Agenda - Council - 08/25/2020 - Laserfiche WebLink

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CC Regular Session 5. 12. Meeting Date: 08/25/2020 By: Bruce Westby, Engineering/Public Works Information Title Adopt Resolution #20-177 Approving Plans and Authorizing Requests for Quotes for 9591 Inverness Lane Drainage Improvements, Improvement Project #20-08 Purpose/Background: Purpose: The purpose of this case is to adopt Resolution #20-177 approving plans and authorizing Requests for Quotes for 9591 Inverness Lane Drainage Improvements, Improvement Project #20-08. Background: In December of 2015, the property owner at 9591 Inverness Lane first contacted Staff to inform us of some drainage concerns regarding the operation of the drainage ditch east of Jarvis Street on both sides of Inverness Lane, which had just been improved that summer as part of the Jarvis Street Reconstruction project. After numerous conversations with Elk River Staff, who led this street reconstruction project, and with Staff from Bolton & Menk, who designed the project, prepared plans and specifications, and inspected construction, some grading modifications were made as part of the project punch list work. Then on June 12, 2016, the property owner at 9591 Inverness Lane reached out again to let us know the ditch appeared to be flowing well and that his concerns had been addressed. In early 2019, the property owner contacted Staff again to report that the swale traversing their back yard, which conveys stormwater runoff from several properties upstream, was full of water and was roughly 10 feet from the back of their house and encroaching under the rear edge of their deck. The property owner said it had never been this full of water before. That spring, Staff began working on plans to improve drainage in the ditch east of Jarvis Street, including collecting survey shots and investigating options for improving drainage in the ditch east of Jarvis Street to prevent water from backing up into the back yard of this property. During late winter and early spring, snow and ice in the ditch prevents runoff from flowing properly, causing stormwater runoff to back up into the swale in the back yard of 9591 Inverness Lane. Staff confirmed the ditch to the south of Inverness does not have proper slope for drainage. Staff originally looked at re -grading the ditch east of Jarvis Street to the existing pond one lot south of Inverness Lane. Due to existing private utilities, poles, impacts to existing mature trees, and to avoid steep ditch side slopes, Staff determined piping the runoff through this stretch to be the more feasible approach. This project proposes to remove the existing bituminous flumes and culvert under Inverness Lane and replace them with storm sewer pipe and catch basins. Storm sewer pipe will then be extended in City right-of-way east of Jarvis Street to the south edge of the property south of Inverness Lane, where it will tie into the existing ditch that routes runoff to an existing stormwater pond. Fill will be placed over the storm sewer pipe, and a shallow swale will be graded above the pipe to route runoff from the street and adjacent properties to the existing ditch and stormwater pond. Attached is a plan sheet showing the proposed improvements, which was reviewed with the property owner. This drainage improvement project is proposed to be completed this fall to avoid another winter season during which the culvert under Inverness Lane could freeze up again on one or more occasions, requiring Public Works crews to open it up to prevent runoff from backing up into the rear yard of 9591 Inverness Lane.