A. 
Land suitability. No land shall be developed which is held to be unsuitable for any proposed use if identified as being environmentally sensitive. Areas identified as being environmentally sensitive include, but are not limited to:
(1) 
All areas mapped as floodplain by the Federal Emergency Management Agency (FEMA), WDNR, or other public or private entity.
(2) 
All wetlands as defined in § NR 103.02(5) of the Wisconsin Administrative Code, including the wetland protection buffer areas identified in the Zoning Code to serve as a protection buffer.
(3) 
All areas within 75 feet of the ordinary high-water mark of navigable streams and lakes, as identified by the City Planning Consultant.
(4) 
All areas having slopes greater than 12%.
(5) 
Areas that are known to provide habitat for rare, threatened or endangered species.
(6) 
Burial sites and Indian mounds.
(7) 
Drainageways that contain running water during spring runoff, during storm events or when it rains. A twenty-five-foot buffer from the edge of the drainage way shall be included. Areas determined to be environmentally sensitive may be included as common open space in a conservation subdivision but shall not be included in the development yield analysis. These lands shall be identified as an outlot or other designation that indicates the land is not available for development.
B. 
Development yield.
(1) 
The number of residential units for a parcel shall be determined in accordance with the following:
(a) 
The development yield analysis in § 650-26C(9) shall establish the base development yield for the parcel.
(b) 
The base development density may be increased if the development complies with one or more of the following standards. Each standard provides a development yield bonus of the greater of one parcel or 5% of the base development yield:
[1] 
Providing for access by the general public to trails, parks or other recreational facilities.
[2] 
Reusing existing buildings and structures which incorporate rural or agrarian themes, including but not limited to those sites inventoried by the State Historical Society of Wisconsin.
[3] 
Preservation of Environmental features.
[4] 
Restores native prairie and provides a management plan for perpetual maintenance.
[5] 
Improves water quality through stormwater management standards and practices, that exceed the minimum standards of Article IV of Chapter 660, Zoning, of the Municipal Code, and, as approved by the City's Engineering Consultant and the Public Works Committee.
[6] 
Provides a minimum seventy-five-foot setback and natural buffer from all environmental features.
[7] 
Restores or enhances the functional classification of wetlands using techniques approved by the USDA-NRCS and the WDNR.
[8] 
Provides 70% or more of the gross acreage as open space in the development. Rights-of-way, stormwater outlots, and platted private property shall not count towards open space requirements.
(2) 
For parent parcels less than 80 acres in area, the maximum bonus permitted is the greater of three parcels or 15% of the base development density. For parent parcels 80 acres or greater in area, the maximum bonus permitted is the greater of four parcels or 20% of the base development density. All development yield bonuses shall be calculated to the nearest tenth. In cases where the total combined development yield bonus results in a fraction, all such fractions shall be rounded up to the next whole number.
C. 
Performance standards.
(1) 
General consideration. Conservation subdivisions must identify a conservation theme or themes. This theme shall be identified at the time of the initial application. Conservation themes may include, but are not limited to, forest stewardship, water quality preservation, farmland preservation, natural habitat restoration, viewshed preservation, or archaeological and historic properties preservation. The Plan Commission and City Forester shall have the ability to specify which areas shall be preserved.
(2) 
Agricultural use. If agricultural uses are proposed to be maintained, lots shall be configured in a manner that maximizes the usable area remaining for such agricultural uses, with appropriate buffers between agricultural uses and residential structures.
(3) 
Residential lot requirements. Residential parcels located within conservation subdivisions shall conform to the PDD Planned Development District zoning regulations and the following:
(a) 
Lots shall be in conformance with the design standards identified in § 650-32E(1), (6), (7) and (12).
(b) 
All lots and dwellings shall be grouped into clusters of no more than 20 dwelling units. Said clusters shall:
[1] 
Be located to minimize negative impacts on the natural, scenic, and cultural resources of the site, and minimize conflicts between incompatible uses.
[2] 
Avoid encroaching on rare plant communities, high-quality environmental resources, or endangered resources as may be identified by the WDNR.
(c) 
Lots shall be configured to minimize the amount of road length required for the subdivision.
(d) 
All lots shall abut open space on at least one side. A minor street may separate lots from said open space.
(e) 
Lots shall be oriented around one or more of the following:
[1] 
A central green or open space.
[2] 
A physical amenity such as a meadow, stand of trees, or other natural or restored feature.
(4) 
Open space standards. Open space shall be designated as part of the development.
(a) 
The minimum required open space is 60% of the gross acreage less lands granted for density bonuses as stated in Subsection B of this section. Rights-of-way, stormwater outlots, and platted private property shall not count towards open space requirements.
(b) 
All open space shall be owned and maintained under one of the alternatives listed in Subsection C(6) below, and as approved by the City.
(c) 
The uses within the open space shall be accessible to the residents of the development. These uses may also be available to the general public providing the proper approvals are received. The required open space shall be undivided and restricted in perpetuity from future development, as specified in Subsection C(5) below.
(d) 
That portion of open space designed to provide plant and animal habitat shall be kept as intact as possible. Trails shall be designed to avoid fragmenting these areas.
(e) 
Accessible open space in upland areas shall be available for recreational uses such as trails, play fields, or community gardens but should be designed in a manner that avoids adversely impacting archeological sites.
(f) 
A pathway system connecting open space areas accessible to neighborhood residents, and connecting these areas to neighborhood streets and to planned or developed trails on adjacent parcels shall be identified in the plan.
(g) 
The following areas or structures may be located within the open space area and shall be counted toward the overall open space percentage required:
[1] 
Parking areas for access to and use of the open space developed at a scale limited to the potential users of the open space.
[2] 
Privately held buildings or structures, provided they are accessory to the use of the open space.
[3] 
Shared septic systems and shared water systems.
(5) 
Ownership and maintenance of common areas. The designated common open space and common facilities may be owned and managed by one or a combination of the following:
(a) 
An incorporated homeowners' association. Membership in the association is mandatory for all purchasers of homes in the development and their successors. The homeowners' association bylaws, guaranteeing continuing maintenance of the open space and other common facilities, and the declaration of covenants, conditions and restrictions of the homeowners' association shall be submitted for approval to the City as part of the information required for the preliminary plat.
(b) 
A condominium association established in accordance with the Condominium Ownership Act, Chapter 703 of the Wisconsin Statutes. If the common open space and facilities is to be held under the Condominium Ownership Act, Chapter 703 of the Wisconsin Statutes, the condominium instruments shall identify the restrictions placed upon the use and enjoyment of the common open space. All common open space shall be held as a "common element" as defined in § 703.02 of the Wisconsin Statutes.
(c) 
A nonprofit conservation organization. If the common open space is to be held by a nonprofit conservation organization, the organization must be acceptable to the City of Lake Mills. The conveyance to the nonprofit conservation organization must contain appropriate provisions for reversion in the event that the organization becomes unwilling or unable to uphold the terms of the conveyance.
(d) 
The City of Lake Mills or another governmental body empowered to hold an interest in real property. The City may accept the common open space, provided the common open space is accessible to the public and provided the City agrees to and has access to maintain the common open space.
(e) 
An individual who will use the land for open space purposes as provided by a conservation easement.
(6) 
Streets. Right-of-way widths and design standards shall be in conformance with design standards identified in Subsection C(3) and (4).
A. 
General. In accordance with § 650-33A A.
B. 
Survey monuments. In accordance with § 650-33B.
C. 
Grading. In accordance with § 650-33C.
D. 
Surfacing. In accordance with § 650-33B.
E. 
Curb and gutter. In accordance with § 650-33E.
F. 
Recreation trails and pedestrian-ways. In accordance with § 650-33G.
G. 
Sewage disposal facilities. When private sanitary sewer facilities are proposed to serve a conservation subdivision, such facilities may be located on the individual parcel serviced by the facility, or may be located within common open space areas subject to recording proper easements for use and maintenance. When public sanitary sewer facilities are available to the conservation subdivision, the subdivider shall construct sanitary sewerage facilities in accordance with § 650-33H.
H. 
Stormwater drainage facilities. In accordance with § 650-33I.
I. 
Water supply facilities. In accordance with § 650-33J.
J. 
Other utilities. In accordance with § 650-33K.
K. 
Street lamps, signs, and trees. In accordance with S§ 650-33L.
L. 
Improvement to Existing Half-Streets. In accordance with § 650-33M.
All construction and/or installation of improvements shall commence in a proposed Conservation Subdivision in accordance with the standards as outlined in § 650-33 of this chapter.
A developer's agreement and performance guarantee and surety may be required in lieu of requiring special assessment of all public improvements prior to the approval and recording of the final plat or certified survey map for a conservation subdivision in accordance with § 650-35 of this chapter.