PEMBROKE, N.H. --To investigate how a river disperses chemicals added to the water, the U.S. Geological Survey will be injecting harmless dye into sections of 13 rivers in New Hampshire starting in October 1999, in cooperation with the New Hampshire Department of Environmental Services.
This year-long time-of-travel study is authorized by Congress as part of the Safe Drinking Water Act Amendments of 1996 and is funded through the U.S. Environmental Protection Agency's Source Water Protection Program. The methods of analyses and the benefits of the study are to provide the state and towns along the 13 rivers with information on the possible effects of a real chemical spill on the water quality of public water supplies that are withdrawn from rivers.
"The purpose of the study is to simulate, or create, a harmless artificial spill with the dye to determine what happens to a substance as it travels downstream from the point a chemical enters the river," said Erick Boehmler, Hydrologist and Project Chief. This method, called time-of-travel, will be used to sample water from the Ammonoosuc, Androscoggin, Connecticut, Contoocook, East Branch Pemigewasset, Exeter, Lamprey, Mascoma, Merrimack, Oyster, Piscassic, Salmon Falls, and Sugar Rivers by the end of the year-long project.
"The time-of-travel method works on the principle that spilled substances dissolve in water, so the USGS will track the injected dye by sampling water from the point of entry in the river downstream past the point where water is withdrawn for public supply," says Boehmler. By simulating a spill and analyzing the concentrations of dye as it flows downstream, the following questions can be answered:
Officials in the towns along the section of a river that is to be studied will be notified by the USGS before sampling begins.
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