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State Announces Its 2007 Fall Drawdown of Lakes Concord, NH – The New Hampshire Department of Environmental Services (DES) announced today that the annual fall drawdown of the lakes and ponds controlled by dams operated by DES will be initiated during the next few months according to the schedule below. The depth of drawdown listed below is not from the current level, but is from the normal full pond level. Since the hydrologic conditions and recreational uses of these water bodies vary, the degree and date of the start of drawdown for each lake is varied and could be affected by the amount of rainfall during the period. In addition, the actual date at which the drawdown will begin could vary by a few days based on operational constraints. Lake drawdowns are conducted each fall to reduce winter ice damage to shoreline properties and to reduce spring flooding. Drawdowns also give property owners an opportunity to conduct any necessary repairs to their waterfront property, provided they first secure a permit from the DES Wetlands Bureau at (603) 271-2147.
Generally, lake levels are allowed to return to the normal full pond level in the spring. However, Angle Pond is allowed to return to normal at the beginning of December, and Chesham Pond is lowered by 4 feet starting Columbus Day for a period of 6 to 8 weeks and the level will be brought up to 2 feet below the normal full pond level for the remainder of winter. Not included in this schedule is Lake Winnipesaukee. Unlike the other lakes in this schedule, Lake Winnipesaukee is not purposely drawn down in the fall. Instead, each year on Columbus Day, the releases from Lakeport Dam are reduced from a normal minimum of 250 cubic feet per second (cfs) to a flow between 30 and 50 cfs for a period of up to two weeks to allow for maintenance of the dams and hydropower facilities on the Winnipesaukee River. The flow of 30 to 50 cfs is the minimum flow needed to maintain the downstream aquatic life during this period. By the middle of the fall, Lake Winnipesaukee is, on average, 15 inches below its springtime full level due to evaporation and releases from the lake that have occurred over the course of the summer. As a result of the reduction in the amount of water released from the dam after Columbus Day, the lake level does not drop for the remainder of the month of October and is generally maintained at this level through the month of December. Depending on the amount of snow on the ground in the winter, the lake level may be lowered further beginning in January to a depth of two feet below the normal full level. A plot of the average lake levels throughout the year for Lake Winnipesaukee is provided on DES’s website at http://www.des.state.nh.us/dam/graph.htm. Also included are updated plots of this year’s lake levels, releases from the dam, and precipitation.
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