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Source-linked reports with geographic coverage including Connecticut.

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Water resources inventory of Connecticut Part 1: Quinebaug River basin

The Quinebaug River basin is blessed with a relatively abundant supply of water of generally good quality which is derived from precipitation that has fallen on the basin. Annual precipitation has ranged from about 30 to 67 inches and has averaged about 45 inches over a 44-year period. Approximately 21 inches of water are returned to the atmosphere each year by evaporation and transpiration; the remainder of the annual precipitation either flows overland to streams or percolates downward to the water table and ultimately flows out of the basin in the Quinebaug River. During the autumn and winter months precipitation normally is sufficient to cause a substantial increase in the amount of water stored underground and in surface reservoirs within the basin, whereas in the summer most of the precipitation is lost through evaporation and transpiration, resulting in sharply reduced streamflow and lowered ground-water levels.

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Hydrogeologic data in the Quinebaug River basin, Connecticut

This report presents hydrologic and geologic data collected by the U.S. Geological Survey during an investigation of water resources in the Quinebaug River basin of Connecticut in cooperation with the Connecticut Water Resources Commission. The Quinebaug River basin occupies about 425 square miles in the northeastern part of the State, including the towns of Brooklyn, Griswold, Killingly, Plainfield, Pomfret, Putnam, Sterling, and Thompson, and parts of Canterbury, Hampton, Lisbon, North Stonington, Preston, Voluntown, and Woodstock. A companion interpretive report evaluating the water resources of the basin will be published as Connecticut Water Resources Bulletin 8. The data on the following pages serve to document and supplement that report, and should be especially useful in planning the development of water resources at specific localities.

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Water resources of the Hartford-New Britain area, Connecticut

The Hartford-New Britain area includes the metropolitan areas of Hartford and New Britain and parts of several adjoining towns. Water used in the area is withdrawn from the principal streams and aquifers at an average rate of 463.5 mgd (million gallons per day). Sufficient water is available from these sources to meet present requirements and those for many years to come, although local shortages may develop in some areas as the result of problems of distribution and treatment. About 98 percent of all water used in 1957 was from surface sources. More than 425 mgd was required by industry, and about 23 mgd was for domestic water supply. The Farmington River upstream from Collinsville is the chief source of water for public supply in the Hartford-New Britain area, whereas the Connecticut River is the chief source of water for industry. An average of about 40 mgd is withdrawn from the upper Farmington River for public supply, and about 404 mgd is withdrawn by industry from the Connecticut River for nonconsumptive use and returned directly to the stream. The Connecticut River is the source of the largest quantity of water in the area. The flow of the stream at Thompsonville may be expected to equal or exceed about 2,000 mgd 95 percent of the time, and the flow should not be less than this amount for periods longer than 12 days. The flow below Thompsonville is increased by additions from the Scantic, Farmington, Park, and Hockanum Rivers and from numerous smaller tributary streams. The available streamflow data for the aforementioned rivers have been summarized graphically in the report. The chemical quality of water in the Connecticut River is good, except for short periods when the iron concentration is high. In addition to the removal of iron some other treatment may be necessary if water from the Connecticut River is used for special purposes. The chemical quality of the tributary streams is good, except the quality of the Park River, which is poor. Thus the Connecticut River in the vicinity of Hartford offers an almost unlimited source of water of good chemical quality to the Hartford, New Britain area. The Connecticut River and many of its tributaries, however, are polluted to some degree, and the cost of treatment for pollution and of delivery of water to the area presents an economic problem in the further development of these sources. The Hartford-New Britain area in the vicinity of Hartford has been plagued by floods since the time of its settlement. Most of the damage to property and loss of life in the Hartford area has been caused by flooding of the Connecticut and Park Rivers. Floods have occurred on the Connecticut River and its tributaries in every month of the year, but the most severe floods occur in the spring and fall. The most devastating flood on the Connecticut River occurred on March 21, 1986, when the stage at Hartford reached 37.0 feet above mean sea level. The maximum flood on the Park River occurred on August 19, 1955, when the stage reached 43.5 feet above mean sea level. Floods on the other tributaries have been frequent and some have been large, but damage has not been as great because the streams flow mostly through rural areas. Small to moderate supplies of water suitable for domestic use and for small municipalities and industries are available from wells in the Hartford-New Britain area. Moderate supplies are obtainable from five definable sand-and-gravel aquifers and from widespread consolidated sedimentary rocks. Yields to individual wells range from 15 to 400 gpm (gallons per minute) for wells penetrating sand and gravel and from 1 to 578 gpm for wells penetrating consolidated sedimentary rocks. Sand and gravel deposits bordering the Connecticut River downstream from Rocky Hill afford the greatest potential for the development of large supplies of ground water. Small supplies ranging from 1 to 40 gpm are obtainable from glacial till and from consolidated crystalline rocks.

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Geology and ground-water resources of the Bristol-Plainville-Southington area, Connecticut

The Bristol-Plainville-Southington area straddles the boundary between the New England Upland and the Connecticut Valley Lowland sections of the New England physiographic province. The western parts of Bristol are Southington lie in the New England Upland section, an area of rugged topography underlain by metamorphic rocks of Palezoic age. The eastern part of the area, to the east of a prominent scarp marking the limit of the metamorphic rocks, is in the Connecticut Valley Lowland and is underlain by sedimentary rocks and interbedded basaltic lava flows of Triassic age. The lowland is characterized for the most part by broad valleys and low intervening linear hills, but in the eastern parts of Plainville and Southington, basaltic rocks form a rugged highland. The bedrock is largely mantled by glacial deposits of Wisconsin age. On hills the glacial deposits are mainly ground moraine, and in valleys mainly stratified. The metamorphic rocks comprise the Hartland Formation, Bristol Granite Gneiss of Gregory (1906), and Prospect Gneiss. These formations contain water in fractures, principally joints occurring in regular sets. The rocks generally yield supplies of 5 to 15 gpm (gallons per minute) to drilled wells averaging about 140 feet in depth. The rocks of Triassic age in the area are the New Haven Arkose, Talcott Basalt, Shuttle Meadow Formation, Holyoke Basalt, and East Berlin Formation. The formations contain water principally in joints and other fractures and, to a lesser extent, in bedding-plane openings and pore spaces. Drilled wells penetrating these rocks generally range from 100 to 200 feet in depth and yield an average of nearly 20 gpm. The maximum yield obtained from a well in these rocks is 180 gpm. The ground moraine of Pleistocene age is composed principally of till. The deposit averages about 24 feet in thickness, and wells penetrating it average about 16 feet in depth. The ground moraine yields small supplier of water suitable for household use when tapped by shallow large-diameter wells. The stratified glacial deposits, which are as much as 300 feet thick, comprise ice-contact and proglacial deposits and deposits of generally obscure origin termed 'undifferentiated stratified deposits.' The ice-contact and undifferentiated stratified deposits, some of which underlie proglacial deposits, are coarse grained and contain gravel beds from which supplies of as much as 1,400 gpm can be obtained. The proglacial deposits are, on the whole, finer grained than the other stratified deposits, but in places they allow development of wells producing as much as 500 gpm. However, the stratified glacial deposits throughout much of the Bristol-Plainville-Southington area are fine grained and provide only small supplies.

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