Rain gardens, also called bioretention basins, are shallow depressions that catch and hold stormwater runoff to promote water infiltration into the ground and evaporation to the atmosphere. They mimic and restore natural drainage patterns and are classified as a Low Impact Development or “green infrastructure” strategy. They were first developed in the 1990s in milder climates, and research at ESF has shown they can handle winter snow and road salt.
Increasing development overloads “grey infrastructure” drainage systems, causing more frequent flooding and pollution of receiving waters, which can include raw sewage from combined sewer overflows. These systems also prevent water from entering the soil, lowering the water table and stressing aquatic ecosystems with lower water levels that are too hot in dry summer weather. Rain gardens provide urban areas with stormwater protection while improving ecological functions. They help restore the natural water cycle and improve water quality to meet the Clean Water Act goals of fishable and swimmable waters. Most of the water falling on rain gardens moves, or infiltrates, into the soil. This sustains plants that provide aesthetic benefits, wildlife habitat, and shade to cool buildings and sidewalks, and improve local air quality. A portion of the water percolates farther into the soil, recharging groundwater which keeps streams healthy. Infiltration also removes common urban pollutants from water. This rain garden provides important teaching and research opportunities at ESF. Students monitor flow rates using the V-notch weirs and level sensors, while soil temperature and moisture probes combined with climate data provide feedback to researchers and designers seeking to optimize the performance of these systems.
Rain gardens are an important part of green infrastructure and are recommended by New York and federal stormwater guidelines. They are highly adaptable, with a variety of landscaping options; are easy to establish; and work equally well for residential homes, industrial parking lots, or commercial shopping districts. They are a critical part of improving the local environment while reducing costly and long-term problems at the downstream portions of the urban watershed.