§ 170.10 Minimum Improvements

The improvements set forth below shall be considered the minimum improvements necessary to protect the public health, safety, and welfare.

1. All of the minimum improvements mandated by this section shall be designed and constructed in accordance with the requirements of this chapter and Chapters 165 and 166 and the minimum requirements of all applicable State or federal regulatory agencies or departments.

2. The subdivider must provide evidence of any and all construction permits, highway or road easements and access, or other appropriate documentation from State or federal regulatory agencies prior to approval of the final plat. Easements from all utility companies with approval by the Fire Chief will also be required.

3. It is required that in all new residential and commercial subdivisions all on-site utility lines including but not limited to, electric, communications, street lighting, and gas lines shall be installed underground except as hereinafter provided. For the purpose of this section, appurtenances and associated equipment such as, but not limited to, surface-mounted transformers, pedestal-mounted terminal boxes, and meter cabinets may be placed aboveground.

4. The City reserves the right to request changes to a proposed subdivision that may exceed the municipal capacities for streets, sewer, water, or other services. In the event the City requires a system which is greater than is needed to service the subdivision itself, the City shall pay on a prorata basis for the excess cost over that which is necessary to service the subdivision itself. Other subdivisions which connect with the systems shall on a prorata basis reimburse the City for the cost of the additional system, which shall service that subdivision and meet all City specifications. The systems shall extend to the subdivision boundaries as necessary to provide for future extension of the sewers by adjacent property.

A. Streets in General. The subdivider of land being subdivided shall provide the grading of the entire street right-of-way, alley, or public place and provide appropriate paving, including curb and gutter on all streets.

(1) Under some circumstances the City may require, as a condition for approval of the plat, dedication and improvement of a street having a width greater than 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 other areas. In such event, the City shall pay on a prorata basis for the excess cost over that which is necessary to service the subdivision itself. Other subdivisions which connect with the systems shall on a prorata basis reimburse the City for the cost of the additional system, which shall service that subdivision and meet all City specifications. The streets shall, upon final approval and acceptance by the City, become the property of the City. The street shall be constructed in compliance with Chapter 166.

B. Sanitary Sewer System in General. The subdivider of the land being platted shall make adequate provision for the disposal of sanitary sewage from the platted area with due regard being given to present or reasonably foreseeable needs. There shall be constructed, at the subdivider’s expense, a sanitary sewer system including all necessary pumping stations, pumping equipment, sewer access holes, and all other necessary or desirable appurtenances 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 sewer. The City’s role in reviewing the plans is to determine the sanitary sewer’s placement, size, and route. The sanitary sewer system shall be constructed in compliance with Chapter 95.

(1) Under some circumstances the City may require, as a condition for approval of the plat, installation of a sanitary sewer that is larger than necessary to meet the needs of the platted area, but necessary to complete the City sanitary sewer system as it relates to both the area being platted and other areas. In such event, the City shall pay on a prorata basis for the excess cost over that which is necessary to service the subdivision itself. Other subdivisions which connect with the systems shall on a prorata basis reimburse the City for the cost of the additional system, which shall service that subdivision and meet all City specifications.

(2) The City’s inability to efficiently collect or treat wastewater may be grounds for rejection of a proposed subdivision. A proportional fee may be requested by the City, from the subdivider, to pay for the necessary upgrades in the sewer system.

(3) The sewer system improvements shall, upon inspection, approval, and acceptance by the City, become the property of the City.

(4) The subdivider must provide evidence of construction permits from the Iowa Department of Natural Resources and other applicable State and federal agencies prior to approval of the final plat.

C. Stormwater System. The subdivider of land being platted shall install and construct a stormwater system adequate to serve the area, including anticipated extension of use to serve additional areas. The Stormwater system shall be constructed in compliance with Chapter 166.

(1) The stormwater drainage system shall be separated and independent of any sanitary sewer system. The acceptable standard for sizing storm sewers is to be a five-year, 24-hour storm event or as specified under current design standards.

(2) Under some circumstances the City may require, as a condition for approval of the plat, installation of a stormwater system that is larger than necessary to meet the needs of the platted area, but necessary to complete the City stormwater system as it relates to both the area being platted and other areas. In such event, the City shall pay on a prorata basis for the excess cost over that which is necessary to service the subdivision itself. Other subdivisions which connect with the systems shall on a prorata basis reimburse the City for the cost of the additional system, which shall service that subdivision and meet all City specifications.

(3) Stormwater facilities shall be located in the road right-of-way where feasible, or in the perpetual unobstructed easements of appropriate width.

(4) In the stormwater design phase, the subdivider shall study the effect of each subdivision on existing downstream drainage facilities outside the area of the subdivision. The subdivider’s drainage studies together with such other studies as shall be appropriate shall serve as a guide to needed improvements. Where it is anticipated that the additional runoff incident to the development of the subdivision will overload an existing downstream drainage facility, the Council may withhold approval of the subdivision until provision has been made for the recovery of the cost for the improvement of said potential condition in such sum as the Council shall determine. No subdivision shall be approved unless adequate drainage will be provided to an adequate drainage watercourse or facility.

(5) The subdivider must document that adequate stormwater detention is included in the storm sewer design. This may require work outside of the proposed subdivision’s boundaries which is the sole responsibility of the subdivider. The City may require this work to be undertaken to protect surrounding properties as a condition for approval of the subdivision.

(6) The stormwater system shall, upon inspection, approval, and acceptance by the City, become the property of the City. However, the City may not own any detention basin or other storage facility and may require written provisions for the maintenance of the facility.

D. Sewage Disposal. Connection to the public sanitary sewer system is required within the corporate limits “where feasible.” Private sewage disposal is allowed outside the City limits, but within the area of subdivision jurisdiction, as approved by the State Health Department.

(1) The Council with the advice of its appointed officers shall define “where feasible” regarding the requirement of connection to the public sanitary sewer system for residential subdivisions.

(2) In the event connecting to the public sanitary sewer system is determined “not feasible,” the Council may approve by a minimum of a three-quarters majority vote of the entire Council, a private sanitary sewage disposal system which may be subject to one or more of the following conditions: (a.) City approval of the private sewage disposal system. (b.) City approval of the type of private sewage disposal system. (c.) City approval and inspection of the proposed plans, specifications and construction of the private sewage disposal system. (d.) Compliance with Chapter 98, and rules and regulations of the Johnson County Board of Health and the State Health Department. (e.) Execution of a contract or agreement, that may run with the land, for payment by special assessment or other means for the total project cost of the extending of City lines and facilities necessary to supply public sanitary sewage treatment at a later date. (f.) Execution of a contract or agreement, that may run with the land, for termination and removal of the private sewage disposal system, in compliance with all ordinances and county and state requirements, and requiring connection to the public sanitary sewer system.

(3) The requirements, conditions and provisions contained in this section shall in no way circumvent or negate applicable County, State or Federal requirements.

E. Water Main System in General. The subdivider of land being platted shall install and construct a water main system to adequately serve all lots or parcels of land within the platted area, with regard to the present and reasonably foreseeable needs of the entire area, and shall connect the same to the City’s existing water mains.

(1) Design shall comply with Chapter 158.

(2) The City’s inability to generate, treat, or distribute water may be grounds for rejection of a proposed subdivision. A proportional fee may be requested by the City, from the subdivider, to pay for the necessary upgrades in the water system.

F. Other Improvements. The owner and subdivider of the land being platted shall be responsible for the installation of sidewalks within the street area erosion control measures, and street lighting. All such improvements shall be subject to approval by the City Engineer and the City. All improvements addressed in Chapter 158 shall be constructed in compliance with the provisions of that chapter.

G. Clustered Mailboxes.

(1) All new residential or commercial developments platted after the adoption of these subdivision regulations† that receive curbside delivery of mail shall have clustered mailboxes, unless an exception is approved by the United States Postal Service. The location of mailbox clusters shall be noted on the plat.

(2) Mailbox clusters serving residential developments shall be conveniently located for residents. To that end, mailbox clusters should be located within one block or approximately 600 feet walking distance, whichever is less, from any residential property served by said mailbox cluster. Adjustments to this distance criteria may be approved when there are not enough lots within one block or 600 feet to form a cluster. Mailboxes should be located in a manner that provides safe access for residents; e.g., does not require residents to cross heavily trafficked streets, etc. Driveways shall be allowed no closer than 12 feet from the location of a clustered mailbox as measured along the curb line of the fronting street. Mailboxes must be located in a manner that will not violate the City’s intersection visibility standards. Locations and design must be approved by the City and the United States Postal Service. Depending on the size and location of the clustered mailbox, the City may require a vehicular pull-over lane built to City specifications.

(3) Mailbox clusters shall be located on a concrete pad built to City specifications. To provide for pedestrian access, a five-foot-wide concrete sidewalk shall be provided from the mailbox cluster to the adjacent public street and sidewalk. An accessible route shall be provided according to ADA Standards for Accessible Design. The cost of installation including, but not limited to, box units, concrete pad, and sidewalk access shall be borne by the developer, and subsequent maintenance shall be carried out by the United States Postal Service.

H. Utilities.

(1) The subdivider shall provide installation of electric distribution lines, street gas mains, telephone lines, and other facilities in any new subdivision as are needed, before final approval shall be given to the final plat. The subdivider shall be responsible for making the necessary monetary arrangements to provide for such utilities as are needed and, in addition, shall provide for underground facilities in residential subdivisions and commercial subdivisions with each utility company. In providing for said utility transmission lines, the subdivider shall make sure that adequate connections are provided to each subdivision lot of utilities as needed.

(2) The subdivider shall also submit the proposed street lighting placements for Council approval. Upon receiving the submission, along with the final plat and construction plans, the Council shall cause the same to be reviewed by the City Engineer. The City Engineer shall determine the appropriate location for the street lights in the subdivision. In all new subdivisions, decorative street lights shall be selected by the subdivider, from an approved list provided by the City. All costs in connection with the furnishing of street lighting placements, the decorative polies, light fixtures, and related parts, in new subdivisions, shall be the responsibility of the subdivider.

(3) The subdivider shall provide all necessary easements in the subdivision for placement of all utilities including street lights, and will submit to the City at the time the final subdivider’s agreements is presented, all proposed easements for use in the subdivision.

(4) As a condition of the approval of the final plat by the City, the preliminary and final subdivision plat shall be presented to the designated representatives of the utility companies serving this subdivision area for the purpose of review and concurrence that sufficient easements have been obtained and shown on the final plat to accommodate placement of their particular utility service lines.

(5) All proposed utility line locations in public rights-of-way or municipal easement shall be reviewed by the City for the purpose of avoiding location, topographic, or other conflicts. In no case shall the permanent utility lines or appurtenances be constructed prior to authorization and approval of the final plat by the City.

I. Underground Public Utility Facilities.

(1) It is required that in all new residential and commercial subdivisions all on-site utility lines including, but not limited to, electric, communications, street lighting, and gas lines shall be installed underground except as hereinafter provided. For the purpose of this section, appurtenances and associated equipment such as, but not limited to, surface-mounted transformers, pedestal-mounted terminal boxes, and meter cabinets may be place aboveground.

(2) Underground facilities need not be installed in the following instances:

a. Any increase of service size including single-phase to three-phase conversion;

b. For any new service when utility poles exist along abutting property lines which are not separated by an alley or public right-of-way and no additional utility poles are required.

c. Installation of new or replacement feeder lines or transmission lines located within the City’s subdivision jurisdiction.