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Pumping should be conducted during off-peak periods between runoff events <br />(such as after spring snowmelt or in the late fall), since pumping during a <br />large runoff event will not appreciably reduce the peak water level in Mooney <br />Lake. Pumping during off-peak conditions will reduce impacts on <br />downstream conveyance systems. <br />Pumping will likely be needed only every 3-5 years. <br />C.Other Considerations <br />The installation of an outlet in Mooney Lake will require a permit from the Minnesota <br />Department of Natural Resources. MnDNR area hydrologist Ceil Strauss was contacted <br />in March, 1999, to discuss permitting considerations. She outlined the following <br />requirements: <br />The final control elevation for Mooney Lake can be no lower than 1.5 feet <br />below the OHW of 988. Setting the control water level at a higher elevation <br />will be governed by flood risk considerations. <br />MnDNR’s main concern will be to assure that the discharges from Mooney <br />Lake will not cause flooding problems downstream. Dry weather pumping is <br />a good strategy to avoid potential problems, but MnDNR will require an <br />operating plan that specifies when and how the lift station would be operated, <br />when pumping would cease, etc. <br />MnDNR has no records of eurasian milfoil infestations in Mooney Lake, so <br />screening of the intake would not be required. <br />D.City Staff Input <br />On April 2,1999, Minnehaha Creek Watershed District staff and staff met with city <br />representatives from Plymouth, Medina, Orono, and Wayzata to review the information <br />presented above. The purpose of the meeting was to solicit input from city staff in <br />selecting z recommended outlet option for Mooney Lake. Meeting attendees generally <br />supported Option 1. A draft report for review and comment was also distributed to the <br />cities of Plymouth, Medina, Orono, and Wayzata in May, 2000. Comment letters <br />received from the various cities are included in Appendix A. <br />IV.Recommendations <br />A.Recommended Option <br />The following recommendations are made for the proposed Mooney Lake outlet. <br />1.Route. The route outlined in Option 1 is preferred and is shovvn in Figure 3. <br />Inspite of its potentially higher cost, this route is recommended for the following <br />reasons: <br />Mooney Lake Outlet <br />Feasibility Study