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Research about Connecticut

Source-linked reports with geographic coverage including Connecticut.

At least 109 records · Page 6Linked to original sources
USGS1997

Hydrogeology and water quality of a surficial aquifer underlying an urban area, Manchester, Connecticut

The quality of water along flowpaths in a surficial aquifer system in Manchester, Connecticut, was studied during 1993-95 as part of the National Water Quality Assessment program. The flowpath study examined the relations among hydrogeology, land-use patterns, and the presence of contaminants in a surficial aquifer in an urban area, and evaluated ground water as a source of contamination to surface water. A two-dimensional, finite-difference groundwater- flow model was used to estimate travel distance, which ranged from about 50 to 11,000 feet, from the source areas to the sampled observation wells. Land use, land cover, and population density were determined in the source areas delineated by the ground-water-flow simulation. Source areas to the wells contained either high- or medium-density residential areas, and population density ranged from 629 to 8,895 people per square mile. Concentrations of selected inorganic constituents, including sodium, chloride, and nitrite plus nitrate nitrogen, were higher in the flowpath study wells than in wells in undeveloped areas with similar aquifer materials. One or more of 9 volatile organic compounds were detected at 12 of 14 wells. The three most commonly detected volatile organic compounds were chloroform, methyl-tert-butyl ether, and trichloroethene. Trichloroethene was detected at concentrations greater than the maximum contaminant level for drinking water (5 micrograms per liter) in samples from one well. Four pesticides, including dichloro diphenyl dichloroethylene, dieldrin, dichloroprop, and simazine were detected at low concentrations. Concentrations of sodium and chloride were higher in samples collected from wells screened in the top of the saturated zone than in samples collected from deeper zones. Volatile organic compounds and elevated concentrations of nitrite plus nitrate as nitrogen were detected at depths of as much as 60 feet below the water table, indicating that the effects of human activities on the ground-water quality extends to the bottom of the surficial aquifer. The age of ground water, as determined by tritium and 3helium concentrations, was 0.9 to 22.6 years. pH, alkalinity, and calcium were higher and concentrations of dissolved oxygen were lower in ground-water samples with ages of 10 years or more than in samples younger than 10 years. In addition, concentrations of sodium, chloride, and nitrite plus nitrate nitrogen were low in ground-water samples with ages of 10 years or more, indicating that concentrations of these compounds may be increasing with time or that the recharge areas to these wells may have had less intensive urban land use. Methyl-tert-butyl ether was detected only in wells with ground water ages of less than 11 years, which is consistent with the date of introduction of this compound as a gasoline additive in Connecticut. Analysis of additional samples collected for analysis of stable nitrogen isotopes indicated that the most likely source of elevated concentrations of nitrate nitrogen was lawn and garden fertilizers, but other sources, including wastewater effluents, soil organic nitrogen, and atmospheric deposition, may contribute to the total. Population density was positively correlated (at the 97 percent confidence level) to concentrations of nitrite plus nitrate as nitrogen. Water quality in the Hockanum River aquifer has been degraded by human activities, and, after discharge to surface water, affects the water quality in the Hockanum River. On an annual basis, ground-water discharge from the study area to the river (as measured at a downstream continuous-record gaging station) contributes about 5 percent of the annual load of nitrite plus nitrate nitrogen, but, during low flow, contributes 11 percent of the nitrite plus nitrate nitrogen, 32 percent of the calcium, and 16 percent of the chloride to the river.

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USGS1997

A pair of roseate terns fledges three young with limited human assistance

Hays (1994) reported that a trio of Roseate Terns ( Sterna dougallii ) raised three fledglings in 1991 at Great Gull Island, New York. Despite the regular occurrence of "supernormal" clutches of three or more eggs (Norton 1988, Hays 1994, Shealer and Zurovchak 1995), we are not aware of any reports of three young being fledged by just two adult Roseate Terns. Here we report a pair that, with limited human assistance given to the initially smallest chick for two weeks, fledged three young in 1994 at Falkner Island off the coast of Connecticut.

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USGS1996

Trends in surface-water quality in Connecticut, 1969-88

Surface-water-quality data from selected monitoring stations in Connecticut were analyzed for trend, using the Seasonal Kendall test, for water years 1969-88, 1975-88, and 1981-88. The number of constituents and stations evaluated varied with the different time periods. The 39 monitoring stations included 26 freshwater streams with associated discharge data, 7 tidally affected streams, 4 harbor stations, and 2 surface impoundments. Flow-adjustment procedures were used where possible to minimize the effects of stream- flow variability on trend results. The drainage area of the monitoring stations includes approximately 5,000 mi 2 covering the State of Connecticut and about 11,000 mi 2 in upstream drainage areas outside of the State. Drainage basin size for the freshwater streams ranges from 4.1 mi 2 to 9,660 mi 2 . Land uses in the drainage basins range from undeveloped forested areas to highly urbanized metropolitan areas. During the period covered by the trend study, the State's population has grown, suburban development has increased, agricultural land use has decreased, and wastewater-treatment practices have improved. Increases in specific conductance and in the concentrations of calcium, magnesium, chloride, sulfate, dissolved solids, and total solids were geographically widespread and numerous during water years 1975-88 and indicate a general increase statewide in dissolved constituents in streamflow, both in urbanized and less developed areas. The effects of increasing urbanization, including municipal and industrial wastewater, septic system leachate, nonpoint runoff, and atmospheric deposition of contaminants, are possible causes for these increases. Decreases in turbidity and in the concentrations of total phosphorus, total organic carbon, and fecal coliform bacteria were geographically widespread and numerous during 1975-88. This general decrease in suspended material and bacteria may be attributable to basic improvements in the treatment of municipal and industrial wastewater during the period of record. Decreasing concentrations of total phosphorus may also be related to decreases in agricultural land use and to a decline in the use of detergents containing phosphorus. Detected decreases in total organic carbon and turbidity may have been caused, in part, by changes in sampling or analytical methods. Increases in total nitrogen, total organic nitrogen, and total nitrite-plus- nitrate were geographically widespread and numerous during 1975-88 and appear to indicate effects from both point sources in urbanized basins and nonpoint sources in less developed basins. The number of stations with increasing concentrations of nitrogen constituents was much smaller during 1981-88 than during 1975-88. Decreases in total ammonia nitrogen were detected at 11 stations during 1981-88. Decreases in total ammonia, sometimes paired with increases in total nitrite-plus-nitrate, may result from improvements in wastewater treatment. Increases in the concentration of dissolved oxygen, or dissolved oxygen as a percent of saturation, were geographically widespread and numerous during 1969-88 and 1975-88. Increases were less common during 1981-88. Increases in dissolved oxygen in urbanized basins may be related to major improvements in wastewater treatment during the 1970's and 1980's. The magnitude of the trends detected during 1969-88 may have been affected in part by a change, around 1974, in the model of the instrument used to measure dissolved oxygen in the field. Statewide increases in pH were detected during 1969-88, 1975-88, and 1981-88, in both urbanized and less developed basins. The widespread increases in pH were unexpected, given the relatively acidic quality of precipitation in the region during the study period. Only two decreases in pH were detected, both in relatively undeveloped basins. Increases in pH in urbanized areas may be related to decreasing concentrations of ammonia and to requirements for neutralization of municipal and industrial wastewater.

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USGS1995

Water resources data, Connecticut, water year 1994

Water resources data for the 1994 water year for Connecticut consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels of ground-water wells. Specifically, it contains: (1) discharge records for 44 streamflow-gaging stations; (2) stage-only records for 4 tidal-gaging stations; (3) 41 partial-record or miscellaneous streamflow stations; (4) water-quality records for 14 streamflow-gaging stations, for 15 ungaged stream sites, for 2 lakes and reservoirs, for 22 miscellaneous stations, and for 67 wells; and (5) water-level records for 91 observation wells. Locations of these sites are shown on Figures 1, 2 and 3. Additional water data were collected at various sites involved in the systematic data-collection program and are published as miscellaneous measurements and analyses. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Connecticut.

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USGS1995

Geohydrology of the Gallup's Quarry area, Plainfield, Connecticut

The geohydrology of the Gallup's Quarry area in Plainfield, Connecticut was characterized by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, to provide a preliminary framework for future remedial efforts. Gallup's Quarry, an inactive sand and gravel pit, was the site of unregulated disposal of an unknown volume of chemical wastes from at least the summer of 1977 until January 1978. Existing information collected for the Connecticut Department of Environmental Protection during 1978-82 showed that ground water beneath Gallup's Quarry and adjacent land to the northwest was contaminated by organic and inorganic compounds. There is also some evidence for contamination of Mill Brook, which is located north and northwest of the disposal areas. Geologic mapping and subsurface data show that unconsolidated surficial materials up to 90 feet thick overlie fractured crystalline bedrock in most of the Gallup's Quarry area. The surficial materials consist primarily of stratified drift and till. Texture changes vertically and laterally within the stratified drift; grain size ranges from very coarse to fine. Till blankets the bedrock surface beneath the stratified drift and is a few feet to as much as 25 feet thick. Bedrock is exposed at land surface in a hill in the southeastern part of the quarry and slopes to depths of up to 90 feet beneath the area west and north of the disposal sites. The bedrock is a dark, fine-grained, fractured and jointed blastomylonite and hornblende gneiss of the Quinebaug Formation. It is likely that a west- northwest-trending fault is present in the bedrock beneath Gallup's Quarry; this fault, if present, may provide a preferential pathway for ground-water flow and contaminant transport. The principal horizontal direction of ground-water flow and movement of dissolved contaminants in the stratified drift was to the northwest of the waste-disposal areas toward Mill Brook in 1978. Estimates of average annual recharge based on regional analyses for 1978-91 are 30 inches in areas where stratified drift are exposed and 9.6 inches in areas where till and crystalline bedrock are exposed. The hydraulic conductivity of the coarse-grained stratified drift, identified in earlier U.S. Geological Survey studies as part of an aquifer capable of yielding large quantities of water, may be several hundred feet per day. The hydraulic conductivity of the till, based on regional information, is likely 0.04 to 24 feet per day. More detailed geohydrologic information is required to develop effective remedial programs at Gallup's Quarry, particularly in the areas north and west of the waste-disposal areas. Detailed subsurface geologic mapping and definition of head distribution and other hydraulic properties of each geohydrologic unit would indicate directions and rates of ground-water flow. Most importantly, the present extent of contamination of water and sediments throughout the area will have to be determined.

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USGS1995

Geohydrology and water quality of the Durham Center Area, Durham, Connecticut

Contaminated ground water is widespread and persistent beneath the Durham Center area in the town of Durham, Conn. Most of the contaminants are organic halides, usually trichloroethene, 1,1,1-trichloroethane, and tetrachloroethene. Less extensive chemical contamination of surface water, soil, and glacial sediments also has been detected. Two manufacturing companies, located at the northern and southern ends of this largely residential area, are believed to be the principal sources of the organic compounds detected in ground water. The contamination of water in the bedrock, the primary source of drinking water throughout the area, is the major environmental concern. Maximum concentrations of trichloroethene in three bed- rock wells range from 4,500 to about 5,500 mg/L (micrograms per liter). Concentrations of trichloroethene greater than 5 mg/L, the maximum contaminant level established for drinking water by the U.S Environmental Protection Agency, have regularly been detected in water samples from many other bedrock wells for at least 9 years. The geohydrology of the area is highly complex. Compact lodgment till that is up to 30 feet thick and probably fractured, overlies the bedrock. The bedrock is lithologically heterogeneous, and con- sists mostly of red fluvial sandstone, siltstone, and conglomerate; it is locally interbedded with black lacustrine shales and gray sandstones. Lithology and stratigraphy interpreted from borehole-geophysical logs at Durham Center are consistent with the Portland Formation subfacies described in earlier geologic studies. Beds strike nearly north-south and dip gently eastward. At least one high-angle normal fault transects the bedrock; it strikes northeast and dips northwest. Acoustic televiewer logs, measurements at out-crops, and azimuthal, square-array, resistivity data indicate a dominance of northeast-striking fractures that dip steeply northwest and southeast. Less prevalent strike directions are north to east-north-east. The till and sedimentary bedrock are dual-porosity, dual-permeability media. The hydraulic conductivity of the bulk mass of till is believed to be on the order of tenths of a foot per day to about 2.5 feet per day, with a total porosity of about 25 percent and an estimated average fracture porosity of less than 1 percent. The reported transmissivities of the bedrock range from less than 1 to about 17,000 feet squared per day and storativity is generally about 10-4, but the accuracy of these values is uncertain. The intergranular porosity of the sandstone units is estimated to average 5 percent, and estimates of fracture porosity from square-array, resistivity soundings at two sites were 1.1 and 2.7 percent. The bedrock has characteristics of both a single aquifer and a multi-unit, artesian or leaky aquifer system. A local ground-water-flow system that includes the upper part of the bedrock is unconfined. A large- scale flow system in deeper parts of the bedrock has transported organic compounds across topographic drainage divides. Borehole-geophysical logs and head measurements indicate that the natural ground- water-flow system in the bedrock has been altered by drilled wells that connect fractures and by with- drawals from wells. A conceptual model of the movement and fate of organic contaminants suggests that (1) nonaqueous phase organic halides are retained near their source; (2) flow is primarily through fractures in the till and through fractures and bedding-plane openings in the sedimentary rocks; (3) retardation of contaminants occurs primarily by diffusion from fractures into the aquifer matrix; and (4) transport directions of dissolved organic halides are controlled by a combination of natural hydraulic gradients, hydraulic gradients produced by the cyclical pumping of wells, and by the strike directions of bedrock faults, fractures, and bedding planes.

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USGS1995

Surface-geophysical techniques used to detect existing and infilled scour holes near bridge piers

Surface-geophysical techniques were used with a position-recording system to study riverbed scour near bridge piers. From May 1989 to May 1993, Fathometers, fixed- and swept-frequency continuous seismic- reflection profiling (CSP) systems, and a ground-penetrating radar (GPR) system were used with a laser-positioning system to measure the depth and extent of existing and infilled scour holes near bridge piers. Equipment was purchased commercially and modified when necessary to interface the components and (or) to improve their performance. Three 200-kHz black-and-white chart-recording Fathometers produced profiles of the riverbed that included existing scour holes and exposed pier footings. The Fathometers were used in conjunction with other geophysical techniques to help interpret the geophysical data. A 20-kHz color Fathometer delineated scour-hole geometry and, in some cases, the thickness of fill material in the hole. The signal provided subbottom information as deep as 10 ft in fine-grained materials and resolved layers of fill material as thin as 1 ft thick. Fixed-frequency and swept-frequency CSP systems were evaluated. The fixed-frequency system used a 3.5-, 7.0-, or 14-kHz signal. The 3.5-kHz signal penetrated up to 50 ft of fine-grained material and resolved layers as thin as 2.5-ft thick. The 14-kHz signal penetrated up to 20 ft of fine-grained material and resolved layers as thin as 1-ft thick. The swept-frequency systems used a signal that swept from 2- to 16-kHz. With this system, up to 50 ft of penetration was achieved, and fill material as thin as 1 ft was resolved. Scour-hole geometry, exposed pier footings, and fill thickness in scour holes were detected with both CSP systems. The GPR system used an 80-, 100-, or 300-megahertz signal. The technique produced records in water up to 15 ft deep that had a specific conductance less than 200 µS/cm. The 100-MHz signal penetrated up to 40 ft of resistive granular material and resolved layers as thin as 2-ft thick. Scour-hole geometry, the thickness of fill material in scour holes, and riverbed deposition were detected using this technique. Processing techniques were applied after data collection to assist with the interpretation of the data. Data were transferred from the color Fathometer, CSP, and GPR systems to a personal computer, and a commercially available software package designed to process GPR data was used to process the GPR and CSP data. Digital filtering, predictive- deconvolution, and migration algorithms were applied to some of the data. The processed data were displayed and printed as color amplitude or wiggle-trace plots. These processing methods eased and improved the interpretation of some of the data, but some interference from side echoes from bridge piers and multiple reflections remained in the data. The surface-geophysical techniques were applied at six bridge sites in Connecticut. Each site had different water depths, specific conductance, and riverbed materials. Existing and infilled scour holes, exposed pier footings, and riverbed deposition were detected by the surveys. The interpretations of the geophysical data were confirmed by comparing the data with lithologic and (or) probing data.

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USGS1994

Water resources data, Connecticut water year 1993

The Water Resources Division of the U.S. Geological Survey, in cooperation with State agencies, obtains a large amount of data pertaining to the water resources of Connecticut each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Connecticut."

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USGS1994

Behavior and successful nesting of American oystercatchers on Falkner Island, Connecticut, in 1993

Falkner Island, a two hectare unit of the Stewart B. McKinney National Wildlife Refuge, is located at 41°13'N, 72°39'W in Long Island Sound about 5 km south of Guilford, Connecticut. This island, described in detail by Helander (1988), is the nesting site of a mixed colony of several thousand Common Terns ( Sterna hirundo ) and a few hundred Roseate Terns ( S. dougallii ) (Spendelow 1994a,b). This colony has been studied by the staff of the Falkner Island Tern Project (FITP) since 1978 (Spendelow 1982, Spendelow and Nichols 1989). In 1993, I made opportunistic observations of a pair of American Oystercatchers ( Haematopus palliatus ) and their young. I describe here their nesting activity and behavior. I did not find similar published material on much of the behavior I observed or on oystercatcher breeding biology in Connecticut. Oystercatchers have attempted to nest in Connecticut since the late 1970s (Proctor 1981, Anon. 1982) [not in 1980 in Westbrook as misstated earlier (Zingo 1992) ]. A first attempt by American Oystercatchers to nest on Falkner Island in 1991 was unsuccessful (Zingo 1992). Although a pair of oystercatchers was seen on Falkner Island several times from April to August 1992, they made no apparent attempt to nest. In 1993, however, a pair (Figure 1) successfully fledged two young. Although young have been produced previously elsewhere in the state (e.g., Dewire 1981, Rosgen 1986, Taylor 1989), these were the first young produced in New Haven County.

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USGS1994

Two hybrid common x roseate terns fledge at Falkner Island, Connecticut

Although these two similarly-sized species are sympatric throughout much of their breeding range, there are few published records of hybridization between Roseate ( Sterna dougallii ) and Common ( S. hirundo ) Terns. Records include at least five from Europe (Witherby and Ticehurst 1908, Perry 1972, Robbins 1974, Burggraeve 1977, van den Berg 1980) and only one from North America (Hays 1975), but we are aware of several unpublished records of hybridization at colonies in Massachusetts (I. Nisbet, pers. comm.) and New York (J. Burger, pers. comm.). Differences in sexual display probably serve as the principal barrier to hybridization (Palmer 1941 ), and in the northeastem United States where both species breed, Common Terns tend to nest in more open areas while Roseate Terns tend to nest in or under cover (Hays 1975, Nisbet 1981, Spendelow 1982, Burger and Gochfeld 1988). From 1984 through 1993, we recorded several instances of interbreeding in a mixed colony of several thousand Common Terns and a few hundred Roseates at the Falkner Island Unit of the Stewart B. McKinney National Wildlife Refuge. This 2-ha island is located at 41 °13'N and 72° 39'W in Long Island Sound, approximately 5 km off the coast of Guilford, Connecticut. Spendelow (1982) briefly described the island and the areas used by the nesting terns; a more detailed description of the island is in Helander (1988). The mixed pair we observed in 1993 nested in a subcolony of about 25 pairs of Roseates on the southeast section of the island's rocky beach, where we put out 30 boxes to create more protected nest sites for Roseate Terns. Here we present a summary of their successful nesting, which we followed almost daily from several days prior to the laying of the first egg until departure of these birds from the colony site.

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USGS1993

Effects of land use on quality of water in stratified-drift aquifers in Connecticut

Activities associated with agricultural, residential, commercial, and industrial land uses have affected water quality in 4 stratified-drift aquifers in Connecticut. Water-quality data from 116 shallow wells were segregated by land use. Nonparametric statistical analysis indicate that 27 water-quality variables differ at the 0.05 significance level for samples from at least one land-use area. Most constituent concentrations or detection frequencies are lowest in samples from undeveloped areas. Groundwater quality is more adversely affected in tilled than untilled agricultural areas. Twenty percent of wells in tilled areas yielded water with nitrogen concentrations > 10 mg/L. Atrazine was detected in one-third of the wells in tilled areas. Median concentrations of most inorganic constituents are higher in sewered than in unsewered residential areas. One or more of 17 volatile organic compounds were detected in 62 percent of wells in unsewered areas. Chloroform was detected in sewered areas significantly more often than in undeveloped, tilled agricultural, and unsewered residential areas. Water beneath commercial areas is most adversely affected. Median sodium, chloride, and dissolved solids concentrations are highest in samples from commercial areas. Tetrachloroethylene was detected in 50 percent of wells in commercial areas at concentrations up to 1,300 microg/L. Trichloroethylene and 1,2-transdichloroethylene were found in more than 40 percent of wells in commercial areas. In industrial areas, 91% of the wells sampled contained 1 or more of 12 volatile organic compounds. Chloroform was the most commonly detected compound followed by tetrachloroethylene and 1,1,1-trichloroethane. (USGS)

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USGS1993

Water resources data, Connecticut, water year 1992

Water resources data for the 1992 water year for Connecticut consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels of ground-water wells. Specifically, it contains: (1) discharge records for 44 streamflow-gaging stations, and for 1 tidal volume streamflow station; (2) stage-only records for 3 tidal-gaging stations; (3) 29 partial-record or miscellaneous streamflow stations; (4) water-quality records for 13 streamflow-gaging stations, for 17 ungaged stream sites, for 1 tidal-gaging station, for 2 lakes and reservoirs,; and (5) water-level records for 46 observation wells. Locations of these sites are shown on Figures 1, 2 and 3. Additional water data were collected at various sites involved in the systematic data-collection program and are published as miscellaneous measurements and analyses. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Connecticut.

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USGS1992

Surficial materials map of Connecticut

The unconsolidated deposits overlying bedrock in Connecticut range from a few feet to several hundred feet in thickness. These earth materials significantly affect human development of the land. Most of the unconsolidated materials are deposits of continental glaciers that covered all of New England at least twice during the Pleistocene ice age. These glacial deposits are divided into two broad categories, glacial till and glacial stratified deposits. Till, the most widespread glacial deposit, was laid down directly by glacier ice and is characterized by a nonsorted matrix of sand, silt, and clay with variable amounts of stones and large boulders. Glacial meltwater deposits are concentrated in both small and large valleys· and were laid down by glacial meltwater hi streams and lakes in front of the retreating ice margin during deglaciation. These deposits are characterized by layers of well-sorted to poorly sorted gravel, sand, silt, and clay. Postglacial sediments, primarily floodplain alluvium and swamp deposits, make up a lesser proportion of the unconsolidated materials of Connecticut. Alluvium is largely reworked from glacial materials and has similar physical characteristics.

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USGS1992

Water resources data, Connecticut water year 1991

The Water Resources Division of the U.S. Geological Survey, in cooperation with State agencies, obtains a large amount of data pertaining to the water resources of Connecticut each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Connecticut."

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