Why Use a Bioswale? Ecologically sound treatment of runoff. Includes: Hydrocarbons Heavy Metals Sediment Nutrients And many more possibilities Would otherwise pollute downstream water ecosystems Figure 1.2 [bren study]
How a Bioswale Operates Channels runoff from assigned watershed Dimensions critical to efficient operation Heavy volume flow is diverted Figure 1.3 [bren study]
Water enters forebay of Bioswale Water enters backbay Sediments settle Phytoremediation occurs Output exits outlet pipe into natural or constructed waterway Figure 1.4 [bren study] How a Bioswale Operates, continued
Phytoremediation Breakdown in soil, or accumulation in shoots and leaves Certain plants for certain contaminants Broad application (TNT) Figure 1.5 [soil.edu] Using plants to remove, transfer, or stabilize, contaminants in soil, sediment, and groundwater.
Results of Bioswale Use Dramatic reduction of sediments Lower flow velocities Lower flow velocities Reduction of hydrocarbons, nutrients, and metals EPA studies of Superfund sites: 30-70% decreases EPA studies of Superfund sites: 30-70% decreases Mature plants more efficient at removal Efficiency increases with size of Bioswale High volume flow decreases efficiency
Additional Benefits and Alternatives Benefits: Ecological Preservation Ecological Preservation Flood control Flood control Aesthetic Value Aesthetic Value Inexpensive in comparison Inexpensive in comparison Alternatives Stormceptor (Costly) Stormceptor (Costly) FossilFilter (high maintenance) FossilFilter (high maintenance)
Conclusion Bioswales meet increasing demand for mitigation measures to stop pollution from urban environments Bioswales work Sedimentation Sedimentation Phytoremediation Phytoremediation