For about 10 years, the U.S. Geological Survey (USGS) has monitored water quality and streamflow in three agricultural drainage ditches in an effort to evaluate the influence of best management practices on water quality. These ditches are small tributaries to oxbow lakes located in the Mississippi Alluvial Plain of northwestern Mississippi--two sites (LWSR and LWT2) drain to Lake Washington and one site (BLT1) drains to Bee Lake. Streamflow was intermittent at these sites and the ditches were dry much of the year. When streamflow was present, flows were measured on 15-minute intervals and water-quality samples were collected over the course of the flow event using an automated sampler. These datasets were aggregated by flow event and include various flow statistics (mean flow, peak flow, total flow volume, and event duration), flow-weighted mean concentration (total constituent load divided by total flow volume) and total constituent load for each flow event. The water-quality constituents include total nitrogen, organic nitrogen, ammonia, ammonia plus organic nitrogen (total Kjeldahl nitrogen), nitrate plus nitrite, total phosphorus, organic carbon, chloride and suspended sediment; USGS parameter codes 00600, 00605, 00610, 00625, 00630, 00665, 00680, 99220, and 80154. All samples were unfiltered. Data were collected from approximately 2007-2016, depending on the site.