SITE PLAN REVIEW, AND NATURAL RESOURCE PROTECTION

COMMENTARY: For developments utilizing individual sewage disposal systems and/or private wells, evidence that adequate sewer and water facilities exist or can be provided to serve the proposed use may be provided in the form of a letter or permit from the Lake County Health Department approving the proposed facilities. For developments utilizing public or community sewer and/or water facilities, evidence that adequate sewer and water facilities exist or can be provided to serve the proposed use may be provided in the form of a letter or permit from the agency controlling the facilities (e.g., the Lake County Department of Public Works) stating that sufficient capacity exists to serve the proposed use and that the proposed connection points and preliminary design of the improvements have been approved, and that the applicant is in the process of completing that agency’s permitting and approval process. |
COMMENTARY: Evidence that an access permit can be obtained may be provided in the form of a letter from the highway authority having jurisdiction stating that the access location and preliminary design has been approved and that the applicant is in the process of completing that jurisdiction’s permitting and approval process. |
COMMENTARY: Reviews conducted as part of site capacity calculation/site plan review process do not take the place of other required reviews, such as those conducted at time of site development permit. |
Calculation of Base Site Area |
Calculation of Base Site Area | ||
Step 1 | Determine gross area of site based on an on-site survey. | — |
Step 2 | Subtract land area of existing roads and land within existing utility and drainage easements and existing access easements. | — |
Step 3 | Subtract land that is not contiguous. | — |
A. A separate parcel that has access to a road and is of sufficient size to support independent development but that does not abut, adjoin, or share common boundaries with the rest of the development or is rendered physically inaccessible to the main parcel by the presence of a railroad, existing land use, major stream, or other natural or man-made barrier, such that common or integrated use of the two parcels is not physically possible. (Site capacity for these parcels shall be calculated separately.) | — | |
B. A separate parcel that does not have access to a road or is not of sufficient size to support independent development and that does not abut, adjoin, or share common boundaries with the rest of the development or is rendered physically inaccessible to the main parcel by the presence of a railroad, existing land use, major stream, or other natural or man-made barrier, such that common or integrated use of the two parcels is not physically possible, thus rendering the land unavailable for development purposes. | — | |
Step 4 | Subtract land that was reserved for resource purposes in a previously approved subdivision plat (e.g., floodplain or recreation area) | — |
Step 5 | Subtract land used or proposed for residential uses, whenever a mix of nonresidential and residential uses are proposed. (In the case of the site capacity calculation for the proposed residential use, subtract the land proposed for nonresidential use.) | — |
Equals “Base Site Area” | ||
Calculation of Net Site Area | ||
Step 1 | Determine base site area (see § 151.070(D)(1)) | — |
Step 2 | Subtract regulatory floodplains [and flood-prone areas with 100+ acres of tributary drainage area (see § 151.071(B))] | — |
Step 3 | Subtract wetlands (1/4 Ac. +) (see § 151.071(C)) | — |
Step 4 | Subtract nonlinear water bodies (see § 151.071(E)) | — |
Step 5 | Subtract linear water bodies (see § 151.071(G)) | — |
Equals “Net Site Area” | ||
Calculation of Resource-Protected Land Area | ||||||
Resource Type [1] | Land Area of Resource (Acres) | Protection Ratio | Resource-Protected Land Area | |||
Calculation of Resource-Protected Land Area | ||||||
Resource Type [1] | Land Area of Resource (Acres) | Protection Ratio | Resource-Protected Land Area | |||
1 | Regulatory floodplains [and flood-prone areas with 100+ acres of tributary drainage area (see § 151.071(B)) [2]] | ( _[3] | x | 1.00) | = | — |
2 | Wetlands (1/4 Ac. +) (see § 151.071(C)) | ( _[3] | x | 1.00) | = | — |
3 | Nonlinear water bodies (see § 151.071(E)) | ( _[3] | x | 1.00) | = | — |
4 | Linear water bodies (see § 151.071(G)) | ( _ | x | 1.00) | = | — |
Wetland and water body buffers [wetland, linear water body and nonlinear water body buffers (see §§ 151.071(D), (F), and (H))] | ( _ | 0.80) | = | — | ||
6 | Mature woodlands/groves (see § 151.071(I)) | ( _ | x | 0.70[4]) | = | — |
7 | Young woodlands (see § 151.071(I)) | ( _ | x | 0.50[4]) | = | — |
Equals total Resource-Protected Land area | ||||||
[1] If two or more resources overlap, only the resource with the higher protected ratio shall be calculated. | ||||||
[2] Uses/developments allowed within floodplains are not required to include floodplains in calculations. | ||||||
[4] Woodland resources may be reduced pursuant to § 151.071(I)(6)(e), replacement of woodland credit. | ||||||
Calculation of Recreation Land Area (Residential) | ||
Step 1 | Take maximum number of dwelling units proposed | — |
Step 2 | Multiply by 0.055 (based on county average household size) | x |
Equals total recreation land area required (acres) | 0 | |
* No recreation land area is required if the calculation yields a requirements of less than 0.5 acre. | ||
Calculating Required Open Space |
Calculating Required Open Space | ||
Step 1 | Take total Resource-Protected Land area (from subsection (D)(3)(b)1., above) | |
Step 2 | Add total Recreation Land Area (from subsection (D)(3)(b)2., above) | + |
??? | Equals Capacity-Based Open Space Requirement | = |
Step 3 | Take Base Site Area (subsection (D)(1)) | |
Step 4 | Multiply by zoning district (minimum) open space ratio (see § 151.125) | x |
??? | Equals District-Based Open Space requirement | = |
Step 5 | Take higher of Capacity-Based or District-Based Open Space Requirement; equals minimum Open Space Requirement | = |
Calculation of Maximum Floor Area | ||
Step 1 | Take Net Site Area (see subsection (D)(2) above) | |
Step 2 | Multiply by zoning district maximum floor area factor (see § 151.125) | x |
Equals “Maximum Floor Area” | ||
Calculation of Maximum Impervious Area | ||
Step 1 | Take Net Site Area (see subsection (D)(2)) | |
Step 2 | Multiply by zoning district maximum impervious surface ratio (ISR) (see § 151.125) | x |
Equals “Maximum Impervious Surface” | ||
Calculation of Resource-Protected Land Area | ||||||
Resource Type[1] | Land Area of Resource (Acres) | Protection Ratio | Resource-Protected Land Area | |||
Calculation of Resource-Protected Land Area | ||||||
Resource Type[1] | Land Area of Resource (Acres) | Protection Ratio | Resource-Protected Land Area | |||
1 | Regulatory floodplains [and flood-prone areas with 100+ acres of tributary drainage area (see § 151.071(B))[2]] | ( _[3] | x | 1.00) | 0 | |
2 | Wetlands (1/4 Ac. +) (see § 151.071(C)) | ( _[3] | x | 1.00) | = | |
3 | Nonlinear water bodies (see § 151.071(E) | ( _[3] | x | 1.00) | = | |
4 | Linear water bodies (see § 151.071(G) | ( _ | x | 1.00) | = | |
5 | Wetland, linear water body and nonlinear water body buffers (see § 151.071(D), (F), and (H)) | ( _ | x | 0.80) | 0 | |
6 | Mature woodlands/groves (see § 151.071(I)) | ( _ | x | 0.70[4]) | = | |
7 | Young woodlands (see § 151.071(I)) | ( _ | x | 0.50[4]) | = | |
Equals total “Resource-Protected Land Area” | ||||||
[1] If two or more resources overlap, only the resource with the higher protected ratio shall be calculated. | ||||||
[2] Uses/developments allowed within floodplains are not required to include floodplains in calculations. | ||||||
[4] Woodland resources may be reduced pursuant to § 151.071(I)(6)(e), replacement of woodland credit. | ||||||
COMMENTARY: Unified Development Ordinance, Appendix N entitled “High-Quality Aquatic Resources” provides guidance in determining non-mitigatable wetlands. |

COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: The Lake County Wetland Inventory maps and the aerial photographs available on the Lake County web page or in the Department of Planning, Building and Development may be referenced to determine if the wetland present on the property extends beyond the limits of the property boundary. |
COMMENTARY: For additional guidance with soil erosion/sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: Stormwater basins may be allowed within the protected wetland buffer areas pursuant to § 151.146 of this chapter. These basins, when properly designed, act as sediment basins and improve the quality of water entering the adjacent wetland. For guidance in designing stormwater facilities that meet this intent, refer to the following sources: Illinois Environmental Protection Agency/Natural Resources Conservation Services, Technical Reference Manual (Lake County Stormwater Management Commission), Native Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois (USDA Natural Resources Conservation Service in cooperation with U.S. Fish and Wildlife Service and U.S. Army Corps of Engineers), Urban Stormwater Best Management Practices for Northeastern Illinois Course Notebook (Northeastern Illinois Planning Commission), Reducing the Impact of Urban Run-Off: Advantages of Alternative Site Design Approaches (Northeastern Illinois Planning Commission for Illinois Environmental Protection Agency). |
COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: Stormwater basins are allowed within protected nonlinear water body buffer areas. These basins, when properly designed, act as sediment basins and improve the quality of water entering the adjacent water body. For guidance in designing stormwater facilities that meet this intent, please refer to the following sources: Illinois Environmental Protection Agency/Natural Resources Conservation Services Illinois Urban Manual, Technical Reference Manual developed by the Lake County Stormwater Management Commission, Native Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois prepared by USDA Natural Resources Conservation Service in cooperation with U.S. Fish and Wildlife Service and U.S. Army Corps of Engineers, Urban Stormwater Best Management Practices for Northeastern Illinois Course Notebook prepared by the Northeastern Illinois Planning Commission, Reducing the Impact of Urban Run-Off: Advantages of Alternative Site Design Approaches, prepared by Northeastern Illinois Planning Commission for Illinois Environmental Protection Agency. |
COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: For additional guidance with soil erosion/sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: Stormwater basins are allowed within protected linear water body buffer areas. These basins, when properly designed, act as sediment basins and improve the quality of water entering the adjacent water body. For guidance in designing stormwater facilities that meet this intent, please refer to the following sources: Illinois Environmental Protection Agency/Natural Resources Conservation Services Illinois Urban Manual, Technical Reference Manual developed by the Lake County Stormwater Management Commission, Native Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois prepared by USDA Natural Resources Conservation Service in cooperation with U.S. Fish and Wildlife Service and U.S. Army Corps of Engineers, Urban Stormwater Best Management Practices for Northeastern Illinois Course Notebook prepared by the Northeastern Illinois Planning Commission, Reducing the Impact of Urban Run-Off: Advantages of Alternative Site Design Approaches, prepared by Northeastern Illinois Planning Commission for Illinois Environmental Protection Agency. |
COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |

Weighted average woodland protection ratio | = | (Mature woodland area x .70) + (Young woodland area x 0.50) |
Total woodland area |
COMMENTARY: For additional guidance with soil erosion/sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
Zoning District | Minimum Protection Area (%) |
LC, RC, GC | 15 |
LI, II, GO | 30 |
All other | 45 |
Plant Material Required Per Acre | Minimum Size of Plant Material | |
Option 1 | 10 Canopy trees | 3-inch caliper size |
20 Canopy trees | 2-inch caliper size | |
30 Understory trees | 2-inch caliper size | |
Option 2 | 10 Canopy trees | 3-inch caliper size |
50 Understory trees | 1-1/2-inch caliper size | |
COMMENTARY: Native prairies present on the site should be identified and restored after consultation with representatives of the Illinois Department of Natural Resources. |
COMMENTARY: For guidance on designing wet bottom stormwater detention basins or basins that function as wetlands, applicants should consult the following sources: Illinois Environmental Protection Agency/Natural Resources Conservation Services Illinois Urban Manual, Technical Reference Manual developed by the Lake County Stormwater Management Commission, Native Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois prepared by USDA Natural Resources Conservation Service in cooperation with U.S. Fish and Wildlife Service and U.S. Army Corps of Engineers, Urban Stormwater Best Management Practices for Northeastern Illinois Course Notebook prepared by the Northeastern Illinois Planning Commission, Reducing the Impact of Urban Run-Off: Advantages of Alternative Site Design Approaches, prepared by Northeastern Illinois Planning Commission for the Illinois Environmental Protection Agency. |

SITE PLAN REVIEW, AND NATURAL RESOURCE PROTECTION

COMMENTARY: For developments utilizing individual sewage disposal systems and/or private wells, evidence that adequate sewer and water facilities exist or can be provided to serve the proposed use may be provided in the form of a letter or permit from the Lake County Health Department approving the proposed facilities. For developments utilizing public or community sewer and/or water facilities, evidence that adequate sewer and water facilities exist or can be provided to serve the proposed use may be provided in the form of a letter or permit from the agency controlling the facilities (e.g., the Lake County Department of Public Works) stating that sufficient capacity exists to serve the proposed use and that the proposed connection points and preliminary design of the improvements have been approved, and that the applicant is in the process of completing that agency’s permitting and approval process. |
COMMENTARY: Evidence that an access permit can be obtained may be provided in the form of a letter from the highway authority having jurisdiction stating that the access location and preliminary design has been approved and that the applicant is in the process of completing that jurisdiction’s permitting and approval process. |
COMMENTARY: Reviews conducted as part of site capacity calculation/site plan review process do not take the place of other required reviews, such as those conducted at time of site development permit. |
Calculation of Base Site Area |
Calculation of Base Site Area | ||
Step 1 | Determine gross area of site based on an on-site survey. | — |
Step 2 | Subtract land area of existing roads and land within existing utility and drainage easements and existing access easements. | — |
Step 3 | Subtract land that is not contiguous. | — |
A. A separate parcel that has access to a road and is of sufficient size to support independent development but that does not abut, adjoin, or share common boundaries with the rest of the development or is rendered physically inaccessible to the main parcel by the presence of a railroad, existing land use, major stream, or other natural or man-made barrier, such that common or integrated use of the two parcels is not physically possible. (Site capacity for these parcels shall be calculated separately.) | — | |
B. A separate parcel that does not have access to a road or is not of sufficient size to support independent development and that does not abut, adjoin, or share common boundaries with the rest of the development or is rendered physically inaccessible to the main parcel by the presence of a railroad, existing land use, major stream, or other natural or man-made barrier, such that common or integrated use of the two parcels is not physically possible, thus rendering the land unavailable for development purposes. | — | |
Step 4 | Subtract land that was reserved for resource purposes in a previously approved subdivision plat (e.g., floodplain or recreation area) | — |
Step 5 | Subtract land used or proposed for residential uses, whenever a mix of nonresidential and residential uses are proposed. (In the case of the site capacity calculation for the proposed residential use, subtract the land proposed for nonresidential use.) | — |
Equals “Base Site Area” | ||
Calculation of Net Site Area | ||
Step 1 | Determine base site area (see § 151.070(D)(1)) | — |
Step 2 | Subtract regulatory floodplains [and flood-prone areas with 100+ acres of tributary drainage area (see § 151.071(B))] | — |
Step 3 | Subtract wetlands (1/4 Ac. +) (see § 151.071(C)) | — |
Step 4 | Subtract nonlinear water bodies (see § 151.071(E)) | — |
Step 5 | Subtract linear water bodies (see § 151.071(G)) | — |
Equals “Net Site Area” | ||
Calculation of Resource-Protected Land Area | ||||||
Resource Type [1] | Land Area of Resource (Acres) | Protection Ratio | Resource-Protected Land Area | |||
Calculation of Resource-Protected Land Area | ||||||
Resource Type [1] | Land Area of Resource (Acres) | Protection Ratio | Resource-Protected Land Area | |||
1 | Regulatory floodplains [and flood-prone areas with 100+ acres of tributary drainage area (see § 151.071(B)) [2]] | ( _[3] | x | 1.00) | = | — |
2 | Wetlands (1/4 Ac. +) (see § 151.071(C)) | ( _[3] | x | 1.00) | = | — |
3 | Nonlinear water bodies (see § 151.071(E)) | ( _[3] | x | 1.00) | = | — |
4 | Linear water bodies (see § 151.071(G)) | ( _ | x | 1.00) | = | — |
Wetland and water body buffers [wetland, linear water body and nonlinear water body buffers (see §§ 151.071(D), (F), and (H))] | ( _ | 0.80) | = | — | ||
6 | Mature woodlands/groves (see § 151.071(I)) | ( _ | x | 0.70[4]) | = | — |
7 | Young woodlands (see § 151.071(I)) | ( _ | x | 0.50[4]) | = | — |
Equals total Resource-Protected Land area | ||||||
[1] If two or more resources overlap, only the resource with the higher protected ratio shall be calculated. | ||||||
[2] Uses/developments allowed within floodplains are not required to include floodplains in calculations. | ||||||
[4] Woodland resources may be reduced pursuant to § 151.071(I)(6)(e), replacement of woodland credit. | ||||||
Calculation of Recreation Land Area (Residential) | ||
Step 1 | Take maximum number of dwelling units proposed | — |
Step 2 | Multiply by 0.055 (based on county average household size) | x |
Equals total recreation land area required (acres) | 0 | |
* No recreation land area is required if the calculation yields a requirements of less than 0.5 acre. | ||
Calculating Required Open Space |
Calculating Required Open Space | ||
Step 1 | Take total Resource-Protected Land area (from subsection (D)(3)(b)1., above) | |
Step 2 | Add total Recreation Land Area (from subsection (D)(3)(b)2., above) | + |
??? | Equals Capacity-Based Open Space Requirement | = |
Step 3 | Take Base Site Area (subsection (D)(1)) | |
Step 4 | Multiply by zoning district (minimum) open space ratio (see § 151.125) | x |
??? | Equals District-Based Open Space requirement | = |
Step 5 | Take higher of Capacity-Based or District-Based Open Space Requirement; equals minimum Open Space Requirement | = |
Calculation of Maximum Floor Area | ||
Step 1 | Take Net Site Area (see subsection (D)(2) above) | |
Step 2 | Multiply by zoning district maximum floor area factor (see § 151.125) | x |
Equals “Maximum Floor Area” | ||
Calculation of Maximum Impervious Area | ||
Step 1 | Take Net Site Area (see subsection (D)(2)) | |
Step 2 | Multiply by zoning district maximum impervious surface ratio (ISR) (see § 151.125) | x |
Equals “Maximum Impervious Surface” | ||
Calculation of Resource-Protected Land Area | ||||||
Resource Type[1] | Land Area of Resource (Acres) | Protection Ratio | Resource-Protected Land Area | |||
Calculation of Resource-Protected Land Area | ||||||
Resource Type[1] | Land Area of Resource (Acres) | Protection Ratio | Resource-Protected Land Area | |||
1 | Regulatory floodplains [and flood-prone areas with 100+ acres of tributary drainage area (see § 151.071(B))[2]] | ( _[3] | x | 1.00) | 0 | |
2 | Wetlands (1/4 Ac. +) (see § 151.071(C)) | ( _[3] | x | 1.00) | = | |
3 | Nonlinear water bodies (see § 151.071(E) | ( _[3] | x | 1.00) | = | |
4 | Linear water bodies (see § 151.071(G) | ( _ | x | 1.00) | = | |
5 | Wetland, linear water body and nonlinear water body buffers (see § 151.071(D), (F), and (H)) | ( _ | x | 0.80) | 0 | |
6 | Mature woodlands/groves (see § 151.071(I)) | ( _ | x | 0.70[4]) | = | |
7 | Young woodlands (see § 151.071(I)) | ( _ | x | 0.50[4]) | = | |
Equals total “Resource-Protected Land Area” | ||||||
[1] If two or more resources overlap, only the resource with the higher protected ratio shall be calculated. | ||||||
[2] Uses/developments allowed within floodplains are not required to include floodplains in calculations. | ||||||
[4] Woodland resources may be reduced pursuant to § 151.071(I)(6)(e), replacement of woodland credit. | ||||||
COMMENTARY: Unified Development Ordinance, Appendix N entitled “High-Quality Aquatic Resources” provides guidance in determining non-mitigatable wetlands. |

COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: The Lake County Wetland Inventory maps and the aerial photographs available on the Lake County web page or in the Department of Planning, Building and Development may be referenced to determine if the wetland present on the property extends beyond the limits of the property boundary. |
COMMENTARY: For additional guidance with soil erosion/sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: Stormwater basins may be allowed within the protected wetland buffer areas pursuant to § 151.146 of this chapter. These basins, when properly designed, act as sediment basins and improve the quality of water entering the adjacent wetland. For guidance in designing stormwater facilities that meet this intent, refer to the following sources: Illinois Environmental Protection Agency/Natural Resources Conservation Services, Technical Reference Manual (Lake County Stormwater Management Commission), Native Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois (USDA Natural Resources Conservation Service in cooperation with U.S. Fish and Wildlife Service and U.S. Army Corps of Engineers), Urban Stormwater Best Management Practices for Northeastern Illinois Course Notebook (Northeastern Illinois Planning Commission), Reducing the Impact of Urban Run-Off: Advantages of Alternative Site Design Approaches (Northeastern Illinois Planning Commission for Illinois Environmental Protection Agency). |
COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: Stormwater basins are allowed within protected nonlinear water body buffer areas. These basins, when properly designed, act as sediment basins and improve the quality of water entering the adjacent water body. For guidance in designing stormwater facilities that meet this intent, please refer to the following sources: Illinois Environmental Protection Agency/Natural Resources Conservation Services Illinois Urban Manual, Technical Reference Manual developed by the Lake County Stormwater Management Commission, Native Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois prepared by USDA Natural Resources Conservation Service in cooperation with U.S. Fish and Wildlife Service and U.S. Army Corps of Engineers, Urban Stormwater Best Management Practices for Northeastern Illinois Course Notebook prepared by the Northeastern Illinois Planning Commission, Reducing the Impact of Urban Run-Off: Advantages of Alternative Site Design Approaches, prepared by Northeastern Illinois Planning Commission for Illinois Environmental Protection Agency. |
COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: For additional guidance with soil erosion/sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
COMMENTARY: Stormwater basins are allowed within protected linear water body buffer areas. These basins, when properly designed, act as sediment basins and improve the quality of water entering the adjacent water body. For guidance in designing stormwater facilities that meet this intent, please refer to the following sources: Illinois Environmental Protection Agency/Natural Resources Conservation Services Illinois Urban Manual, Technical Reference Manual developed by the Lake County Stormwater Management Commission, Native Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois prepared by USDA Natural Resources Conservation Service in cooperation with U.S. Fish and Wildlife Service and U.S. Army Corps of Engineers, Urban Stormwater Best Management Practices for Northeastern Illinois Course Notebook prepared by the Northeastern Illinois Planning Commission, Reducing the Impact of Urban Run-Off: Advantages of Alternative Site Design Approaches, prepared by Northeastern Illinois Planning Commission for Illinois Environmental Protection Agency. |
COMMENTARY: For additional guidance with soil erosion/ sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |

Weighted average woodland protection ratio | = | (Mature woodland area x .70) + (Young woodland area x 0.50) |
Total woodland area |
COMMENTARY: For additional guidance with soil erosion/sediment control matters, applicants are encouraged to refer to the Technical Reference Manual developed by the Lake County Stormwater Management Commission. |
Zoning District | Minimum Protection Area (%) |
LC, RC, GC | 15 |
LI, II, GO | 30 |
All other | 45 |
Plant Material Required Per Acre | Minimum Size of Plant Material | |
Option 1 | 10 Canopy trees | 3-inch caliper size |
20 Canopy trees | 2-inch caliper size | |
30 Understory trees | 2-inch caliper size | |
Option 2 | 10 Canopy trees | 3-inch caliper size |
50 Understory trees | 1-1/2-inch caliper size | |
COMMENTARY: Native prairies present on the site should be identified and restored after consultation with representatives of the Illinois Department of Natural Resources. |
COMMENTARY: For guidance on designing wet bottom stormwater detention basins or basins that function as wetlands, applicants should consult the following sources: Illinois Environmental Protection Agency/Natural Resources Conservation Services Illinois Urban Manual, Technical Reference Manual developed by the Lake County Stormwater Management Commission, Native Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois prepared by USDA Natural Resources Conservation Service in cooperation with U.S. Fish and Wildlife Service and U.S. Army Corps of Engineers, Urban Stormwater Best Management Practices for Northeastern Illinois Course Notebook prepared by the Northeastern Illinois Planning Commission, Reducing the Impact of Urban Run-Off: Advantages of Alternative Site Design Approaches, prepared by Northeastern Illinois Planning Commission for the Illinois Environmental Protection Agency. |
