Description: SWMP2007 WetlandsThe Conservation Management Institute (CMI) has updated the existing USFWS National Wetlands Inventory (NWI) and Delaware Statewide Wetland Mapping Project (SWMP) data to meet or exceed NWI procedures and the guidelines of the Federal Geographic Data Committee's Wetland Mapping Standard (document FGDC-STD-015-2009) employing heads-up photo interpretation in a softcopy environment. We identified wetlands with a minimum mapping unit (MMU) of 0.5 acres with smaller, highly recognizable polygons (e.g., ponds) mapped down to approximately 0.10 acres. Photo interpreters (PIs) identified the wetland targets at a scale of approximately to 1:10,000 with delineations completed at 1:5,000 and, occasionally, larger as necessary. Polygons were then attributed with a code corresponding to the existing NWI classification scheme (Cowardin et al. 1979) and Delaware specific modifiers, where applicable. The update was completed in ESRI's ArcGIS 9.3.x using 2007 Color Infrared, obtained from the State of Delaware. All spatial and classification changes were made manually using standard photogrammetric techniques. When it was necessary to use ancillary datasets to aid in decisions, PIs would consult one or more of the following: Soil Survey Geographic Database (SSURGO), 1992 color infrared, National Hydrography Dataset (NHD), National Elevation Dataset (NED), NWI, and USGS Topographic maps. After we completed the delineation and attribution of the wetland polygons, datasets were inspected through an in-house quality control process for spatial, classification, and topologic errors before being sent to the U.S. Fish and Wildlife Service (USFWS) and the State of Delaware for final review and corrections. Additionally, the wetlands layer was run through the USFWS verification tool to further ensure the accuracy of polygons and the codes assigned to them. CMI completed the LLWW classification following guidelines provided by the USFWS. These classifications were derived from the Cowardin code, NHD, topography, and spatial relationships between wetlands. We assigned the initial codes based through a largely automated process. Where applicable, this process uses the Cowardin codes to attribute Landscape and Water body type. The next step largely uses water regime and spatial relationships to attribute Landform. We then manually attributed the NHD to assign Water flow. We manually reviewed the dataset and modified the attributes to create a correct and logical dataset. As the automated classification tends to use too fine a scale, we completed the finer step at a smaller scale than the initial classification in consultation with the Fish and Wildlife Service and the State of Delaware. Delaware modifiers are based off spatial data and guidance provided by DNREC. Wetland functional analysis was performed in consultation with Dr. Ralph Tiner of the USFWS.The USFWS and the State of Delaware contracted with the CMI to complete an updated and enhanced version of the existing NWI and SWMP for Kent, New Castle and Sussex Counties in Delaware. The area encompasses approximately 54 full and partial USGS quadrangles. This work involved updating the current existing NWI and SWMP data using more recent 2007 imagery, as well as including enhanced wetland data in the form of Landscape, Landform, Water flow path, and Water body type (LLWW; Tiner 2003). Wetlands were classified using Cowardin et al. (1979) and Delaware specific modifiers for rare, unique, and locally significant wetlands.Wetlands listed in the *Attribute* column are classified using the above referenced Cowardin system, where some wetland polygons have an 'H' modifier preceding their classification. These wetlands are known as 'Hwetlands' and consist of hydric soils having natural vegetation but lacking a photointerpretable wet signature. Hwetlands have the dominant soil type from SSURGO listed in the *musym* attribute column. This designation does not imply the lack of hydrology to qualify as wetland, only that during the mapping exercise no wet signature was evident and could be due to dense evergreen vegetation, lack of normal rainfall or groundwater at the time of photography, being artificially drained, etc. Hwetland polygons require localized verification on site to determine wetland extent. Landscape level functional assessment conducted during this mapping evaluated 11 separate functions. Wetlands were rated as either High or Moderate where appropriate for 8 of the 11 for functions: Bank and Shoreline Stabilization (BSS); Carbon Sequestration (CAR); Coastal Storm Surge Detention (CSS); Nutrient Transformation (NT); Other Wildlife Habitat (OWH); Streamflow Maintenance (SM); Sediment Retention (SR); and Surface Water Detention (SWD). Fish and Aquatic Invertebrate Habitat (FAIH) received a designation of High, Moderate, or Stream where appropriate. Provision for Waterfowl and Waterbird Habitat (WBIRD) received a designation of High or WoodDuck where appropriate. Provision for Unique, Uncommon, or Highly Diverse Wetland Plant Communities (UWPC) received a designation of Region where appropriate.Wetlands listed in the *DE_Modifier* column are those polygons where a special Delaware modifier(s) has been added to reference unique ecological communities that may harbor rare, threatened or endangered (RTE) plants and animals. Some wetland polygons may have more than one Delaware modifier designation. These numeric codes and their associated ecological community types are: (2)Delaware Coastal Plain Seasonal Pond; (3)Atlantic White Cedar; (4)Bald Cypress; (5)Interdunal Swale; (6)Acidic Fen; (12)Groundwater Seepage Wetland (Black Ash, Amphibian, and/or Stream). Adjacent wetland polygons or wetland polygons with the potential to harbor RTE's may have been tagged as part of the mapping process. For more information on these modifiers, please contact the Delaware Natural Heritage and Endangered Species Program at 302-739-9124.Data is ENV_Saltwater_Tidal_Buffer Enterprise Geodatabase Feature Class made available from DNREC's Enterprise Geodatabase.
Copyright Text: This data was created in partnership with funding from both the U.S. Fish and Wildlife Service, National Wetlands Inventory (NWI) and the Delaware Department of Natural Resources and Environmental Control (DNREC). Virginia Tech's Conservation Management Institute (CMI) is the project contractor. Lead contact: DNREC -- Mark Biddle (302-739-9939) mark.biddle@state.de.us Other Project Principals: USFWS, NWI -- Ralph Tiner Virginia Tech CMI -- Kevin McGuckin