Floating Wetlands for Cost Effective Water Quality and Habitat Restoration
Presentation Abstract
A variety of floating wetlands have been used to improve water quality in estuaries and various types of freshwater bodies. These systems also increase fish and wildlife habitat, and benefit aesthetic and recreational values. The primary mechanism for water quality improvement is the uptake of dissolved nutrients by biofilm growth on wetland plant roots, which reduces nutrient availability for floating or attached algae growth in the water body. Advanced floating wetland designs provide aeration and circulation of water through the root system to increase nutrient uptake by the biofilm, and also reduce internal nutrient inputs caused by low dissolved oxygen and high pH in the water and underlying sediments of stagnant water bodies. In addition, artificial root systems can be added to floating wetlands to greatly increase the surface area for biofilm growth. For example, floating wetlands have reduced total phosphorus concentrations by 40 - 90 percent in eutrophic lakes and ponds. Wetland designs may include a diverse structure of native marine or freshwater plants, bird nesting habitat or temporary bird exclusion netting, forage fish or salmon rearing habitat among the root system, and underwater netting for predatory fish exclusion. Wetland structures consisting of HDPE tubing attached by stainless steel shackles, and a plant matrix consisting coir fibers within nylon netting provides systems that are resistant to waves, corrosion, and decay. Floating wetland shapes and sizes vary to fit site constraints, and are particularly suitable for areas with hardened shorelines where construction of shoreline wetlands on adjacent property is costly or infeasible. At a cost of $30/square foot, floating wetlands provide a cost effective alternative to shoreline wetland construction for water quality and habitat restoration in Puget Sound and its freshwater bodies.
Session Title
Session S-05F: Ecosystem Restoration: Geomorphic Context, Design Considerations, and Success Stories
Conference Track
Restoration
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
1-5-2014 5:00 PM
End Date
1-5-2014 6:30 PM
Location
Room 6C
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Constructed wetlands--Washington (State)--Puget Sound; Water quality--Washington (State)--Puget Sound; Restoration ecology--Washington (State)--Puget Sound
Geographic Coverage
Salish Sea (B.C. and Wash.); Puget Sound (Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Floating Wetlands for Cost Effective Water Quality and Habitat Restoration
Room 6C
A variety of floating wetlands have been used to improve water quality in estuaries and various types of freshwater bodies. These systems also increase fish and wildlife habitat, and benefit aesthetic and recreational values. The primary mechanism for water quality improvement is the uptake of dissolved nutrients by biofilm growth on wetland plant roots, which reduces nutrient availability for floating or attached algae growth in the water body. Advanced floating wetland designs provide aeration and circulation of water through the root system to increase nutrient uptake by the biofilm, and also reduce internal nutrient inputs caused by low dissolved oxygen and high pH in the water and underlying sediments of stagnant water bodies. In addition, artificial root systems can be added to floating wetlands to greatly increase the surface area for biofilm growth. For example, floating wetlands have reduced total phosphorus concentrations by 40 - 90 percent in eutrophic lakes and ponds. Wetland designs may include a diverse structure of native marine or freshwater plants, bird nesting habitat or temporary bird exclusion netting, forage fish or salmon rearing habitat among the root system, and underwater netting for predatory fish exclusion. Wetland structures consisting of HDPE tubing attached by stainless steel shackles, and a plant matrix consisting coir fibers within nylon netting provides systems that are resistant to waves, corrosion, and decay. Floating wetland shapes and sizes vary to fit site constraints, and are particularly suitable for areas with hardened shorelines where construction of shoreline wetlands on adjacent property is costly or infeasible. At a cost of $30/square foot, floating wetlands provide a cost effective alternative to shoreline wetland construction for water quality and habitat restoration in Puget Sound and its freshwater bodies.
