Irrigation water quality management under the impact of climate change

Agriculture is vital for human survival and irrigation water quality plays an important role in agricultural growing and harvest. Although Taiwan has abundant rainfall, the uneven distribution of rainfall in time and space makes the irrigation water management difficult. In the past two decades, climate change has led to frequent occurrence of extreme weather events and global disasters, and the increase in the frequency and intensity of extreme events enhances the potential disaster risk in Taiwan, impacting the water resource management severely. Meanwhile, industrial wastewater is a significant pollution source, and the surface water quality would be further deteriorated if the industrial wastewater was not treated properly before its release. In Taiwan, the needs of water resources for domestic and industrial uses have the higher allocation priority than that for agricultural use, considering the political concerns and economical contribution. Oftentimes, a supplementary water resource to meet irrigation need is required due to the scarce of available water resources. The situation may become even worse under the influence of climate change.

Given the information above, this study explored the irrigation water quality variation under the influence of climate change on agricultural water resource management. The Taoyuan City (including Taoyuan irrigation Shimen irrigation areas) were selected as the study area. The potential impact of climate change on irrigation water quality, considering factors of pollution discharges and economic development, was assessed. Adaptive strategies including stabilizing irrigation water demand, strengthening irrigation water supply and building an agricultural technology auxiliary system were discussed. The result showed that the increasing frequency of heavy rainfall events in Bade, Xinwu, and Guanyin Districts. The surface pollutant would be washed out easily during heavy rainfall events, impacting neighboring water bodies. On the other hand, drought events appear in Daxi and Fuhsing Districts in extreme climate events. Therefore, a new strategy for sustainable water management is needed.