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Before the city approves a Final Plat, the subdivider shall give satisfactory assurance of the provision of the following improvements:
(1) Monumentation shall be provided according to I.C.A. § 355.6.
(2) A permanent benchmark meeting USGS standards with a brass plate inscribing the number and elevation shall be accessibly placed within subdivisions exceeding one acre when directed by the City Engineer, the elevation of which shall be referred to the USGS datum and accurately noted on the subdivision plat.
(3) All official benchmarks, monuments or triangulation stations shall be preserved in precise location.
(B) Grading and surface drainage.
(1) Grading and the provision of surface drainage facilities shall minimize damage to the natural features of the subdivision and avoid erosion onto adjoining properties.
(2) Grading shall be accomplished in such a manner as to prevent ponding in excess of eight inches in the event of a complete failure of the storm sewer system.
(3) Drainage easements shall be provided in all cases when surface waters from more than two lots are conveyed down a property line.
(4) All street and alley rights-of-way shall be graded to full width and to the line and in a manner approved by the City Engineer. The grade of all streets, alleys and sidewalks shall be established by ordinance.
(5) Within Flood Plain Overlay Districts indicated on the Zoning Map of Marshalltown principal building sites are to be filled and graded so that the first floor and basement floor will be at a point no lower than one foot above the flood protection elevation for the principal building site and shall be designed to extend at such elevation at least 15 feet beyond the limits of the anticipated structure. However, no filling or excavation shall be permitted which will adversely affect the capacity of floodways and tributary channels, drainage ditches or other drainage facility. The City Engineer shall approve only those improvements which provide adequate protection from floods.
(C) Storm water sewerage and erosion control.
(1) The subdivider shall construct a storm sewer system adequate to serve the area, including anticipated extension of use to serve additional areas. The storm sewer system shall be constructed in accordance with design standards of the city and at sewer grades approved by the city. The design shall be based upon rain storms of ten year frequency and to carry the runoff anticipated from the development of tributary areas at the density indicated on the Comprehensive Guide Plan.
(2) The subdivider shall provide at his own cost all storm sewers below 25" in size, and shall pay an amount equal to the cost of the 24" size for all sewers required above the 24" size.
(3) The subdivider shall provide an erosion control plan to prevent siltation onto adjacent property, the public street, or into storm water intakes.
(4) The subdivider shall provide and maintain, temporary seeding, silt fences, and erosion control matting to prevent erosion until permanent seeding is growing.
(5) The subdivider shall provide at their sole cost a subdrain tile line system to provide access from each lot to the storm sewer system. In areas that have storm sewer, tile laterals shall be extended to each lot. In areas that don't have storm sewers, tile line extensions shall be provided behind each curb extending from an existing storm sewer or ditch outlet to each property frontage.
(D) Sanitary sewerage.
(1) The subdivider shall make adequate provision for the disposal of sanitary sewage from the platted area. He shall at his expense construct a sanitary sewer system including all necessary pumping stations, pumping equipment, manholes and laterals to the street right-of-way lines to provide for the discharge of sanitary sewage from all lots or parcels of land, within the platted area to a connection with the city's sanitary sewers. The sewerage system shall be constructed in accordance with the design standards of the city and at the sewer grades as approved by the city.
(2) The subdivider shall provide at his own cost all sanitary sewers below eleven inches in size and shall pay an amount equal to the cost of ten inch size for all sanitary sewer required above the ten inch size.
(3) The Plan and Zoning Commission may waive the requirements of this division (D). When gravity sanitary sewers are not feasible, provided septic systems meet the specifications of the City Engineer as to soil type and density, minimum lot size, drainage area, area density, and such other specifications he may impose. In addition, the subdivider shall install a dry sewer that will meet all requirements of § 157.006(D)(1) above.
(E) Water supply system. Lots shall be served by the Marshalltown public water supply system in accordance with plans and specifications of the city.
(F) Street paving, curbs, gutters and sidewalks.
(1) The subdivider shall pave all streets with full depth asphalt or concrete paving. The subgrade and street improvement shall be constructed in accordance with the design standards of the city, and shall adequately reflect the classification of the street, its location and anticipated volume of traffic. The installation of the streets shall be under the supervision of the City Engineer and the subdivider shall be required to pay a reasonable charge for the engineering and inspection service.
(2) Curbs and gutters shall be required for all lots and on all arterial and collector streets, except if part of a Planned Unit Development. Curb and gutter shall also be required on the side adjacent to the proposed subdivision when the subdivision abuts an existing platted street with a rural type street cross section unless the topography or other circumstances wouldn't justify such installation. In those circumstances, the developer shall provide the city a payment in the amount equal to those improvements required but not constructed to be placed in an escrow account for the city to use in the future when those improvements are constructed.
(3) Sidewalks shall be provided by the subdivider in all residential subdivisions and in all commercial and industrial development areas and in all blocks adjacent to a block containing a school or planned to contain a school. Additional walks shall be provided as required by the City Council.
(a) Commercial and industrial zoned lots and subdivisions shall have a sidewalk system which provides pedestrians a safe access to all buildings from the public street entrances.
(b) For all zoning districts, grading for sidewalk improvements is required at the time of final plat, if sidewalks are not installed at the time of final plat.
(c) Sidewalk must be installed before occupancy of the property is permitted.
(d) Remaining sidewalks must be installed within a period of two years on all undeveloped lots in a subdivision once 70% of the lots in the subdivision have sidewalks.
(e) All sidewalks in a subdivision must be installed within ten years of the date the final plat was approved.
(f) If an undeveloped lot is sold to an owner of an adjacent developed lot for the purpose of free space, parking, or an undetermined future need, then the undeveloped lot must have sidewalks installed at the time of sale.
(4) Disabled access to sidewalks by curb ramping. Provisions shall be made for curb ramping to sidewalks on all corners at each street intersection and other locations as required by the City Council.
(G) Street lights and street name signs. Street lights shall be provided by the subdivider equal to or exceeding the minimum design standards of the city and the plans of the Commission, if any. Street name signs will be provided by the city.
(H) Street terraces. The street terraces shall be graded and seeded according to city specifications.
(I) Public telephone, electric utility (15kv and below), cable TV, and other wire service utilities.
Underground service shall be required except by variance by the Council. The subdivider shall be responsible for making necessary arrangements for the installation of such facilities, shall assure that they do not interfere with other underground utilities and that incidental appurtenances, such as transformer enclosure, and the like shall be located so as not to be unsightly or hazardous to the public.
(J) Major utility transmission lines. All major utility transmission lines designed to provide utility distribution through a new subdivision shall be placed underground or located so as to provide the least possible effect upon the subdivision.
(Ord. 14688, passed 2-11-2002)