State Announces Its 2020 Fall Drawdown of Lakes

Concord, NH – The New Hampshire Department of Environmental Services (NHDES) announced today that the annual fall drawdown of the lakes and ponds controlled by dams owned by NHDES will be initiated according to the schedule below.
 

1. Grafton Pond will be drawn down 8 feet again this year for a two to three-week period for some minor maintenance of the dam. This drawdown will start on October 5 and the lake level will be raised to the normal two-foot drawdown level after work on the dam is complete.
2. The drawdown of Horace Lake will begin on October 30 this year, which is approximately two weeks later than normal.
3. The drawdown of Howe Reservoir will start in early September for maintenance work on the dam.
4. These larger lakes generally do not reach their full drawdowns until mid or late March. The values listed above are generally the maximum levels reached, although during any given year the levels reached can be either higher or lower due to weather conditions.
5. Union Meadows Dam will have a drawdown to facilitate some minor maintenance that needs to be done and to facilitate an inspection of the upstream side of the dam. As soon as work all work is complete, the lake level will be allowed to return to full pond.

The depth of drawdown listed above is not from the current level, but is from the normal full pond level. Because of the drought conditions the state has been experiencing through the summer, the levels of many of these lakes are already a foot or more below full. As a result, NHDES will not be making its normal special releases from Horace Lake and Northwood Lake for downstream recreation this year, but intends to resume them next fall. However, on Saturday, October 31, a release will be made from Greggs Falls Dam in Goffstown to provide an opportunity for canoeing and kayaking in the Piscataquog River downstream. The release will begin at 11:00 AM.

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 NHDES Wetlands Bureau at (603) 271-2147.

Generally, lake levels are allowed to return to the normal full pond level in the spring. However, the drawdowns of Opechee and Winnisquam Lakes, which occur on a two-year interval, last only approximately two weeks. This year, the lowering of Opechee Lake will begin on October 17, and it will likely take two days to pass the water from Opechee Lake downstream through Winnisquam Lake. Therefore, the level of Winnisquam Lake is not expected to drop noticeably until October 19. On October 30, flows at Lakeport Dam will be increased to refill Opechee Lake, and the level of Winnisquam Lake should begin to rise late in the day on November 1.

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, in the fall after 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. This year the reduction will be begun on October 17.

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. 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 on the NHDES website. 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 5 years. In the event a party may wish to conduct such a drawdown, please contact the NHDES 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 (up to 5 years) for your project can be avoided.