Agenda - Council - 07/26/2016 - Laserfiche WebLink

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no. Our Mission: To work"ettrer to resposibty grow our community,and to provide quality,cost-effective.and efficient government services. CC Regular Session 7.3. Meeting Date: 07/26/2016 By: Bruce Westby,Engineering/Public Works Information Title: Adopt Resolution 916-07-135 Approving Plans and Specifications and Authorizing Bids for Improvement Project 916-95,Zeolite Street Storm Sewer Extension Purpose/Background: Purpose: The purpose of this case is to consider adopting Resolution 916-07-135 approving plans and specifications and authorizing advertisements for bids for Improvement Project 916-95,Zeolite Street Storm Sewer Extension. Background: In 2006,during development of Ramsey Town Center 8th Addition, a portion of the trunk storm sewer system along the west side of Zeolite Street from 147th Lane to the south side of Bunker Lake Boulevard was installed. This trunk storm sewer system was designed to convey storm water drainage from Ramsey Town Center 8th, 9th, and I Oth Additions,as well as additional areas to the north,to"Lake Ramsey",cast of Zeolite Street and south of Bunker Lake Boulevard. The last few hundred feet of this trunk line under Bunker Lake Boulevard and into Lake Ramsey was proposed to be constructed with 73"Arch Reinforced Concrete Pipe (A-RCP) storm sewer. Attached is a plan sheet from RTC 8th Addition showing a portion of the proposed 73"A-RCP storm sewer alignment and profile north of Bunker Lake Boulevard. However,this plan sheet does not show the entire portion of trunk storm sewer that was constructed in 2006 extending to the south side of Bunker Lake Boulevard. The City never received as-built record plans for RTC 8th Addition so this is the only plan sheet available. While the 73"A-RCP storm sewer was being constructed, questions arose as to whether the remaining unconstructed portion of the 73"A-RCP trunk storm sewer outlet to Lake Ramsey should be down-sized to save on construction costs. While options were being considered,the end of the storm sewer pipe was simply covered with a sheet of plywood and the pipe and plywood were backfilled. The housing market then collapsed meaning the outlet was not immediately needed so the pipe covered with the plywood sheet was simply left buried without an outlet. The plywood sheet eventually rotted and failed in 2012. At that time,the rotted plywood was replaced with another sheet of plywood as the storm sewer was anticipated to be extended later that year,which then never occurred. The 73"A-RCP storm sewer line incorporates an outlet pipe from the undeveloped triangular parcel in the northwest corner of the intersection of Bunker Lake Boulevard and Zeolite Street,more commonly known as COR Three North Commons. After the 73"A-RCP storm sewer line fills with a little over a foot of stormwater runoff,the excess stormwater flows back out of the COR Three North Commons outlet pipe where it is then stored in a low area until it infiltrates into the ground. The 73"A-RCP storm sewer pipe therefore typically has a foot or more of standing water in it,meaning the sheet of plywood blocking the end is continually wet which makes it even more prone to rotting.