Lake level

The graph below represents the level of Lake Wentworth and Crescent Lake over time as well as the opening of the gate in the Crescent Lake Dam for a given date.

The time period shown can be controlled by clicking one of the Zoom intervals in the upper left-hand corner of the chart. The intervals available are: one day (1d), five days (5d), one month (1m), three months (3m), six months (6m), one year (1y), and the full set of data since the beginning of record keeping in 2003 (Max). The default is Max.

As you pass the mouse cursor along the line, the actual numeric value for the lake level on a given date is displayed in blue in the upper left-hand corner.

At the same time, the numeric value for the gate opening in the Crescent Lake dam is displayed in red in the same corner. (Note that a value of -1 for the gate opening means that no value was entered for the date in question.)

What the numbers mean

The lake level numbers above refer to gauge readings at the Crescent Lake dam or in the Smith River at the Whitten Neck bridge (where a gauge has been calibrated to match the one at the dam). The readings apply to both Crescent Lake and Lake Wentworth.

The numbers on the right side of the graph represent feet above sea level, so that a reading of 34.10 on the gauge represents a lake level of 534.10 feet above sea level. The same principle holds for the water levels referenced in the state order described below.

The gate opening numbers refer to the distance the sluice gate has been opened at the time the respective water level reading was taken. The gate (shown in the bottom center of the illustration below) determines the flow rate from Crescent Lake through the dam to the river below.

Crescent Lake dam control hut

Crescent Lake dam control hut

As the gate is only 4 feet tall, the maximum distance that the gate can be opened is 4 feet. If the table shows a gate opening of 0 feet, the gate is fully closed and there is minimal water flow through the dam.

State water level schedule

The state of New Hampshire requires the town of Wolfeboro to operate the dam in accordance with the following schedule:

  • From June 15 to Labor Day, the water level is to be at 34.20 on the gauge but not below 32.70 on the gauge, with the variation being permissible to allow for evaporation and/or below average rainfall.
  • By Columbus Day the water level is to have been decreased to 33.20 on the gauge, and by December 15 is to have been further decreased to 32.20 on the gauge.
  • From December 15 to April 15, the water level is to be maintained at 32.20 on the gauge.
  • From April 15 to June 15, the water level is to be increased from 32.20 on the gauge to 34.20 on the gauge, with frequent inspections by the owner to control discharge to prevent damage due to high water.
  • At all times care is to be exercised to prevent water from flowing over the permanent crest of the dam.
  • Once every five years beginning on September 10, 1993, the water level is to be drawn down to 30.70 on the gauge by the following October 10 and held at that level until the following November 10 to permit repairs to lake shore properties and installations.
  • During periods of drought or flooding, the level of Lake Wentworth/Crescent Lake may fall below or extend above the limits set forth in the state order. These conditions are considered to be natural occurrences and are not to be attributed to the dam owner.