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HomeMy WebLinkAbout7C - Maple Hills Homes Ass. Sanitary Sewer STAFF AGENDA REPORT AGENDA #: PREPARED BY: DATE: 7C GREG ILKKA, DIRECTOR OF PUBLIC WORKS/CITY ENGINEER MAPLE HILLS HOMES ASSOCIATION PROPOSED SANITARY SEWER AND WA TERMAIN PROJECT APRIL 21, 1997 SUBJECT: INTRODUCTION: The purpose of this Agenda item is to address issues surrounding a project for sanitary sewer and watermain being proposed for the Maple Hills Homes Association. Staff and the project proposer have been unsuccessful in resolving these issues and the project proposer has requested this issue be raised for Council consideration. BACKGROUND: The Maple Hills Homes Association is comprised of homeowners in the heavily wooded 9 lot Maple Hill plat located to the east of Pike Lake Trail and south of Holy Cross Lutheran Church along CSAH 42. The area was platted in 1973 before the existing requirements for infrastructure were established. The homeowner's association approached the City Council on August 5, 1996, to request permission to install privately financed sanitary sewer to serve the homes and lots in the plat. The Council directed that both sanitary sewer and watermain be installed at the same time. The homeowner's association has now had plans and specifications prepared for both sewer and water for the project. DISCUSSION: The plans for the proposed project do not comply with City standards. The sewer and water are proposed to be laid in the same trench at a horizontal separation of two (2) to three (3) feet. The City standard for this separation is ten (10) feet. The ten foot standard is in accordance with the "City Engineers Association of Minnesota" Standard Specification for Utilities. The proposers have designed their project with a lesser separation in order to allegedly save 30-50 trees during the construction of the project, though they have not provided any topographic information to support this number. The designer for the project proposer refers to the Minnesota Department of Health (MDH) specifications which provide "when local conditions prevent a horizontal separation of 10 feet, a 162(1eflfkgrltreek Ave. S.E., Prior Lake, Minnesota 55372-1714 / Ph. (612) 447-4230 / Fax (612) 447-4245 AN EQUAL OPPORTUNITY EMPLOYER watermain may be laid closer to a storm or sanitary sewer provided that: a. the bottom of the watermain is at least 18 inches above the top of the sewer; or b. where this vertical separation cannot be obtained, the sewer shall be constructed of materials and with joints that are equivalent to watermain standards of construction and shall be pressure tested to assure water tightness prior to backfilling." The project proposer has indicated a willingness to construct to the MDH specifications. The City specifications do not address this deviation because it is primarily aimed at situations where rock is encountered, which is not a concern in Prior Lake. In addition to the separation issue, there is an issue concerning the accessibility of fire apparatus. Currently, due to the narrow road width, short turning radii, and trees so close to the road, the fire department most likely could not get their trucks into the area in the event of fire. The Uniform Fire Code requires fire access roads to have a minimum unobstructed width of twenty (20) feet. This does not exist now, and it is not clear if this would exist upon the completion of the proposed project. The roads are private, yet the plat dedicated a fifty (50) foot public utility easement along the centerlines of the existing traveled ways. When asked why a fifty foot easement, the project proposer indicates they were planning for the future. Staff does not propose dedicating the streets to the public and meeting City standards for width, we only ask that the project comply with the Uniform Fire Code. It is staffs position that the additional trees lost in providing the ten (10) foot utility separation will be insignificant compared to the number of trees lost in complying with the Uniform Fire Code. I expect that Mr. Jim Boerhave representing the Homeowner's Association will be present to address the Council on this subject. ISSUES: Public Works staff sees a number of issues related to the proposed utility separation on the project: -+Public Health and Safety. The close proximity of the sewer and water increases the probability that a watermain break could cause undermining and rupture of the sewer thus leading to contamination of the entire water system. In addition, the inability of the fire department to access the area in the event of a fire is of great concern. MAPUflLL.DOC -+Maintenance. Although the MDH has a specification that allows for a lesser separation, the MDH does not have to maintain the system. The equipment we currently use for utility repair is not specialized enough to easily contend with two pipes as near as 2 feet together. Pipes in this close proximity makes working on either one very difficult. It is staffs desire to develop a system that is maintainable for the long haul, utilities will generally last 30-50 years. Further, trees so close to the roadway make it extremely difficult to maneuver with equipment. Any dig to repair a utility essentially closes the road to homeowners as well as emergency services. -+Past Practice. There has been no project previously constructed that has deviated from the ten foot horizontal separation. The project proposer's have indicated their area is unique because of the trees, but with the many utility projects that went in the 1970's there were plenty of areas that lost trees due to the separation requirement. The unique part of this area is the public utility easement with private road. Where previous projects aligned with a street project there would not have been a width problem because the City standard for street width was sufficient to provide for the ten (10) foot separation of utilities. -+Precedence. Staff is particularly concerned about the precedent a deviation from the standard would set. There are still many undeveloped areas within the City that may some day want utility service. This is not to mention any annexations that may occur in the near or distant future. Staff believes it is appropriate in this instance to conform with City design standards and it is staffs desire to develop a system for the long term out to 50 years. Staff appreciates the homeowner's desire to maintain the character of the environment and minimize the loss of trees. Trenchless technology exists that would allow them to construct the system to our standards with little tree loss. However, these methods are expensive. From the staff perspective, the trench less approach is a "win-win" allowing trees to be protected while maintaining the 10 foot horizontal separation. ALTERNATIVES: The alternatives are: 1. Support staff recommendation to construct utilities in accordance with City standards. MAPLHlLL.DOC RECOMMENDATION: ACTION REQUIRED: MAPLHlLL.DOC 2. Overturn staff recommendation to construct utilities in accordance with City standards and provide staff with direction. 3. Deny this item for a specific reason and provide staff with direction. 4. Table this item until some date in the future. Alternative No. 1 A mlion a~d second Ie: recommended anemative. it \ I REVIEV I.