km² and 33.31 km² respectively,The rapid increase in arable land during this period is the result of a reduction in grass and woodland,especially a decrease in grassland area;2000-2012 years,woodland,grassland,water and construction land increased by 139.08km²,270.92 km²,16.64km² and 1.89 km²,respectively,The decrease of cultivated land was the most obvious in this period,so the increase of forest land and grassland mostly came from the decrease of cultivated land.?3?The maximum water production depth,water production depth,total water yield and water production coefficient fluctuated in the upper reaches of Shiyang River in 1986-2012years,The maximum water production depth,water production depth and total water yield increased by 7.47mm,7.13mm and 0.78×10⁸m³,respectively,and the coefficient of water production decreased by 0.08%,1986-2012 years,the water depth and water production capacity of the upper reaches of Shiyang River have been improved,but the water production capacity has not been fully restored by 2012?4?The eight river,the maximum water production depth is Xiying River?193.87mm?,Dajing River water depth?83.14mm?,the minimum total water yield is up to the East River.Among them,West River,Gulang River and Dajing River in 2012 produced more water than in 1986;The water depth?217.18mm?and water yield coefficient?46.246%?of unused land in the upper reaches of Shiyang River are the largest;The water production depth firstly increased and then decreased with the elevation of the sea,and reached the maximum value at3901-4300m?275.06mm?,while the water production coefficient in the 3901-4300m interval was the largest?55.51%??5?1986-2000 climate change of Shiyang River has positive effect on reducing the water depth and land use change on water depth decrease inhibition is reversed,the positive effect is7.79 times the reverse inhibition.2000-2012,the increase of climate change on the water depth also plays a positive role in promoting the land use change and increase of water depth to reverse inhibition,its positive effect is 6.71 times the reverse inhibition.?6?The climate change of each river system in the upper reaches of Shiyang River in1986-2000 years has a positive effect on the change of water production depth.Huangyang River,Zamu River,East River and West River have are positive roles in promoting the change of land use change on the water depth.Dajing River,Gulang River,Jinta river and Huangyang River have are passive roles in promoting the change of land use change on the water depth.The climate change of each river system in the upper reaches of Shiyang River in 2000-2012years has a positive effect on the change of water production depth.