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27 records · Page 2Linked to original sources
USGS1986

Water resources inventory of Connecticut Part 9: Farmington River basin

The Farmington River basin covers 435 square miles in north-central Connecticut upstream from Tariffville and downstream of the Massachusetts state line. Most water in the basin is derived from precipitation, which averages 48 inches (366 billion gallons) per year. An additional 67 billion gallons of water per year enters the basin from Massachusetts in the West Branch of the Farmington River, Hubbard River, Valley Brook and some smaller streams. Of the total 433 billion gallons, 174 billion gallons returns to the atmosphere through evaporation and transpiration. 239 billion gallons flows out of the study area in the Farmington River at Tariffville, and 20 billion gallons is diverted for Hartford water supply. Variations in streamflow at 23 continuous-record gaging stations are summarized in standardized graphs and tables that can be used to estimate streamflow characteristics at other sites. For example, mean flow and low-flow characteristics such as the 7-day annual minimum flow for 2-year and 10-year recurrence intervals, have been determined for many partial-record stations from the data for the 23 continuous-record stations. Of the 31 principal lakes, ponds, and reservoirs in the basin, eight have usable storage capacities of more than 1 billion gallons. Two of the largest, Colebrook River Lake and Barkhamsted Reservoir, have more than 30 billion gallons usable storage. Floods have occurred in the area in every month of the year. The greatest known flood on the Farmington River was in August 1955, which had a peak flow of 140,000 cubic feet per second at Collinsville. Since then, three major floodcontrol reservoirs have been constructed to reduce the hazards of high streamflow. The major aquifers underlying the basin are composed of unconsolidated materials (stratified drift and till) and bedrock (sedimentary, igneous, and metamorphic). Stratified drift overlies till and bedrock in valleys and lowlands; it averages about 90 feet in thickness, and is capable of large sustained yields of water to individual wells. Based on hydrologic characteristics and available recharge, sixteen stratified-drift areas are selected as the most favorable for large-scale development. Potential yields can be estimated by several methods. Small water supplies can be obtained from all aquifers. Wells in bedrock yield at least one to two gallons per minute at most sites. The probability of adequate yields for domestic supply is greater from sedimentary than from crystalline bedrock and is also greater from stratified-drift overburden than from till. The quality of water from all sources in the basin is good except where adversely affected by swamp drainage, aquifer composition or human activities. The water is generally low in dissolved-solids concentration and is soft to moderately hard. Surface water is less mineralized than ground water, especially during high-flow conditions when it is primarily direct runoff. Samples of water collected from 20 streams during high flow had 34 mg/L median dissolved-solids concentration and 16 mg/L median hardness. Samples collected from the same sites at low flow had 52 mg/L median dissolved solids and 28 mg/L median hardness. In contrast, water from wells had 112 mg/L median dissolved-solids concentration and 60 mg/L median hardness. Iron and manganese occur in objectionable concentrations ~n a few parts of the basin where streams drain swamps and aquifers are rich in iron- and manganese-bearing minerals. Five percent of streams at high flow, 21 percent at low flow, and 7 percent of ground-water samples contained iron in sufficient concentration to cause stains on plumbing fixtures and laundry. Human activities have modified the quality of water in parts of the basin. The high bacterial content of the Pequabuck River. and the high nitrate and chloride concentrations in some ground-water samples, are evidence of man’s influence. The quantity and quality of water in the basin’s streams and aquifers are satisfactory for a wide variety of uses. and, with suitable treatment, may be used for most purposes. The total amount of water used by 21 principal public supplies within the basin was 29 billion gallons in 1970. About 70 percent of this was used for domestic and commercial purposes, and nearly 30 percent was used by industry. Analyses of water from these systems show good quality.

Connecticut↗
USGS1982

Water resources inventory of Connecticut Part 10: Lower Connecticut River basin

The lower Connecticut River basin study area in south-central Connecticut includes 639 square miles and is drained principally by the Connecticut River and by seven smaller streams that flow directly to Long Island Sound between the West River on the west and the Connecticut River on the east. The population in 1979 was estimated to be 210,380. Much of the industrial development and population centers are in the Mattabesset River basin in the northwestern part, and the largest water use is also in the Mattabesset River basin. Precipitation averages 47 inches per year and provides an abundant supply of water. About 20 inches returns to the atmosphere as evapotranspiration, and the remainder either flows directly to streams or percolates to the water table, eventually discharging to Long Island Sound. Small quantities of water are exported from the basin by the New Haven and Meridan Water Departments, and small quantities are imported by the New Britain Water Department and Metropolitan Direct Commission. Precipitation during 1931-60 resulted in an average annual runoff of 302 billion gallons. In inflow from the Connecticut River is added to the average annual runoff, the 4,370 billion gallon s per year is potentially available for water ue. The domestic, institutional, commercial, and industrial (other than cooling water) water use for 1970 was 7 billion gallons, which is only 3 percent of the total water used, whereas 97 percent of the total is cooling water for power plants. Approximately 60 percent of the 7 billion gallons is treated before being discharged back to the streams. The total amount of fresh water used during 1970 was estimated to be 256,000 million gallons (Mgal), of which 247,000 Mgal was used for cooling water at stream electric-generating plants. The quantity for domestic, commercial, industrial, and agricultural used was 9,000 Mgal, which was approximately 120 gallons a day per person. Public water systems providing 70 percent of these requirement and all the systems supplying water met the drinking water standards of the Connecticut General Assembly (1975). Till is widespread and generally provides only small amounts of water. Wells in till normally yield only a few hundred gallons of water daily and may be inadequate during dry periods. The thickness of of till ranges from 0 to 15 feet; a median thickness of 26 feet is estimated from information provided in drillers' logs of 467 wells penetrating underlying bedrock. The till is generally used only as an emergency or secondary source of water. Bedrock aquifers underlie the entire area and include sedimentary and crystalline (igneous and metamorphic) rock types. These aquifers supply small and usually reliable quantities of water to wells and are the chief source of water for many rural homes and farms., About 90 percent of the wells tapping bedrock yield at least 2 gal/min. The median yields from wells tapping aquifers in sedimentary, igneous, and metamorphic rocks are 11, 8, and 6.5 gal/min, respectively. The quantity of water potentially available from stratified drift was estimated on the basis of hydraulic characteristics of the aquifers, mathematical modeling of the aquifer system, and evaluation of natural and induced recharge. Long-term yields estimated or ten areas underlain by significant thickness of stratified drift range from 0.4 to 4.4 million gallons per day (Mgal/d). A change in well spacing or numbering could increase the long-term yields, but detailed modeling verification studies are needed to confirm optimal well locations. The chemical and physical (turbidity, color, taste, and sediment load) quality of water is good. The water if generally low in dissolved solids and is classified as soft to hard. Surface water is less mineralized than ground water, especially during high flow, when it is primarily derived from surface runoff rather than groundwater runoff. A median dissolved-solids concentration of 42 milligrams per liter (mg/L) and median hardness of 18 mg/L were determined from water samples collected from 26 streams during the high-flow period. During the low-flow period, median dissolved-solids concentration of 61 mg/L and median hardness of 27 mg/L were determined from sample from the same streams. The quality of water in stratified-drift and crystalline-rock aquifers is generally better than that in the sedimentary-rock aquifers. Water from 32 wells tapping stratified drift had median dissolved-solids concentrations of 116 mg/L; and 33 wells tapping stratified drift and 42 tapping crystalline rock had median hardness of 73 mg/L and 68 mg/L, respectively. Water from 32 wells tapping sedimentary rock had median dissolved concentrations of 231 and 156 mg/L, respectively. Sedimentary rock generally yields the hardest water. Iron and manganese occur objectionable concentrations in places, particularly in water from streams draining swamps and in water from aquifers either rich in iron and manganese-nearing minerals or where the reducing environment for solution of these minerals is favorable. Concentrations of iron in excess of 0.3 mg/L were found in 35 percent of the high streamflow samples, and in 45 percent of the ground-water samples. Most of the high iron and manganese concentration in streams and aquifers are found east of the Connecticut River. Human activities and tidal influence along the coast have modified the quality of water in much f the study area. The greatest influence from human activities has been in the northwestern part, in the Mattabesset River basin. There, the quality of water has been affected by domestic and animal wastes, which cause high dissolved-solids concentrations, high nitrate and phosphate loads and high bacterial counts. In the entire area, high nitrate in groundwater occur only locally, and its presence in an individual water supply is chiefly a function of its proximity to sources of contamination, of well construction, and of thickness of overburden. Thirty public-supply wells did have water that had high sodium concentrations or objectionable iron and manganese concentrations, but these are not considered health hazards in the concentrations found in the water samples. Streams, wetlands, and some aquifers along the sough boundary of the basin contain salty water because of tidal movement or extensive ground-water withdrawals. High sediment concentrations also occur as a result of tidal influence in this area.

Connecticut↗
USGS1966

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.

Connecticut↗
USGS2003

Peak-flow frequency estimates for U.S. Geological Survey streamflow-gaging stations in Connecticut

Annual peak-flow data from 128 U.S. Geological Survey streamflow-gaging stations in Connecticut with at least 10 consecutive years of record were used to estimate peak-flow magnitudes for 1.5-, 2-, 10-, 25-, 50-, 100- and 500-year recurrence intervals (exceedance probabilities of 0.67, 0.50, 0.10, 0.04, 0.02, 0.01, and 0.002, respectively). Peak-flow frequency analyses of annual peak flows through the 2001 water year were performed using the procedures in the publication 'Guidelines for Determining Flood-Flow Frequency,' commonly referred to as Bulletin 17B, by the Interagency Advisory Committee on Water Data (1982). A generalized skew coefficient of 0.34, with a standard error of prediction of 0.51, was developed to improve peak-flow frequency estimates in the state; this replaces the generalized skew coefficients for Connecticut shown in Bulletin 17B.

Water-Resources Investigations Report↗
USGS1950

Bibliography of publications relating to ground water in Connecticut

The United States Geological Survey is currently investigating the ground-water resources of Connecticut in cooperation with the State Water Commission. As part of this cooperative project, in order to summarize the knowledge already gained about ground water in the State, a bibliography of reports dealing with ground water in Connecticut has been prepared. A compilation entitled "Bibliography and index of publications relating to ground water prepared by the Geological Survey and cooperating agencies", by G. A. Waring and O. E. Neinzer, was issued as U.S. Geological Survey Water-Supply Paper 992 in 1947. The following compilation lists all the papers in Water-Supply Paper 992 that refer to Connecticut plus other short reports not included in the letter. The first studies of ground water in Connecticut were begun in 1903 by Professor H. E. Gregory of Yale University under the auspices of the U.S. Geological Survey. The early studies were of the reconnaissance type, covering large sections of the State, and were concerned mainly with the relation of the bedrock geology to the water supply. The results were published in several Water-Supply Papers of the Geological Survey. In 1911 a cooperative agreement for the study of the ground-water resources of Connecticut in which each party shared equally in the expenses was made between the Federal Survey and the Connecticut State Geological and Natural History Survey. As a result more detailed studies in smaller areas were undertaken. Active field work covering more than half the State was continued through 1923 under this arrangement and the results published in eight U.S. Geological Survey Water-Supply Papers. After an eleven year period of inactivity and with the inauguration of the Federal Emergency Relief Commission, detailed studies of ground water in Connecticut were begun again in October 1934 as a project of the Emergency Relief Commission (later the Works Progress Administration). The project was sponsored by the Connecticut State Water Commission, the State Planning Board, and the U.S. Geological Survey. The technical direction of the work was undertaken by the Geological Survey. The project consisted of an inventory and mapping of wells and springs in the State by towns and the recording of weekly observations of water levels in selected wells. The data collected through October 1939 were published in six mimeographed bulletins and one typewritten bulletin by the Works Program Administration. In 1939, when it became necessary to curtail the work being carried on by the Works Progress Administration, cooperation was arranged between the Federal Ecological Survey and the State Water Commission to continue investigations relative to the over-development of ground-water supplies in the New Haven area. From time to time additional funds have been made available to meet growing demands by the State for data on its ground-water supplied and the present cooperative program between the U.S. Geological Survey and the State Water Commission is a continuation of the original arrangement. It is estimated that about 14 per cont of the State has been covered by recent ground-water surveys and in addition some data are available for another 20 per cent of he State.

Connecticut↗