Simulation of Annual Water Yield in the Upper Heihe River Basin from 1990 to 2018 Based on InVEST

Abstract

Based on InVEST model， this paper evaluates annual water yield in the Upper Heihe River Basin in the past 30 years with soil， meteorological and land use/cover data in 1990， 2000， 2010 and 2018 as inputs， and the spatiotemporal geographically weighted regression method （GTWR） is used to analyze the spatiotemporal heterogeneity of the impact of precipitation， potential evapotranspiration and net primary production （NPP） on water yield services， so as to explore the temporal and spatial evolution characteristics of water production services in the upper reaches of Heihe River Basin， reveal the water production capacity and differences under different underlying surfaces combined with land use and cover change （LUCC）， and identify the leading driving factors and driving intensity in different regions.The results show that： （1） The average of total water yield in the four periods from 1990 to 2018 was 1.67×109 m3， the average water yield depth was 167.11 mm， the annual water production in 2018 was the highest （205.80 mm）， and the annual water production in 2000 was the lowest （137.01 mm）.（2） The contribution of grassland to the total water yield was the largest （76.5%）， while the average water yield depth of ice， snow and desert was the highest and that of forest land was the lowest.（3） The positive effect of precipitation on water yield was significant， and the negative driving effect of potential evapotranspiration on water yield was obvious， while the negative driving effect of NPP on water yield was strong and the positive driving effect was weak.（4） The influence of various factors on water yield showed obvious heterogeneity.The precipitation dominant region was the high value region of precipitation and water yield in the central and eastern regions.The potential evapotranspiration dominant region was the low value region of potential evapotranspiration in the western region， and the NPP dominant region was the high value region of NPP in the eastern region.The water yield in the research area fluctuates greatly between time， and the water production service is unstable as a whole.The effect of NPP on water yield is more complexity and variability than precipitation and potential evapotranspiration.

Keywords

• the upper heihe river basin
• invest
• annual water yield
• driving factors
• temporal and spatial heterogeneity