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STAFF REPORT <br />TO:Mayor Keis and Members of City Council <br />FROM:Bill Dircks, Public Works Director <br />DATE:August 23, 2019 <br />RE:Twin Lake Update <br />Current Operations: <br />The six-inch pump was set up the last week in July and began pumping on July 31. The pump has <br />remained on all day and night during the week and has only been shut off on the weekends. The <br />lake level was 872.78 on July 29 and it began dropping at a pretty good rate. It was 872.08 on <br />August 9 and the sanitary sewer manhole cover was out of the water. The level only needed to drop <br />a few inches more and the manhole could have been raised. <br />Unfortunately, more than five inches of rain fell between August 13 and August 20. The large <br />amount of rain was too much for the pump and the water level was back up to 872.42 on August <br />19th. It didn’t increase dramatically but it was enough to submerge the manhole by approximately <br />two inches of water once again. <br />The good news is that West Vadnais Lake/wetland has not risen back up to the overflow stage so <br />there is no extra water getting to Twin Lake that shouldn’t be. The only water getting into the lake <br />is the water from Twin Lake Court and Trail, the Five-Star Mobile Home Park, and the Frattalone <br />property south of the railroad tracks. <br />The pump had been operating in an idle mode prior to the rain events and the result was a very <br />efficient lowering of the lake. Now that the level is back up the pump was throttled up to try and <br />catch up and get back to where a level below 872 so the manhole can be raised. Once the manhole <br />is raised the pump will be turned off and removed from the site. <br />Long Term Solutions: <br />There are two solutions being worked on right now by the Ramsey Washington Metro Watershed <br />District. One involves keeping the water from West Vadnais Lake out of Twin Lake and the other <br />involves lowering the overflow to the MnDOT system on the south side of the lake. <br />West Vadnais – The Watershed District has applied for a permit from MnDOT to pump water from <br />the West Vadnais wetland area into the MnDOT system before it gets to Twin Lake. A sump <br />manhole would be constructed that would enable a pump to be dropped in and start pumping water <br />from the sump across Twin Lake Blvd. and out to the MnDOT system well north of Twin Lake. As