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New Hampshire Department of Environmental Services


The Clean Lakes Program involves the diagnostic evaluation of water quality within a given watershed. Lakes and ponds in New Hampshire are recommended for the Clean Lakes Program if data from other monitoring programs, like the NHDES Lake Survey Program or the Volunteer Lake Assessment Program (VLAP), show signs of declining water quality over time.

The New Hampshire Clean Lakes Program at the NHDES was established in 1990 and is governed by RSA Chapter 487, Section 487:15. At that time, the general court recognized that rapidly escalating pressures of shorefront development and recreational uses of public waters had placed increasing strains upon the state’s lake resources, thereby accelerating the eutrophication process in many of our public lakes through nuisance growths of aquatic macrophyton and phytoplankton (algae) and thus posing a threat to water quality. The general court further recognized the need to restore, preserve and maintain the state’s lakes and ponds in order that these significant environmental, aesthetic and recreational assets will continue to benefit the social and economic well-being of the state’s citizens.

Diagnostic studies are typically conducted over the course of a 16-month period, and hydrologic and nutrient inputs to lakes and ponds from their watersheds are monitored for a range of chemical, biological, physical and ecological parameters. Land use patterns and characteristics are also evaluated through the course of this study. These data are used to develop hydrologic and nutrient budgets for the lake, and are ultimately used to pinpoint elevated sources of nutrients or other inputs to the waterbody from its watershed.

Volunteers from the lake or pond are encouraged to assist in collecting samples, much like their role in the VLAP program. A strong relationship with the lake association and local town(s) is integral in formulating a long-term management strategy for the lake and its watershed.

NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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