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WHAT IS A WETLAND?

Wetlands are distinct areas of land that are frequently or permanently saturated with fresh water. These areas attract many species of plants and animals and are often the most ecologically diverse places on Earth. Wetlands play a critical part of the local water cycles, slowing freshwater runoff to prevent flooding and digesting pollutants in the runoff. Land development often destroys wetlands, leading to stormwater problems. Understanding what wetlands need for proper functioning, and how human activity disrupts these processes, is important to protecting these habitats.

Characteristics of Healthy Wetlands

  • Supporting rare plant and/or plant communities: The National Wetland Plant List 2014 Update of Wetland Ratings
  • Invasive species are absent, or if present have minimal cover
  • Little human caused alteration of native vegetation, or vegetation has recovered from disturbance (ie. logging, herbicides, etc.)
  • Little or no human-caused alterations to wetland topography or soils
  • Key ecological processes are intact; no human caused changes to hydrology or nutrients/sediments, or the wetland has recovered from any changes
  • Expected diversity of species and functional groups present

Human Alterations of Wetlands

Alterations induced by post-modern settlement that degrades the composition, structure, functions, and/or ecological processes of intact ecosystems.

Examples include:

  • Hydrological alteration
  • Nutrient enrichment
  • Invasive/non-native species
  • Sedimentation
  • Removal of vegetation
  • Soil compaction
  • Habitat conversion
  • Increase in toxins/pollutants/heavy metals
  • Changes in fire regime
  • Introduced pests/pathogens

Wetland Regulations

Washington State laws require that wetlands protected under the Growth Management Act and the Shoreline Management Act be delineated using a manual that is developed by Ecology and adopted into rules (RCW 36.70A.175; RCW 90.58.380).

The changes are effective March 14, 2011.

The latest federal delineation manual and its supplements should now be used to delineate wetlands in the state.

You can find the federal delineation manual and its supplements on Ecology’s Wetland Delineation web page:http://www.ecy.wa.gov/programs/sea/wetlands/delineation.html. To see the updated rule language go to:http://www.ecy.wa.gov/laws-rules/SMA2010/1007.html.

If you have any questions about wetland delineation, contact: Tom Hruby, PhD Senior Ecologist Washington State Department of Ecology P.O. Box 47600 Olympia WA 98504 or email tom.hruby@ecy.wa.gov

Selecting Wetland Mitigation Sites Using a Watershed Approach (Western Washington)

For more information on wetlands, go to the Washington State Department of Ecology’s Wetlands website.

 

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