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All residential subdivisions and other districts, which may contain residential use, shall be so designed as to meet the neighborhood park and open space needs of its residents. Such needs may be met by dedication and acceptance of public parkland or by reservation by covenant of private open space, provided, there shall exist sufficient covenants running with the land to insure adequate maintenance by the property owners benefiting from such open space. In those proposed subdivisions where the City Trail Plan details passage through all or a part of the area, the gross area dedicated to the trail system shall be included in the open space dedication required for the subdivision.
STANDARDS FOR DESIGN AND DEVELOPMENT
The standards and details of design contained herein are intended only as minimum requirements (unless specifically noted otherwise) to allow the general layout of the subdivision to be adjusted to a wide variety of circumstances. However, in the design and development of the plat, the subdivider should use standards consistent with the site conditions to provide an economical, attractive, and quality community.
The Commission and Council shall have the right to retain or modify 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 owner’s statement or deed restrictions. Such regulations shall be intended to protect the appearance and value of the area surrounding the proposed subdivision and also to assure the implementation of the intended character and community style in the same. A “statement of character” shall generally refer to the intended uses to be established in the proposed subdivision and may refer to variables such as land uses, building square footage, building setbacks, size or height of structures, or other physical characteristics of the intended development. The term “character” does not refer to plat details such as lot sizes, lot line locations, or other technical details outlined on the proposed subdivision plat. No subdivision shall be approved and accepted by the City unless it conforms to the minimum requirements contained herein. When standards are not explicitly stated in this chapter, design requirements revert to the most current version of the Iowa Statewide Urban Design and Specifications (SUDAS). In addition to these requirements, all subdivision shall comply with the following:
1. The general nature, extent of lots, street layout, and uses detailed in the Comprehensive Plan and other such plans including, but not limited to, a Major Street Plan or Park and Trails Plan as adopted by the City, and other ordinances adopted by the City.
2. City standards and regulations as adopted by the Council, boards, commissions, and agencies of the City (City Engineer).
3. All applicable statutes, rules, and regulations of the State of Iowa and its duly constituted agencies.
Land within a proposed subdivision which is found to be unsuitable for any primary use building construction by reason of flooding, ponding, poor drainage, adverse soil conditions, adverse geological formations, unsatisfactory topography, or other conditions likely to be harmful to the public health, safety, or general welfare shall not be developed for said construction, unless such unsuitable conditions are corrected to the satisfaction of the City. Other land features that shall be deemed to be unusable for construction shall be any that are judged to be an environmentally sensitive land feature including wetlands and adjacent drainage areas important to the natural function of the wetlands, steep slopes, and significant tree stands. In this case the City may require the subdivider to proceed under a cluster PUD subdivision, described herein.
1. Council-Required Exclusions. Prior to the approval of the Preliminary Plat, the Council shall, with a recommendation from the Commission, prepare a report stating the reasons for the exclusion of the area from building development and for needed protection of the designated area or the surrounding area outside of the proposed subdivision or both. The report shall be forwarded to the subdivider and state options for including the designated area in the subdivision as part of an open space, trail area, or inclusion in part of the stormwater design area. The subdivider shall be provided the opportunity to present data for a proposed use of the area, which will provide protection and preservation of the involved area and afford the subdivider an acceptable use of the area. Upon receipt of the subdivider’s proposal, the Council shall, after receipt of the Commission review and recommendation regarding the same, review and act upon the proposal. The Council may approve the proposal, modify the proposal, or defer the proposal to further consideration of alternative uses of the area.
Any area of land in a proposed subdivision which is detailed within the Flood Hazard Area on a FEMA Digital Flood Insurance Rate Map (DFIRM) adopted by the City shall utilize the land use regulations and guidelines as provided in the Floodplain Management Ordinance as adopted by the City. (See Chapter 160)
The design standards for improvements herein contained 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. In addition to the standards set forth in this chapter, the Council, with assistance of the City Engineer, may from time to time adopt by resolution, technical standards for public improvements. Such technical standards may vary for classes of improvements and shall contain the minimum acceptable specifications for the construction of said improvements. Upon adoption by the Council by resolution, the technical standards for public improvements shall have such force and effect as if they were fully set forth herein.
1. Water Main System. The required water infrastructure improvements, including fire hydrants, for the proposed subdivision shall be designed and installed in accordance with the Code of Iowa, the applicable standards and requirement of the Iowa Department of Natural Resources, Chapters 90 through 93 of this Code of Ordinances, the City Technical Standards, and the Board of Health regulations. The plans and specifications for the improvements shall be prepared and signed by an engineer registered in the State of Iowa. Said water system lines and fixtures shall be established within public street rights-of- way, or public easements of sufficient width to allow adequate access for future maintenance, repair, and reconstruction of said facilities, including excavation. Water supply lines, including the location of all fire hydrants, shall be shown on the Preliminary Plat.
2. Sanitary Sewer System. The sewage collection system and pumping system (if required) for the proposed subdivision shall be designed and installed in accordance with the Code of Iowa, the applicable standards and requirement of the Iowa Department of Natural Resources, Chapters 95 through 100 of this Code of Ordinances, the City Technical Standards, and the Board of Health regulations. The plans and specifications for the improvements shall be prepared and signed by an engineer registered in the State of Iowa. Said sanitary sewage collection lines and accessories shall be established within public street right-of-way or public easements of sufficient width to allow adequate access for future maintenance, repair and reconstruction of said facilities, including excavation. Main sewer collection lines shall be shown on the Preliminary Plat. Storm sewerage, foundation drains, roof drains, and similar installations shall not be connected to the sanitary sewer system as noted in Chapter 97.01 of this Code of Ordinances.
3. Storm Sewer System.
A. The storm sewer system shall be designed and installed to convey the stormwater naturally flowing through the site prior to the development, and that from within the subdivision after all improvements are installed and structures are completed on all lots according to the allowed use.
B. Underground storm sewer pipe shall be installed throughout the subdivision and connected to an existing storm sewer (if available) or to an approved outfall. Facilities shall be designed to convey drainage through the site equivalent to the 100-year storm in a developed state.
C. On-site drainage facilities shall be designed to provide sufficient detention facilities to reduce the release rate to the equivalent of a five-year recurrence interval storm when the property was in an undeveloped state.
D. Plans and specifications for the improvements shall be prepared and signed by an engineer registered in the State of Iowa and submitted along with a copy of the design computations with the construction plans.
E. The storm sewer lines shall be adequately sized to receive drainage from foundation drains or sump pumps. Sump pump drain lines shall be installed at the back of the curbs on both sides of the streets unless PCR storm sewer pipe has been installed which could collect and convey sump pump drainage. Sump pump drain lines will be required unless it can be shown by the subdivider that they are not needed to the satisfaction of the City with recommendation by the City Engineer.
F. Lots shall be laid out so as to provide positive drainage away from all buildings and individual lot drainage shall be coordinated with the general storm drainage pattern for the area. Drainage shall be designed so as to avoid concentration of storm drainage water from each lot to adjacent lots.
4. Streets. The following standards shall apply to all streets to be planned and located within the proposed subdivision. .
A. General Requirements.
(1) The street layout shall provide access to all lots and parcels of land within the proposed subdivision.
(2) New subdivisions shall make provisions for continuation and extension of arterial and collector streets.
(3) Residential streets shall be arranged so as to discourage through traffic.
(4) Alleys shall be allowed in the R1-60 residential, commercial, and industrial districts.
(5) Half-streets shall be prohibited except where essential to the reasonable development of the subdivision and adjoining tract. The half-street in the adjoining tract shall be platted, improved, and dedicated with the subdivision under consideration.
B. Rights-of-way shall be provided as follows:
(1) Arterial streets, 80 feet.
(2) Collector streets, 70 feet.
(3) Residential/commercial/industrial streets with on-street parking, 60 feet.
(4) Commercial/industrial streets without on-street parking, 50 feet.
(5) Cul-de-sac turnarounds, 120 feet in diameter.
(6) Alleys in residential, commercial, or industrial district, 20 feet.
C. Paving shall be completed on all streets in accordance with the following:
(1) Paving Specifications. All streets being dedicated for public use shall be surfaced by the subdivider from curb to curb with minimum six-inch layer of Portland cement concrete (PCC) or equivalent of Hot-Mix Asphalt (HMA) in accordance with designs and specifications as stated in the Iowa Statewide Urban Design and Specifications Manual (SUDAS). The design street thickness shall be based upon the minimum PCC Pavement thickness recommended in the latest edition of the Iowa Statewide Urban Design and Specifications Manual or in the latest edition of the AASHTO Guide for Design of Pavement Structures street classification, zoning classification, and utilizing reinforced or non-reinforced design.
(2) Curb and Gutter Construction. Curb and gutter shall be installed on all streets in the plat being dedicated for public use and shall be constructed of Portland cement concrete in accordance with designs and specifications set forth in these regulations and at grades established by the regulations. A mountable or “lip” curb shall be used to eliminate the necessity of breaking out curb sections for installation of driveways. Curbs shall be ground down to accommodate ingress/egress approaches and not cut.
(3) Minimum pavement widths including curb and gutter shall be provided as follows:
a. Arterial streets, 45 feet.
b. Collector streets, 41 feet.
c. Residential streets, 31 feet.
d. Commercial streets, 31 feet.
e. Industrial streets, 27 feet.
f. Cul-de-sac turnarounds, 90 feet in diameter.
g. Alleys, 16 feet.
A. Grade. Grading shall be completed to the required grade on all streets for the full width of the right-of-way and fill shall be compacted sufficiently to assure adequate support for the specified paving. Grades for new streets shall align to the existing or connected streets. Street grades shall utilize the following maximum limits:
(1) Every street shall have a minimum one-half of one percent slope.
(2) Arterial streets, four percent.
(3) Collector streets, six percent.
(4) Residential/commercial/industrial streets, eight percent.
B. Street Geometrics.
(1) Arterial and collector streets in a subdivision shall extend through to the boundaries thereof.
(2) Street jogs with centerline offsets of less than 125 feet shall be avoided.
(3) Proposed streets shall be adjusted to the contour of the land where possible to provide usable lots and streets of reasonable gradient.
(4) In general, streets shall be of a width at least as great as that of the streets so continued or projected.
(5) Cul-de-sacs shall not exceed 500 feet in length and shall be limited to protect environmentally sensitive areas as described in Section 170.69 of this chapter.
(6) No dead-end streets and alleys will be permitted except at subdivision boundaries. A temporary cul-de-sac or T turn-around area shall be provided where the street terminates at the subdivision boundary when the street length is greater than 150 feet or one lot depth. The street surface shall be extended to the subdivision boundary and exclude the curb and gutter through the cul-de-sac or T turn-around area. The diameter of the street surface for the temporary cul-de-sac shall be 80 feet. The T turn-around shall be a section 14 and one half feet by 15 feet on each side of street. The surface of the turnaround should be the same as the surface of the street. A temporary easement shall be provided on the adjacent property for the temporary cul-de-sac or T-turn around area. The subdivider shall provide to the City a bond or suitable escrow in the amount of the accepted estimate to remove the temporary turn-around area surface, install curb and gutter on the street surface through the area, and install suitable fill material in the vacated area with seeded grass.
C. Intersection Design -
(1) Intersections of more than two streets at a point shall not be permitted.
(2) Intersection of street centerlines shall be between 80 degrees and 100 degrees.
(3) Off-center street intersections will not be allowed.
D. Additional Design Considerations. The arrangement, width, grade, and location of all streets in the proposed subdivision shall conform to the extension of arterial and collector streets as shown on the Comprehensive Plan and within good design parameters to the topographic conditions of the site.
(1) Future and Planned Streets -
a. Where the plat submitted covers only part of a larger tract of land owned by the same proprietor, a sketch of the prospective future street system for the adjacent land shall be furnished, and the overall street system arrangement evaluated during the plat consideration. Easements for the future rights-of-way openings and extensions for streets and utilities to the boundary of the land owned may be made a requirement of the initial plat approval.
b. When a tract is subdivided into larger than normal lots or parcels, such lots or parcels shall be so arranged as to permit the logical location and openings for the extension of the future streets and utility connections with the appropriate resubdivision of the tract. Easements for the future right of- way openings and extensions for streets and utilities may be made a requirement of the initial plat approval.
c. Under some circumstances the City may require, as a condition for approval of the Final Plat, dedication and improvement of a street having a width greater than that necessary to meet the needs of the platted area, but necessary to complete the City street system as it relates to both the area being platted and the adjacent areas. In such event, the City will pay the subdivider the difference in cost of improving the wider street and the street width reasonable to meet the foreseeable needs of the subdivision taken alone or through to the boundary of property owned by the same subdivider. The City may establish a pro rata distribution of the additional cost to be shared by the City and developers of adjacent areas to be served by the upgraded street.
d. Where a proposed subdivision borders an existing narrow street, partially improved street, or when City plans or zoning setback regulations indicate plans for realignment or widening a street that would require use of some of the area in the proposed subdivision, the subdivider shall be required to dedicate, at no cost to the City, the needed area and to share in the expense of the street improvement.
(2) Frontage Streets. Where a subdivision borders on or contains an existing or proposed arterial street, stream corridor, or utility or highway right-of-way, the City may require, for the protection of the residential properties and to afford separation from the barrier, limits to or specific requirements for the lot access and arrangement.
e. Lots shall be designed so as to back onto the primary arterial and front onto a parallel service street, no access shall be provided from the arterial street and screening shall be provided in a strip of land along the rear property line of such lots.
f. A frontage or service road, separated from the primary arterial by a planting or grass strip and having access thereto at suitable points.
g. Lots backing a stream barrier or highway right-of- way may require a street approximately parallel to and on each side of such barrier at a distance suitable for the appropriate use of the intervening land, such as for park purposes in residential districts.
(3) In commercial and industrial developments, the streets and other access ways shall be planned in connection with the grouping of buildings and the provisions of alleys, truck loading and maneuvering areas, and walks and parking areas so as to minimize the conflict of movement between the various types of traffic, including pedestrian.
A. Street Name and Name Signs.
(1) Street names shall be in accordance with the Official Street Name Map as provided in Chapter 139 of this Code of Ordinances. Streets that are in alignment with others already existing shall bear the name of the existing streets.
(2) Street name signs are to be placed at all intersections within or abutting the proposed subdivision. The type and location of said signs is to be approved by the Council and the City shall install all street name signs. The subdivider shall deposit with the City at the time of approval of the construction plans an amount equal to the estimated cost of the installation of all street name signs detailed on the plan.
B. Traffic Control Signs. All intersections within or abutting the proposed subdivision shall have traffic control signs as recommended by the City Engineer utilizing SUDAS regulations and approved by the City. The signs shall be installed by the City and the subdivider shall provide the installation cost as outlined for street name signs.
5. Sidewalks. Sidewalks shall be required along both sides of any street in all residential districts and in commercial and industrial districts unless a waiver is requested. Crosswalks shall utilize the same specifications as sidewalks. In specified areas, the City may require the installation of a sidewalk greater than five feet in width. In these cases, the City may pay for the difference in cost between the five feet width and the greater width sidewalk.
A. Five feet wide sidewalks shall be placed adjacent to each lot frontage or location in the street right-of-way or easement. One edge of the five feet wide or greater sidewalk shall be placed three inches outside the property line.
B. Sidewalks shall be a minimum width of five feet wide and a minimum thickness of four inches made of Portland concrete cement with greater thicknesses as noted in Section 136.08 of this Code of Ordinances. Optional six-feet wide sidewalks and above shall be a minimum thickness of five inches made of Portland concrete cement.
D. Required sidewalk widths along designated trail routes as identified in the Comprehensive Plan, Master Trails Plan, or other approved plans shall be a minimum of eight feet in width.
6. Street Lighting. Selected lighting fixture and pole options shall be in accordance with City standards and in concurrence with the available selections from and service agreement with the City’s electrical supplier, Alliant Energy. Street light wiring shall be placed underground for new residential subdivisions unless determined impractical or unfeasible by the electric utility. General arrangement for lights shall place units at street intersections and mid-way on normal length block. The City Engineer shall review the proposed street lighting plan for adequate illumination for traffic and pedestrian safety in accordance with accepted standards.
7. Electric and Utility Services. All private utilities, including but not limited to gas, electric power, telephone, wired internet, and cable shall be located underground within all residential zoning districts. All private utility equipment and installation shall be designed and installed to meet the standards set forth by the City, Alliant Energy, or the other service providers to the City. The Commission may recommend to the Council, after obtaining approval from the serving utility or agency, that underground requirements be waived if topographical, soil, or other conditions make such installation unreasonable. Transformers, switching boxes, pedestals, and other necessary utility equipment shall be placed within easements or public rights-of-way provided for such facilities. Overhead utilities with underground service lines may be permitted in commercial and industrial zoning districts.
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