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As part of Potawot's treatment system, the swales are designed to maximize the natural treatment of the water. Like all bioswales, the swales have a fairly low grade, in order to slow the water as it travels. This encourages water to collect for extended periods of time, because the longer the water remains, the more sinks into the ground. Much of the water travels in the subsurface, or below the top layer of soil. This promotes the filtering of sediments and pollutants such as metals <ref>"Bioswales Article May 2007" October 28, 2008. [http://www.openlands.org/reports/BioswalesArticleMay2007.pdf]</ref>.
As part of Potawot's treatment system, the swales are designed to maximize the natural treatment of the water. Like all bioswales, the swales have a fairly low grade, in order to slow the water as it travels. This encourages water to collect for extended periods of time, because the longer the water remains, the more sinks into the ground. Much of the water travels in the subsurface, or below the top layer of soil. This promotes the filtering of sediments and pollutants such as metals <ref>"Bioswales Article May 2007" October 28, 2008. [http://www.openlands.org/reports/BioswalesArticleMay2007.pdf]</ref>.


The water levels in the swales are 1-2 inches deep during an average rainfall and 5-6 inches deep at maximum capacity.
The water levels in the swales are shallow. They are 1-2 inches deep during an average rainfall and 5-6 inches deep at maximum capacity.


=== Native Vegetation ===
=== Native Vegetation ===
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[[Category:Potawot]]
[[Category:Potawot]]
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== Further Reading ==
''' Design Manual: Biological Filtration Canal (Bioswale) '''
* http://fiesta.bren.ucsb.edu/~chiapas2/Water%20Management_files/Bioswales-1.pdf
''' Bioswales '''
* http://www.fairshared.com/Technical%20Policy/Bioswale.pdf

Revision as of 06:04, 21 November 2008

Template:115inprogress

Introduction

As part of Potawot's natural water treatment system, it uses swales to manage and treat runoff. Specifically, Potawot uses bioswales, which include vegetation. [1]

The swales are one aspect of Potawot’s commitment to sustainable resource usage. Instead of allowing runoff to become a waste, Potawot has a method to utilize runoff to help restore the native habitat by creating an ideal area for native plant growth. Runoff is filtered in the swales, and pollution is thus controlled. This is one part of the larger Potawot natural water treatment system. Once the water passes through the swales, it empties into the treatment pond. [2]

Locations

Diagram of Potawot's waterflow. Notice the swales in the parking lots. Image is courtesy of Eric Johnson.

The swales are positioned at the Potawot grounds to collect excess runoff. They are designed to use gravity to transport it into the treatment pond. They are located near Potawot’s parking lots, as shown in the diagram. This is due to the fact that non-soil surfaces such as concrete generate large amounts of runoff. This is due to the inability of water to penetrate these materials and sink into the ground during rains. The swales are connected to each other by culverts and form a system to channel runoff into the pond. [2]

Function/Treatment

As part of Potawot's treatment system, the swales are designed to maximize the natural treatment of the water. Like all bioswales, the swales have a fairly low grade, in order to slow the water as it travels. This encourages water to collect for extended periods of time, because the longer the water remains, the more sinks into the ground. Much of the water travels in the subsurface, or below the top layer of soil. This promotes the filtering of sediments and pollutants such as metals [3].

The water levels in the swales are shallow. They are 1-2 inches deep during an average rainfall and 5-6 inches deep at maximum capacity.

Native Vegetation

Native plants and shrubs are deliberately planted and encouraged to grow in the swales. These species are:

  • Scirpus microcarpus - Small-fruited Bulrush
  • Cornus sericea var. stolonifera - Red-twig Dogwood
  • Juncus effuses - Juncus
  • Deschampsia cespitosa - Tuft Hairgrass
  • Alnus rubra – Red Alder
  • Acer circinatum – Vine maple
  • Salix – Willow
  • Carex obnupta – Slough sedge

These plants serve multiple purposes. They assist the filtering process as well as help collect the water in the ground through their roots, including rhizomes. Importantly, they support the larger aim of Potawot to encourage native habitat renewal. [2]

Maintenance

The swales require a mild amount of upkeep to remain functional. This mainly consists of ensuring flow by manually unclogging the culverts. Also, nonnative and invasive plants are removed to preserve the native habitat. [2]

References

  1. Groves, William, Phillip Hammer, Karinne Knutsen, Sheila Ryan, and Robert Schlipf. "Analysis of Bioswale Efficiency for Treating Surface Runoff." October 28, 2008. [1]
  2. 2.0 2.1 2.2 2.3 Johnson, Eric. Interview. October 27, 2008.
  3. "Bioswales Article May 2007" October 28, 2008. [2]

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Further Reading

Design Manual: Biological Filtration Canal (Bioswale)

Bioswales

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