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Water Quality

Have you ever wondered how a state with over 800 public lakes and ponds and 8 aquatic biologists can evaluate the quality of so much water?  Well, it is pretty much an impossible task without the help of many dedicated volunteers located throughout the state of New Hampshire who volunteer their time to the New Hampshire Department of Environmental Services (DES).

This network of volunteers is a result of the New Hampshire Volunteer Lake Assessment Program (VLAP), which was initiated in 1985.  This program serves a dual purpose by establishing a regular volunteer-driven lake sampling program to assist DES in evaluating lake quality throughout the state, and by empowering volunteer monitors and lake residents with information about the health of their water body.  This cooperative effort allows biologists and lake associations to make educated decisions regarding the future of New Hampshire's lakes and ponds.

Fortunately for all of us who love Great Pond, several dedicated volunteers have participated in the VLAP since 1991.  Led by lake resident Dave Ingalls we have 15 years of data compiled to show significant trends in the water quality of Great Pond.  Dave and his crew sample eight specific spots on the lake from May through September.  The samples come from two deep water areas, five tributaries and one outlet.  The samples are sent to the New Hampshire Department of Environmental Services (DES) for evaluation.  During the winter months DES interprets the data and creates a list of recommendations.  The data and recommendations are compiled in an annual report which is sent back to Lake Association for implementation.

One of the biggest dangers to Water Quality is Phosphorous.  The following is an excerpt from the DES's Annual Report that describes the danger in nice detail:

"Like all of us, lakes age over time. Lake aging is the natural process by which a lake fills in over thousands of years.  Lakes fill in with erosional material carried in by tributary streams, with materials directly deposited by the air, and with materials produced in the lake itself.  From the time a lake is created, the aging process begins.  Although many New Hampshire lakes have the same chronological age, they fill in at different rates due to differences in lake depth and size and watershed characteristics.  Eutrophication is the term to describe lake aging that is accelerated by the process of increased nutrient input to the lake.

Lakes can age more quickly than the would naturally die to human impacts, a process called cultural eutrophication.  This accelerated aging results from watershed activities that increase nutrient loading and / or the deposition of other debris, such as fertilizing lawns, converting forest or pasture to cropland, and creating new impervious areas such as rooftops, parking lots, and driveways.  Studies in New Hampshire have shown that phosphorous exports from agricultural lands is at least five times greater than from forested lands and in urban areas may be more than 10 times greater than from forested areas.

The key nutrient in the eutrophication process is phosphorous.  Phosphorous is the limiting nutrient in New Hampshire lakes; the greater the phosphorous concentration in a lake, the greater the biological production.

Phosphorous sources within a lake's watershed septic system effluent, animal waste, lawn fertilizer, eroding roadways and construction sites, natural wetlands, and atmospheric deposition.  Reducing the amount of phosphorous in a lake will typically result in reduced algal concentration."