Measuring the Erosion of an Irrigation Reservoir Levee

Abstract

<abstract> <b><sc>Abstract.</sc></b> Increasing agricultural demands on limited groundwater resources in the Arkansas and Mississippi alluvial floodplain have created a growing need for the development of surface water resources. On-farm irrigation reservoirs are used to reduce dependence on groundwater supplies, but wind-induced wave erosion of levees creates an additional maintenance cost for producers. Measurements of levee erosion in a typical irrigation reservoir in east-central Arkansas were made with a ground-based LIDAR system and used to quantify erosion and estimate maintenance costs for irrigation reservoir levees. Approximately 1350 m³ of soil loss was measured from a 1530 m long levee during a seven-month period between December 2012 and July 2013. The damage was most severe in the northeast corner, where over 3 m of width were lost due to prevailing southerly winds blowing across the longest diagonal fetch length. Based on a typical cost (in 2014) for earth moving of $2.6 m^-3, the cost to repair this loss would be approximately $3,500, resulting in a five-year maintenance cost of $17,500, which is about 16% of the initial cost of the levee. This research provides a basis for decision-making for producers who rely on irrigation reservoirs. Maintenance costs can be projected for a worst-case-scenario of levee erosion, and the cost of protection can be balanced against expected erosion and repair costs.