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sustainable or fiscally responsible to continue to pump groundwater to maintain the lake level <br />at 872. <br />3.Continue to pump to lower the lake level to 871 or lower. According to the staff gauge that <br />was installed in July of 2018, the lake level at that time was recorded at 871.49. At this time, <br />all of the City’s public infrastructure was accessible and there was no immediate threat to any <br />of the habitable structures around the lake. Pumping to 871 would bring Twin Lake down to <br />where it was in 2018 and where it has been for the past two or three years based on anecdotal <br />evidence. Groundwater would likely be a factor at this level and would not be sustainable. <br />Installation of piezometers to measure the groundwater pressure may be required to determine <br />how much of an impact this would have on a continuous pumping operation. Until the <br />groundwater level recedes, it may not be cost-effective to pump at this level or lower. <br />After examining all of the options, staff is recommending that the lake be pumped to the 872 level. <br />This level provides at least two feet of freeboard for the low home and is also the historical overflow <br />for the lake (the bottom of the overflow pipe located under the railroad tracks is approximately 872.2). <br />If the Council agrees, the necessary permit amendments will be submitted to the DNR and MnDOT <br />and pumping to the new level can start as soon as the amendments are approved. If it is determined <br />that the groundwater level is lower than expected and the Council wishes to pump to a lower lake level <br />in the future, a revised permit application can be made at that time. Caution should be taken to pump <br />the lake to a level below 871 feet as it sets a precedent for Twin Lake and all other water bodies in the <br />City. <br />Potential Long-Term Options: <br />The long-term solution could be one of a few different options. One is to put some sort of pipe into <br />Waldo Pond at a level closer to 872. A valve could be put in the pipe to allow the pipe to be shut off <br />during heavy rain events to keep MnDOT water out of Twin Lake. Another is to put a pipe and valve <br />in at a higher level but still below the lowest entry point of the home at 876 feet. A third option is to <br />put a more permanent infrastructure in but still use a pump when necessary rather than a piped outlet to <br />Waldo Pond. These discussions will continue with MnDOT, the Watershed District, and other partners <br />to find a solution so that a planned project will be approved by all parties. <br />The Ramsey-Washington Regional Watershed District has been extremely helpful in this entire <br />process. The Watershed District and Barr Engineering have been very responsive and have answered <br />all of the questions that staff has asked of them to the best of their abilities. They have worked <br />extremely hard to find solutions to the problems that have arisen along the way and have thought about <br />short and long-term impacts on the entire district as decisions have been weighed. It would cost tens <br />of thousands of dollars to have another engineering firm get up to speed on all of the issues with Twin <br />Lake and surrounding water bodies. Staff believes the service provided by the Watershed District and <br />its consulting engineer has been exceptional and will continue to rely on them for their expertise, <br />analysis of options, and guidance going forward.