Wetland polygons selected for the Hackmatack area.

Source: Chicago Metropolitan Agency for Planning's (CMAP) 2005 McHenry County Advanced Identification of Wetlands (ADID). Geodatabase Vector Digital Data. State Plane Coordinate System (Zone 1201), NAD83. Published: January 2007

(Metadata courtesy of CMAP)

Summary
The purpose of this ADID study is to provide information on the wetland resources in McHenry County. It is intended for use as a planning tool for local governments, to facilitate development and resource conservation decision-making, and also for use by the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency (EPA) to assist in the process of issuing wetland permits.

Description
This file is a digital geospatial Environmental Systems Research Institute (ESRI) ArcGIS Version 9.1 feature class (simple feature type) dataset type with a polygon geometry displaying wetlands in McHenry County, Illinois.

The wetlands displayed in this GIS dataset originated from the Advanced Identification of Wetlands program that was completed in 1999. The wetland polygons that originated from that earlier program have been updated using aerial photography that was acquired in the spring of 2005. Spring 2005 aerial photography was used to assess the impact of urbanization on wetlands that had been captured in GIS format in the earlier ADID program. Wetland polygons from the original ADID study that were in the classes High Quality Wetland ("hqw"), High Functional Value Wetland ("hfvw"), Wetland ("w"), and Farmed Wetland ("fw") were inspected and edited, if necessary. The update process can be summarized as follows:

1.) Wetland delineations that were interpreted from the aerial photography to have undergone urban conversion in an amount greater than 80% of their total area, will be assigned the code "UC" to reflect this change.

2.) Wetland delineations that were interpreted from the aerial photography to have undergone urban conversion of less than 80% of their total area will be edited in the update. The edited portions of these wetland delineations will be assigned the code "UC" to reflect this change.

NO wetland delineations were moved from their original position in the update.

All edits, re-classifications, and/or assignments of attributes in the update were made in good judgment and with appropriate consideration given to the horizontal positional accuracy associated with the original ADID GIS dataset. That is, edits, re-classifications, and/or assignments were not made if it was the judgment of the GIS operator that poor horizontal positional accuracy of the original source file was the cause for wetland delineations to overlay impervious surfaces.

This dataset was projected using the Transverse Mercator map projection. The grid coordinate system used is the Illinois State Plane Coordinate System (Zone Number 1201), NAD83, with ground coordinates expressed in U.S. Survey Feet.

Credits
Dave Brandt, United States Department of Agriculture; Sue Elston, United States Environmental Protection Agency; Mike Hoather, Chicago Metropolitan Agency for Planning; Jeffrey Mengler, United States Fish & Wildlife Service; and Brad Semel, Illinois Department of Natural Resources.