Assessment of On-Farm Water Storage (OFWS) Systems as a BMP for Sustainable Irrigation and Nutrient Loading Control in Mississippi

Abstract

Abstract. Groundwater from the Mississippi River Valley Alluvial Aquifer (MRVA) is the primary source of water for irrigation in the Mississippi Delta. While most of East Mississippi is still in dryland production, there is an increasing interest in irrigation in this region, where surface water is the main source of irrigation. Over the last ten years, excessive water withdrawal from the MRVA has led to a net loss of about 4,500,000 acre-ft of water just in the Mississippi Delta. Nutrient loading to local streams and rivers from agricultural fields is another major concern in both Mississippi Delta and in East Mississippi. An On-Farm Water Storage (OFWS) system is a constructed BMP consisting of a tail water recovery ditch and a water storage pond that has the primary goal of reducing downstream nutrient loading by capturing storm runoff and irrigation tailwater. These systems also supply water for irrigation by capturing surface runoff and irrigation tailwater. This paper presents the preliminary findings on the effectiveness of OFWS system in reducing nutrient loading from the study area in East Mississippi. Analysis of storm runoff captured by the OFWS system showed very high nitrate, TN, and TP concentrations. Concentration of nitrate in the storm runoff ranged up to 80 mg/l. Preliminary results conclude that OFWS systems can be an important BMP for reducing downstream nutrient loading to streams and rivers. Analysis of grab samples collected from the storage pond has shown that it can act as a sink to reduce nutrient concentrations in water.