Watershed-Scale Benefits of Using Reclaimed Water for Agricultural Irrigation

Agricultural irrigation is increasing due to climate stress and yield benefits on crops in the Mid-Atlantic region. To lessen groundwater demand, reclaimed water has grown as a popular freshwater alternative for irrigation. While reclaimed water (treated wastewater from wastewater treatment plants (WWTPs)) provides many benefits, additional costs deter farmers from its adoption. This study assesses the economic feasibility of reclaimed water for agricultural irrigation in two Mid-Atlantic watersheds: the Zekiah watershed in southern Maryland and the Greensboro watershed in eastern Maryland and southwestern Delaware. We identified areas most feasible for reclaimed water irrigation based on WWTP capacity, unit prices for water, and yield benefits of irrigation under diverse precipitation scenarios for both watersheds. Under dry precipitation conditions and a unit cost of $0.10 per cubic meter of reclaimed water (m3), 29.77% of cropland in the Zekiah watershed and 34.32% of cropland in the Greensboro watershed are feasible for reclaimed water irrigation, conserving a potential 1,505,154.72 m3 and 12,381,703.45 m3 of freshwater, respectively. However, when reclaimed water pricing and precipitation increase, significantly fewer farms experience sufficient yield benefits to cover reclaimed water costs. Further adoption of reclaimed water irrigation could be enhanced by a cost-share program that covers costs when yield benefits cannot.