Wetland Determinations

Midwest Regional Wetland Plant List (April 28, 2016)

Wetland delineations performed in Lake County, IL, after June 1, 2012, shall use the updated NWPL for the Midwest Region (PDF).

Wetland Development

If potential wetlands, farmed wetlands, or other water bodies appear to be present on a proposed development site (based on a review of Lake County online GIS maps; see Online Maps), the Watershed Development Ordinance (WDO) requires that a wetland determination of the site be performed within three (3) years of an initial permit application date. Wetland determinations are to be performed by, or under the supervision of, a Lake County Certified Wetland Specialist (PDF).

Wetland Determinations on Non-Agricultural Land (Non-Cropland)

The presence and extent of wetlands or other water bodies on non-agricultural lands (i.e., non-croplands) is determined using an on-site procedure in accordance with the current Federal wetland delineation methodology, which includes:
The WDO requires that the delineated boundaries of wetlands/waters be flagged or staked and surveyed for inclusion on site development plans and eventual permitting purposes. A field boundary verification is recommended before surveying the locations of wetland flags. See Jurisdictional Determinations for more information on boundary verifications.

Wetland Determinations on Agricultural Land (Cropland)

If the proposed development site contains agricultural land (i.e., cultivated cropland that has been farmed at least one year in the last five years), an agricultural land wetland determination needs to be performed following the current federal Natural Resource Conservation Service (NRCS) procedures to determine if “farmed wetlands” are present on the site. The NRCS procedures involve an office review of U.S Farm Services Agency (FSA) aerial slide imagery for certain years, depending on the site location, and a field review to confirm the presence of hydric soil(s) in suspected farmed wetland areas. For a further discussion of the NRCS procedures, see SMC Guidance for Agricultural Land Wetland Determinations (March 20, 2012) (PDF).

Digital imagery (jpeg format) of FSA aerial slides for Lake County farmed wetland determinations can be ordered online using the McHenry-Lake SWCD FSA Slides Order Form (PDF). Refer to Section A in the above-referenced SMC Guidance for Agricultural Land Wetland Determinations (March 20, 2012) (PDF) for the designated slide years to be reviewed, depending on which NWS recording station is nearest to your project site-Antioch, Barrington or Waukegan. SMC recommends ordering nine (9) years of FSA aerial slides for each project site, including the two (2) WET indicator slide years, five (5) PRIMARY normal precipitation years, and two (2) SECONDARY normal precipitation years. Note: The online order form indicates that 2002 aerial slides are not available; however, that only applies to McHenry County slides. The 2002 aerial slides are available for Lake County.

To facilitate the Lake County Stormwater Management Commission’s (SMC) review of farmed wetland determinations, we request that copies of all FSA aerial slide images reviewed be provided with the wetland determination report. Slides copies provided in digital format (jpeg) are preferred, but we also will accept color photocopies.

Wetland Determination Report

The WDO requires that a report be provided to document the findings of the wetland determination for the proposed development site. At a minimum, the following contents are required for the report:
  • A plan showing the surveyed boundaries of delineated wetlands/waters within the development site;
  • An aerial photograph showing the on-site delineated wetlands/waters, including field sampling point locations, and approximate boundaries of off-site wetlands/waters on adjoining properties;
  • Copies of reference maps (most recent versions) for the site, including the U.S Geological Survey (USGS) quadrangle map, Lake County Wetland Inventory map, Federal Emergency Management Agency (FEMA) floodplain map, Lake County Soil Survey map, and USGS flood of record map (i.e., hydrologic atlas);
  • U.S Army Corps of Engineers data sheets (current version) and color photographs for each representative wetland and upland sampling point;
  • A written description of each wetland, including a floristic quality assessment (FQA) as determined by methodology contained in Swink, F. and G. Wilhelm’s Plants of the Chicago Region (1994). FQAs shall generally be conducted between May 15 and October 1, which approximates the growing season; and
  • A farmed wetland determination, if applicable - see the "Wetland Determinations on Agricultural Land (Cropland)" above. The approximate boundaries of farmed wetlands on the development site shall be shown on the plan and aerial photograph referenced above.