Wetlands May Be Key to Cleaning Wastewater, Contaminated Groundwater, and Agricultural or Stormwater Drainage

Demands on water resources for municipal, agricultural, and industrial development continue to increase throughout the United States, especially in the arid Southwest. In order to meet these demands, wetland habitats are often depleted or destroyed, yet wetlands are important for maintaining and enhancing biodiversity, improving water quality, and protecting watersheds.

To help satisfy the water resource needs of both humans and wildlife, botanist and professional wetland scientist Joan Daniels from the USGS Fort Collins Science Center investigates the development of constructed wetlands for use as natural water-treatment facilities for water of impaired quality.

"Wetlands are gaining recognition as low-cost, low-maintenance alternatives to some conventional wastewater treatment systems," notes Joan Daniels. "Through our research we hope to demonstrate their effectiveness at providing safe reclaimed water for human needs as well as quality habitat for wildlife."

LEFT: Demonstration Wetland at Henderson, NV, where hummocks are used to improve the effectiveness and sustainability of the treatment wetland as well as provide quality waterfowl habitat. Photo by Joan Daniels, USGS. RIGHT: Demonstration Wetland in San Jacinto, CA, where long-term monitoring results have driven subsequent wetland designs for water quality and habitat improvement. Hundreds of white faced ibis and thousands of tricolored blackbirds have nested in this 10-hectare constructed wetland. Photo by Joan Daniels, USGS.

Many of the projects are joint efforts between the U.S. Geological Survey, the Bureau of Reclamation, and various municipalities and local agencies across the southwestern United States. Currently, a project is being developed with Orange County Water District of southern California to build an 8-acre pilot wetland designed to remediate or degrade endocrine-disrupting compounds from effluent-dominated water prior to its discharge into the Santa Ana River and ultimate recharge into the groundwater. In a separate study, Ms. Daniels and her interagency team have developed construction designs, operation and maintenance plans, and monitoring plans for Beaumont Cherry Valley Water District of Beaumont, California. The goal is to test the ability of two 1-acre pilot wetlands, designed to mimic natural emergent/riparian wetlands, to reduce nitrate concentrations from contaminated groundwater high in nitrate-nitrogen. Various woody and herbaceous aquatic plant species will be planted in the pilot wetlands and evaluated. The wetlands will be monitored for two years to evaluate their water treatment efficiency and wildlife use. If they are determined to be successful, a 6-acre site will be developed to treat the entire contaminated reservoir prior to discharge and/or reuse.

Previous studies at other sites within the southwestern U.S. have shown that both water quality and wildlife habitat can be improved with proper design and operation of the constructed wetlands. However, due to the numerous types of emerging contaminants as well as variations in local substrate, climate, and entire biological systems, additional research is critical to more fully understand and predict how effective these treatment/habitat systems will be over the long-term.

 

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For more information, please contact:

Joan S. Daniels (formerly Joan Thullen)
Denver Field Station
c/o Bureau of Reclamation
P.O. Box 25007 86-68220
Denver, CO 80225-0007
Phone: 303-445-2212
Fax: 303.445.6328
Email: joan_daniels@usgs.gov