A QUANTITATIVE APPROACH FOR MEASURING N-CONCENTRATION AND P-CONCENTRATION CHANGES IN SURFACE RUNOFF FROM A RESTORED RIPARIAN FOREST WETLAND

A recently restored riparian wetland is being evaluated as a bioremedi ation site for nutrients moving downslope from an animal waste applica tion site. in question is the short-term effectiveness of the restored wetland in enhancing the quality of the water leaving the site. Netwo rks of shallow ground-water wells and surface runoff collectors are be ing used to monitor nutrient concentrations and nutrient assimilation as surface and ground water moves through the wetland. A 450-mm H-flum e at the wetland outlet measures the quantity and quality of surface-w ater discharged from the wetland. Runoff is sampled at two locations e ntering the wetland and at two locations near the stream flow. At each location, the runoff is collected in a gutter, passed through a flume , and redistributed through a slotted gutter. Composite samples from e ach runoff event are collected with a low-cost automated sampler and a nalyzed for NO3-N, NH4-N, TKN, PO4-P, Total P, and Cl. Recorded hydrog raphs are used to determine total runoff volume and peak runoff rates of each runoff event. The runoff collectors have operated reliably and seem to be quantifying both hydrologic characteristics of runoff even ts and nutrient concentration changes in surface runoff as it migrates through the wetland. The simple design, low cost, and dependability o f the runoff collection and automated sampling system make it suitable for a variety of research and industrial applications.