The following regulations control the manner in which streets, lots and other elements of the subdivision are arranged on the land.
(A) General.
(1) The subdivision shall conform to the Marshalltown Comprehensive Plan (General Development Plan).
(2) The subdivision shall be designed to serve potential building sites in the most advantageous manner.
(3) Land subject to flooding, improper drainage, erosion, or of slope deemed unsuitable for residential use, shall not be platted for residential occupancy nor shall such land be platted for other use as may continue such conditions, or increase danger to health, safety, life or property.
(B) Streets and alleys.
(1) The design of all streets shall be considered in their relation to existing and planned streets, to reasonable circulation of traffic, to topographical conditions, to runoff of storm waters and to the proposed uses of the area to be served.
(2) Where adjoining areas are not subdivided, the arrangement of streets in new subdivisions shall make provision for the proper projection of streets. When a new subdivision adjoins unsubdivided land susceptible to being subdivided, then the new streets shall be carried to the boundaries of the lands being subdivided.
(3) The following table of standards for street design shall be observed by the subdividers:
Street and alley type | Minimum right-of-way width (lot line to lot line in feet | Minimum roadway width (back to back) in feet | Maximum gradient in percent | Minimum gradient in percent |
Regional arterial | 120 ft. | 69 ft. | 4% | 0.7% |
City arterial | 100 ft. | 49 ft.* | 4% | 0.7% |
Collector | 80 ft. | 45 ft. | 6% | 0.7% |
Industrial | 80 ft. | 31 ft - 45 ft.*** | 6% | 0.7% |
Local streets | 80 ft. | 31 ft. | 6%** | 0.7% |
Alley | 80 ft. | 16 ft. | 6% | 0.7% |
* 68 ft. where parking is allowed
** Steeper grades to a maximum of 10% may be allowed upon recommendations of the City Engineer
*** Actual width shall be established by the City Council at its discretion.
(4) Tangents of at least 100 feet in length shall be introduced between reverse curves on collector streets and 50 feet on lesser streets.
(5) Where new streets extend existing adjoining streets, their projections shall be at the same or greater width, but in no case less than the minimum required width.
(6) Local streets shall be so designed that their use by through traffic will be discouraged.
(7) Street jogs with center line offsets of less than 130 feet shall be avoided.
(8) Insofar as practical, street intersections shall be at right angles.
(9) No dead-end streets shall be approved unless said streets are provided to connect with future streets on adjacent land. In such event, a temporary turn-around shall be provided.
(10) Each cul-de-sac shall be provided at the closed end with a turn-around having a minimum outside roadway diameter of 90 feet and a minimum street property line diameter of 120 feet.
(11) Half-streets shall be prohibited except where the city finds a better design will result and when the city deems it practical to require the dedication of the other half of an arterial, local or collector street when the adjoining property is subdivided.
(12) Where a proposed plat is adjacent to an arterial, the city may require the developer to provide marginal access/frontage streets along the right-of-way of such facilities or they may require that lots should back on the thoroughfare, in which case, vehicular and pedestrian access between the lots and thoroughfare shall be prohibited.
(13) The street arrangements shall not be such as to cause hardship to owners of adjoining property in platting their own land and providing convenient access to it.
(14) Curb lines at street intersections shall be rounded to a minimum of 25 feet.
(15) The provision for alleys shall be discouraged.
(16) A building set-back line safeguarding future street widening or other improvement may be required by the city.
(17) Additional right-of-way may be required by the city along existing collector and arterial streets to meet the requirements of § 157.005(B)(3).
(C) Public easements.
(1) Easements shall be provided for utilities, where necessary. They shall be centered on rear and side lot lines or along the front lot line as required by the utility companies. They shall have continuity of alignment from block to block. At deflection points, easements for pole line anchors shall be provided where necessary.
(2) Where a subdivision is traversed by a watercourse, drainage way, channel or stream, there shall be provided a storm water easement or drainage right-of-way substantially in alignment with the lines of such watercourse, together with such further width for construction or both, as will be adequate for storm water runoff. The easement shall include not only the stream channel, but also adjoining areas that have been subject to flooding in years of heavy runoff.
(3) Where a subdivision is traversed by a watercourse, drainage way, channel or stream, the City Council may require an easement over and across certain portions of the subdivision lying contiguous to said waterway, the width of which the Council shall determine, for green belt public recreation and public access areas, provided, however, that said purposes shall not include use by any motorized means of transportation, except for maintenance vehicles.
(4) Easement widths shall be determined by the City Council as recommended by the City Engineer, except no easement for utility or drainage purposes shall be less than 12 feet in width on rear lot lines and ten feet in width on side lot lines and the same shall be apportioned between abutting and subject property.
(D) Blocks.
(1) The lengths, widths and shapes of blocks and lots shall provide for adequate building sites suitable to the special needs of the use contemplated; provide for convenient access, circulation, control and safety of traffic, and provide for the limitations and opportunities of topography.
(2) Block lengths shall not exceed 1,320 feet and, if possible, shall not be less than 400 feet in length. In blocks longer than 800 feet, a pedestrian crossway with a minimum right-of-way of ten feet shall be required near the center of the block. The use of additional walkways and access ways to schools, parks, scenic points and other destinations may also be required by the City Council.
(3) A block shall be so designed as to provide two tiers of lots of appropriate depth, except where a change of land use, severe topographic conditions or a highway necessitates a single tier of lots in the opinion of the Planning Commission. In these cases the lot depth shall be at least 25 feet greater than minimum requirements.
(E) Lots.
(1) Every lot shall front on a publicly dedicated street except in planned unit developments according to the City Zoning Ordinance and as approved by the City Council.
(2) Where possible, side lot lines shall be at right angles to straight street lines or radial to curved street lines. Lots with frontage on two approximately parallel streets shall be permitted only under unusual circumstances.
(3) Minimum lot sizes within the City shall conform to zoning regulations in force. Corner lots shall be platted at least ten feet wider than the minimum lot width required in the zoning ordinance.
(4) Residential lots, served by septic systems, shall be a minimum of 90 feet wide at the building line and shall have a minimum area and depth as recommended by the City Engineer, provided further that no such lot shall have an area less than 33,000 square feet.
(5) Residential lots on major street intersections and at other intersections having restricted vision clearance due to topographic or other conditions may be required to have a corner radius or other special shape.
(F) Public lands.
(1) Because subdivision activity creates a need for land space devoted to public use in addition to that ordinarily set aside for streets and easements, the city, or the Marshalltown Community School District, or both acting together, may reserve a part or all of a proposed subdivision for public use such as, but not limited to, parks, schools, or playgrounds. The city, or the Marshalltown Community School District, or both acting together, shall purchase any such reserved land within two years after approval of a final plat adjoining such reserved land. This section shall not apply to easements set forth in § 157.005(C).
(2) If the reserved area is to be served by any of the streets, sewers, street lights, or other improvements of any subdivision adjacent to it, the proportionate cost shall be born by the city, or the Marshalltown Community School District, or both acting together.
(G) Natural features. In the subdivision of land, due regard shall be shown for all natural features and historic sites which, if preserved, will add attractiveness and stability to the proposed development.
(H) Restrictive covenants. The subdivider is encouraged to further restrict the use of land within the subdivision to achieve better development. However, any covenants which do not assist orderly, efficient, integrated development and promote the general welfare of the community in the opinion of the Commission may constitute grounds for disapproval of the plat.