In addition to the other requirements of this chapter, subdivisions that trigger and subdivisions that voluntarily choose conservation design shall comply with the following standards.
   A.   General Requirements.
      1.   The proposed development shall be designed to fit the topography, physical features, and soil conditions of the subject site. More specifically, conservation design shall preserve natural drainage patterns, stabilize soils during construction, preserve native vegetation, and protect, enhance, and maintain natural resources.
      2.   It is recommended that the applicant undertake the optional pre-application conference and present a concept plan that identifies all natural resources, conservation areas, open space areas, and physical features, as referenced in § 16.76.030 (Conservation Design Triggers). To the maximum extent practical, these features shall be preserved as open space and protected from negative impacts generated as a result of the development or other land disturbing activities.
      3.   Building sites shall be located to take advantage of open space and scenic views. Lots shall be designed to facilitate the access within neighborhoods and to open space and conservation areas.
      4.   The street network shall be designed to minimize encroachment into natural resources, conservation areas, open space areas, and physical features, as identified in § 16.76.030 (Conservation Design Triggers), and to take advantage of open space vistas.
      5.   Earth grading shall be minimized. The subdivider is required to submit a site plan that delineates where soils will not be disturbed as the result of earthwork, grading, or other construction activities.
   B.   Open Space Requirement.
      1.   Qualifying Open Space. The minimum requirement for open space, as required by conservation design standards, shall be maintained in common open space. Qualifying open space shall be generally maintained in an undeveloped state. Qualifying open space includes, but is not limited to, the following:
         a.   Woods and savannas.
         b.   Wetlands and wetland buffers.
         c.   Streams, waterways, lakes, and ponds.
         d.   Prairies and grasslands.
         e.   Floodplains and flood prone areas, provided that they are maintained as other qualifying open space types on this list.
         f.   Naturally landscaped areas.
         g.   Walking, bicycle, or equestrian trails.
         h.   Naturally landscaped stormwater detention and drainage facilities.
         i.   Areas utilized for installation of water wells, spray irrigation of treated wastewater, excluding treatment and associated wastewater storage facilities, and on-site wastewater treatment systems, excluding septic tanks or other pre-treatment devices and lift stations, provided that they are maintained as other qualifying open space types on this list.
         j.   Areas of greater than twelve percent (12%) slope.
         k.   Pasture and agricultural cropland areas, orchards, community gardens, apiaries, and hen houses.
         l.   Manicured turf grass areas such as those on golf courses, playgrounds, and recreational fields, which are limited to ten percent (10%) of the total area of required open space.
         Qualifying areas do not include parkways, landscape islands, sign easements, berms, or similar installed landscape features. In addition, roads, driveways, parking lots, and rights-of-way do not count towards fulfilling open space requirements. The required perimeter buffer yard may be counted if it is comprised of the resources to be protected as identified in § 16.76.030 (Conservation Design Triggers).
      2.   Open Space Standards.
         a.   Where feasible, degraded remnant natural areas shall be restored to a natural state that will require only routine ecologic management.
         b.   The layout of the development shall be designed to minimize any negative impacts to abutting land with significant natural areas and resources. Buffers shall be provided against natural areas on adjacent properties, and existing wildlife corridors and sensitive ecosystems preserved.
         c.   Open space shall be preserved in large contiguous areas.
         d.   The open space shall be designed to facilitate easy access from all streets and neighborhoods within the development. Open space shall be interconnected with greenways and, if applicable, trail systems both within the development site and connecting to adjacent subdivisions and to local and regional trails.
         e.   Open space shall be dedicated as common open space to be jointly owned by a qualified governmental body, conservation agency, homeowners association, or property owners association.
         f.   Required open space areas cannot be enclosed with man-made fencing, with the exception of areas containing natural or cultural features that require special protection and agricultural and equestrian pastures and trails.
         g.   Required open space areas shall be maintained in perpetuity.
         h.   Required open space areas cannot be improved with any structures or other development. However, the County may approve certain structures that will not negatively impact the natural and open space areas. These exceptions include, but are not limited to, picnic shelters, viewing stands, interpretive signs, and benches. These structures shall be compatible with open space uses. A sign easement may be located in an open space area, however areas dedicated for sign easements are not included in the calculation of required open space. Agricultural exempt structures are allowed in open space areas that are utilized for agricultural purposes; however, areas used by agricultural exempt structures as well as substantially disturbed areas located adjacent or between agricultural exempt structures are not included in the calculation of required open space.
         i.   Permanent boundary signs shall be installed to delineate open space from private property. Placement of signs shall be determined at preliminary plat stage.
      3.   Perimeter Buffer Yard. A minimum fifty-foot (50') width perimeter buffer yard, designated as an outlot(s), shall be maintained around the exterior of the development on all sides. The buffer is measured from the road right-of-way or adjacent exterior property line of the development, as appropriate. This buffer shall be designed to screen new housing or incompatible development, preserve scenic views, or otherwise enhance the landscape as seen from existing perimeter roads. A trail or sidewalk may be constructed within the perimeter buffer. Landscaped berms and entrance signs are allowed in buffers, and roads may cross the buffer.
      4.   Open Space Prohibitions. Use of open space that conflicts with conservation purposes are prohibited. Prohibitions shall be identified in and enforced through the subdivision covenants. The following activities are prohibited, unless allowed by the approved stewardship plan:
         a.   Dumping of grass clippings, yard waste, debris or other objectionable material.
         b.   Storage of material, vehicles, etc.
         c.   Removal of native vegetation or trees.
         d.   Introduction of exotic plant species.
         e.   Manipulation or alteration of natural watercourses or wetlands.
         f.   Filling, grading, drilling, removal of soil or other natural materials, or dredging.
         g.    Water wells and on-site wastewater treatment systems.
      5.   Open Space Ownership and Funding Requirements.
         a.   Dedicated open space shall be protected in perpetuity by a binding conservation easement or similar binding legal instrument recorded with the McHenry County Recorder and granted to one (1) or more of the following entities, which will be responsible for all maintenance, control, and insurance of common areas, including dedicated open space areas. The ultimate owner of open space, as well as the entity responsible for maintaining it, shall be identified and made part of the conservation design covenants and restrictions.
            (1)   A public agency whose primary purpose is open space management is the preferred option.
            (2)   A private land conservation organization whose primary purpose is the preservation and maintenance of conservation areas, natural resources, or agricultural resources is the second preferred option.
            (3)   A homeowners or property owners association, if it is not practical or appropriate for a public agency or private land conservation organization to accept responsibility. If ownership resides with the homeowners/property owners association, membership in the HOA/POA shall be mandatory and automatic for all lot and parcel owners and their successors. The association will have lien authority to ensure the collection of dues from all members.
         b.   The responsibility for maintaining open space and any facilities located thereon is borne by the subdivider until eighty percent (80%) of the lots are sold and the initial letter of credit or bond for establishment of the natural landscape is released. Ownership is then passed to a public agency, a not-for-profit entity whose primary purpose is the preservation and maintenance of open space, or to the homeowners/property owners association.
         c.   In the event the not-for-profit entity or the homeowners/property owners association ceases to exist, the responsibility for maintaining the open space and any facilities is borne by all lot and parcel owners and their successors.
         d.   A cost estimate for natural landscape and ecological restoration activities shall be submitted with the cost estimates for infrastructure and stormwater improvements. The amount of the bond or letter(s) of credit furnished by the subdivider shall be in the amount of one hundred twenty-five percent (125%) of the estimated cost of the work and materials required for these activities. This is a separate bond or letter of credit from that furnished for roads but may be combined with the bond or letter of credit for stormwater work.
         e.   Prior to release of the bond or letter of credit, the developer or homeowners/property owners association shall submit a maintenance bond or letter of credit for ten percent (10%) of the project cost to be valid for two (2) years.
   C.   Clustering of Lots, Structures, and Building Sites.
      1.   Clustering of lots, structures and building sites is required when possible and shall be determined by designing lots, structures, and sites around open space areas, where preference is given to land, not necessarily undisturbed, which either retains or has been substantially restored to its original native character. The following describes the different levels of open space quality, from highest to lowest, and siting approval is based upon the proposed development’s ability to preserve significant portions of open space at the highest quality levels possible.
         a.   Priority 1: Intact natural communities, known habitats of rare and endangered species, natural and restored wetlands, prairies, savannas and woodlands, environmental corridors, significant historic and archaeological properties, and areas with steep slopes.
         b.   Priority 2: Natural landscaped areas created to provide plant and wildlife habitat and open space amenities.
         c.   Priority 3: Areas providing little habitat but providing a viewshed, recreation or a sense of open space.
      2.   Lot and building site size may be reduced below that required by the underlying zoning classification in order to achieve greater preservation and protection of natural resources. The bulk regulations of Table 16.76-2: Conservation Design Residential Yard and Bulk Requirements apply to conservation design. However, the maximum permitted density in any conservation design shall be limited to ninety percent (90%) of the density permitted by the underlying zoning district after subtracting one-half (1/2) of the site acreage located in wetlands, if any.
Zoning District
Minimum Lot Area (In acres) per Dwelling Unit
Minimum Lot Frontage1
Minimum Street Setback
Minimum Rear Setback
Minimum Side Setback
Required Minimum Open Space (% of Entire Site Area)
.75 ac
.6 ac
0.33 ac
0.25 ac
10' or 10% of lot width, whichever is greater
0.5 ac
0.75 ac
1   Lots located on cul-de-sac shall have a lot frontage of not less than 50% of the district standard or fifty (50) feet, whichever is greater.
      3.   Lots shall be located as to minimize negative impacts on the natural, visual, and cultural resources of the site and between incompatible uses and activities.
      4.   Lots shall be designed and sited to:
         a.   Avoid disturbance of ADID high quality habitat wetlands and remnant prairies unless there are no practicable alternatives.
         b.   Avoid disturbance of steep slopes (slopes of twelve percent (12%) or more) unless there are no practicable alternatives.
         c.   Avoid disturbance of woodlands and savannas unless there are no practicable alternatives. In all cases, the subdivider shall preserve at least seventy percent (70%) of the area of woodland and savanna of one (1) acre or larger.
         d.   Avoid disturbance of wetlands and wetland buffers unless there are no practicable alternatives. In all cases, the subdivider shall preserve at least eighty percent (80%) of wetlands and wetland buffers.
         e.   Avoid disturbance of floodplains unless there are no practicable alternatives. In all cases, the subdivider shall preserve at least ninety percent (90%) of floodplains by area.
         f.   Minimize fragmentation of natural areas and open space while also providing for access and views from clusters.
         g.   Minimize disturbance of natural depressions, drainage ways, and sensitive recharge areas to facilitate their use for runoff infiltration and filtering.
         h.   Maintain scenic views of open space from adjacent and proposed roads. Minimize visual impact through the use of landscape.
         i.   Protect high priority aquifer recharge areas as identified in the SARA Map.
         j.   Preserve buildings and sites of historic significance or incorporate them through adaptive reuse.
   D.   Trail Network. Installation of a multi-purpose trail system is encouraged to provide access to open space areas within the subdivision, as well as access to adjacent subdivisions and regional trails. The trail system shall be owned and maintained by the same entity as the open space. A trail ownership and maintenance plan shall be approved by the County prior to the approval of the final plat. The County may require trails to be designed and constructed to meet applicable American with Disability Act (ADA) requirements, if any.
   E.   Landscape Standards. The use of native plant species is required within the perimeter buffer, bio-swales, detention basins, common open space, buffers of streams, lakes, wetlands, and other water bodies, areas. Native plant species consists of grasses, wildflowers, shrubs, and trees that are native to the greater Chicago region as identified in “Plants of the Chicago Region” (Swink and Wilhelm, 1994). The installation of landscape and long-term management shall conform to the approved stewardship plan's maintenance, monitoring, and performance criteria.
   F.   Parking Standards. In addition to the other parking standards of this Ordinance, parking lots in conservation design subdivision shall comply with the following:
      1.   Parking lots shall be designed to maximize the opportunity to infiltrate and filter runoff from the lot. The use of pervious surface is encouraged in lieu of conventional asphalt or concrete paving. However, consideration and mitigation of potential groundwater contamination resulting from the infiltration of stormwater runoff into the subsurface shall be included in the design.
      2.   Parking lot runoff shall be routed to swales and bio-swales. Where curbing is determined to be necessary, frequent curb cuts are required to allow runoff to enter swale and bio-swale structures.
   G.   Stewardship Plan.
      1.   Overview.
         a.   A stewardship plan shall be prepared by a specialist in the area of ecological restoration or natural landscape. The plan shall be comprised of two parts: 1) a short-term plan for the establishment, enhancement, and restoration of natural areas; and 2) a long-term plan for the maintenance and monitoring of natural areas in perpetuity.
         b.   The plan shall be approved as part of the subdivision review process and recorded in the covenants for the subdivision. The plan shall be in text form with appropriate maps and/or graphic renderings that identify the various management units on the site. The plan shall provide specific details and methods regarding the preservation, re-establishment, maintenance, and management of open areas and natural resources in perpetuity on the subject site. It shall be in a format that is easily understood and identify all specific tasks that shall be completed in order to ensure the viability of current and future resources on the site.
         c.   The plan shall address and/or allocate:
            (1)   The short-term enhancement and restoration of remnant natural areas and the establishment of new landscapes.
            (2)   The long-term maintenance and monitoring of such areas.
            (3)   The responsibility and guidelines for performing said tasks and any necessary provisions for replacement costs and long-term capital improvements.
         d.   In addition, the plan shall:
            (1)   Serve as an educational resource for future residents and property owners.
            (2)   Designate and map the ownership of natural features and dedicated open space.
            (3)   Allocate responsibility and guidelines for the maintenance and operation of the dedicated open space and any facilities located thereon, including provisions for ongoing maintenance and long-term capital improvements.
            (4)   Estimate the cost for maintenance, inspection and operation of the dedicated open space areas for said work. The plan shall describe the means by which such funding will be obtained.
            (5)   Provide that the plan cannot be changed without the approval of the County and describe how the plan will be enforced.
         e.   The stewardship plan shall include performance standards for all natural open space areas and naturalized stormwater management facilities and buffers. The performance standards shall identify proposed methods for establishing the areas and require monitoring and maintenance for at least three (3) full growing seasons following initial enhancement, restoration, and planting, or until initial performance standards have been met. The design intent for such areas is to provide an aesthetic, healthy, and diverse community of native vegetation to meet the objectives of soil stabilization, water quality improvement, and wildlife habitat. Minimum performance standards for restoration, planting, maintenance, and monitoring of natural open space and naturalized stormwater facilities are detailed below. Under circumstances where the minimum performance standards are not met, alternative performance standards shall be presented to and approved through the development review process.
         f.   Beyond the initial establishment and restoration period, regular maintenance and management shall be performed in perpetuity to continue to meet the performance criteria and to enhance natural ecologic conditions over time.
      2.   Short-Term Landscape Restoration and Planting Schedule of Stewardship Plan. A site specific restoration and planting schedule shall be submitted to the County with required final engineering plans. The plan shall be prepared by a qualified professional in the field of ecological restoration and/or natural landscape. A cost estimate to be used to calculate the amount of the required bond and/or letter of credit shall also be prepared. At a minimum the plan shall include:
         a.   A map drawn to scale depicting all proposed restoration and planting areas. Identification of proposed management units based on remnant natural areas, soil types, topography, hydrology, and pre-settlement vegetation. Management unit mapping shall also show the overall layout of the development to demonstrate that naturalized areas are adequately set back from structures and other infrastructure so that the potential for fire hazards during controlled or accidental burns is reduced. Where applicable, fire breaks, including those in the form of mowed paths, should also be identified. Aggressive native tree species to be removed shall be noted.
         b.   A list of all plants, seeds, and/or plugs to be used within each management unit. All plantings shall consist of species native to the greater Chicago region, as identified in “Plants of the Chicago Region” (Swink and Wilhelm, 1994), of a local genotype and appropriate for the proposed habitat. The number of plants and plugs to be used and the amount/weight of seed per species shall also be included, along with seeding rates per acre for each species.
         c.   For existing wetland, prairie, savanna, and woodland communities, a schedule of management and enhancement activities for areas proposed for restoration. This schedule shall address methods of weed and brush removal, including herbicide, cutting and hand pulling, replanting necessary to restore native plant diversity, and, where appropriate, sediment removal, re-grading, stabilization, and related measures necessary to restore degraded wetlands and aquatic systems.
         d.   A three-year (3-year) management schedule that includes proposed timing and description of the following: site preparation, application of herbicides, seeding activity, mowing, controlled burns, and similar activities. Areas being restored to native communities should be protected by silt fencing or construction fencing to prevent unnecessary disruption or destruction due to nearby construction activity.
      3.   Short-Term Landscape Restoration and Planting Schedule Preferred Criteria. The success of natural landscape can be affected by the appropriateness of the plant species selected, the effectiveness of the grading and seedbed preparation, the quality of the seed and plant material used, the timing of the planting, and attention to early maintenance. Whenever possible, land shall remain undisturbed until seeding can be accomplished. The success of the project will be formally evaluated by the following vegetation performance standards monitored over time.
         a.   In order to ensure adequate diversity of plants, respond to varying environmental and hydrologic conditions, ensure the establishment of native landscapes that are functional, aesthetic, and cost-effective, and provide reasonable variety to meet aesthetic expectations, the following is required:
            (1)   A minimum of ten (10) species of native plants shall be established within any naturalized stormwater facility, such as naturalized detention basins or swales.
            (2)   A minimum of forty (40) species of native plants shall be established in any upland landscapes.
         b.   By the end of the first full growing season, planted areas shall have ninety percent (90%) vegetation cover and no area larger than one (1) square meter may be devoid of vegetation. A cover crop of annual rye or oats may be used to help achieve this goal. At least seventy-five percent (75%) of the plugs, root stock, and tubers, and fifty percent (50%) of the seeded species should be present and alive. If an area is designed as an aquatic or emergent system, it is anticipated that portions of the submerged area will be periodically exposed and without vegetation cover due to fluctuating water levels. If, by the end of the first full growing season, the basin emergent zones and/or side slopes fail to support the establishment of sufficient vegetation, then corrective measures regarding the fundamental design of the area and/or planting plan are required.
         c.   During the second growing season at least sixty percent (60%) of the permanent species planted in seed form should be evident. Ninety percent (90%) or more of species planted as plugs, root stock and tubers shall also have persisted into the second season. If this fails to occur, a determination shall be made as to why and remedial action is necessary. Remediation may include over-seeding and/or plugging of appropriate species. Finally, undesirable, invasive plant species shall not be prevalent in any of the management units. No invasive, weedy species shall be among the five (5) most dominant plant species in the overall vegetative cover, including any of the following: Reed canary grass (Phalaris arundinacea), Common reed (Phragmites australis), Purple loosestrife (Lythrum salicaria), Non-native thistle (Cirsium spp., Carduus spp.), Sweet clover (Melilotus spp.), Crown vetch (Coronilla varia), Wild parsnip (Pastinaca sativa), Burdock (Arctium spp.), Garlic shallard (Alliaria petiolata), Teasel (Dipsacus spp.), Ragweed (Ambrosia spp.), Kentucky bluegrass (Poa pratensis), Buckthorn (Rhamnus spp.), Sandbar willow (Salix interior), Honeysuckle (Lonicera spp.), Multiflora rose (Rosa multiflora), Box elder (Acer negundo), Canadian Goldenrod (Solidago Canadensis), Queen Anne’s Lace (Daucus carota).
            A more complete listing of common invasive species is found in the “Illinois Nature Preserve Management Guidelines.”
         d.   At the end of the third full growing season, at least seventy-five percent (75%) of the seeded permanent species and ninety percent (90%) or more of species planted as plugs, root stock, and tubers are expected to be established. Alternatively, native perennial species that volunteer on the site, excluding undesirable invasive species, may be counted in determining the preceding criteria. Qualitative vegetative sampling within each management area shall achieve the following in order to be determined a success: a mean “coefficient of conservatism” shall meet or exceed three (3) and the “floristic quality index” shall meet or exceed twenty (20), except in designated stormwater management facilities as per “Plants of the Chicago Region” (F. Swink ad G. Wilhelm).
         e.   The five (5) most dominant species of the overall vegetative cover within each management unit shall not include any of the undesirable species referenced above under the second season performance standards. If the identified level of species development fails to occur, a determination shall be made as to why, and a remedial action plan shall be prepared and submitted to the County for approval. The approved remedial plan shall be implemented and continued monitoring is required beyond the third growing season until these performance criteria are met. Where the minimum performance standards cannot be achieved, a written explanation and alternative performance standards shall be submitted for consideration by the County.
         f.   The landscape installation bond or letter of credit will not be reduced or released until these conditions have been achieved and a maintenance letter of credit has been provided.
      4.   Short-Term Plant Monitoring Requirements. The following tasks shall be performed within each management unit identified in the landscape/planting plan during the first three (3) years. Monitoring and reporting is required annually for a minimum of three (3) full growing seasons during and following restoration and planting. Under circumstances where the minimum performance standards cannot be achieved, alternative performance standards shall be presented to the County for review and approval.
         a.   Plant inventory of all naturally landscaped areas. This inventory shall determine overall vegetative cover, the total number of species, and the prevalence of undesirable/invasive species, consistent with specified performance criteria. This inventory is used to determine where follow-up seeding or planting is needed, and to identify, locate, and remove undesirable weedy species on a timely basis. Permanent transect vegetation sampling techniques should be used within each management unit to adequately document and monitor plant community establishment over the initial three-year (3-year) period. The presence of any plant species observed outside of a transect and not documented by sampling along such transect shall also be noted. Sampling techniques and summaries shall be compiled consistent with methods described in “Plants of the Chicago Region” (F. Swink ad G. Wilhelm).
         b.   Establishment of permanent photographic monitoring locations. Photographs shall be taken to document the establishment of vegetative cover, erosion problems, and other relevant maintenance concerns within each management unit identified in the landscape/planting plan. Photographs shall be of satisfactory quality and resolution to accomplish the intent of the performance standards and shall be taken from the same locations during each monitoring event. A detailed description of the camera/photo location based on distance from a permanent structure, the orientation of the photo, and the vegetation zone being photographed shall be provided. Additional photos should be taken of problem areas and remedial activities.
      5.   Long-Term Landscape Monitoring and Management.
         a.   Long-term monitoring shall be performed on an annual basis until the maintenance bond is released. Monitoring reports shall be submitted to the County for review and approval.
         b.   Continued ecological management shall be provided to maintain a diverse native plant community, consistent with performance criteria, to minimize the proliferation of weeds and undesired woody vegetation, and to prevent erosion. At a minimum, the site shall continue to meet the vegetation performance standards of the third growing season, as specified above, with regard to erosion control, vegetation coverage, species diversity, and control of invasive species. Long-term maintenance consists of controlled burning, generally every one (1) to three (3) years or as dictated by site conditions. To maintain the established native plant communities, spot control and application of herbicides shall be performed, as necessary.
         c.   Long-term maintenance includes the removal of trash or debris and the removal of obstructions from detention basin outlet structures. Periodic removal of accumulated sediment from swales, forebays, and settling basins shall be done to maintain the function and aesthetics of stormwater facilities. At a minimum, sediment shall be removed from forebays and sediment basins when one (1) foot or more of sediment has accumulated.
         d.   The landscape maintenance letter of credit will only be released after these standards have been achieved for two (2) years.
      6.   Reporting Requirements. Monitoring reports are due on February 1 for each required reporting year and shall be submitted in a digital format to the County and include the following:
         a.   A summary of vegetation data collected within each management unit, including an assessment of compliance with performance criteria.
         b.   A description of vegetation maintenance activities, including over-seeding, replanting, control of undesirable weedy species, and an assessment of their effectiveness in meeting performance criteria.
         c.   Photographs and accompanying descriptions taken at permanent monitoring stations.
         d.   A summary of maintenance activities, including the landscape maintenance budgets, for both the current year and the coming year.
   H.   Tree Protection. To the greatest extent possible, significant trees and tree stands that meet the tree inventory and protection standards should be incorporated into protected open space. They should be identified and protected within the stewardship plan.
      1.   Submittals and Standards for Tree Protection.
         a.   As part of the preliminary plat submittal, the subdivider shall submit a tree survey, as defined below, and a tree preservation proposal prepared by a qualified arborist, forester, or similarly qualified professional.
            (1)   The survey shall consist of a scaled drawing that shows the location of all desirable native tree species listed in this section having a diameter at breast height (DBH) of four (4) or more inches. The inventory shall also include all other existing trees with a DBH of eight (8) or more inches, excluding prohibited tree species listed in this section. In the case of a multi-stemmed tree, the diameter of the clump is taken as a whole. The survey shall include, at a minimum, an inventory listing individual trees by tag number, the tree species by common name and scientific name, size (DBH), condition, and any observed problems.
            (2)   The survey shall also include a tree count of desirable native tree species listed in this section having a diameter at breast height (DBH) of between two (2) and four (4) inches. The relative locations of groupings of these trees shall be identified on a site map.
            (3)   Where trees are located in a permanently protected open space area and will be free from any grading activity, identification of individual trees is not required.
         b.   Where mass removal or clear cutting of desirable native trees has occurred, the Staff Plat Review Committee will not accept nor review a proposed subdivision for a period of one (1) year.
         c.   Where individual trees or stands of trees are removed by any cause or for any reason other than those listed on the tree replacement exception, the County may require that the area containing the removed trees or stands of trees be replanted and that the area be dedicated as and made subject to a tree preservation easement, maintained in perpetuity as open space.
         d.   During development and construction activity, all reasonable steps shall be taken to prevent damage to or destruction of protected trees, woodlands, and savannas within protected open space areas. These steps include:
            (1)   Soils shall not be removed, compacted, or otherwise disturbed within the critical root zone.
            (2)   A protective fence approved by the County shall be erected around the critical root zone of any protected tree or woodland area. Signs shall be affixed to said fence indicating the presence of the critical root zone and a protected area.
            (3)   All desirable trees on property adjacent to the subject site and within ten (10) feet of the site’s property line or have a critical root zone extending into the subject site, shall be protected from unreasonable damage by the use of acceptable tree protection measures.
            (4)   Mass cuts and mass grading are prohibited in woodland areas.
            (5)   Boring shall be used to install any underground utilities in tree areas, where feasible.
            (6)   The subdivider shall ensure that all applicable subcontractors are trained in proper tree protection.
            (7)   No excess soil, additional fill, equipment, trailers, liquids, or construction debris is allowed to be placed within the identified critical root zone of any tree.
            (8)   Only protective non-damaging devices or attachments may be attached to any tree during construction.
      2.   Tree Replacement.
         a.   Any protected tree removed pursuant to County approval shall be replaced on an inch-diameter basis as provided for below:
Diameter at Breast Height of Removed Tree
Number of replacement trees required
as measured in diameter at breast height
1.5" trees
2" Trees
2.5" trees
6 inches
7 - 8 inches
9 - 10 inches
11 - 12 inches
13 - 25 inches
26 or more inches
         b.   Tree replacement shall be exercised to the greatest extent possible. When a high density of trees is not appropriate or the full replacement of trees on site would result in the unreasonable crowding of trees, appropriate reductions in the tree replacement amount are allowed. If available, a fee in lieu of payment for tree replacement and ecological restoration may be approved by the County.
         c.   A tree replacement plan shall be prepared by a qualified arborist, forester, or similarly qualified professional in the field of natural resources, and familiar with the native ecosystems of the Chicago region. The tree replacement plan shall depict the location and corresponding elevation of each replacement tree and each preserved tree. Corresponding text shall state the species and diameter of each tree with a description of the proposed management strategy to ensure its health and survival on the property.
         d.   Replacement trees with local genotypes from a two-hundred-fifty mile (250-mile) radius shall be used. All trees shall be high quality, installed free of disease, and in a manner that ensures the availability of sufficient soil and water to sustain healthy growth. Unless otherwise approved by the County, replacement trees shall be selected from the following native species. No species of evergreens are permitted as suitable options to meet tree replacement requirements.
Acer nigrum
Black maple
Acer saccharum
Sugar maple
Carpinus caroliniana
American hornbeam
Carya cordiformis
Bitternut hickory
Carya glabra
Pignut hickory
Carya ovata
Shagbark hickory
Celtis occidentalis
Ostrya virginiana
Quercus alba
White oak
Quercus bicolor
Swamp white oak
Quercus coccinea
Scarlet oak
Quercus ellipsoidalis
Hill’s oak
Quercus macrocarpa
Bur oak
Quercus rubra
Red oak
Quercus velutina
Black oak
Tilia americana
American linden
Prunus Americana
Wild plum
Corylus americana
Malus ioensis
Prairie crab
Viburnum dentatum
Downy arrowood
Amelanchier arborea
Amorpha canescens
Lead plant
Ceanothus americanus
New Jersey tea
Corylus Americana
Crataegus mollis
Downy hawthorn
Lonicera prolifera
Iowa crab
Physocarpus opulifolius
Prunus virginiana
Choke cherry
Ribes americanum
Wild black currant
Ribes missoriense
Wild gooseberry
Salix humilis
Prairie willow
Viburnum acerifolium
Maple leaved viburnum
Viburnum prunifolium
Black haw viburnum
Viburnum rafinesquianum
Downy arrowood viburnum
Xanthoxylum americanum
Prickly ash viburnum
         e.   Consistent with good forestry and ecological practices, replacement trees shall be of either equivalent or a superior quality of species. For example, a softwood tree may be replaced with a hardwood tree, but a hardwood tree cannot be replaced by a softwood tree. In order to preserve and enhance the oak-hickory savannas and woods native to McHenry County, oak and hickory trees shall be replaced in kind with native oak and hickory species.
         f.   Invasive trees and shrubs shall be removed as part of the forestry practices and ecological restoration activities, and are not treated or acknowledged as protected tree species. Aggressive native trees shall be removed as necessary and appropriate for the ecologic restoration of oak-hickory savannas and woods. Proposals to remove such trees shall be identified in the stewardship plan. The following trees do not require replacement nor shall they be planted as replacements for desirable trees:
Acer negundo
Box elder
Acer plantanoides
Norway maple
Acer saccharinum
Silver maple
Ailanthus altissima
Tree of heaven
Elaeagnus angustifolia
Russian olive
Elaeagnus umbellate
Autumn olive
Fraxinus species
Ash species
Gleditsia triacanthos
Honey locust
Juniperus virginiana
Red cedar
Populus species
Poplar species
Rhamnus cathartica
Common buckthorn
Rhamnus fragula
Glossy buckthorn
Robina pseudoacacia
Black locust
Taxodium distichum
Bald cypress
Thuja occidentalis
Arbor vitae
Ulmus pumila
Siberian elm
      3.   Tree Replacement Exceptions. Trees removed by or for any of the following reasons need not be replace provided that the property owner is able to provide documentation that the tree removal met one of the following exceptions:
         a.   Emergencies involving, but not limited to tornados, windstorms, floods, freezes, or other natural disasters.
         b.   Trees that have become, or immediately threaten to become, a hazard to persons, property or other vegetation and require immediate removal or destruction.
         c.   Diseased, dead, or dying trees as confirmed by an arborist, forester, or a qualified professional in the field of natural resources.
         d.   All active orchards and state or federal government approved tree farms are exempt from these terms and provisions, but only in relation to those trees which are planted and growing for the sale or intended sale in the ordinary course of business or for a public purpose.
         e.   Invasive species such as common buckthorn (Rhamnus cathartica), glossy buckthorn (Rhamnus frangula), and honeysuckle (Lonicera sp.), which are commonly removed as part of good forestry practices and ecological restoration, are not protected tree species.
         f.   Trees removed for public roadway and infrastructure improvements and maintenance need not be replaced.
         Tree replacement will be required if trees are removed for any other reason or if the property owner is unable to provide sufficient documentation regarding the cause or purpose of the tree remove.
      4.   Release of Improvement Guarantees. Final approval and release of improvement guarantees will not occur until a final inspection by the County confirms that the conditions of this section have been met. In the event that conditions cannot be met, an alternative proposal shall be prepared. If available, a fee in lieu of payment to be determined by the County may be used to meet the objectives of this section.
   I.   Wastewater Treatment and Disposal Standards.
      1.   Treatment and disposal options that are consistent with state and federal anti-degradation policies shall be utilized. In particular, options that best protect groundwater, wetlands, surface waters, and other natural resources from increased concentrations of nutrients and related pollutants that may impact aquatic life, native plant diversity, and related uses shall be utilized. The McHenry County Department of Health reserves the right to require review by an outside agency or qualified onsite wastewater treatment specialist, including, but not limited to, USDA/NRCS, Illinois Department of Natural Resources, Illinois State Water Survey, and Illinois State Geological Survey.
      2.   A wastewater treatment option shall be selected and implemented based on its ability to ensure groundwater recharge, beneficial reuse of nutrients, protection of groundwater quality, protection of surface water quality, and protection of environmentally sensitive environments. Shallow groundwater flow direction, projected wastewater flows, projected strength of the wastewater, sensitivity of the receiving environment, recharge capability, potential cumulative impact of the chemical, organic, nutrient and bacterial loading on groundwater, and lifetime cost of the system shall be taken into consideration when selecting the wastewater treatment option.
      3.   The wastewater treatment system shall comply with the McHenry County Public Health Ordinance. Sites utilizing Illinois Environmental Protection Agency permitted technology shall conform to all of the requirements of the IEPA and receive all applicable permits prior to the Planning and Development Committee recommending approval of the final plat.
   J.   Violations And Corrective Action.
      1.   If at any time the Zoning Enforcement Officer determines that the open space management entity is in violation of the terms of this Ordinance, the Zoning Enforcement Officer shall give written notice of such violation and demand corrective action sufficient to cure the violation, and where necessary, restore the portion of the property so injured. If the open space management entity fails to cure the violation within thirty (30) days after receipt of notice thereof from the Zoning Enforcement Officer, or, under circumstances where the violation cannot reasonably be cured within a thirty (30) day period, fails to commence or fails to continue to cure such violation until finally cured, the Zoning Enforcement Officer may bring an action in accordance with the enforcement provisions of this Ordinance.
      2.   If the Zoning Enforcement Officer determines that circumstances require immediate action to prevent or mitigate significant damage to the open space or natural areas the County may pursue its remedies without prior notice to the open space management entity. Under such circumstances, the County may enter dedicated open space areas in order to take corrective action necessary to ensure compliance and the provisions of long-term management and stewardship.
(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, § 19.9; Ord. O-201803-ZBA-10-08, passed 3-19-2018; Ord. O-201808-10-033, passed 8-21-2018)