Subdivision of land resulting in five (5) or fewer residential lots is exempt from required conservation design. In all other residential subdivisions, conservation design is required when the development site meets specified individual or cumulative triggers. For the purpose of determining the presence of cumulative triggers, the area of analysis shall include the property to be subdivided along with a buffer area extending two hundred (200) feet around the property. Conservation design is required when:
A. The site contains or abuts within one hundred (100) feet a designated McHenry County Natural Area Inventory (MCNAI) site.
B. The site contains or abuts within one hundred (100) feet a stream, river, lake, and/or wetland designated as Advanced Identification (ADID) high habitat value or high quality.
C. When the cumulative acreage contained by the following resources equals or exceeds twenty percent (20%) of the total area of the area of analysis (as described above):
1. Wetlands, except farmed wetlands.
2. Floodplains and flood of record areas.
3. Glacial kettle holes.
4. Woodlands and savannas based on on-site determination.
5. Remnant prairies based on on-site determination.
6. Soils characterized as having one (1) or more of the following characteristics:
a. Soils identified as “E” slopes and greater, reflecting highly erodible slopes of twelve percent (12%) and greater as defined in Soil Survey Legend, Soil Survey of McHenry County, Illinois, USDA-NRCS, 2002.
b. Soils identified as Depressional hydric soils based on a coverage developed by NRCS using the USDA-NRCS Hydric Soil List, McHenry County: Detailed Soil Map Legend, 12/03/2003.
7. State-designated “Class III Special Resources Groundwater Areas.”
8. Aquifer recharge areas as identified in the SARA Map.
9. Publicly owned or private deed-restricted natural open spaces and preserves.
10. Green infrastructure area as identified in the McHenry County Green Infrastructure Plan. Green infrastructure area beyond the property but within the two hundred-foot (200') buffer is excluded from the calculation.
(Ord. O-201410-10-035, passed 10-14-2014; Ord. O-201601-ZBA-006, passed 1-19-2016; Ord. O-201603-ZBA-010, passed 3-17-2016, § 19.3; Ord. O-201803-ZBA-10-08, passed 3-19-2018; Ord. O-201808-10-033, passed 8-21-2018)