Stormwater runoff is made up of excess rain water which flows into larger bodies of water and storm sewer systems thanks to the abundance of hard surfaces, like concrete. Without concrete, large quantities of water would be absorbed into the ground instead of entering streams and lakes. Stormwater retention ponds collect pollutants, chemicals, and debris from paved surfaces to prevent it from entering into water bodies. Without stormwater retention ponds, this water causes erosion, decreased groundwater recharge and alteration of important aquatic environments.
Retention ponds or "wet ponds" are ponds constructed to treat and store stormwater runoff. Retention ponds are permanent pools of standing water that eventually empty into a receiving water body. Forebays are included in the design of retention ponds to "pretreat" the stormwater before it spills over into a major water feature. Water is treated through sedimentation and nutrient uptake.
Benefits of stormwater retention ponds include:
- Improved water quality in surrounding water bodies. Retention ponds manage stormwater quantity and quality, lessening the transfer of pollutants and chemicals into nearby water bodies.
- Aesthetic appeal. A retention pond may enhance aesthetics via plant selection, plant placement, topography and pedestrian access options.
- Increased biodiversity. Biodiversity is defined as the variation of life forms in a given ecosystem. Landscaping with ponds and different varieties of plants can add to the natural environment.
- Wildlife habitat. Retention ponds provide habitats for animals, organisms, and insects.
- Water conservation. Water that is stored in retention ponds is available for non-potable human uses such as irrigation.
- Flood prevention. Stormwater quantity reductions minimize the risk of flooding in nearby areas.
- Minimization of erosion. Stormwater quantity reductions minimize erosion in the nearby area and along the banks of water bodies.