Wetlands provide numerous beneficial functions to nature and society including fish and wildlife habitat, water quality improvement, flood storage, erosion control, recreational and aesthetic value, and natural products for our own use.
Some in the water-thirsty West have adopted the false notion that wetlands are actually unnecessary or harmful to society. One concern regarding the enhancement of wetlands is the idea that evaporation may increase, thereby wasting scarce water. According to research, this is not the case when increasing the amount of open surface water in an existing wetland within colder northern climates.
Studies consistently show that when the amount of open water is increased in a wetland within this region, water is actually conserved. Specifically, open-water wetlands conserve between 2% – 12% more water than non open-water wetlands.
For more information about evaporation and water conservation in wetlands, please visit the following studies and resources:
King A.C., Mitchell C.A., Howes T. (1997). Hydraulic tracer studies in a pilot scale subsurface flow constructed wetland. Water Science and Technology 35(5), 189-196.
Linacre E.T. 1994. Estimating U.S Class-A pan evaporation from few climate data. Water International 19, 5-14.
United States Bureau of Reclamation. USBR AgriMet website. http://www.usbr.gov/gp/agrimet/
Wallace S.D., Nivala J.A., Parkin G.F. (2005). Relationship between evapotranspiration and pan evaporation in cold-climate subsurface-flow constructed wetlands. IWA Specialist Group on the Use of Macrophytes in Water Pollution Control Newsletter No. 30.
Western Regional Climate Center. (2005). WRCC website. http://www.wrcc.dri.edu/Tweet