(A) Approval. No preliminary or final plat of a subdivision shall be approved by either the Planning and Zoning Commission or by the Council unless it conforms with the minimum standards and requirements contained in this chapter.
(B) Acre subdivision. Whenever the area is divided into lots containing one or more acres and there are indications that such lots will eventually be resubdivided into small building lots, consideration must be given to the street and lot arrangement of the original subdivision so that additional minor streets can be opened which will permit a logical arrangement of smaller lots.
(C) Relation to adjoining street system. The arrangement of streets in new subdivisions shall make provisions for the continuation of the principal existing streets in adjoining additions (or their proper projections where adjoining property is not subdivided) insofar as they may be necessary for public requirements. The width of such streets in new subdivisions shall not be less than the minimum street width established in this code. The street and alley arrangement must also be such as to not cause hardship to owners of adjoining property when they plat their land and seek to provide for convenient access. Whenever there exists a dedicated half-street or alley adjacent to the tract to be subdivided, the other half of the street or alley shall be dedicated.
(D) Street width.
(1) The widths for a major street shall not be less than 66 feet.
(2) The minimum width for a minor street shall be 60 feet.
(E) Alleys. The minimum width of an alley in a residential block shall be 16 feet. (Alleys are not recommended for residential districts except under unusual condition.)
(F) Easements. Public utility easements not less than ten feet in width shall be provided along and adjacent to each street or alley included in the plat and all such utilities will be placed in these easements whenever practical. Such additional easements as may be necessary and appropriate shall also be included in a plat.
(G) Length in blocks. No block shall be longer than 900 feet between street lines, except when special conditions make a longer block more desirable.
(H) Width of blocks. The width of blocks shall not be more than 300 feet, except that when such requirements would entail unusual and substantial difficulties or hardships or when it is desired to provide a development containing large residential lots, the Planning and Zoning Commission and the Council may modify such requirements and allow the subdivider to plat blocks of other widths.
(I) Terminal streets. Terminal residential streets or cul-de-sacs may be established where necessary to afford access to all lots. No terminal street may be platted longer than 500 feet and all such terminal streets shall terminate in a circular open space having a minimum diameter of 100 feet.
(J) Lot lines. All side lines of lots shall be at right angles to straight street lines, or radial to curved street lines, unless a variation of this rule will give a better street and lot plan. Lots with double frontage shall be avoided.
(K) Size and shape of lots. The minimum dimensions for rectangular lots shall be 66 feet in width, the minimum dimensions for a cul-de-sac or curved lots shall be 60 feet in width at the building line, and in no case shall a lot that is to be used for residential purposes contain less than is required by the lot area regulation of the zoning district in which the property is located. A portion of each platted lot not less than 66 feet in dimension shall abut a public street or public way.
(L) Corner lots.
(1) All corner lots shall have extra widths sufficient to permit the maintenance of building lines on both the front and side streets as required by the applicable zoning provisions.
(2) Lots on major street intersections and at all other points likely to be dangerous shall have a radius of not less than 15 feet at the street corner; on business lots a chord may be substituted for the circular arc.
(M) Easements along streams. Whenever any stream or important surface water course is located in an area that is being subdivided, the subdivider shall make adequate provision for straightening or widening the channel so that it will properly carry surface water and shall provide and dedicate to the city an easement along each side of the stream, which easement shall be for the purpose of widening, improving or protecting the stream. The width of such easement shall not be less than ten feet from each bank of the stream, and the total width of the easement shall be adequate to provide any necessary channel relocations and straightenings.
(N) Improvements. It is the determination of the City Council, in furtherance of the health, safety and general welfare of the citizens of the city, that all new subdivisions shall have the benefit, where feasible, of the following improvements: integral monolithic paved concrete street and curb, sanitary and storm sewers, water mains and fire hydrants, electric service and street lighting, and access to parks and green areas. Therefore, no final plat of any subdivision shall be finally approved until one or more of the following alternative methods of ensuring the construction of required improvements has been accomplished:
(1) Construction of said improvements in accordance with city specifications prior to approval of the final plat;
(2) In regard to integral monolithic paved concrete street and curb, sanitary and storm sewers, and water mains and fire hydrants, the developer may meet the requirements for final plat approval by posting with the city a surety bond or cash in a supervised escrow account conditioned upon construction of all required improvements by a date approved by the Council and stated in said surety bond or escrow agreement. The amount of the surety bond or escrow deposit shall not be less than 110% of the estimated cost of the uncompleted improvements. If the improvements are not completed within the specified time, the city may require performance by the surety or use the funds deposited in escrow, or any necessary portion thereof, to complete construction of the improvements. The Council shall have the authority and discretion to establish different dates for the construction of each of the improvements;
(3) (a) Subject to the approval of the Council, in its discretion, the city and the developer may enter into a development agreement which may provide for the construction and installation of integral monolithic paved concrete street and curb, sanitary and storm sewers, and water mains and fire hydrants in the development by the city and which may provide for the collection of utility fees, connection fees or the imposition of special assessments to recover or offset all or part of the cost of the improvements constructed or installed by the city.
(b) In evaluating any such proposed development agreement, the City Council shall consider the following factors:
1. The benefit to the city of the proposed development;
2. The apparent need or demand for the development proposed;
3. The cost and feasibility of extending sanitary sewer, storm sewer and water mains to serve the development;
4. The likelihood that the city will recover its costs or receive benefit from utility charges, connection fees, special assessments or increased property tax revenue as the result of the development;
5. The quality and extent of security provided to the city that the costs to be incurred by the city will be recovered or that commensurate benefits will be received; and
6. Any other relevant factors.
(4) In regard to electrical service and street lighting, the developer may provide to the city the certification of the provider of electrical service to the subdivision establishing that appropriate arrangements have been made between the developer and the provider of electrical service such that the provider of electrical service to the subdivision guarantees and warrants that necessary electrical services and street lighting will be constructed in the subdivision by a date stated in the certification and approved by the Council;
(5) The regulations and standards for the improvements required herein shall be as follows.
(a) Grading and improvements of streets. Integral monolithic paved concrete street and curb constructed in any subdivision shall conform to the city’s specifications throughout the subdivision.
(b) Sewers. A lateral connection to the sanitary sewer main shall be extended to each lot line. Storm sewer inlets shall be designed and located as needed to serve the subdivision. Installations of sanitary and storm sewers shall be in accordance with the standards and specifications of the city. The certification of a licensed engineer that sewer improvements have been completed pursuant to city specifications shall be filed with the city upon completion of the improvements.
(c) Water mains and fire hydrants. The development shall cause water mains, fire hydrants and appurtenances to be installed. A lateral connection to the water main shall be extended to each lot line. Such installments shall be in accordance with the standards and specifications of the Water Department. The location of all fire hydrants shall be approved by the Water Department. The certification of a licensed engineer that water mains, service lines and hydrants have been completed pursuant to utilities’ specifications shall be filed with the city upon completion of the improvements.
(d) Electrical service and street lighting. The developer shall install electrical service to each lot in the subdivision and shall provide for street lighting. Such electrical service and street lighting shall be designed, constructed and installed pursuant to the standards and regulations established by the Board of Trustees of the municipal utilities, or if electrical service is to be provided by an entity other than municipal utilities, according to the standards and regulations imposed by the Public Works Director.
(e) Inspection during installation. Periodic inspection during the installation and construction of improvements shall be made by the Public Works Director, or his or her duly authorized agent, in order to assure conformity with the approved plans and specifications. The developer shall notify the proper administrative officer when each phase of the installation is completed and ready for inspection.
(6) (a) As convenient access to parks and recreational areas and the preservation of green space is a significant benefit to owners and occupants of residential properties, each proprietor of a plat located in the A or B Residential Zoning District of the city shall consider including parks, recreational areas and green space in a proposed plat for the benefit of owners and occupants of property in the subdivision.
(b) Such areas may be established and maintained by the proprietor, by an organization or association of property owners in the subdivision or may, upon approval of the Park Board, be dedicated to and accepted by the city.
(7) The construction of new sidewalks, in accordance with city specifications, is required when a lot in a residential subdivision platted after July 16, 2012, is improved, unless this requirement is waived by specific action of the City Council. Sidewalk construction shall be a requirement of a building permit and shall be accomplished within the building permit.
(O) Trails. The proprietor of a subdivision plat shall consult the current master plan maintained by the city for the development of trails in the city. If the master plan indicates the planned development of trails in the area to be platted, the plat shall include a ten-foot expansion of major street right-of-way to accommodate the future placement of a trail. The proprietor of a plat shall include, in the application for plat approval, a statement confirming that the city’s master trail plans have been considered and that the plat includes additional right-of-way for trails, if required, consistent with the master plan.
(P) Stormwater management.
(1) Definitions. For the purpose of this division (P), the following definitions shall apply unless the context clearly indicates or requires a different meaning.
EROSION. The detachment, transportation and deposition of soil particles by water or wind. Sheet erosion, rill erosion, gully erosion, lake bank and stream bank erosion and streambed erosion are common types of EROSION that create sediment laden runoff, which moves sediment to a point of deposition down gradient from its point of origin.
IMPERVIOUS SURFACES. Surfaces through which water cannot penetrate. IMPERVIOUS SURFACES are mainly constructed surfaces, rooftops, sidewalks, patios, roads and parking lots covered by impenetrable materials such as asphalt, concrete, brick and stone. These materials seal surfaces, repel water and prevent precipitation and meltwater from infiltrating soils. Soils compacted by urban development are also highly impervious.
LAND DISTURBING ACTIVITY. Any earth movements that alter the surface of the land that may result in soil erosion from wind and water and the movement of sediment and sediment related pollutants off site, including, but not limited to, grading, topsoil removal, road or bank cutting, waterway construction or enlargement, excavation, filling or stripping of vegetation, or creation of a new subdivision. The following activities are excluded from this definition:
1. Excavation, filling or a combination thereof involving less than three cubic yards and tilling, vegetation and/or tree cover removal from an area less than 1,000 square feet;
2. Tilling, planting or harvesting of agricultural, horticultural or forest crops;
3. Minor activities, such as residential gardening, landscaping, repairs and maintenance work;
4. Installation of public utility lines and connections, fence posts, signposts, telephone poles, electric poles and other kinds of posts or poles;
5. Installing septic tanks and drainage fields, unless these are to serve a building whose construction is a land disturbing activity;
6. Emergency work to protect life or property; and
7. Construction, relocation, alteration or maintenance of public improvements by a public body.
LOW IMPACT DEVELOPMENT (LID). Stormwater control strategies that combine resource conservation and a hydrologically functional site design with pollution prevention measures to reduce development impacts to better replicate natural watershed hydrology and water quality. Using several strategies, LID controls runoff discharge, volume, frequency and quality to mimic pre-development runoff conditions. Stormwater best management practice (BMP) techniques and/or structures, as defined in the Iowa Stormwater Management Manual, shall be incorporated to remove 80% of the total suspended solids (TSS). These development practices shall address water quality volume of 1.25 inches of rainfall in a 24-hour period. Examples of low impact development techniques include:
1. Better site design;
2. Bioretention cells;
3. Bioswales; and
4. Rain gardens.
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES). Section 402 of the U.S. Clean Water Act, being 330 U.S.C. § 1342, contains the National Pollutant Discharge Elimination System (NPDES) regulations. The key aspect of this section is that any land disturbing activity that impacts one acre or more is required to obtain an NPDES permit from DNR. The application process requires that the applicant certify that an adequate stormwater pollution prevention plan (SWPPP) has been developed for the site.
PERMEABLE PAVEMENT. A breathable pavement surface that allows water to flow freely through it, filtering water as it flows and draining into an underlying bedding of additional filters.
PERVIOUS SURFACES. A ground cover through which water can penetrate at a rate comparable to that of water through undisturbed soils. Examples include turf systems and pervious pavers.
1. Concrete pavers/Uni Eco-Stone. Interlocking concrete paving blocks separated by holes (pores) that are filled with gravel. This grid paving system is designed for commercial and residential vehicle load applications. Drainage openings in the paving surface allow stormwater to infiltrate.
2. Concrete (open cell) pavers/Turfgrid. The Turfgrid paving system offers an open cell concrete structure with 40% open area designed to be planted with turf. The system protects turf roots and soil from compaction due to foot and vehicle traffic.
3. Recycled plastic pavers/Grasspave. Grasspave is similar to the Turfgrid system (above) which provides for turf planting, but is manufactured with 100% recycled plastic. This paving system offers load bearing strength while protecting vegetation root systems from compaction. Open cells enable root development and storage capacity for rainfall from storm events.
SEDIMENT. Detached particles of soil that move via an erosion process.
SILT SCREEN. A fencing screen material manufactured for the purpose of capturing and retaining soil, silt and sediment from water and gravity runoff from a land slope. SILT SCREEN supported by posts to form a continuous soil, silt or sediment barrier is called a silt screen fence.
SILTATION. The deposition of sediment moving via the erosion process. Deposition is usually considered to occur off site from where the erosion that is generating the sediment is occurring.
(2) Stormwater management. For all new subdivisions which include property within zoning districts, CBD, C-1, C-2, D, E or MH, a stormwater management plan compliant with this division (P)(2) shall be required, implemented and followed. The following guidelines apply:
(a) The stormwater management plan shall include, but not be limited to, the following: proposed final grading conditions with explanation of how adjacent areas will be impacted by grading and compaction, current natural drainage and how it will be impacted after completion, vegetative map with existing vegetation before and after construction and stormwater management system to be used during and after construction;
(b) The plan shall provide for management of water quality for construction activities and for post-construction conditions;
(c) The plan shall minimize the impact of stormwater on adjacent and downstream properties;
(d) The plan shall be developed to comply with the Iowa Stormwater Management Manual and shall use a design rainfall event of 1.25 inches in 24 hours for computing water quality volume (WQv);
(e) Low impact development is encouraged, and should be incorporated into the plan unless the site is not suitable in supporting low impact development practices;
(f) It is recommended that 30% of the original open space of the property be designed to manage stormwater;
(g) The use of impervious surfaces should be mitigated with low impact development designs to assist in stormwater management on the property. The use of pervious surfaces should be emphasized. The use of pervious surfaces for parking to enhance low impact development stormwater management is encouraged. For impervious parking areas, as a rule of thumb, an area equal to 10% of the parking area is recommended, to incorporate rain gardens, bioretention cells or grass swale conveyances;
(h) This stormwater management plan shall be designed by a licensed engineer; and
(i) For lots exceeding three acres, the post-development runoff rate resulting from 1.25 inches of rain in a 24-hour period shall not exceed 125% of the pre-development runoff rate; for lots not exceeding three acres, the post-development runoff rate for rainfall not exceeding 1.25 inches of rain in a 24-hour period shall not exceed 200% of the pre-development runoff rate.
(3) Consultant. The city may contract with a qualified consulting engineer to review, comment and advise the city as to any stormwater management plan that has been submitted for review. All costs associated with such a consultant shall be borne by the developer.
(Prior Code, § 9-13-4) (Ord. 97, passed 6-19-1961; Ord. 103, passed 7-16-1962; Ord. 206, passed 8-1-1977; Ord. 211, passed 11-7-1977; Ord. 218, passed 7-3-1978; Ord. 219, passed 8-21-1978; Ord. 226, passed 7-2-1979; Ord. 361, passed 7-5-1988; Ord. 427, passed 9-8-1992; Ord. 471, passed 8-5-1996; Ord. 546, passed 3-19-2001; Ord. 572, passed 7-1-2002; Ord. 616, passed 12-6-2004; Ord. 734, passed 11-21-2011; Ord. 866, passed 6-7-2021)