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05-22-17 CC WS MinutesCITY OF SHOREWOOD CITY COUNCIL WORK SESSION MONDAY, MAY 22, 2017 MINUTES 1. CONVENE CITY COUNCIL WORK SESSION 5755 COUNTRY CLUB ROAD COUNCIL CHAMBERS 6:00 P.M. Mayor Zerby called the meeting to order at 6:01 P.M. A. Roll Call Present. Mayor Zerby; Councilmembers Johnson, Labadie, Siakel, and Sundberg; Administrator Lerud; Director of Public Works Brown; and, Engineer Hornby Absent: None B. Review Agenda Labadie moved, Johnson seconded, approving the agenda as presented. Motion passed 510. 2. STORMWATER DRAINAGE / FREEMAN PARK Engineer Hornby explained that after the heavy rain events in June 2014 the City heard from residents about drainage concerns. The then Council directed staff to review drainage issues in the Freeman Park area, the area downstream from there along Grant Lorenz Road where there has been a significant amount of erosion and Strawberry Lane. Strawberry Lane was added to meet the Capital Improvement Program (CIP) funding schedule for the Strawberry Lane reconstruction and trail. He stated that based on this discussion he would like to incorporate some of the alternative drainage improvements into the City's Comprehensive (Camp) Plan. Many of the improvements would be longer term. He highlighted the report which focused on five areas. Shorewood Oaks Development — Some basements were flooded during the June 2014 100, year event. The flooding was due to most homes having a private draintile connection to a lateral sewer connecting to the City's storm sewer system. That was done to provide a gravity means for drainage of the foundation in addition to a sump pump. It was a method to do a local ground water dewatering because the water table was so high when the development was put in. During the event the pond was at capacity. The storm sewer was over capacity and surcharged the foundation drain line. That resulted in basement flooding. The simplest and most cost competitive improvement would be to use a trenchless construction method and line the pipe with a PVC liner. That would block the drainage system. The City would have to notify property owners that they have to make sure their sump pump's discharge point is far enough away from the house so it is outside of the excavation area. There could be some recycling of water with this improvement. Another improvement would be to install backflow preventers at the source. The preventer would block any drainage surcharge from going into the house. This improvement would require digging up each yard. Another option would be to disconnect private draintile from the City's system. CITY OF SHOREWOOD WORK SESSION MEETING MINUTES May 22, 2017 Page 2 of 6 Director Brown explained that in the 1990s the League of Minnesota Cities (LMC) recommended cities no longer allow a direct connect to a sewer system. There had to be a break of some sort so that when the ultimate outlet was over capacity the water would squirt out of the ground or there would be some other relief in place so the water did not go into someone else's basement. Councilmember Labadie stated it was her understanding that is what happened along Tuxedo Road. The sump pumps pumped the water out, but the ground was so saturated it seeped back into homes. Labadie then stated the PVC liner in the pipe would make the capacity of the pipe smaller. She asked why that would be of benefit. Director Brown clarified a private property owner's system would be blocked. It would force a property owner to disconnect from the system. Councilmember Siakel stated the liner in the pipe would make foundation drain inoperable. Labadie asked what a backflow preventer is. Engineer Hornby explained it is a valve that is put in line. If water tries to flow back in there is a ball that is pushed to block the flow back into the house. If there is any grit in the line those could be problematic because it could leak. Engineer Hornby explained when evaluating solutions he tried to look at those where no one single home would get more water than others. For example, if the draintile lines in the street were plugged at the downstream manhole where they connect the house closest to that plug would get all of the water. The way to do it would be to line the pipe or disconnect each individual foundation drain. Then every owner's sump pump would have to keep up with what is coming in through the foundation. Councilmember Johnson stated in 2014 a number of residents in that area had sump pumps that ran every two minutes. If the draintile system is removed he asked if sump pumps could keep up with that. Engineer Hornby explained he thought during that event the pumps were running that often because the water was backing up. One resident told staff that his sump pump hardly runs unless there is a significant rain event. Johnson stated there is one resident in Ashland Woods who has a sump pump that runs every three minutes. Director Brown clarified the hydraulic characteristics would not be changed around the house. What would be changed is where the water outlets. A sump pump would not run any more frequently or less frequently unless it was being back fed. Councilmember Siakel asked where the City's responsibility begins and ends with the Shorewood Oaks Development. Director Brown explained the City has a responsibility to manage surface water. It is the property owner's responsibility to manage their house envelope which includes the sump pump drainage. The 1966 topography drawings show that the Shorewood Oaks site was full of cattails and swamp grass; it was a wetland that got developed. The hydraulic characteristics were not great to begin with. The City chose to take on that added responsibility of putting in the system. That allowed the development to happen. The City took on additional liability by doing that. He does not think that would happen today for a new development. The LMC would not allow that. He then explained the City's Ordinance stipulates that water from a sump pump cannot be discharged directly to a public right -of -way (ROW); there has to be some distance. Ultimately, most of that drainage will flow to the roadway and public ROW. Councilmember Sundberg stated when the development was done she asked if the system was designed to handle the water. Director Brown explained when it was installed it was probably sized properly. It is connected to the main stormwater system. That main system has been taxed with handling more runoff over time. That development is pressurizing and backing up the other systems. CITY OF SHOREWOOD WORK SESSION MEETING MINUTES May 22, 2017 Page 3 of 6 Sundberg then stated if property owners are asked to disconnect their foundation drain and rely on their sump pump to pump the water outside the hydraulics in the area would not be conducive to that. Brown reiterated the City would not be changing anything going on around the envelope; that would remain constant. It would be a matter of where the water would end up. Councilmember Siakel stated the parking lot in Freeman Park was regraded and some improvements were made to mitigate some of the drainage issues. Based on what staff has presented the drainage issue is bigger than just Shorewood Oaks. She stated she thought the City needs to have a plan for dealing with the water once it is pumped out of a house and flows off a property on to public roadways. Director Brown stated Shorewood has an ad hoc storm water system; it has been piecemealed together to make it work. From his perspective he thought it was time for Shorewood to focus on a trunk system throughout many areas in the City. That need was reinforced the previous very rainy weekend. Engineer Hornby resumed his presentation of the report. Strawberry Lane — The terrain is very flat and is prone to standing water. There is a need for the water to be able to flow somewhere. Strawberry Lane is a tributary to the channel along Grant Lorenz Road. Five alternatives were evaluated for providing a piped outlet. Each alternative would require either the expansion of the existing pond or the creation of a new pond to provide rate control. The five alternatives are: 1. Route the runoff to an area that already holds stormwater which is located south of the Lake Minnetonka LRT Trail. It would require another stormwater retention pond south of Smithtown Road. For a variety of reasons including cost staff deemed this alternative not feasible. 2. This would take Strawberry Lane runoff up to Smithtown Road into a pond and then back out to drain up to Grant Lorenz Road. It would require reconstructing part of Smithtown Road where the City just installed storm sewer and a sidewalk. It would be somewhat costly. Staff has discounted this alternative. This would involve having Strawberry Lane runoff crossing Church Road crossing Cathcart Drive down Beverly Drive and discharge into an existing wetland. This would use some of the concepts used in a plan that was in place in 1975. This alternative would solve some existing problems. It would divert water away from an area with an existing drainage issue. There are some areas the City does not have enough easement in to construct in to get the storm sewer through. Also, it would require very deep construction (15 — 20 feet for 1500 feet) to adequately drain Strawberry Lane. That would be cost prohibitive. Therefore, staff does not deem this to be feasible. 4. This would take part of Strawberry Lane runoff down to just north of the LRT Trail and cross over to an existing pond in a subdivision. The pond does not have an outlet; one would have to be provided so it would discharge into an existing wetland. This would go down Afton Road. It would be very costly to do. 5. Staff thought the best alternative would be to direct the Strawberry Lane storm sewer to a to -be- constructed Smithtown Retention Pond via a drainage corridor through the Pebble Brook addition. The northern two - thirds of Strawberry Lane could be drained into there. Alexander Lane CITY OF SHOREWOOD WORK SESSION MEETING MINUTES May 22, 2017 Page 4 of 6 could also be drained into that pipe. The Shorewood Oaks area could take the runoff from a small portion of Strawberry Lane. The cost for this would be very competitive. This alternative requires a little more investigation. Channel along Grant Lorenz Road (along the west side of the road) — There are water level and erosion issues causing driveway and culvert damage. In some spots the channel is 10 or more feet in depth. The intent would be to restore the channel and get some vegetation growing in there again. Some of the tree canopy would have to be reduced to allow sun light to get to the vegetation. The to- be- constructed Smithtown Retention Pond would help slow the storm water flow down. For two to ten year storm events the channel could still be used. For high flows there would still be a stormwater pond. For heavy rain events the pond would have an outlet. A bypass pipe would be put in that would go down Grant Lorenz Road at the north end. After going through a long complex system with wetlands in between the water eventually flows into Lake Minnetonka. Strawberry Gardens Pond is a small isolated pond. It is very flat and wet in that area. There would be value in installing a pipe as an outlet for the Pond. It would probably provide some drainage relief for the back yards of some of the properties in that area. The approximate cost for a bypass with retention, including a pond, along Grant Lorenz Road was about $900,000. Road reconstruction was estimated to cost $2.275 million. Upstream diversion at Strawberry Gardens would cost about $600,000. That would involve pushing the water to the west of the wetland. For the little benefit that would be gained that cost is too high. Alexander Lane Pond — When there is high water in Freeman Park the Pond cannot drain. There is a need for an outlet such as running a pipe over to Strawberry Lane and having the water flow through that system. The estimated cost would be $43,000 including a 25% contingency. Church Road Ponding — There is a persistent problem of water ponding in the road just before the cul- de -sac. There is an area where the water drains off of the street with just a spillway. The spillway has been subject to getting clogged with vegetation. It does not take long for the vegetation to grow back up. It requires a lot of maintenance to keep it clear. There is a ditch that takes the water to the Lake Minnetonka LRT Regina] Trail to the south to existing culverts where it crosses. A short section of pipe could be installed to help get the water to the culverts. The estimated cost would be $29,000 including a 25% contingency. Hornby stated the next step is to modify the Comp Plan to include: alternative 5 for Strawberry Lane (estimated cost $242,000); adding a pond just south of Smithtown Road; and installing a bypass pipe (estimated to be a 60 -inch storm pipe) at Grant Lorenz Road. Council will have to decide if Grant Lorenz Road should be reconstructed or just restored after adding the pipe; restoration would cost about one -half of the cost of reconstruction. Mayor Zerby noted that in 2008 WSB prepared a Surface Water Management Plan for the City. It includes a lot of information. WSB took a similar high level approach for that Plan. He asked Engineer Hornby if that plan would be updated and then be incorporated into the Comp Plan. Engineer Hornby stated there will be some engineering services required that would be in addition to the consultant services for the more extensive updates to the Comp Plan. The City is going to have to update its 2008 Surface Water Management Plan with new rules and that would go through a Minnehaha Creek Watershed District review. CITY OF SHOREWOOD WORK SESSION MEETING MINUTES May 22, 2017 Page 5 of 6 Zerby asked if the City did any of the projects identified in the 2008 Plan. Hornby clarified a number of lower level drainage issues were addressed. Engineer Hornby noted the Surface Water Management Plan has to be updated every 10 years. Councilmember Johnson asked if stormwater improvements to Strawberry Lane and Alexander Lane are dependent on Strawberry Lane being reconstructed. Engineer Hornby confirmed that and noted that Strawberry Lane has been shifted around in the CIP. That is currently scheduled for reconstruction in 2018 but that is unlikely to happen because initial project work has not yet been done. Director Brown stated he thought it prudent for staff to review the utility fee for storm water and recommend an increase to ensure funding for the improvements Councilmember Siakel asked if the storm water management projects would be included in the 5 -year CIP. Engineer Hornby stated he thought it would take longer than that to do them. Engineer Hornby stated staff has been discussing that if properties become available that could be used for ponding the City should consider purchasing them. Or at a minimum, contact the property owners to find out if they are willing to sell them or at least give the City the first right of refusal. Councilmember Johnson stated it is his understanding that water should flow along both sides of the LRT Trail. There is a great deal of debris there. Has there been any discussion with the Hennepin County Regional Rail Authority (HCRRA) about cleaning that debris out. Engineer Hornby noted staff has spoken with HCRRA representatives about that. Director Brown noted the HCRRA and the Three Rivers Park District (TRPD) like the vegetation in that corridor. To adequately clean out that corridor would require removing many of the trees in the bottom ditch area to keep the water flowing. The HCRRA and the TRPD are not very supportive of doing that. Engineer Hornby stated that applies to trees that are lying down. The root balls for trees that are standing have grown out of the ground because it is so wet and that blocks drainage. Councilmember Siakel asked if doing the lower cost improvements near Alexander Lane and Church Road sooner would help alleviate the issues for some of the property owners. Engineer Hornby stated there is a low point in Church Road just before the cul -de -sac. The Alexander Lane improvement is dependent on Strawberry Lane or taking other action such as building a pipe to the LRT Trail on its own or constructing a channel that would cut across Freeman Park. Councilmember Sundberg asked if changing weather patterns are factored into the plans. For example, 100 -year rainfalls are happening every few years. Engineer Hornby explained that recently the hydrograph curves for the nation have been updated. The runoff curves used when designing ponds and storm sewer systems have been changed. Storm sewer is designed more conservatively. For storm ponds and overland flow Atlas 14 curves are used. Director Brown stated a storm water system is built to handle the larger storms. No matter what the capacity is will be an event that is so quick and so powerful that the capacity will be exceeded. The goal is to balance the costs against the impacts. Over the past weekend he spent a lot of time with property owners who were very upset that water was flowing where it usually does not flow. He dealt with one property owner where water was lapping at their front door; that was a problem. Mayor Zerby stated he thought what was presented and discussed was a good start. CITY OF SHOREWOOD WORK SESSION MEETING MINUTES May 22, 2017 Page 6 of 6 Councilmember Labadie stated she thought it was a great presentation. Councilmember Johnson asked if there is a way to notify property owners about these types of meetings. Mayor Zerby stated the City could hold an open house once there is more information available. Councilmember Siakel stated there needs to be more detail available before doing that. Engineer Hornby stated that public process would be done for the Comp Plan updates. For smaller individual issues like Shorewood Oaks property owners in that area would be contacted and invited to a neighborhood meeting. Mayor Zerby announced that the Council was going to move to the large conference room to conduct interviews of applicants for the Park Commission. Administrator Lerud encouraged Council to reach consensus about a candidate before it comes out of the meeting. The selected candidate would be appointed during Council's June 12 meeting. 3. PARK COMMISSION INTERVIEWS Council interviewed Nathanial Gorham, 6065 Galpin Lake Road, and Holly Ashmore, 6060 Riviera Lane, for consideration of appointment to the Park Commission for a three -year term. 4. ADJOURN Sundberg moved, Johnson seconded, Adjourning the City Council Work Session of May 22, 2017, at 7:05 P.M. Motion passed 5/0.