Performance Analysis of a Wet-Retention Pond in a Small Agricultural Catchment

AbstractUrban wet-retention pond performance has been extensively studied for many water contaminants. However, very few studies have focused on wet-retention pond efficiency under agricultural production systems. This study presents the results drawn from a 5-year data set collected on a retention pond constructed in Saint-Samuel (Canada) at the outlet of a 23.1-hectare watershed under cash crop production. A total of 62 runoff events were analyzed for hydrological performance, 20 events for total suspended solids (TSS), 11 events for total nitrogen (TN), and 14 events for total phosphorus (TP). Peak flows were reduced by 38% on average and the retention pond reduced the frequency and duration of exceedance of the erosion threshold. Drawdown times for 50, 75, 90, and 100% of the runoff volume were 7, 18, 28, and 42 h, respectively. The mean detention time was 3.2 h compared to the watershed lag time of 3.4 h. Mean removal efficiency ratios based on event-mean concentrations (EMC) and event-total loads (E...