Journal Article

Assessing irrigation water shortage in the middle reaches of the Heihe River Basin under future climate scenarios

LIU Meixian, WU Zihan, ZHANG Xinyu, ZHANG Fan, ZHANG Sunxun

2025

Overview

【Objective】Climate change is projected to increase the frequency of extreme weather events such as flooding and drought. This paper evaluates the risk of agricultural water shortage in the middle reaches of the Heihe River basin under different climate change scenarios.【Method】Using the CMIP6 SSP scenarios (SSP126, SSP245, and SSP585), downscaled meteorological data were integrated with the BP neural network, the Hargreaves model, and crop coefficients to predict changes in irrigation water availability and demand in the middle reaches of the Heihe River. Copula functions were applied to model the joint distribution of water supply and demand and assess the risk of water scarcity.【Result】Calculations for the period from 2024 to 2100 show that average annual irrigation demand is expected to increase by 10.21%, 11.73%, and 14.59% under SSP126, SSP245, and SSP585, respectively. The associated average annual growth rates will be 0.17%, 0.16%, and 0.18%, with the maximum-to-minimum annual runoff volume ratio being 1.21, 1.27, and 1.34, respectively. SSP126 will see an increased probability of wet-dry and wet-wet alternation, while SSP245 will exhibit the highest probability of wet-dry and normal-normal alternation. SSP585 will experience a decrease in the probability of wet-dry alternation and an increase in the probability of normal-normal alternation. Water scarcity risk is below 0.6 under the SSP126 scenario, below 0.6 in some years under SSP245, and consistently above 0.6 under the SSP585 scenario.【Conclusion】Runoff in the upstream regions and irrigation demands in the midstream regions of the Heihe River basin are both expected to increase under all SSP scenarios. Water scarcity risks are projected to decrease under the SSP126 and SSP245 scenarios, while SSP585 scenarios presents the highest water scarcity risk and SSP126 presents the lowest. These findings can inform the development of strategies to mitigate the impact of climate change on water scarcity in the catchment.

• Publisher: Science Press
• Subject: future climate change; copula function model; probability of water supply and demand combination; irrigation water shortage risk; middle reaches of heihe river