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1d TH 101 North Watermain Proj. 07-07: Authorize Preparation of Plans & Specs CITY OF CHANHASSEN 7700 Market Boulevard PO Box 147 Chanhassen, MN 55317 Administration Phone 952.2271100 Fax: 952.227.1110 Building Inspections Phone 952.227.1180 Fax: 952.2271190 Engineering Phone: 952.227.1160 Fax: 952.2271170 Finance Phone 952.227.1140 Fax 952.2271110 Park & Recreation Phone: 952.2271120 Fax 952.227.1110 Recreation Center 2310 Coulter Boulevard Phone: 952.227.1400 Fax: 952.227.1404 Planning & Natural Resources Phone: 952.227.1130 Fax: 952.227.1110 Public Works 1591 Park Road Phone: 952.2271300 Fax: 952.2271310 Senior Center Phone 952.227.1125 Fax: 952.227.1110 Web Site www.ci.chanhassen.mn.us -1d- - MEMORANDUM TO: Paul Oehme, City Engineer/Dir. Of Public Works Joseph Shamla, Project Enginee~ ~ . January 22, 2007 FROM: DATE: SUBJ: TH 101 Watermain Improvements Project No. 07-07: Authorize Preparation of Plans & Specifications REQUESTED ACTION Authorize preparation of plans and specifications for the TH 101 watermain. BACKGROUND The City is having problems with a stretch of 12" trunk watermain along TH 101 between Choctaw Circle and Fox Hollow Drive. Numerous breaks have occurred in this section of pipe in the last few years. The breaks that have occurred are chunks of pipe that are breaking away. These types of breaks are attributed to the "hot" or corrosive soils in this area. In inspecting the pipe after breaks, the pipe is showing additional areas of corrosion that could lead to additional breaks. The watermain is close to the TH 101 roadway, therefore, the southbound lane of TH 101 is closed to get equipment mobilized and to do the work when watermain breaks occur. If a major break were to occur, it is possible that TH 101 could be washed out. The east water treatment plant coming online in the spring is estimated to increase the water pressure in this area about 10 psi. This amount of increased pressure could cause other failures of this pipe. Based on preliminary soils investigations, it is estimated that approximately 1,100 LF of watermain is in the corrosive soils area and should be replaced. Staff proposes to address the problem by replacing the existing watermain with a 12" high density polyethylene (HDPE) watermain. The existing pipe is proposed to be abandoned in place. The new HDPE watermain is proposed to be constructed under the walking trail and farther away from TH 101. The advantage of using HDPE pipe is that it is flexible and will not deteriorate in corrosive soils. Also, the pipe can be directionally drilled which results in less restoration work then open cutting the pipe and will allow the work to be completed sooner. The trail will need to be potholed where the new pipe connects to the old pipe. The trail patches will be temporarily patched after the work is complete and permanently patched in the spring by the Street department. HDPE pipe is used extensively on watermain applications and has been used successfully The City of Chanhassen . A growing community with clean lakes, quality schools, a charming downtown, thriving businesses, winding trails, and beautiful parks. A great place to live, work, and play Paul Oehme January 22, 2007 Page 2 on several recent city projects. Staff will notify the property owners in the area when the construction will start and the estimated duration of the trail closure. The Engineering department is proposing to prepare the plans and specifications and bid the project out. Also, staff will be responsible for the construction administration of the contract. Surveying and soils investigation work will be completed by others. The project is proposed to be bid in February and have construction start in late February or early March. This project will need to be completed while the frost is still in the ground so that it is not invasive to the trail and wetland areas. If the project is delayed to the point that the frost is no longer present in the ground, the project may have to be delayed until December 2007. Funding for this project has been budgeted in the 2007 CIP, Project W-033. The current project estimate for the work is $120,000. RECOMMENDA TION Staff is recommending Council authorize preparation of plans and specifications for the TH 101 watermain improvements. Attachments c: Kelley Janes, Chanhassen Utility Superintendent G:IENGIPUBLICI07.07 Hwy. 101 Dir. BorelAuthorize P&S 012207.doc Capital Improvement Program City of Chanhassen, MN 2007 thru 2011 Contact Unassigned Department Water System Improvements Type Improvement Useful Life Unassigned Category Utilities Priority nla Project # W-033 Project Name TH 101 Trunk Watermain Replacement Account # 1 700-0000-4751 Account # 3 Account #2 Total Project Cost $200,000 Description . A segment of 12" watermain along 1H 101 from Brule Circle to Gray Fox Curve has had several watermain breaks over the past years. Inspection of the watermain indicates this watermain has deteriorated significantly due to the hot soils in the area, is in very poor condition and should be replaced. Justification To reduce emergency calls and disruption of water service to residents. Expenditures Construction 2007 200,000 200,000 2008 2010 Total 200,000 200,000 2011 2009 Total Funding Sources Water Utility Fund 2007 200,000 Total 200,000 2008 2009 2011 Total 200,000 200,000 2010 I~~~ 121 Project Area January, 2007 G:\ENG\Public\07 -07\Maps\Extent of project.mxd Hwy 101 Watermain Improvement Project Area City Project #07-07 January, 2007 G:\ENG\Public\07-07\Maps\Extent of Project.mxd