INFORMATION 02-22-2011 - Laserfiche WebLink

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INFORMATION c V~~ MEMORANDUM TO: Mayor and City Council FROM: Nicola Blake-Bradley, Environmental Technician DATE: January 31, 201 I SUBJECT: Lake Orono Drawdown Request Denied In August 2010, the Elk River Lake Orono Improvement Association presented a petition to the City Council and requested that the City of Elk River apply fox a permit to draw down Lake Orono by approximately five feet to proactively treat the Curly Leaf Pondweed (CLP) infestation within the lake. Curly Leaf Pondweed is an invasive plant, spread both by sexual and asexual reproduction, which allows it to rapidly cause navigational and recreational problems. An annual permit for hand pulling the plant has not been successful in eradicating the CLP so an alternative method was sought. Because Lake Orono is a reservoir with a "flow-through" river, chemical application for CLP is not a viable option due to low retention time in Lake Orono. On September 7, 2010, the City Council approved staff's request to submit an application to the MN Department of Natural Resources (DNR) to draw down the lake following a public hearing where people spoke both in favor and against the proposal. A permit request was submitted to the Area Hydrologist on September 8, 2010 for the drawdown. The City received a letter denying the permit request dated January 12, 2011. The DNR staff has determined that significant effects to the resources would result. The consensus of the staff is that "a drawdown would not be appropriate due to the low level of infestation and the impacts on flora and fauna (not targeted, but that would nevertheless suffer or be eradicated)". In an a-mail message, the Area Hydrologist shared comments from the DNR Invasive Species Specialist Brittany Hummel as listed below: • Considering the fact that the CLP infestation is not extensive, and • Considering that a threatened species lives in the lake, and • Considering that a drawdown may adversely affect the fishery, and • Considering that CLP turions are coming from upstream, the lake will always be colonized by CLP turions, and • Considering that a hard freeze can damage water lily tubers