*WINNER* Nutrient Retention in a Reconnected Riparian Forested Wetland

Abstract

Restoring connections between rivers and floodplain wetlands can improve water quality downstream. The USDA Natural Resources Conservation Service’s Wetlands Reserve Program (WRP) has restored many wetlands in the Lower Mississippi River Valley by increasing floodplain-river connections. We are studying water quality changes over three years in a restored agricultural wetland in western Kentucky after reconnection with a large agricultural ditch via levee breaks. Floodwater quality is being measured over 24 h as stream water flows from the levee, through the forest, and into a remnant stream channel using 11 automated water samplers to monitor particulate and nutrient concentrations, and 23 water level loggers to estimate flow paths and discharge. Results from the first flood show nutrient and particulate concentrations were higher and more variable earlier in the flood and closer to levee breaks. Total suspended solids (TSS) concentration was a strong predictor for both total nitrogen (TN) and total phosphorus (TP) in the forest and near the remnant channel, indicating deposition of TSS is positively related to TN and TP retention. This relationship was stronger for TP than TN, and increasing N:P ratios over time show that more phosphorus was retained than nitrogen. This initial sampling event verified that nutrient retention occurs in this reconnected forest. Future work will incorporate nutrient and hydrology data from this, and subsequent floods, which will provide a more complete picture of nutrient retention provided by this reconnected wetland.