Irrigation Efficiency Trap and Hydrologic Outcomes

This research article investigates the relationship between farm-scale irrigation decisions and basin-scale hydrology, focusing on the Henrys Fork watershed in Idaho. It documents how changes in irrigation practices, particularly the shift from surface irrigation to center-pivot sprinkler systems, have impacted hydrologic outcomes over time. The study utilizes a combination of irrigator interviews, aerial and satellite imagery, and statistical streamflow analysis to assess the effects of these practices on water diversion and return flows from 1978 to 2022. Findings indicate a significant decrease in annual surface-water diversion and return flow to the river, highlighting the unintended consequences of improved irrigation efficiency. The article discusses the concept of the irrigation efficiency trap, where efforts to enhance water use efficiency at the farm level can lead to increased water consumption at the basin scale. It emphasizes the need for a comprehensive understanding of the socio-hydrological dynamics involved in irrigation management to inform effective water conservation strategies.