Discuss Investigations 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.

On August 23, 2011 the City Council accepted a petition, from residents in the neighborhood near 149th Lane NW and TH 47, requesting that the City review the drainage problems associated with the wetland complex in that location.  The area is largely comprised of the RAMSEY MEADOWS subdivision (5 separate subdivisions), which was built around a large wetland complex and included significant easements encompassing the 100 year flood elevation.  The petition was initiated by the resident at 5410 149th Lane NW because they had a considerable amount of standing water in their backyard.  Staff conducted a site visit and reviewed plat documents for the property in question, and determined that the backyard of all the homes along the east side of 149th Lane had rather large platted drainage and utility easement at the rear of their properties that corresponded to the 100 year flood elevation of the surrounding water body.

At that time staff also reviewed the wetland outfall and downstream receiving bodies (pipes, ponds, culverts, and ditches) to determine whether there was an obstruction that could be holding back the water.  While no obstructions were found it was discovered that the outlet pipe from the wetland, that was installed as part of the TH 47 reconstruction project, may have been installed at an incorrect elevation.  Staff immediately modified that structure, and was able to provide some relief of surface water levels.  It was also determined that the property owner had constructed some improvements in their backyard (retaining wall construction and/or grading revisions) that may have reduced some of the storage capacity in the area and compounded the flooding situation on their parcel.  Council direction from that meeting was to analyze the sub-watershed for this area in an effort to determine whether improvements could be made that would correct the concern identified and provide additional relief from long term flooding.

Staff prepared a brief RFP, 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 recently completed their analysis and compiled a report that references potential solutions for each area identified.  Attached to this case is their final report; the summaries and recommendations section in the beginning gives a brief overview of their findings and will be used as the basis of our conversation.  Also 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.  Staff is seeking input from the Council on prioritizing potential stormwater improvements for the areas that have been identified, and developing a program for implementation. The final report prepared by Hakanson Anderson presents multiple options for each specific area, which could be further refined based upon Council direction received.

As a result of some of the localized flooding that occurred Rum River Hills Golf Course filed a claim with the City seeking reimbursement for damages and loss of revenue.  The claim was forwarded to the League of Minnesota Cities (LMCIT) for processing.  Attached is the claim as submitted by Rum River Hills, and the LMCIT response and settlement offer.

For informational purposes, I have also attached a precipitation summary of the entire state that shows the amount of rain received in the 4 month period from April 1, 2011 through August 1, 2011.  This exhibit shows that the City of Ramsey received almost twice as much rainfall over this 4 month period, as compared to the statewide average since these records began being collected.  It also shows that we were one of the top three areas for amount of precipitation received during this 4 month period.

The Capital Improvement Program (CIP) lists a $75,000 annual expenditure for the next 5 years to address city wide drainage enhancements. Other projects have previously been identified for corrective action, and those will be evaluated with some of the items on the attached summary list for prioritization and potential improvements; these will be brought back at a future date for Council consideration.

Staff recommends receiving input from the Public Works Committee to assist in prioritizing and developing a program that would address the flooding concerns identified and associated with the unprecedented 2011 spring/summer rainfall.

There may also need to be some discussion related to the Rum River Hills insurance claim settlement proposed by the LMCIT.  The correspondence was forwarded to the property owner approximately one month ago, and to date there has been no response.  We have invited representatives from the golf course to tonight's meeting.