The following are standards for the design of a subdivision. For additional information and requirements, refer to the zoning and subdivision ordinances in this chapter for information and requirements relating to the adopted Public Improvement Design Standards. The subdivision design standards contained herein are intended only as minimum requirements so that the general arrangement and layout of a subdivision may be adjusted to a wide variety of circumstances. However, in the design and development of the plats and construction plans the subdivider should use standards consistent with the site conditions and the City Public Improvement Design Standards so as to assure an economical, pleasant and durable neighborhood.
A. Character of Development. The Commission shall have the right to consult with the subdivider regarding the type and character of development that will be permitted in the subdivision, and may require that certain minimum regulations regarding this matter be incorporated in the restrictive covenants. Such provisions shall be intended to protect the character and value of the surrounding development and shall also tend to secure the most appropriate character of the development in accordance with long-range projections of the Comprehensive Plan. If there are material changes to the restrictive covenants after filing the Final Plat, the City shall have the right to stop issuing building permits until changes in the covenants can be agreed upon by the City.
B. Preservation of Scenic, Historic, and Natural Features.
1. Existing features which would add value to residential development, such as trees, watercourses, historic and archeological sites and similar irreplaceable assets, shall be shown on the preliminary plat and shall be preserved, insofar as possible.
2. To the maximum extent possible, development shall be located to preserve natural features of the site, to avoid areas of environmental sensitivity, and to minimize negative impact and alteration of natural features and drainage patterns.
3. The subdivider shall give maximum consideration to the preservation of the following areas as open space, to the extent consistent with reasonable utilization of land:
a. Wetlands and other unique environmental areas.
b. Significant stands or mature specimens of trees.
c. Flood plain lands, other than areas that have already experienced substantial development.
d. Slopes in excess of 15% as measured over a 10-foot interval.
e. Habitats of endangered species.
4. Land Suitability. Land which the City has found to be unsuitable for subdivision due to potential flooding, drainage problems or other features likely to be harmful to the general health, safety and welfare of the future residents shall not be subdivided, unless satisfactory methods of development for such lands are formulated by the developer and approved by the Commission, the Council and any other official governmental body having jurisdiction. Major waterways and ditches shall not be straightened or channelized without a plan for storm water management and erosion control measures.
C. General Guidelines for Subdivision Layout. Subdivisions shall be designed to comply with the following overall performance objectives:
1. Avoidance of adverse effects on ground water and aquifer recharge.
2. Reduction and minimizing of cut and fill.
3. Avoidance or reduction of unnecessary impervious surfaces.
4. Prevention of flooding and encroachment of water onto other properties.
5. Provision of adequate access to lots, including alternative routes to lots and sites within the subdivision and minimizing of cul-de-sacs.
6. Mitigation of negative environmental effects on surrounding properties, including effects of shadow, noise, odor, traffic, drainage, and utilities.
7. Respect for the urban character and traditional layout of Mount Vernon, including providing continuity to established street and community facility networks; establishing linkages and connections between new development and existing parts of the city; and preserving historically and architecturally significant sites and buildings, determined as those sites or districts either listed on or determined to be eligible for listing on the National Register of Historic Places, as determined by the State Historic Preservation Officer or the Mount Vernon Historic Preservation Commission.
8. Dedication of arterial, collector, and key local streets on the general alignments specified in the Comprehensive Plan or the street planning map.
9. The Planning and Zoning Commission and City Council shall take the above Site Design objectives into account during their review and approval of preliminary plat applications.
D. Blocks. Pedestrian ways may be required to allow access through the block for pedestrians in very long blocks. In general, blocks of more than six hundred feet (600') in length should have a pedestrian way near the center of the block. Blocks in TR Traditional Residential zoning districts should not ordinarily exceed 300 feet in length.
E. Easements.
1. An easement for utilities, at least sixteen feet (16’) in width, centered on the lot lines, shall be provided along the rear line of each lot, and along side lines where necessary to provide a continuous easement. If necessary easements of greater width may be required along lot lines or across lots, and easements of lesser width may be approved if accepted by utility companies and easements shall connect with easements in adjoining properties. Easements shall be approved in writing by any public or private utility company intending to use such easement for their facilities, such approval to be submitted prior to approval of the final plat.
2. Whenever any stream or important surface water course is located in an area that is being subdivided, the subdivider shall, at his or her own expense, make adequate provision for improvement of the channel so it will properly carry the increased surface water runoff from developed ground and shall provide and dedicate to the City an easement along each side of the stream. Such easements shall be for the purpose of improving, maintaining or protecting the stream. Easements shall extend not less than twenty feet (20’) on each side of the centerline of the waterway, and the total width of the easement shall be adequate to cover the 100 year flood flow calculated for a fully developed drainage basin upstream.
F. Lots.
1. Each lot shall conform in size and shape to the requirements set forth in the Zoning Ordinance as necessary for providing an adequate building site.
2. Each lot shall be provided by means of a public street with satisfactory access to an existing public street.
3. Each lot shall be provided with not less than twenty feet (20’) of access frontage to a public street.
4. For the purpose of complying with minimum health standards, in subdivisions where buildings are to be served by septic tanks, the size of lots shall be sufficiently large to accommodate adequate drainage fields. Standards set forth by the Linn County Health Department and the State Board of Health shall be met.
5. Side lot lines where possible shall be at right angles or radial to the street lines.
G. Monuments. Monuments shall be placed at block corners, points of curves, change in direction along lot lines, and at each lot corner. All monuments shall be of solid steel, not less than 1/2 inch diameter and thirty inches (30”) long, and properly marked with the license number of the land surveyor responsible for the subdivision.