Provide City Council Recommendation for Gibbon Street and 173rd Avenue Drainage Improvements Feasibility Report

Purpose:
The purpose of this case is to provide a recommendation to the City Council for accepting the Gibbon Street and 173rd Avenue Drainage Improvements Feasibility Report (draft copy attached), and for moving forward with a project.

Background:
Over the years, City Staff has received numerous reports of flooding and wet basements from owners of properties located in various low-lying, land-locked areas of the City. The year 2014 was particularly wet resulting in numerous reports of flooding and wet basements. This included the property owners at 17421 Gibbon Street NW who contacted the City in the spring of 2014 with high water concerns. They stated that water was coming up through their basement floor from the adjacent wetlands. Staff visited the site in 2014 and observed that the surrounding wetlands were full and the water level was near the road two lots to the north. The flow direction was not readily apparent, though there may have been a slight east to west flow indicating that water may flow to the north when water levels are high enough. Staff did not observe any water flowing over Gibbon Street, or that standing water was threatening to flood any homes. This area is land-locked meaning no overland drainage routes exist that are lower than the lowest openings of the homes in the area.

On March 31, 2015, several property owners addressed the Public Works Committee to inquire if the City could do anything to help them with their drainage issues. Based on direction from the Public Works Committee, with subsequent ratification by the City Council, City Staff was directed to analyze the drainage areas for three areas that reported the most significant flooding issues in 2014. Brief background information on these three areas is included below. The areas are listed in order of priority based on the significance of the reported damage. Though several other property owners contacted the City about standing water on their properties during the 2014 spring snow melt, the three areas discussed herein continued to experience high water levels long after the snow melt was finished. Property owners from the other areas never contacted the City again which indicated that their issues were not as significant.

Gibbon Street north of 173rd Avenue
This area is in the Deerwood Plat which was platted in 1974. The area to the west was platted in 1991 as Wildwood Acres. Drainage and utility easements were recorded over some wetlands in the plat and over County Ditch 27 which runs across the north side of the plat and through wetlands that were not encumbered with drainage and utility easements. There are also drainage and utility easements along the lot lines from the ROW to the wetlands. This area is relatively flat with minimum elevation change. The residents at 17421 Gibbon Street NW reported high water levels around their home and water coming into the basement. The home is a split level style with a 4 foot basement. The nearest wetland and easement recorded on the plat are on the north side of the next lot to the north and extend onto the 2nd lot to the north. The address of the parcel with the majority of the wetland is 17511 Gibbon Street. There is a drainage and utility easement on the west side of Gibbon Street that connects to the easements on the Wildwood Acres plat. West of the Wildwood acres plat is an un-platted parcel. A County Ditch runs through this parcel. A drainage and utility easement exists west of Gibbon Street across from the wetland at 17511 Gibbon Street. This easement also connects with the easements on Wildwood Acres.

162nd Lane West of Ramsey Boulevard
This area is un-platted and does not have drainage and utility easements. The residents at 6855 162nd Lane NW contacted the City about the high water elevation in the adjacent wetland. There are a series of wetlands in the back yards north of this parcel. All of the surrounding area is up to 20 feet higher than the wetlands.

156th Lane East of TH 47/Saint Francis Boulevard
This area is platted and has some drainage and utility easements. The residents at 5220 156th Lane NW contacted the City about the level of the pond in their back yard. The ponding area did not have an outlet when the plat was recorded in 1973. A pipe was installed under TH 47 in 2003 to provide a stormwater outlet from a new subdivision. A pipe was also installed along 155th Lane and along lot lines from the wetland east of TH 47 to this pond. An outlet for this pond was installed with the Highlands at River Park Project in 2003. This pipe outlet is lower than the pipe installed with the Reilley Estates plat in 1978. The pond at 5220 156th Lane NW does drain; however, the water level has to be higher than the invert of the pipe downstream. The previous owners of the property came before the City Council in 2011 concerned about the proximity of the standing water to their septic system drain field. The City paid to have the drain field relocated outside of the drainage easement. The water was contained within the drainage and utility easement in 2014.

On March 31st the Public Works Committee determined it would be cost-prohibitive to address all drainage concerns throughout the City. It was therefore confirmed that the Gibbon Street area was experiencing the most significant issues and that Staff should research drainage solutions for this area first, and that the results of the research should be brought back to the Public Works Committee for further consideration. Attached are minutes from the March 31, 2015 Public Works Committee meeting for reference.

On June 16, 2015, Staff presented four possible options for alleviating localized flooding issues in the Gibbon Street area to the Public Works Committee. A figure showing the location, alignment and profile view of each of the four options is attached. Minutes from this meeting are also attached. The four options are as follows:

Option #1: This option requires installing a pipe in an existing drainage and utility easement. The initial plan was to install approximately 800 feet of pipe by jacking to avoid large trees within the easement and cutting a deep trench through Iguana Street. This was determined to be infeasible after further investigation for the following reasons. The jacking pit would need to be placed in one wetland and the receiving pit and pipe fusing area would need to be in the second area. Both areas are over 400 feet from the nearest road. Access would require acquisition of additional easements. The fused pipe may tend to sink into the wetland prior to being pulled back. The City did a project in 2012 where the boring machine was placed on upland in an existing easement extending to the street. The welding of the pipe was done on planking extended from an existing road. The jacked length was approximately 800 feet. The total project cost was $160,000. The Gibbon street project would require additional easements and restoration of all disturbed lawn surfaces.

Option #2: This option requires cleaning the existing County Ditch that runs north of this development. This option is not feasible because it would require lowering the existing surface area of some wetlands up to 2 feet which is not permitted under the Wetland Conservation Act.

Option #3: This option considered the suggestion of the property owners at 17421 Gibbon Street NW for using a different set of drainage and utility easements to provide drainage to the west. Evaluations of this route indicated that there are two high areas that would need to have pipe installed and that there is minimal elevation difference between the beginning and ending points. This route is not feasible.

Option #4: This option considered extending storm sewer pipe south in the Gibbon Street right-of-way, then west along the 173rd Avenue right-of-way to provide positive drainage from the area to County Ditch 66. This appears to be feasible. The location and elevation of existing small utilities along the route would need to be determined during final design to better define the scope of this process. The normal water level of the existing wetland east of Gibbon Street would also need to be explored in detail during final design. This option was estimated to cost between $275,000 and $300,000, which does not include the acquisition of easements which would be determined during final design.

Following discussion of these options, the Public Works Committee recommended that the City Council consider ordering a feasibility study to further refine option #4 for the Gibbon Street and 173rd Avenue drainage improvements, including an analysis and determination of specific costs, how costs could be paid for, and whether any City policies would need to be created or amended in doing so. On October 27, 2015, City Council directed staff to prepare a Feasibility Report based on option #4. A draft copy of this report is attached to this case.

Approximately 25 minutes for presentation and discussion.

Observations:
Available options for effectively draining low-lying, land-locked areas include installing gravity storm sewer to drain the water to another area at a lower elevation, installing storm sewer lift stations to pump the water to a higher elevation where it can then flow to lower elevations via gravity sewers or ditches, pumping the water using a portable pump and flexible hosing to another location where it can then flow to lower elevations via gravity sewers or ditches, or by promoting infiltration by constructing infiltration basins, ponds or trenches. Unfortunately, it is typically not an option to use a portable pump and hose to pump water elsewhere in Ramsey due to the relatively flat terrain and extensive distance between grade breaks. The other options typically require installing thousands of feet of sewer and purchasing numerous, and often large, easement areas, and/or installing lift stations, all of which can cost hundreds of thousands of dollars (or more) per area.

As part of preparing the Feasibility Report, Staff researched whether any grant opportunities existed that might be of help to these residents by assisting with enhancements for private sump pump/drain tile systems, or with new basement waterproofing improvements. Numerous property owners who contacted staff in years past regarding their wet basements did not have back-up sump pumps in the event their primary pump failed, which resulted in their home being flooded. Private systems can also be enhanced by adding battery back-up in the event their power fails for an extended duration.

Staff is not aware of any legal obligations requiring the City to financially assist private property owners experiencing wet basements due to the intrusion of ground water. If an improvement project were to be completed by the City it could set a precedent for the City to follow in other areas throughout the City in future years.

Alternatives:
Alternative #1 - Motion recommending that the City Council accept the Feasibility Report but deny approval of a drainage improvement project pending development of a cost-effective, equitable funding program.

Alternative #2 – Motion of other.

The estimated cost for the proposed option #4 improvements is $325,000. The Feasibility Report includes a list of potential funding sources including external grants, City Stormwater Funds, and/or special assessments to benefiting properties for all or a portion of the cost of the improvements, pursuant to Minnesota Statutes Chapter 429, the City Charter, and the City’s adopted Special Assessments Policy.

Staff recommends alternative #1.

Though City Project No. 16-88 is feasible and can be constructed in 2017, given the estimated cost of $325,000, and the small number of benefiting properties, the proposed improvements are not cost-effective and should only be constructed if benefiting properties are specially assessed for all or a significant portion of the improvements, and/or if external funding is available to fund all or a significant portion of the improvements.

Motion recommending that the City Council accept the Feasibility Report but deny approval of a drainage improvement project pending development of a cost-effective, equitable funding program.