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.  
 
Estimated construction costs for this project total $59,000 and are based on final plans as prepared by City Staff.  Construction staking is proposed to be provided by a consultant at an estimated cost not to exceed $5,000.  A proposal for construction staking will be presented to the City Council at the time Staff requests approval of a construction contract to the contractor submitting the lowest quote, which is anticipated to occur on September 22nd.  All project costs are proposed to be split evenly between the Stormwater Management and Stormwater Utility Funds.  
 
Upon Council approval, Staff proposes to solicit quotes from several local grading contractors with a quote submittal deadline of 10 a.m. on Thursday, September 10th. On September 15th the Public Works Committee can then review quotes and provide a recommendation to the City Council for award of a construction contract on September 22nd. Based on the current bid environment Staff anticipates receiving good quotes.  
 
This project is anticipated to take 5 to 10 days to complete, with substantial completion specified for October 23, 2020.  Final payment will be issued in 2021 after turf is established and all work is approved. 

All project costs are proposed to be split evenly between the Stormwater Management and Stormwater Utility Funds.

Staff recommends adopting Resolution #20-177 approving plans and authorizing Requests for Quotes for 9591 Inverness Lane Drainage Improvements, Improvement Project #20-08.
 
On August 18, 2020, the Public Works Committee discussed this project and ultimately recommended City Council authorization to solicit Requests for Quotes for 9591 Inverness Lane Drainage Improvements, Improvement Project #20-08.  However, the Public Works Committee asked if Staff had explored the option of extending a culvert under Jarvis Street to discharge the stormwater into the ditch west of Jarvis Street, which is located in the City of Elk River.  The City Engineer indicated he would discuss this with the design engineer and would report back prior to requesting Council approval of a construction contract, which is currently anticipated to occur on September 22nd. Below is a summary of Staff’s findings related to this design option.
 
Per the record drawings for the 2015 Jarvis Street Reconstruction project, the invert of the culvert on the south side of Inverness Lane is 885.80. Commercial Lots exist on the west side of Jarvis Street, which currently have 12-inch concrete driveway culverts. The culverts on the west side of Jarvis Street are approximately 0.7-feet or 8-inches higher than the culverts east of Jarvis Street, meaning the ditch and culverts west of Jarvis Street would all need to be lowered at least 1-foot.
 
This option would require extending an 18-inch concrete culvert approximately 50-feet to the west side of Jarvis Street. This could either be accomplished by directional drilling or open trenching.  Directional drilling is much more costly, but considering the required pavement removal and replacement costs it would likely be the more cost-effective method.  Approximately 100-feet of the ditch west of Jarvis Street would then need to be re-graded to lower it, or 100-feet of storm sewer could be installed. Then, 144-feet of 12-inch concrete culvert would need to be removed and replaced with 18-inch concrete culvert to accommodate the additional drainage from east of Jarvis Street.  Four (4) commercial driveway aprons would also need to be removed and replaced.  Also, several ponds exist west of the commercial lots which accept all drainage from the west side of Jarvis Street.  These ponds would need to be analyzed to determine if they have enough capacity to accommodate the additional drainage from east of Jarvis Street.  If the ponds don’t have enough capacity, they would need to be re-graded, along with the swale between Jarvis Street and the ponds.
 
Based on the work summarized above, this option does not appear to be more cost-effective than the design currently proposed in the attached plans.  In addition, the required design analysis would likely prevent this project from being completed this year. For these reasons, Staff does not recommend pursuing this option.  

Adopt Resolution #20-177 approving plans and authorizing Requests for Quotes for 9591 Inverness Lane Drainage Improvements, Improvement Project #20-08.