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HomeMy WebLinkAboutfrom MCWD �����- ....:. . �Il�nel�aha Creel� : '�� �Vatershed Distrlct . , ; Imprcving Quality of Water, Quality of Life CS�`� �;"_.;.=_.�: µ Established in 1967 Maii: l�/L� 30O S�XT� /�/� �• 18202 Minnetonka Blvd., Deephaven,MN 55391 Phone:(952)471-0590 7une 10, 2003 Fax:(952)471-0682 Dear Mooney Lake Resident: Email: The purpose of this letter is to provide an update on the Mooney Lake high water adminC�minnehahacreek.org level situation and what action has been taken since last fall to address this problem. Record rainfall received last summer and fall resulted in the highest water levels ever Web Site: recorded on Mooney Lake and caused flooding of low-lying properties,but no www.minnehahacreek.org structures, along the shoreline of the lake. The water level peaked at an elevation of 991.5 on September 8, 2002. To reduce the risk of structural flooding of homes along the lake,the Minnehaha Creek Watershed District(MCWD) and City of Plymouth acted cooperatively to implement an emergency pumping plan last fall to lower water levels on Mooney Lake as much as possible prior to winter freeze up. Board of Managers The pumping was authorized by the Minnesota Department of Natural Resources (DNR) under a general pernut, which allowed temporary pumping on an emergency Pamela Blixt basis for flood protection. Water was pumped from the southeast bay of Mooney James Calkins Lake through an above-ground pipe and into a ditch along the north side of County Road 6 that drains into Pinetree Pond in Plymouth. Water was pumped out of lake Lance Fisher on a continuous basis over a two-month period in October and November. Susan Goetz Monica Gross Earlier this year the MCWD prepared an emergency pumping plan and applied for a pernut from the DNR to cover additional emergency pumping if required this year Richard Miller and into the future. Representatives of the MCWD,Hennepin County, and the Cities ScottThomas of Plymouth,Medina, and Orono met previously in November 2002 and January 2003 to review progress of the emergency pumping described above and to establish target water surface elevations for Mooney Lake to guide future pumping operations. It was mutually agreed upon that emergency pumping would start and stop when Mooney Lake water levels reach elevations 990.0 and 989.0,respectively in the spring/summer and reach elevations 989.0 and 988.0, respectively in the fall. The permit was issued by the DNR last month on May 20, 2003 approving the emergency pumping plan and the established target pumping elevations. Upon termination of last year's emergency pumping, the water level of Mooney Lake had dropped to an elevation of 990.0 in early December 2002. The lower water levels were a result of both the pumping and natural losses from infiltration and evaporation. During the pumping period,the month of October was wetter than normal, while the month of November was extremely dry. Water levels on Mooney Lake were monitored by the MCWD over the winter by taking water level measurements through the ice. Water levels continued to drop reaching a low point on February 27, 2003 at an elevation of 988.5, a drop of three feet from its record high in September 2002. A staff gauge was installed on Mooney Lake in early April Printed on recycled papercontaining at least 3096 post consumer waste. T:�A lS5�A4�299�hluouey-Azsideni Lcemr 6-3-03.Joc � 2003 as soon as the ice along the edge of the lake h d melted. Weekly water level readings and readings after significant rainfall events have been aken since that time. Water levels on Mooney Lake this spring remained below elevatio 989.0 until mid-May when water levels went up as a result of heavy rainfall received in the Tw' Cities area. Based on the water level reading taken today,the lake is now at an elevation of 989. ,which is about 10 inches below the established spring/summer target pumping elevatio of 990.0 feet. Water levels on the lake will continue to be monitored throughout the yeaz and t e MCWD and City of Plymouth are prepazed to initiate emergency pumping utilizing a tempor pumping system similaz to the one implemented last fall should lake levels reach the t get pumping elevations approved under the DNR pernut. �� The MCWD has also begun work on the emergenc pumping infrastructure study. Due to the occasional need to conduct emergency pumping an the relative high costs associated with constructing an intake structure and purchasing pu ps,it was deternvned by the MCWD, Hennepin County,and the local communities that a more feasible altemative would be to look into the possibility of installing a permanent electri al power supply and underground , conveyance pipes to accommodate future emergenc pumping. Once the permanent infrastructure system is in place and should emerge cy pumping be required,a dewatering contractor would be hired to install and operate sub ersible pumps placed in the lake, similar to those used last fall. Our engineers,Wenck Associates,Inc.,met with C' y of Plymouth staff last month to review potential pumping routes for a permanent system he study will evaluate three or four pumping routes and associated costs with installing the pe nent infrastructure system to provide flood protection. It is anticipated that the study will be c mpleted and presented to the MCWD Board of Managers later this month. Thank you for your patience and understanding as e work towards a solution to address the high water problems on Mooney Lake. Please feel ree to contact me at 952-471-0590 if you have any questions regarding this letter. Sincerely, . . on, A 'nist or � Minnehaha Creek Watershed District cc: Plymouth City Manager Medina City Manager Orono City Manager I MCWD Board of Managers � Commissioner Penny Steele � The Honorable Judy Johnson District Engineer T:V01&5�04�299VNooay-Resident l.etter 6�3-03.doc .