Field Delineation. Potential wetlands and other waters of the U.S. were formally delineated on July 5, 2012 by URS wetland scientist, Xxx Xxxxxxxx. Wetlands were `delineated in accordance with the routine on-site methodology described in the Corps of Engineers’ (Corps) Wetlands Delineation Manual (Environmental Laboratory 1987). This method uses a three-parameter approach to determine if an area is a jurisdictional wetland. The three parameters are soil, vegetation, and hydrology. Under normal circumstances (undisturbed conditions), a potential jurisdictional wetland must have positive wetland indicators of hydric soils, wetland hydrology, and a dominance of hydrophytic vegetation. Positive wetland indicators include field indicators and published data such as United States Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS) lists of hydric soils. The following sections describe the general diagnostic characteristics and some of the typical positive wetland indicators for each parameter. Hydric Soils: Soils are considered hydric if the soil is classified as hydric by the NRCS or if field indicators that are associated with reducing soil conditions are present. The NRCS defines a hydric soil as a soil that formed where conditions of saturation, flooding, or ponding occurred long enough during the growing season to develop anaerobic conditions in the upper portion of the soil profile. Local and national soil surveys published by the NRCS are used to determine the types of soil present in an area. Field indicators of hydric soils are identified in the “Field Indicators of Hydric Soils in the United States, Guide for Identifying and Delineating Hydric Soils” published by the U.S. Department of Agriculture Natural Resources Conservation Service (USDA 2010). Field indicators may also include organic hydric soils (or histisols), histic epipedons, sulfidic material, aquic or peraquic moisture regimes, reduced soil conditions indicated by oxidized rhizospheres, soil color, including gleyed soils, soils with mottles and/or low-matrix chroma, and iron and manganese concretions.
Field Delineation. Scientists verified wetland boundaries in the field during the summer and fall of 2000. The primary activity of these trips was to ground-truth the office-based preliminary delineation and adjust premapped boundaries to actual on-the-ground conditions. HDR and Corps of Engineers staff met in the field in May 2000 to discuss the delineation methods that would be used. The ground-truthing included identification of wetlands based on the wetland identification methodology described in the Corps of Engineers Wetland Delineation Manual (USACE, 1987). This methodology followed a three-parameter approach to wetland identification and delineation, using the criteria of hydric soils, dominant hydrophytic vegetation, and wetland hydrology. For questionable locations (as determined from office premapping) and at other selected locations throughout the project area, Corps of Engineers’ data sheets and photographs of the project area wetlands were completed. These will be provided to the Corps of Engineers in a Preliminary Jurisdictional Determination report. Where wetland sites were similar to areas where a data form had previously been completed, scientists completed a less detailed examination. Geographic coordinates were logged at all data collection locations. Qualitative information was also collected for identification of wetland functions and values. Much of the fieldwork was done in the vicinity of alternatives that are no longer under consideration, but the findings are applicable throughout the project area.
