skip navigation
New Hampshire Department of Environmental Services

Lake Water Quality Reports
A variety of reports presenting the water quality of New Hampshire lakes and ponds are provided. They include Acid Rain Monitoring for Remote Ponds and Accessible Ponds, Trophic Surveys available as Summary Data or Trophic Reports, Volunteer Lake Assessment Reports, Diagnostic Studies, and Water Quality Reports to Congress. The reports present the results of various lake monitoring programs that were designed for different purposes and measure different parameters.

Acid Rain Monitoring
Two groups of lakes (remote ponds and accessible ponds as described below) are routinely monitored for acid rain-related parameters to evaluate long-term trends. The results for 10 lakes from each of the two groups are provided to the New England Governors-Eastern Canadian Premiers (NEG-ECP) Water Quality Monitoring Network as part of a northeast North American acid trend program.

For more information, contact Scott Ashley at or (603) 271-2968, or Walt Henderson at or (603) 271-8802.

Remote Ponds
Each spring the NH Fish and Game Department stocks brook trout into remote trout ponds by helicopter. At the time of the stocking, a water sample is collected from mid-lake at a 0.5 meter depth and analyzed for acid rain parameters. The program was initiated in 1981. A total of 60 different ponds have been sampled in the program with a core of 23 ponds sampled essentially every year through 2005. Because of budgetary constraints at Fish & Game, only the ten NEG-ECP trend ponds have been sampled since 2006. Many of these ponds are at high elevation and are the most susceptible to the impacts of acid rain because of small watersheds, shallow to no soils and elevated precipitation rates.
See the Remote Ponds Report Adobe Acrobat Reader Symbol

For more information, contact Scott Ashley at or (603) 271-2968, or Walt Henderson at or (603) 271-8802.

Accessible Ponds
The outlets of 20 accessible headwater ponds are sampled twice a year, at spring and fall overturn when outlet waters are representative of in-lake conditions, and analyzed for acid rain parameters. The program began in 1983 and is designed to complement the remote pond program by documenting acid rain trends in low elevation, non-colored ponds.
See the Accessible Ponds Report Adobe Acrobat Reader Symbol

For more information, contact Scott Ashley at or (603) 271-2968, or Walt Henderson at or (603) 271-8802.

Lake Trophic Surveys
This program was initiated in 1975 with the intention of determining trophic state of lakes and ponds greater than 10 acres as required by the federal Clean Water Act. By collecting physical, chemical, and biological measurements, 780 lakes and ponds received trophic class ratings and tens of thousands of data points were gathered from 1975 - 2008. The program was discontinued in 2008 and revamped in 2013, allowing NHDES to continue to make informed decisions concerning changes in trophic status, provide the public recent water quality information on specific waterbodies, monitor regional environmental influences, and facilitate water quality stewardship of New Hampshire’s waterbodies.

Click here to access lake trophic survey reports. Explanatory information for data presented in the trophic reports is provided in the link below. See Explanatory Information Adobe Acrobat Reader Symbol

Additional lake data is provided by VLAP (see below).

For more information, contact Kirsten Nelson at or (603) 271-1152.

Summary Data
A listing of the most frequently asked for data for all lakes and all summer sampling dates is provided in the summary report. An explanation of the parameters listed, along with a table to compare one lake's value to the average value for all New Hampshire lakes, is provided in the explanation report.
See the Summary Data

For more information, contact Kirsten Nelson at or (603) 271-1152.

Volunteer Lake Assessment Program
Individual yearly reports for lakes that participate in the Volunteer Lake Assessment Program (VLAP) are provided. Most lakes are sampled once a month for three summer months, with an emphasis on the trophic parameters chlorophyll (planktonic algae biomass), water transparency and total phosphorus. The tributaries of each pond are also sampled for phosphorus.

For more information, contact Sara Steiner at or (603) 271-2658.

Diagnostic Studies
These are in-depth studies of lakes designed to determine the sources and magnitudes of phosphorus entering a lake, and to make recommendations to reduce the phosphorus load. Studies generally last 12 to 16 months, and all tributaries and the outlet are sampled for water and phosphorus inputs.
See the Diagnostics Studies

For more information, contact Andy Chapman at or (603) 271-5334.

Water Quality Reports to Congress
The federal Clean Water Act requires states to provide a water quality report to EPA (and then to Congress) every two years. The report is often referred to as the 305(b) water quality report and 303(d) list of impaired waters. Waters are assessed to determine if they meet water quality criteria established to protect the uses of the water such as swimming, boating and aquatic life. Details about the program along with the most recent available assessments of individual lakes are provided.
New for the 2010 assessments is the inclusion of phosphorus and chlorophyll data for the assessment of the aquatic life use. Phosphorus and chlorophyll criteria used in the assessments differ based on a lake’s trophic class. The “best” (most oligotrophic) trophic class for each lake surveyed during the 35 year trophic survey program was used for the 2010 assessments.
Final Trophic Classes for 2010 Assessment Adobe Acrobat Reader Symbol

For more information, contact Gregg Comstock at or (603) 271-2983, or Ken Edwardson at or (603) 271-8864.



Adobe Acrobat Reader Symbol Adobe Acrobat Reader format. Download a free reader from Adobe.

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

copyright 2014. State of New Hampshire