CONCORD — The annual fall drawdown of the lakes and ponds controlled by dams owned by the New Hampshire Department of Environmental Services will be initiated according to the following schedule.
The Suncook Lakes in Barnstead, part of the Suncook River, will be drawn down five feet on Oct. 1, one of the first to be drawn down. Crystal Lake in Gilmanton, part of the Suncook River, will be drawn down three to four feet, also on Oct. 1. The Crystal Lake drawdown is in conjunction with upstream bridge work. Upon completion, the water level will be raised to the usual winter drawdown level.
The depth of drawdowns are not from the current levels, but is from the normal full levels. Due to changing ice and hydrologic conditions, these levels can vary throughout the winter. Since the hydrologic conditions and recreational uses of these water bodies vary, the degree and date of the start of drawdown for each lake vary 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.
Most other Lakes Region bodies of water will be drawn down on Oct. 11. Sunset Lake in Alton, part of the Suncook River, will be drawn down seven feet. Shellcamp Pond in Gilmanton, part of Academy Brook, will be drawn down two feet. Barnstead Parade in Barnstead, part of the Suncook River, will be drawn down 1.5 feet. Webster Lake in Franklin, part of Chance Brook, will be drawn down two feet.
Lake Kanasatka in Moultonborough, a tributary to Lake Winnipesaukee, will be drawn down 1.5 feet on Nov. 1.
Newfound Lake in Bristol, part of the Newfound River, which will be drawn down two feet, and Squam Lake in Ashland, part of the Squam River, which will be drawn down 2.5 feet, both on Oct. 11., are some of the larger lakes that generally do not reach their full drawdowns until mid or late March. The drawdown values are generally the maximum levels reached, although during any given year the levels reached can be either higher or lower due to weather conditions.
Not included in this schedule is Lake Winnipesaukee. Unlike the other lakes, Lake Winnipesaukee is not purposely drawn down in the fall. Instead, after Columbus Day, the releases from Lakeport Dam are reduced from a normal minimum of 250 cubic feet per second to a flow between 30 and 50 cubic feet per second for up to two weeks to allow for maintenance of the dams and hydropower facilities on the Winnipesaukee River. This is the minimum flow needed to maintain the downstream aquatic life during this period. This year the reduction will begin on Oct. 18.
By mid-fall, Lake Winnipesaukee is on average 15 inches below its springtime full level due to evaporation and releases from the lake over the course of the summer. Because of this summer’s drought, the level of the lake is already at that elevation. When the amount of water released from the dam is reduced after Columbus Day, the lake level is not expected to drop significantly for the remainder of the month of October and, if drought conditions ease in the fall and winter, it is expected to remain relatively stable through the month of December absent any major rainfall events. 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 at nh.gov. Also included are updated plots of this year’s lake levels, releases from the dam, and precipitation.
The NH Fish and Game Department recommends that if special drawdowns are to be conducted for the purposes of repairing property such as retaining walls or private boat ramps they occur only once in every five years. In the event a party may wish to conduct such a drawdown, contact the DES Dam Bureau immediately after receiving all permits required for such work, so that the drawdown can be coordinated with any other work at the same water body being proposed by other parties. In this way the number of special drawdowns can be minimized, and unexpected delays of up to five years for these projects can be avoided.
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.