How do I do a Wetland Delineation?
Wetland delineation is a process for identifying and mapping wetland boundaries, which is essential for regulatory and conservation purposes. In western Washington, wetland delineations are conducted following the guidelines outlined in the 1987 U.S. Army Corps of Engineers (USACE) Wetlands Delineation Manual and the Western Mountains, Valleys, and Coast Region (WMVC) supplement.
1. Understanding the Three Factors
The USACE manual and regional supplements emphasize three key factors for wetland delineation: soils, plants, and hydrology. These factors are used to identify wetland boundaries based on the presence of certain indicators.
Soils: Wetland soils are characterized by hydric soil indicators, which are formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part.
Plants: Hydrophytic vegetation, or plants adapted to grow in wet conditions, is another key indicator of wetlands. Wetlands support a prevalence of plants that are typically adapted for life in saturated soil conditions.
Hydrology: Hydrology refers to the presence of water at or near the surface of the soil for a sufficient duration during the growing season to influence plant growth and soil characteristics.
2. Conducting the Delineation
The delineation process involves fieldwork to identify and map wetland boundaries based on the three factors mentioned above. Field observations, soil sampling, and plant identification are key components of this process. The delineation is conducted by qualified wetland scientists or professional ecologists trained in the USACE manual and regional supplements.
3. Completing the Associated Forms
After the delineation is completed, various forms need to be filled out to provide detailed information about the wetland site and the delineation findings. In Washington state, a Washington State Department of Ecology certified professional must complete a rating of the wetland. This rating considers the characteristics and functions of the wetland to determine its category and subsequently its applicable buffer size. The rating and wetland category helps assess the ecological significance of the wetland and guides decision-making regarding its management.
4. Reporting and Delineation Rating
Once the delineation is complete, a report summarizing the findings is prepared. The report includes maps showing the wetland boundaries, descriptions of the soils and vegetation, and an assessment of the hydrology. The report also details the rating performed based on the quality and function of the wetland, which helps determine the level of protection and potential mitigation required.
If you're in need of wetland delineation services in Washington State, look no further! Ocinro offers comprehensive wetland delineation services adhering to the USACE 1987 manual and regional supplements. Contact us for more information and to request a free quote.