A. Responsibility for Installation and Warranty. It is the intent of the City that all development within areas designated for urban development within the City of Mount Vernon's Comprehensive Plan shall be connected to public utilities. The subdivider shall be responsible for the installation and/or construction of all improvements required by this chapter, and shall warrant the design, material and workmanship of such improvements, installation and/or construction for a period of three (3) years from the date of acceptance by the City. Such warrant shall be by a maintenance bond, shall be subject to review by the City Attorney, shall specifically assure the expedient repair or replacement of defective improvements under warranty and shall indemnify the City from any and all costs or losses resulting from or contributed to such defective improvements.
B. Plan Review. All plans, specifications, installation and construction required by this chapter shall be subject to the review, approval and inspection by the City Engineer or other authorized City representative. The subdivider shall furnish the City Engineer with a construction schedule prior to commencement of any and/or all construction and shall notify the City Engineer not less than twenty- four (24) hours in advance of readiness for required inspections. The developer shall be responsible for construction staking, inspection and materials testing and the developer's engineer shall certify that all public improvements have been completed in conformance with the approved plans and specifications prior to the City Engineer's review and recommendation for acceptance.
C. Streets. All street improvements shall be designed in accordance with City Public Improvement Design Standards by an engineer.
D. Stormwater Management.
1. All subdivisions shall have a storm water management system that is adequate to prevent the undue or unplanned retention of storm water on the site. Undue retention does not include:
a. Retention through planned facilities.
b. Retention not substantially different from pre-existing conditions.
2. The design of the storm water management system shall be consistent with general and specific concerns and standards of the Comprehensive Plan and the drainage control programs of applicable public agencies. Design shall be based on environmentally sound site planning and engineering techniques as per SUDAS and ISWMM.
3. To the maximum degree possible, drainage from subdivisions shall conform to natural contours of land and not disturb pre-existing drainageways.
4. Adjacent properties shall not be unduly burdened with surface water from the subdivision. Specifically:
a. No action shall unreasonably collect and channel storm water onto lower properties.
b. The volume or rate of post development run off shall not exceed the amount of predevelopment runoff, and is to be managed in a manner consistent with Iowa statute and existing case law regarding such flows.
5. Design shall use the best available technology to minimize offsite' runoff, encourage natural filtration, simulate natural drainage, and minimize discharge of pollutants. Best available technology may include retention basins, swales, porous paving, and terracing.
6. No surface water may be channeled into a sanitary sewer system.
7. Where possible, a subdivision's drainage system shall coordinate with that of surrounding properties or streets.
8. All storm sewers, catch basins, culverts and drainage improvements shall be designed in accordance with City Public Improvement Design Standards, by a Professional Engineer.
E. Erosion Control.
1. The subdivider shall submit an erosion control plan, prepared and certified by a licensed Professional Engineer, for any land disturbing activity with the construction drawings prior to start of construction. All grading activities must be carried out consistent with this approved erosion control plan.
2. Certification by the Linn County Conservation District of the erosion control plan for land disturbing activities, as defined by Section 161A.64 of the Code of Iowa, shall be submitted as required.
F. Wastewater Management and Sanitary Sewers.
1. All sanitary sewer systems shall be designed, by an engineer, in accordance with Iowa Department of Natural Resources (IDNR) Public Improvement Design Standards.
2. All lots in proposed subdivisions shall be served with a public sanitary sewer main and gravity sewer service connections, unless the City approves a variance at the preliminary plat stage.
3. If the developer feels that connection to the existing City Sewer System presents geographic or geologic barriers which make such connection unfeasible and wishes to serve the lots with private sewage disposal systems, he or she shall present an Economic Feasibility Study, and an Environmental Impact Study prepared by a Professional Engineer, comparing the costs of constructing the public versus private system. This report shall be submitted with the preliminary plat and a request for variance from providing a public sewer connection.
4. In addition, if the developer proposes to serve the lots with a private sewer service system, he or she shall show the proposed system for each lot on the preliminary plat and submit percolation tests for each lot, taken at the proposed absorption field sites to determine the size of field required for each lot. The plat and percolation test results shall be submitted to the Linn County Health Department (LCHD) for review and approval, which shall be evidenced to the City by a letter from the LCHD, submitted to the City with the preliminary plat. The City shall consider all these submittals in reviewing a developer's proposal for private sewage disposal systems and to determine if public sewer service is feasible or private systems may be permitted.
5. The developer's engineer shall furnish the City with three (3) certified copies of as-built plans showing service line locations and final sewer and maintenance hole locations, lengths, elevations and grades.
6. If private sanitary sewer systems are permitted for each lot, they shall be allowed only with the following provisions:
a. All successive lot owners shall agree to connect to the City sewer system if it is installed to the corner of their lot. The lot owner shall be required to connect to the City sewer system within two years after construction of the City system.
b. When the lot owner is connected to the City sanitary sewer system, the existing private sanitary sewer system shall be abandoned in conformance with all local, County and State standards. Abandonment shall be completed within six (6) months following connection to the City sanitary sewer system.
G. Sidewalks. Sidewalks shall be installed in conformance with Chapter 136 of the Code of Ordinances. Sidewalks shall be installed by the builder prior to issuance of an occupancy permit. The Zoning Administrator may require the subdivider to install temporary sidewalks where uncompleted sidewalks represent a nuisance or safety concern. The subdivider may provide a temporary sidewalk consisting of crushed stone. The Subdivision Agreement shall define the sum of money to be escrowed into a special city fund equal to the cost associated with special assessment of said amount of sidewalk. This cost is typically 2.5 times the construction cost of the sidewalk. A conditional 30-day occupancy permit may be issued and may be extended dependent upon weather conditions. Such request for a conditional occupancy permit shall be coordinated by the zoning administrator in consultation with the Building Official.
H. Electric and Communication Utility Cables.
1. Primary Line - the main source of electricity or communication service. The primary line shall be underground depending on its location on the lot. Underground lines may be located at either the front or back lot lines within the area of perpetual easement.
2. Secondary Lines - branch lines from the primary line to the user. All secondary lines must be buried.
3. Street Lighting - When underground electrical service is provided, the subdivider shall install street lighting as follows:
a. Ornamental posts selected from options available through Alliant.
b. Black colored.
c. Height of street lighting shall be 20 feet.
d. Spacing of street lights shall be approximately 200 feet apart.
4. Communication Cables - The subdivider shall arrange for the installation of telephone, cable television or other communications cables.
I. Gas mains. Gas mains shall be installed underground and located to comply with City Public Improvement Design Standards.
J. Water Supply.
1. Water shall be supplied to all proposed subdivisions by connecting to the existing City water system unless the developer requests a variance from the City Council.
2. The proposed water distribution system for all subdivisions shall include water mains, fire hydrants and valves designed and constructed in conformance with City Public Improvement Design Standards. No variance from this will be allowed.
3. The developer shall provide a water service line to each lot, stubbed to the property line in conformance with City and State Design Standards and City Water Department procedures and practices.
4. If a variance is requested to provide a private and/or community well, the developer shall submit with the preliminary plat an Economic Feasibility Study Report, and an Environmental Impact Study prepared by an Engineer, which documents the cost of providing City water service to the subdivision versus a private and/or community well system for water supply.
5. If a private and/or community well is proposed by the developer and approved by the city during the preliminary plat review stage, it shall be designed and constructed in accordance with regulations of the Iowa Department of Natural Resources and the Linn County Board of Health who shall approve its construction prior to the issuance by the City of certificates of occupancy for any building in the subdivision.
6. If a private and/or community well system is permitted by the City, it shall be allowed only with the following provisions:
a. The private well system and all distribution lines, hydrants, valves and appurtenances shall remain the property of the developer and/or Homeowners Association.
b. The developer and all successive lot owners shall agree to connect to the City water system if it is installed to the subdivision. The lot owner shall be required to connect to the City sewer system within two years after construction of the City system.
c. When the subdivision is connected to the City water system, all existing lot owners shall be required to disconnect from and abandon their existing private and/or community well in conformance with all local and State standards, and shall share equally in the cost of same. Abandonment shall be completed within six (6) months following connection to the City water system.
d. When the subdivision is connected to the City water system, the City will accept dedication of the existing distribution system, provided it has been properly certified, maintained and as-built plans have been submitted to and approved by the City Engineer, pursuant to subsection 9 below.
7. The developer's engineer shall observe all water system construction and shall certify that the construction was done in accordance with the plans and specifications issued for the project.
8. The developer's engineer shall furnish the City three (3) certified as-built construction plans showing the final locations of all water mains, valves, hydrants and service taps, lines and curb stops.
9. Both the developer's engineer's certificate of completion and as-built construction plans for the water system shall be furnished to the City upon completion of public improvements and request for City acceptance, even when the water system will remain under private ownership. The certificate and as-built drawings will remain on file with the City for reference and use when the subdivision is connected to City water and the City considers accepting dedication of the water distribution system.