(A) Streets.
(1) Gravel surfaces are prohibited.
(2) Streets shall be graded in accordance with a plan approved by the City Engineer.
(3) An obstacle clear free zone shall be provided adjacent to the roadway in accordance with the standards of the Minnesota Department of Transportation Road Design Manual.
(4) For rural design roadways, the in-slopes of the ditches shall be at a 1:4 (rise over run) and back slopes of the ditch shall be at 1:3 (rise over run). The ditch bottom shall be 4 feet wide unless suitable erosion control can be provided.
(5) The design of all pavements shall be in accordance with all applicable specifications of the Minnesota Department of Transportation at the time of construction. The designed thickness of the pavement shall be in accordance with the standards shown below, but in no case shall there be less than 6 inches of Class 5 or higher and 2 inches of bituminous. More stringent design may be required by the approving engineer.
Classification | Pavement Design; Axle Load |
Arterial Collector Street | 9 tons |
Local Street | 7 ton minimum |
(6) To determine sub-grade soil classifications, soil samples shall be collected and analyzed by a qualified testing laboratory. Reports of the soil analysis shall be submitted to the engineer with the pavement plans. Soil samples shall be taken along the centerline of the proposed road at intervals not exceeding 300 feet.
(7) Concrete or bituminous curb and gutter shall be constructed on both sides of urban designed streets and in areas where the road grade exceeds 4%. The construction shall be in accordance with Standard Specifications for Highway Construction, MNDOT No. 2531 or No. 2535.
(8) All boulevards shall have 4 inches of topsoil (black dirt) placed on them and then seeded or sodded.
(9) All required walks shall be concrete 4 inches thick placed on a 4-inch gravel base. Grades shall be as approved by the City Engineer. Sidewalks shall be placed in the public right-of-way. Bituminous walks or alternative paving, such as paving stones, are allowed if approved by the City Engineer.
(Prior Code, Ch. 401 § 1001.01)
(B) Utilities.
(1) Placement. All utilities shall be placed underground. All groundwork shall be completed prior to street surfacing.
(2) Where larger facilities required. Where a larger size water main, sanitary sewer, storm drain or similar facility is required to serve areas outside the subdivision, the larger facility required must be constructed. Additional cost is to be borne by the benefiting properties and the assessments are to be determined by the city.
(3) Sewer, urban areas.
(a) No public sanitary sewer facility shall be extended which is not in conformance with the city's Comprehensive Plan.
(b) Where trunk line sanitary sewer facilities are available, the subdivider shall install sanitary sewers and connect the sanitary sewers to the trunk line sewers. Extension of the public sewer system shall be designed to provide public sewer service to each lot.
(c) In the event that such facilities are not available but, in the opinion of the city, can be made available within a reasonable period of time, the sewers and all necessary laterals extending from the main sewer to the street curb shall be installed and capped for future connection as service becomes available.
(d) Construction and inspection of the sanitary sewer must be in conformance with the city's specifications.
(4) Water supply, urban areas.
(a) Where mains from a public water system are available, the subdivider shall install water mains in the plat and connect the mains to the public water system.
(b) Extensions of the public water supply shall, when available, be designed to provide public water service to each lot.
(c) Construction and inspection of the water supply system must be in conformance with city specifications.
(5) Sewer, rural areas.
(a) Where lots cannot be connected with a public sewer system, provision must be made for sanitary sewer facilities consisting of an individual disposal device for each lot. Such provision shall be in accordance with Chapter 157, Individual Sewage Treatment System Regulations. This does not mean that the installation of individual disposal devices shall be at the expense of the subdivider.
(b) 1. Any subdivision or lot not provided with off-site sewer facilities shall be subject to soil and percolation tests to determine whether the lot size proposed will meet minimum standards of health and sanitation due to limitation of soils as shown on existing soil maps. Such tests shall be made at the expense of the subdivider and a preliminary plat map shall be submitted identifying the specific locations where tests were made.
2. Sufficient soil borings shall be performed on each proposed lot by a certified soil tester to assure suitable soils exist for long-term sewage disposal.
(c) The lot area and topography must be such that it will accommodate an adequate disposal system to service the residence for the estimated number of unsewered years.
(6) Water supply-rural areas. Wells shall be constructed in accordance with all rules and regulations of the Minnesota Department of Health.
(Prior Code, Ch. 401 § 1001.02)
(C) Stormwater drainage.
(1) A drainage system shall be required and may include a storm sewer system or a system of open ditches, culverts, pipes, catch basins and ponding areas, or a combination system. Such facilities shall be installed and easements dedicated as will adequately provide for the drainage of surface waters.
(2) Drainage way easements or land dedication may be required when such easements or land is needed in the public interest for purposes of floodplain management, proper drainage, prevention of erosion, pedestrian access to water bodies, or other public purposes.
(3) In connection with preliminary plat review and recommendation, provisions for surface water disposal, drainage and flood control within the boundaries of the proposed property division shall be submitted.
(4) The rate of surface runoff within the boundaries of a proposed property subdivision shall not, in any event, be greater than the rate of runoff existing on the proposed subdivision prior to the proposed development. For the purposes of this regulation,
SURFACE WATER RUNOFF is water flowing on or very near the surface. The volume of surface water runoff may be regulated if it appears the use and development of downstream properties or water resources may be unreasonably interfered with as a result of the subdivision.
(5) Provisions shall be made for controlling runoff by construction or enhancement of ponding facilities on-site and within the boundaries of the proposed property division. Such ponding facilities should provide for both permanent and temporary storage runoff.
(6) An applicant shall install or construct, on or for the proposed land disturbing or development activity, all stormwater management facilities necessary to manage increased runoff so that the 2-year, 10-year and 100-year storm peak discharge rates existing before the proposed development shall not be increased and accelerated channel erosion will not occur as a result of the proposed land disturbing or development activity.
(7) The applicant shall give consideration to reducing the need for stormwater management facilities by incorporating the use of natural topography and land cover, such as wetlands, ponds, natural swales and depressions, as they exist before development to the degree that they can accommodate the additional flow of water without compromising the integrity or quality of the wetland or pond.
(8) The following stormwater management practices shall be investigated in developing a stormwater management plan in the following descending order of preference. A combination of successive practices may be used to achieve the applicable minimum control requirements. Justification shall be provided by the applicant for the method selected.
(a) Natural infiltration of precipitation on-site. The purpose of this provision is to encourage the development of a stormwater management plan that encourages natural infiltration. This includes providing as much natural or vegetated areas on the site as possible, minimizing impervious surfaces, and directing runoff to vegetated areas rather than to adjoining streets, storm sewers, and ditches;
(b) Flow attenuation by use of open vegetated swales and natural depressions;
(c) Stormwater retention facilities; and
(d) Stormwater detention facilities.
(9) An applicant may also make an in-kind or monetary contribution to the development and maintenance of city stormwater management facilities designed to serve multiple land disturbing and development activities undertaken by 1 or more persons, including the applicant.
(10) Stormwater detention facilities shall be designed according to the most current technology as reflected in the MPCA publication "Protecting Water Quality in Urban Areas" and shall contain, at a minimum, the following design factors:
(a) A permanent pond surface area equal to 2% of the impervious area draining to the pond or 1% of the entire area draining to the pond, whichever amount is greater;
(b) An average permanent pool depth of 4 to10 feet;
(c) As an alternative to divisions (C)(10)(a) and (b) above, the city may require that the volume of the permanent pool be equal to or greater than the runoff from a 2-inch rainfall for the fully developed site;
(d) A permanent pool length-to-width ratio of 3:1 or greater;
(e) A minimum protective shelf extending 10 feet into the permanent pool with a slope of 10:1, beyond which the slopes shall not exceed 3:1;
(f) A protective buffer strip of vegetation surrounding the permanent pool at a minimum width of 16.5 feet shall be provided;
(g) A device to keep oil, grease, and other floatable material from moving downstream as a result of normal operations shall be provided;
(h) Stormwater detention facilities for new development must be sufficient to limit peak flows in each subwatershed to those that existed before the development for the 10-year storm event. All calculations and hydrologic models/information used in determining peak flows shall be submitted along with the stormwater management plans; and
(i) All stormwater detention facilities must have a catch basin to remove coarse grained particles prior to discharging into a watercourse or storage basin.
(Prior Code, Ch. 401 § 1001.03)
(D) Erosion control during construction.
(1) Erosion control shall be performed in accordance with the recommended practice of the Washington County Soil and Water Conservation District and the applicable Watershed Management Organization. All best management practices shall be consistent with the Minnesota Construction Site Erosion and Sediment Control Planning Handbook.
(2) The following criteria apply only to construction activities that result in runoff leaving the site:
(a) Channelized runoff from adjacent areas passing through the site shall be diverted around the disturbed areas, if practical. Sheetflow runoff from adjacent areas greater than 10,000 square feet in area shall be diverted around disturbed areas unless shown to have resultant runoff rates of less than .05 feet/second across the disturbed area for the 1-year storm. Diverted runoff shall be conveyed in a manner that will not erode the conveyance and receiving channels.
(b) All activities on the site shall be conducted in a logical sequence to minimize the area of bare soil exposed at any 1 time. The limits of grading must be shown on the erosion control plan.
(c) All disturbed ground left inactive for 14 or more days shall be stabilized by seeding or sodding (prior to September 15) or by mulching, covering, or other equivalent control measures.
(d) For sites with more than 10 acres disturbed at 1 time, or if a channel originates in the disturbed area, one or more temporary or permanent sedimentation basins shall be constructed. Each sedimentation basin shall have a surface area of at least 1% of the area draining to the basin and at least 3 feet of depth constructed in accordance with accepted design specifications. Sediment shall be removed to maintain a depth of 3 feet. The basin discharge rate shall also be sufficiently low as to not cause erosion along the discharge channel or the receiving water.
(e) For sites with less than 10 acres disturbed at 1 time, silt fences, straw bales, or equivalent control measures shall be placed along all side slope and down slope sides of the site. If a channel or area of concentrated runoff passes through the site, silt fences shall be placed along the channel edges to reduce sediment reaching the channel. The use of silt fences, straw bales, or equivalent control measures must include a maintenance and inspection schedule.
(f) Any soil storage piles containing more than 10 cubic yards of material should not be located with a down slope drainage length of less than 25 feet from the toe of the pile to a roadway or drainage channel. If remaining for more than 7 days, they shall be stabilized by mulching, vegetative cover, tarps, or other means. Erosion from piles which will be in existence for less than 7 days shall be controlled by placing straw bales or silt fence barriers around the pile.
(g) In-street utility repair or construction soil or direct piles located closer than 25 feet to a roadway or drainage channel must be covered with tarps or suitable alternative control if exposed for more than 7 days. The storm drain inlet must be protected with straw bales or other appropriate filtering barriers.
(Prior Code, Ch. 401 § 1001.04)