Rain gardens or bioretention areas are designed to capture stormwater runoff, filter it through a special media and allow it to infiltrate, evapotranspire or flow out. Rain gardens consist of excavated basins equipped with a perforated pie underdrain. The underdrain is covered by a special soil- compost media in which specific vegetation is planted.
Proposed to be constructed in the southern portion of the AgriLife Campus the rain garden will have curb openings with a concrete flume that will allow for runoff to drain to a collection point within the garden for automatic sampling and flow measurement. A surface overflow box will drain water to an underground pipe away from the median. Additionally, the drainage layer of the rain garden will house perforated pipes that will assist in soil infiltration. A flow measurement device will measure the overflow and perforated pipe. Water quality samples will be collected with an automatic sampler. A pressure transducer will be installed within a well point to measure soil water storage. The outflow will drain into a depression/ ditch via a flume. Plants will be selected based on optimal performance of the rain garden, including treatment of the storm water.Overall, the monitoring data will be used to quantify total water inflow (runoff), outflow (runoff and infiltration), soil water storage, and pollutant balances. The rain garden will also be maintained beyond the scope of this project as a demonstration for the public.