Gaining Clarity on the State of New Hampshire's Waters

July is Lakes Awareness Month. So designated by the US Environmental Protection Agency (EPA), it is part of the Year of Clean Water celebration in honor of the 30th anniversary of the Clean Water Act.

In accordance with this celebration, amateur water quality scientists in New Hampshire and across the continent will participate in the 10th annual Great North American Secchi Dip-in.

The "Dip-In" is an international effort in which volunteers produce a "snapshot" of the clarity of water in the United States and Canada. Sponsored by the North American Lake Management Society and EPA, the Dip-In is directed by Kent State University biologist, Dr. Robert Carlson.

From June 28 until July 13, it's expected that more than 2,500 volunteers from water monitoring programs will measure water clarity in their favorite lake, reservoir, river or estuary. Most will use an instrument called a "Secchi Disk," a flat, horizontal, black and white disk that is lowered from a rope into the water until it disappears. The disk itself is named after the Jesuit priest, Pietro Angelo Secchi, who used the disk more than 150 years ago in the Mediterranean Sea.

The depth the disk disappears from view is a measure of the transparency of the water. The water color and particles of silt or clay or small microscopic plants called algae affect the transparency, and therefore is a measure of some forms of pollution. Measuring water clarity over a season and from year to year allows for the tracking of water quality changes in the short and long-term.

The previous Dip-In's provided valuable information about water quality. The resulting summary maps made each year show considerable regional differences in transparency. Lakes in the northern parts of the United States and in Canada typically have the clearest conditions, while lakes in agricultural regions of the Midwest have some of the lowest water clarity. Transparencies found during the Dip-In range from one inch to more than 65 feet. In New Hampshire, lake water clarity measurements range from 16 inches to over 50 feet with an average of about 12.5 feet.

Analysis of the "Dip-In" questionnaires has found that opinions of water quality vary considerably from region to region. A person in Minnesota, New Hampshire or Canada, for example, may think a lake is degraded if the transparency is less than six feet while in other states, a lake with a transparency of only a foot may be considered beautiful.

Dr. Carlson suggests these regional differences mean people become accustomed to the quality they see every day. Most sobering may be the possibility everyone grows up thinking their environment is normal. Small changes in water quality may go unnoticed. Fortunately, there are volunteer monitors who record these changes in water quality year after year. Without their observations, our environment might change unnoticed.

New Hampshire is fortunate in that almost a thousand citizen monitors keep tabs on the water quality of its lakes and estuaries. The New Hampshire Lakes Lay Monitoring Program, under the coordination of UNH Cooperative Extension and the Center for Freshwater Biology, has been training and supporting volunteer monitors for over 25 years. The NH Dept. of Environmental Services has a similar program, the Volunteer Lake Assessment Program, that also supports volunteer monitoring throughout the state. The UNH Sea Grant/UNH Extension Great Bay Coast Watch has volunteers monitoring sites in Great Bay, harbors, and the tidal coastal rivers.

All these programs measure Secchi Disk transparency as well as other important water quality indicators. They allow agency scientists and University researchers to gain a better understanding of water quality trends throughout the state and to determine what activities and conditions lead to water quality changes. Measurements confirm that much of the variations are caused by polluted runoff created clearing of the land (removal of trees and native vegetation) and the increases in impervious areas like roads, driveways and rooftops.

Volunteer water quality monitoring data have proven to be instrumental in the protection and improvement of a number of lakes facing water quality degradation. Over the years this monitoring also has provided for the establishment of baseline conditions of our pristine lakes so we can insure that they remain that way.

Support your local volunteer monitoring program. To find our more about lake and stream volunteer monitoring call UNH Cooperative Extension at 603-862-3848 or NH DES at 603-271-2658. For information on the Great Bay Coast Watch call 603-749-1565. More information on the Great American Secchi Dip-In is available on the World Wide Web at: http://dipin.kent.edu/ .