Strengths

  • Pollutant removal for stormwater runoff
  • Provides stormwater peak flow and volume control as well as water quality control where stormwater infiltration is used.
  • Reduces temperature impacts of runoff.
  • Can be applied in almost any soils or topography.
  • Provide aesthetic values.

Limitation

  • Bioretention areas should only be used on small sites (i.e., five acres or less) as larger ponds tend to clog.
  • Should be separated from the water table to ensure that the groundwater never intersects with the bottom of the bioretention area, which prevents possible groundwater contamination and practice failue.

Bioretention pond

Application: Aquifers, bridge abutments, drainage, roads, footpaths, stormwater outfall, wastewater treatment plants

Description: A bioretention pond is a shallow planted depression designed to retain or detain stormwater before it is infiltrated or discharged downstream. The primary component is a filter bed, which has a mixture of sand, soil, and organic material as the filtering media with a surface mulch layer. During storms, surface runoff is directed into shallow, landscaped depressions as sheet flow or concentrated flow. It temporarily ponds 6-12 inches above the mulch layer and then rapidly filters through the bed. The depressions incorporate many of the pollutant removal mechanisms that operate in a forested ecosystem such as microbial soil processes, infiltration, evapotranspiration and plants. They create an environment for runoff reduction, filtration, biological uptake, and microbial activity, and provide high pollutant removal. Depending on the design, they can provide retention or detention of runoff water, and will trap and remove suspended solids and filter or absorb pollutants to soil and plant material. Bioretention ponds can be included in the designs for yards, commercial developments, parking lot islands, and roadways.

Contribution to climate resilience: A bioretention pond detains stormwater before it is infiltrated or discharged downstream, thus improving water quality (by removing pollutants) and reducing erosion and other damage associated with runoff. It thus reduces the negative impacts of heavier rainfall and storms, which are expected to increase (in the wet season) with climate change.

Supplementary sources of information:

http://www.fxbrowne.com/html/gs-facts/gs-factsheet05v9.pdf

http://www.stormwatercenter.net/Assorted%20Fact%20Sheets/Tool6_Stormwater_Practices/Filtering%20Practice/Bioretention.html

http://www.vwrrc.vt.edu/swc/NonPBMPSpecsMarch11/VASWMBMPSpec9BIORETENTION.htm

https://xpsolutions.atlassian.net/wiki/display/XDH/Bioretention

http://drenajeurbanosostenible.org/blog/page/12/

Background image credit: Flickr

This resilience-building measure is sourced from the Water Resource Adaptation Guide (2019) published by the National Council for Sustainable Development at the Ministry of Environment in Cambodia. The full Guide is available to download at URL https://ncsd.moe.gov.kh/sites/default/files/2019-10/Water%20Resources%20Adaptation%20Guide_March%202019_En.pdf