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Cooperative Efforts in
Ground-Water Protection —
A Connecticut History

By Robert L. Melvin, Hugo F. Thomas, and Robert E. Moore

Ground water accounts for 12 percent (144 million gallons per day) of all freshwater withdrawals in Connecticut and supplies drinking water to a third of the State's population (fig. 1). Water is withdrawn through 1,200 community wells (public supply), 3,300 non-community wells (restaurants, hospitals, schools, and so forth), and more than 250,000 individual home wells. Efforts to protect ground water go back at least 20 years to passage of the Connecticut Clean Water Act in 1967. Connecticut today has a comprehensive groundwater protection strategy. In developing this strategy, the State has relied heavily upon natural-resource information, largely developed through cooperative efforts with the U.S. Geological Survey (USGS). Modern topographic, geologic, and hydrologic maps, long-term basic data and statistics on water quality and use, quantitative eval

uations of aquifers, and process-oriented hydrologic research are essential components of the natural-resource information base on which the State relies.

The goal of Connecticut's groundwater protection strategy is, wherever feasible, to restore all ground water to or to maintain it at drinking-water quality without treatment. The strategy for achieving this goal is based on a partnership between the State and its 169 municipalities for the management of this resource. The goal and strategy are derived from the Connecticut Clean Water Act of 1967, which mandated the prevention and control of water pollution through a system of water-quality standards and permit and enforcement authorities. The purpose of the Act is to protect and enhance the waters of the State for public health and welfare, water supplies, fisheries, recreation, and all similar uses (fig. 2).

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define potability, the Water-Quality Standards are used to set and control water uses. Ground water in all areas of the State has been mapped and classified in one of four standards of use. This system is the keystone for all ground-water management programs. The system provides the highest levels of protection for over 90 percent of Connecticut's ground water, prohibits many activities in areas that overlie those waters, and establishes the basis for the siting and cleanup of land-based wastedisposal facilities. As a final key element, the ground-water strategy in Connecticut is not considered a distinct entity. Owing to the hydrologic setting, this strategy is looked upon as a component of a more comprehensive water-quality strategy that includes both ground water and surface water. The hydraulic connection between ground water and surface water, the localized nature of most ground-water flow systems, and the fact that the divides between ground-water and surface-water drainage basins coincide in many areas have all played an important role in the development of the State's ground-water protection programs (fig. 3).

The ground-water strategy developed from the Water Quality Standards encompasses a series of State- and locallyadministered programs that were designed on the basis of the hydrogeology, potential pollution sources, and ground-water uses of the State. The management elements that are part of the strategy cover a broad range of activities. Most of these elements, however, rely to some degree on a general understanding of the probable impacts of different human activities on water quality; the relations between ground water and surface water; the hydrodynamics of ground-water flow, including the effects of pumping water from wells; and the transport and fate of chemical substances in the saturated zone.

Resource Information

Today, in Connecticut, it is common practice for State and local agencies to support water-quality and related land-use decisions with a wealth of natural-resource information. Such information also provides the physical and conceptual framework for most of the ground-water protection programs that have been developed

(fig. 4). The source of that wealth of information can largely be attributed to almost a century of cooperation between the State and the USGS. Equally valuable contributions were also made through informal collaboration between the State, USGS, and the university community, including the first modern-era bedrock geologic map of Connecticut, compiled in 1907, and the first map of the glacial geology of the State, prepared in 1929.

Cooperative Programs

Connecticut State agencies had some of the earliest formal cooperative programs with the USGS. An agreement to produce topographic maps of the State was concluded in 1890, and in 1911 a cooperative program to inventory ground-water resources was initiated. In 1972, the State of Connecticut created the Department of Environmental Protection and formed a central unit, the Natural Resources Center, to be responsible for the integration of all natural-resource data collection. Since then, this unit has been responsible for managing almost all cooperative programs and for disseminating the resulting information to the user community. The naturalresource information most widely used in ground-water protection programs was largely obtained through mapping, monitoring, and process-oriented hydrologic research conducted during the past 40 years.

It is only natural that the earliest cooperative program produced topographic maps of the State. Besides the inherent information on hydrography, relief, and culture, these maps provide the standard base necessary for resource inventories and field-oriented research.

In 1985, consistent with a philosophy that led to the partnership 95 years earlier, Connecticut entered into a cooperative agreement with the USGS to produce and maintain statewide coverage of standard digital data of the 1:24,000-scale-series maps. The digital data will be used in a computerized geographic information system that will serve as the predominant source of digital maps in Connecticut.

After nearly a half century of informal relations, the Connecticut Geological and Natural History Survey, USGS, and other members of the geological community met in 1948 to develop a unified long-range

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program of geologic research. Seven years later, in 1955, a formal cooperative program to conduct bedrock and surficial geologic mapping of the State began. Over the next 30 years, Federal and State geologists, including several also affiliated with universities, worked to complete the program, which led to publication in 1985 of a 1:125,000-scale bedrock geologic map of the State that synthesized the results of the bedrock mapping. Cooperative efforts are presently underway to digitize the geologic data and incorporate them in Connecticut's geographic information system.

The modern era of cooperative hydrologic studies began in 1960 with State adoption of the "Long Range Plan for Connecticut." This plan was prepared, at the request of the State, by the Connecticut Water Resources Division Council, and it called for a series of comprehensive hydrologic studies for each major drainage basin in the State. A cooperative program for these studies was initiated in 1961 and completed in 1975. In each basin, hydrolo

gists defined streamflow and water-quality characteristics; mapped the extent, lithology, and hydraulic properties of stratifieddrift aquifers; evaluated water quality in streams and aquifers; identified and described existing water-supply and wastedisposal systems; and analyzed the potential for additional development of surfaceand ground-water resources. These interdisciplinary basin studies benefited considerably from the modern topographic and geologic maps that were produced through the other cooperative programs. In turn, the hydrologic studies contributed to the completion of geologic mapping and set priorities for the revision of topographic maps.

Integrating Hydrogeologic Data
To Protect Ground Water

Between 1970 and 1980, there was a significant transition in the USGS cooperative programs in Connecticut. Although

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