Many proposed development sites in Lake County, Illinois, contain Waters of the United States (WOTUS) and/or Isolated Waters of Lake County (IWLC). However, developments frequently are designed to avoid impacts to wetlands and waters.
Wetland protected by silt fence during construction.
In such cases, the applicant can request a Letter of No Wetland Impact (LONI) review as part of the Watershed Development Permit process. Alternately, the enforcement officer for the certified community where the development will occur (or the Lake County Stormwater Management Commission, SMC, for non-certified communities) has the discretion to require that the applicant obtain a LONI from the regulatory certified wetland specialist (CWS) to confirm that the design will not impact WOTUS or IWLC.
The following items are needed for the regulatory CWS to perform the LONI review:
A cover letter clearly describing the proposed development activity.
Site development plans (particularly grading, utility, and soil erosion/sediment control plans), including the boundaries of all wetlands and other water bodies on the site.
An “80-150” wetland hydrology analysis, when there is a substantive modification of tributary drainage area or surface runoff volume to preserved IWLC on the development site (refer to Section 1006 in the Lake County Watershed Development Ordinance (WDO) for details on the “80-150” wetland hydrology requirement. Note: the wetland hydrology requirement does not apply to preserved WOTUS. A jurisdictional determination may be required to assess the regulatory applicability of the “80-150” hydrology requirement.
For preserved WOTUS only, if required by SMC or the IWLC-certified community: A letter from the U.S Army Corps of Engineers (USACE) stating the proposed development will not impact the WOTUS. This item typically is requested only on “very close calls,” based on the proximity of the proposed site development to the WOTUS (e.g., proposed grading within ±10 feet of a delineated WOTUS boundary).