Dynamic Evaluation Of Water Resources Quantity In Yalong River Basin

For traditional and existing water resources assessment,we generally conduct statistics and assessments on the quantity,quality,temporal and spatial distribution characteristics of water resources,as well as development and utilization conditions,and current status in river basins or administrative regions on an annual scale.However,with the increasing degree of water resources development and utilization and the increasing demand for protection,annual-scale water resources evaluation on the one hand cannot support the increasingly urgent demand for refined water resources management in terms of timeliness and refinement;on the other hand,with the increasing intensity of human development and utilization of water resources,the hydrological cycle and underlying surface conditions of the basin have undergone strong changes,and traditional water resources evaluation methods may have large errors.This paper is based on the national key research and development program subject "Dynamic Evaluation and Prediction of the Quantity of Water Resources"(2018YFC0407701).The Wetspa model is a kind of the distributed hydrological model.Considering the impact of human activities and reservoir storage variables,a natural-social water cycle coupling model,which based on the Wetspa model,has been estabished for the Yalong River Basin to evaluate the amount of water resources in the Yalong River Basin.The main research contents and results are as follows:(1)Based on the Wetspa model,this paper established a coupling model of natural water cycle and social water cycle for the Yalong River Basin.In the model,daily hydrometeorological data was used to calibrate and verify the parameters.Daily and monthly nash efficiency coefficient NSE and relative error RE were used to evaluate the performance of model and analyze the applicability of the model in the Yalong River Basin.The results show that the daily Nash coefficients of all stations are greater than 0.5,the monthly Nash coefficients are all greater than 0.65,and the absolute value of the relative error is less than 20%,indicating that the Wetspa model has applicability in the Yalong River Basin.It is feasible to evaluate the water resources of the Yalong River Basin with the dual coupling model of natural-society water cycle based on Wetspa model.(2)In this study,water resources volume indicators,describing the dynamic changes of water resources,such as surface storage variables,underground storage variables,and inbound and outbound water volume,have been introduced to evaluate the water resources in the river basin on a monthly scale,which applies a positive effect on the water resources dynamic assessment.(3)In the paper,in order to explain the impact of reservoir regulation and social water cycle processes on the results of water resources evaluation,the difference in parameter sensitivity,parameter values and water production were analyzed between two modes,that the reservoir storage variables or water withdrawal is added in the model or not.The results show that in the evaluation of water resources,without considering the impact of reservoir regulation or the social water cycle,the results of water resources evaluation,including surface water resources,ground water resources and total water resources,will be on the low side.