Consider Storm Sewer Improvements on Sodium Street - A Continuation of Discussions Related to 2011 Flooding Concerns

Last summer the City experienced several significant rainfall events that lead to many localized flooding concerns, and resident complaints.  The large volumes of precipitation that occurred over a short period of time appears to have elevated the groundwater within areas of the City, and prohibited the generous rate of infiltration that typically takes place in the Anoka sandplain.  Throughout the summer and fall staff worked hard at registering and responding to the calls, and evaluating the situations on an individual basis to determine whether quick fixes could be implemented (culvert obstructions, re-ditching, etc.) to alleviate the immediate concerns.

This item was discussed at the Public Works Committee on August 15, 2011, and at that time staff summarized the areas of concern that were being investigated based upon citizen complaints received.  The attached summary was presented at the meeting; which outlines the concern identified, actions steps to evaluate the concern, additional investigations that would be necessary to fully understand the situation, and recommendations for specific projects that could be implemented rather quickly and inexpensively. At that time we classified the issues into 3 categories:

1. Those that required no further action.  They were evaluated and corrected, or did not need correcting because the water was fully contained within a dedicated drainage & utility easement (functioning as designed).
2. Those that required additional investigation and evaluation before deciding on a long term solution, and implementing corrective actions.
3. Those that had an identified recommendation for immediate action.

At that meeting the Committee briefly discussed the areas of concern, and directed staff to prepare plans and specifications for the items identified in category 3.  Once this direction was ratified by the City Council on September 13, 2011, and the plans completed, it was too late in the season to secure bids and complete the improvements in 2011.  It was then decided to delay construction until 2012, where some of the improvements could be completed by inclusion in the street maintenance program.  Staff is in the process of finalizing plans for these items and intends to solicit quotes for the improvements this spring/summer.  Depending on the direction staff receives for potential improvements to alleviate some of the outstanding concerns identified over the next couple of months, additional plans can be incorporated into one plan set for bidding.

The resident has been provided with a copy of the agenda and invited to attend the meeting.

Staff prepared a brief RFP in the fall of 2011, to investigate the areas of concern, and distributed it to members of the City's consultant pool in the fall of 2011.  The goal of this project was to have an independent third party evaluate the areas, provide options for corrective actions, and associated estimates to implement the work.  Hakanson Anderson was awarded the project to undertake these investigations, and they have since completed their analysis and compiled a report that references potential solutions for each area identified.  Attached to this case is the final report.

This item was introduced in general terms at the February Public Works Committee meeting, with the direction being that staff would come back before the committee over the next several months to discuss the merits of each potential improvement in more detail.  Staff received information this March 13 that Rum River Hills Golf Course submitted information to the League of Minnesota Cities regarding their claim, and that the League will be be issuing a response around March 16.

Tonight we would like to focus on a couple of the projects that are located in neighborhoods that are proposed to receive street maintenance activities this summer.  I would like to draw your attention to section 6 related to Sodium Street.

The house at 16756 Sodium Street (Lot 5, Block 2, Klemish Addition) experiened water in the basement during the heavy rain.  The existing ditch on the west side of Sodium has minimal grade and there is minimal grade between the house and the ditch. This may have allowed infiltration to raise the groundwater level in this area.

The report recommend installing a culvert under Sodium Street, regrading the west ditch of Sodium Street, constructing a berm to keep water in the ditch, and replacing the existing driveway culvert.  The ditch would be graded to drain south and a culvert would be installed along the south property line to drain the water to the west.  Klemish Addition was platted with 10 foot drainage and utility easements along the front, sides and back lot lines.  The estimated cost for these improvements is $12,225. 

Additional temporary and permanent easments may be required to complete the work.  These will need to be negotiated with the owner.

This neighborhood is included in the proposed 2012 seal coating program.  The pipe could be installed in advance of the seal coating.

In the fall of 2011, while staff was in the process of updating the City's Capital Improvement Program (CIP), we budgeted additional funds to stormwater improvement projects over the next two years in an effort to address some of these concerns.  The Capital Improvement Program (CIP) lists a $75,000 annual expenditure for the next 5 years to address city wide drainage enhancements.

Staff recommends installing a culvert under Sodium Street, regrading the west ditch of Sodium Street, constructing a berm to keep the water in the ditch, and replacing the existing driveway culvert.  The ditch would be graded to drain to the south and a culvert would be installed near the south property line to drain the water to the west.  The estimated cost of these improvements is $12,225.

Motion to recommend the City Council include the work at 16756 Sodium Street (Installing a culvert under Sodium Street, regrading the west ditch of Sodium Street, constructing a berm to keep the water in the ditch, and replacing the existing driveway culvert. The ditch would be graded to drain to the south and a culvert would be installed near the south property line to drain the water to the west.) in the proposed 2012 Sealcoating Program.