Watershed Management Bureau

  Lakes Management and Protection

    Lake Water Quality Reports

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 Water Quality Monitoring Network as part of a northeast North American acid trend program.

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. 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

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

This program was initiated in 1975 and is designed to measure the trophic state of a lake as required by the federal Clean Water Act. Physical, chemical and biological measurements are made at each lake, once during the winter and once during the summer. Lakes are sampled once every 15 to 20 years and essentially all New Hampshire lakes and ponds have been surveyed at least once in the program. Trophic survey information is presented in the summary data and trophic reports below.

Summary Data

A listing of the most frequently asked for data for all lakes and all summer sampling dates is provided in this report. The report, designed for the lay person, consists of two parts. The first is a brief report explaining the parameters listed, along with a table to compare one lake's value to the average value for all New Hampshire lakes. The second part is an appendix presenting the actual data.

SEE THE SUMMARY DATA

Trophic Reports

The most recent trophic report for each lake is available. Each report consists of six pages. The first two pages present morphological data, summer and winter biological and chemical data, the trophic classification and comments on the results. The next four pages consist of a bathymetric map showing depth contours, temperature and dissolved oxygen profile data, a map portraying the type, location and abundance of rooted aquatic plants and a table identifying the letters used on the plant map. Explanatory information is also provided in a separate file.

SEE EXPLANATORY INFORMATION

SEE THE TROPHIC REPORTS

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.

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 DIAGNOSTIC STUDIES

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.