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At least 73 records · Page 4Linked to original sources
USGS2007

Salinity increases in the navajo aquifer in southeastern Utah

Salinity increases in water in some parts of the Navajo aquifer in southeastern Utah have been documented previously. The purpose of this paper is to use bromide, iodide, and chloride concentrations and del oxygen-18 and deuterium values in water from the study area to determine if oil-field brines (OFB) could be the source of increased salinity. Mixing-model results indicate that the bromide-to-chloride X 10,000 weight ratio characteristic of OFB in and outside the study area could not be causing the bromide depletion with increasing salinity in the Navajo aquifer. Mixing-model results indicate that a mixture of one percent OFB with 99 percent Navajo aquifer water would more than double the bromide-to-chloride weight ratio, instead of the observed decrease in the weight ratio with increasing chloride concentration. The trend of the mixing line representing the isotopically enriched samples from the Navajo aquifer does not indicate OFB as the source of isotopically enriched water; however, the simulated isotopic composition of injection water could be a salinity source. The lighter isotopic composition of OFB samples from the Aneth, Ratherford, White Mesa Unit, and McElmo Creek injection sites relative to the Ismay site is a result of continued recycling of injection water mixed with various proportions of isotopically lighter make-up water from the alluvial aquifer along the San Juan River. A mixing model using the isotopic composition of the simulated injection water suggests that enriched samples from the Navajo aquifer are composed of 36 to 75 percent of the simulated injection water. However, chloride concentrations predicted by the isotopic mixing model are up to 13.4 times larger than the measured chloride concentrations in isotopically enriched samples from the Navajo aquifer, indicating that injection water is not the source of increased salinity. Geochemical data consistently show that OFB and associated injection water from the Greater Aneth Oil Field are not the source of salinity increases in the Navajo aquifer.

Water Resources Bulletin↗
USGS2007

Relation between stream-water quality and geohydrology during base-flow conditions, Roberts creek watershed, Clayton County, Iowa

An investigation to determine the relation between stream water quality and geohydrology in the Roberts Creek watershed, Clayton County, Iowa, was conducted during selected base-flow periods in 1988-90. Discharge measurements were made and water samples collected for analyses of nutrients and selected herbicides in 19 subbasins along the main stem and tributaries of Roberts Creek. The areal extent of unconsolidated and bedrock units subcropping in each subbasin was quantified. The hydrologic data were correlated statistically with the geologic data to determine relations. Roberts Creek generally gained water and had larger nitrogen concentrations in subbasins in which loess and alluvial material were underlain primarily by low-permeability till and shale units. Roberts Creek generally lost water and had lower nitrate concentrations in subbasins with subcropping karstic units. Nitrogen concentrations decreased in streams underlain by the karstic units because the nitrogen removed by biological processes was not replaced by ground-water inflow. Seepage from Roberts Creek to ground water in areas of subcropping karstic carbonate rocks reduced the flow, which reduced the velocity, causing increased residence time of water in the stream. The additional residence time may allow additional time for biological processes to remove nitrogen from solution. There was no significant relation between dissolved orthophosphate or atrazine and the underlying geology.

Iowa↗
USGS2007

Assessment of gully-control structures in the Rio Nutria watershed, Zuni reservation, New Mexico

During the latter part of the 19th century and the early part of the 20th century, a major cycle of erosion, arroyo cutting, and gullying occurred in the southwestern United States. Since this erosion cycle began, many projects to control erosion, such as the Civilian Conservation Corps projects in the 1930s, were initiated. However, in the Southwestern United States few studies have documented the effect of these structures in reducing erosion or their effect on gully systems. As part of a watershed rehabilitation project on the Zuni Reservation, New Mexico, 47 structures made either of earth or rocks and 23 rock and brush structures were assessed. Sixty percent of the 47 earth or rock structures have breached and relative to dam height, 65 percent of 47 structures are more than 50 percent silted. Of the 23 rock and brush structures, 22 percent have breached or are close to breaching. Reasons for breaching of all structural types may be piping, scour immediately below the structures, large runoff and large drainage area, poor maintenance, headcutting, and active arroyo deepening and widening. In most cases, documentation does not exist on structure design, the specific purpose for a structure, or when these structures were built.

Water Resources Bulletin↗
USGS2007

Frequency-duration analysis of dissolved-oxygen concentrations in two southwestern Wisconsin streams

Historically, dissolved-oxygen (DO) data have been collected in the same manner as other water-quality constituents, typically at infrequent intervals as a grab sample or an instantaneous meter reading. Recent years have seen an increase in continuous water-quality monitoring with electronic dataloggers. This new technique requires new approaches in the statistical analysis of the continuous record. This paper presents an application of frequency-duration analysis to the continuous DO records of a cold and a warm water stream in rural southwestern Wisconsin. This method offers a quick, concise way to summarize large time-series data bases in an easily interpretable manner. Even though the two streams had similar mean DO concentrations, frequency-duration analyses showed distinct differences in their DO-concentration regime. This type of analysis also may be useful in relating DO concentrations to biological effects and in predicting low DO occurrences.

Wisconsin↗
USGS2007

Integrating a geographic information system, a scientific visualization system, and a precipitation model

Investigating natural, potential, and human-induced impacts on hydrologic systems commonly requires complex modeling with overlapping data requirements, plus massive amounts of one- to four-dimensional data at multiple scales and formats. Given the complexity of most hydrologic studies, the requisite software infrastructure must incorporate many components including simulation modeling and spatial analysis with a flexible, intuitive display. Integrating geographic information systems (GIS) and scientific visualization systems (SVS) provides such an infrastructure. This paper describes an integrated system consisting of an orographic precipitation model, a GIS, and an SVS. The results of this study provide a basis for improving the understanding of hydro-climatic processes in mountainous regions. An additional benefit of the integrated system, the value of which is often underestimated, is the improved ability to communicate model results, leading to a broader understanding of the model assumptions, sensitivities, and conclusions at a management level.Investigating natural, potential, and human-induced impacts on hydrologic systems commonly requires complex modeling with overlapping data requirements, plus massive amounts of one- to four-dimensional data at multiple scales and formats. Given the complexity of most hydrologic studies, the requisite software infrastructure must incorporate many components including simulation modeling and spatial analysis with a flexible, intuitive display. Integrating geographic information systems (GIS) and scientific visualization systems (SVS) provides such an infrastructure. This paper describes an integrated system consisting of an orographic precipitation model, a GIS, and an SVS. The results of this study provide a basis for improving the understanding of hydro-climatic processes in mountainous regions. An additional benefit of the integrated system, the value of which is often underestimated, is the improved ability to communicate model results, leading to a broader understanding of the model assumptions, sensitivities, and conclusions at a management level.

Water Resources Bulletin↗
USGS2007

Streamflow trends in Wisconsin's driftless area

Trends in streamflow characteristics were analyzed for streams in southwestern Wisconsin's Driftless Area by using data at selected gaging stations. The analyses indicate that annual low flows have increased significantly, whereas annual flood peaks have decreased. The same trends were not observed for forested areas of northern Wisconsin. Streamflow trends for other streams in southeastern Wisconsin draining predominantly agricultural land were similar to trends for Driftless Area streams for annual low flows. The causes for the trends are not well understood nor are the effects. Trends in annual precipitation do not explain the observed trends in streamflow. Other studies have found that erosion rates decreased significantly in the Driftless Area, and have attributed this reduction to a change of agricultural practices, which increase infiltration, decrease flood peaks, and increase low flows.Trends in streamflow characteristics were analyzed for streams in southwestern Wisconsin's Driftless Area by using data at selected gaging stations. The analyses indicate that annual low flows have increased significantly, whereas annual flood peaks have decreased. The same trends were not observed for forested areas of northern Wisconsin. Streamflow trends for other streams in southeastern Wisconsin draining predominantly agricultural land were similar to trends for Driftless Area streams for annual low flows. The causes for the trends are not well understood nor are the effects. Trends in annual precipitation do not explain the observed trends in streamflow. Other studies have found that erosion rates decreased significantly in the Driftless Area, and have attributed this reduction to a change of agricultural practices, which increase infiltration, decrease flood peaks, and increase low flows.

Water Resources Bulletin↗
USGS2007

Simulation of temporal changes in rainfall-runoff characteristics, Coon Creek basin, Wisconsin

Stream flow for 67 years was simulated for Coon Creek at Coon Valley, Wisconsin, for three conditions in the drainage basin: (1) conditions in the 1930s; (2) conditions in the 1970s, excluding flood-detention reservoirs; and (3) conditions in the 1970s, including flood-detention reservoirs. These simulations showed that the changes in agricultural practices over 40 years (1940-80) reduced the 100-year flood by 53 percent (from 38,900 to 18,300 cubic feet per second). The flood-detention reservoirs reduced the 100-year flood by an additional 17 percent (to 15,100 cubic feet per second). The simulation was accomplished by calibrating a precipitation-runoff model to observed rainfall and runoff during two separate periods (1934-40 and 1978- 81). Comparisons of model simulations showed that differences between the model calibrations for the two periods were statistically significant at the 95 percent confidence level.

Water Resources Bulletin↗
USGS2007

Residence time of water discharging from the Hanging Gardens of Zion Park

The Hanging Gardens are a unique feature of Zion National Park. Knowledge of the source and residence time of water discharging from the Hanging Gardens is necessary to help preserve these features. Ground-water chemical and isotopic data distinguish the discharge from seeps and springs into two groups, one of low and one of high conductivity. Water with low conductivity likely originates as recharge near the steps and springs, and it only interacts with the Navajo Sandstone. High conductivity water, on the other hand, originates as recharge on the tops of plateaus to the east, where it interacts with marine rocks of the Carmel Formation. Carbon dating of these ground waters indicates that the low conductivity water is essentially modern recharge, while the high conductivity water was recharged 1,000 to 4,000 years ago.The Hanging Gardens are a unique feature of Zion National Park. Knowledge of the source and residence time of water discharging from the Hanging Gardens is necessary to help preserve these features. Ground-water chemical and isotopic data distinguish the discharge from seeps and springs into two groups, one of low and one of high conductivity. Water with low conductivity likely originates as recharge near the seeps and springs, and it only interacts with the Navajo Sandstone. High conductivity water, on the other hand, originates as recharge on the tops of plateaus to the cast, where it interacts with marine rocks of the Carmel Formation. Carbon dating of these ground waters indicates that the low conductivity water is essentially modern recharge, while the high conductivity water was recharged 1,000 to 4,000 years ago.

Water Resources Bulletin↗
USGS2007

Springflow effects on chemical loads in the Snake River, south-central Idaho

The 150-kilometer middle reach of the Snake River (middle Snake) in south-central Idaho receives large quantities of water from springs discharging along the north side of the river from the regional Snake River Plain aquifer. Water-quality samples collected from nine north- side springs in April 1994 indicated that springs in the upstream part or the reach had larger concentrations of dissolved solids, dissolved nitrate, total nitrogen, tritium, and heavy isotopes of hydrogen and oxygen than to springs in the downstream part of the reach. Because the spring chemistry varies in the reach, discharge from the springs resulted in a degradation in water quality in some parts or the middle Snake and improvements in water quality in other parts. Depending on the annual discharge in the Snake River, the contribution from the north-side springs represented 32 to 66 percent of the discharge, 32 to 57 percent of the dissolved solids, 26 to 50 percent of the total nitrogen, and 7 to 14 percent of the total phosphorus transported annually from the middle Snake. Synoptic sampling showed that the north- side springs contributed 84 percent of the discharge and 35, 40, and 10 percent of the dissolved solids, total nitrogen, and total phosphorus lead, respectively, to the Snake River during the peak of the irrigation season in 1994.

Water Resources Bulletin↗
USGS2007

Factors affecting herbicide yields in the Chesapeake Bay watershed, June 1994

Median concentrations and instantaneous yields of alachlor, metolachlor, atrazine, cyanazine, and simazine were generally highest at sites in the Lower Susquehanna River Basin and in agricultural subbasins. Instantaneous herbicide yields are related to land use, hydrogeologic setting, streamflow yield, and agricultural row cropping practices. The significance of these relations may be affected by the interdependence of the factors. The percentage of basin area planted in corn is the most influential factor in the prediction of herbicide yield. Instantaneous yields of all five herbicides measured in June 1994 related poorly to averaged 199094 herbicide use. Annually averaged herbicide-use data are too general to use as a predictor for short-term herbicide yields. An evaluation of factors affecting herbicide yields could be refined with more-current land use and land cover information and a more accurate estimate of the percentage of basin area planted in corn. Factors related to herbicide yields can be used to predict herbicide yields in other basins within the Chesapeake Bay watershed and to develop an estimate of herbicide loads to Chesapeake Bay.Median concentrations and instantaneous yields of alachlor, metolachlor, atrazine, cyanazine, and simazine were generally highest at sites in the Lower Susquehanna River Basin and in agricultural subbasins. Instantaneous herbicide yields are related to land use, hydrogeologic setting, streamflow yield, and agricultural row cropping practices. The significance of these relations may be affected by the interdependence of the factors. The percentage of basin area planted in corn is the most influential factor in the prediction of herbicide yield. Instantaneous yields of all five herbicides measured in June 1994 related poorly to averaged 1990-94 herbicide use. Annually averaged herbicide-use data are too general to use as a predictor for short-term herbicide yields. An evaluation of factors affecting herbicide yields could be refined with more-current land use and land cover information and a more accurate estimate of the percentage of basin area planted in corn. Factors related to herbicide yields can be used to predict herbicide yields in other basins within the Chesapeake Bay watershed and to develop an estimate of herbicide loads to Chesapeake Bay.

Water Resources Bulletin↗
USGS2007

Variables indicating nitrate contamination in Bedrock Aquifers, Newark Basin, New Jersey

Variables that describe well construction, hydrogeology, and land use were evaluated for use as possible indicators of the susceptibility of ground water in bedrock aquifers in the Newark Basin. New Jersey, to contamination by nitrate from the land surface. Statistical analyses were performed on data for 132 wells located throughout the Newark Basin. Concentrations of nitrate (as nitrogen) did not exceed the U.S. Environmental Protection Agency maximum contaminant level of 10 milligrams per liter (mg/L) in any of the water samples (U.S. Environmental Protection Agency, 1991). Variables that describe hydrogeology and well construction were found not to be statistically significant in relation to concentrations of nitrate. This finding can be attributed to the complex nature of flow in bedrock aquifers and mixing of water from shallow and deep water-bearing zones that occurs within these wells, which are constructed with long open intervals. Distributions of nitrate concentrations were significantly different among land-use groups on the basis of land use within both a 400- and an 800-m radius zone of the well. The median concentrations of nitrate (as N) in water from wells in predominantly urban-residential (2.5 mg/L) and agricultural areas (1.8 mg/L) were greater than the median concentration of nitrate in water from wells in predominantly undeveloped areas (0.5 mg/L).

Water Resources Bulletin↗
USGS1967

Water resources inventory of Connecticut Part 2: Shetucket River Basin

The Shetucket River basin has 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 inches to 75 inches and has averaged about 45 inches over a 35-year period. Approximately 20 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 Shetucket River or as underflow through the deposits beneath. 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 basins whereas in the summer most of the precipitation is lost through evaporation and transpiration, resulting in sharply reduced streamflow and lowered groundwater levels. The mean monthly storage of water in the basin on an average is 3.5 inches higher in November than it is in June. The amount of water that flows out of the basin in the Shetucket River represents the total amount of water potentlally available for use by man. Annual runoff from the entire basin above the Quinebaug River has ranged from about 13 to 42 inches since 1929, and has averaged about 23 inches (300 billion gallons). Although runoff indicates the total amount of water potentially available, it is usually not economically or legally feasible for man to use all of it. On the other hand, with increased development, It is possible that some water will be reused several times. The water available may be tapped as it flows through the area or is temporarily stored in streams, lakes, and aquifers. The amounts that can be developed vary from place to place and time to time, depending on the amount of precipitation, on the size of drainage area, on the thickness, permeability and areal extent of aquifers, and on the variations in chemical and physical quality of the water. Differences in streamflow from point to point are due primarily to differences in the proportion of stratified drift in the drainage basin above each point, which affect the timing of streamflow, and to differences in precipitation, which affect the amount of streamflow. Information on streamflow from gaging stations may be extended to ungaged sites by accounting for both of these factors ,in calculations. Future floods on the upper Willimantic River or the Shetucket River are unlikely to cause major damage so long as buildings are not constructed below the highest flood elevations to be expected with the present system of reservoirs for flood control. Ground water can be obtained from wells almost anywhere in the Shetucket River basin, but the amount obtainable from individual wells at any particular point depends upon the type and water-bearing properties of the aquifers present. For practical purposes, the earth materials in the basin comprise three aquifers--stratified drift, till, and bedrock, Stratified drift is the only aquifer generally capable of yielding more than 100 gpm to individual wells. This aquifer covers about 18 percent of the basin and occurs chiefly In lowlands where it overlies till or bedrock. Coefficient of permeability of the coarse-grained unit of stratified drift averages about 1,900 gpd per sq ft. Drilled, screened wells tapping this unit, are known to yield from 200 to 675 gpm. Dug wells in coarse-grained stratified drift should supply at least 2 gpm per foot of drawdown over an 8-hour period. Fine-grained stratified drift has an average coefficient of permeability of about 400 gpd per sq ft and can usually yield to dug wells supplies sufficient for household use. Till and bedrock are widespread in extent but can provide only small to moderate water supplies. Till is tapped chiefly by dug wells; permanent supplies of more than 200 gpd can be obtained from dug wells at a majority of sites in areas of till, but there are many sites where the till is too impermeable or too thin to provide this much water throughout the year. The coefficient of permeability of till ranges from about 0.2 gpd per sq ft to 55 gpd per sq it. Bedrock Is tapped chiefly by drilled wells, about 90 percent of which will supply at least 3 gpm. Very few, however, will supply more than 50 gpm. The amount of ground water potentially available In an area depends upon the amount of groundwater outflow, the amount of ground water in storage, and the quantity of water available by Induced infiltration from streams and lakes. From data on permeability, saturated thickness, recharge, yield from aquifer storage, well performance, and streamflow, preliminary estimates of ground-water availability can be made for any point in the basin. Long-term yields estimated for 15 areas especially favorable for development of large ground-water supplies ranged from 1.3 to 61.8 mgd. Detailed site studies to determine optimum yields, drawdowns, and spacing of individual wells are needed before major ground-water development is undertaken In these or other areas. The chemical quality of water in the Shetucket basin Is generally good to excellent. Samples of naturally occurring surface water collected from 32 sites contained less than 61 ppm of dissolved solids and less than 32 ppm of hardness. Water from wells is more highly mineralized than naturally occurring water from streams. Even so only 7 percent of wells sampled yielded water with more than 200 ppm of dissolved sol-ids and only 9 percent yielded water with more than 120 ppm of hardness. Even in the major rivers, which are used to transport industrial waste, the dissolved mineral content is less than 100 ppm and hardness rarely exceeds 40 ppm. One notable exception occurs in the lower reaches of Little River where an exceptional amount of industrial waste is discharged into the river near Versailles. This waste is particularly noticeable during low streamflow. Iron and manganese In both ground water and surface water are the only constituents whose concentrations commonly exceed recommended limits for domestic and industrial use. Most wells in the basin yield clear water with little or no iron or manganese, but distributed among them are wells with ground water that contains enough of these dissolved constituents to be troublesome for most uses. iron concentrations in naturally occurring stream water exceeded 0.3 ppm under tow-flow conditions at 20 percent of the sites sampled. Large concentrations of iron in stream water result from discharge of iron-bearing ground water or from the discharge of water from swamps. In swamps the iron is released largely from decaying vegetation. Ground water more than 30 feet below the land surface has a relatively constant temperature, usually between 48°F and 50°F. Water temperature in very shallow wells may fluctuate from about 38°F in February or March to about 55°F in late summer. Water temperature in the larger streams fluctuates much more widely, ranging from 32°F at least for brief periods in winter, to about 85°F occasionally during The quantity of suspended sediment transported by streams in the basin is negligible, though amounts large enough to be troublesome may occur locally at times. The total amount of water used In the Shetucket Rlver basin for all purposes during 1961 was about 5,810 million gallons~ which is equivalent to 208 gpd per person, Public water systems supplied the domestic needs of nearly half the population of the basin; 10 systems were sampled, all of which provided water of better quality than the U.S. Public Health Service suggests for drinking water standards.

Connecticut↗
USGS1968

Water resources inventory of Connecticut Part 3: lower Thames and southeastern coastal river basins

The lower Thames and southeastern coastal river basins have a relatively abundant supply of water of generally good quality which is derived from streams entering the area and precipitation that has fallen on the area. Annual precipitation has ranged from about 32 inches to 65 inches and has averaged about 48 inches over a 30-year period. Approximately 22 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 report area through estuaries and coastal streams or as underflow through the deposits beneath. 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 report area, whereas in the summer most of the precipitation is lost through evaporation and transpiration, resulting in sharply reduced stream-flow and lowered ground-water levels. The mean monthly storage of water on an average is about 3.8 inches higher in November than it is in June. The amount of water that flows through and out of the report area represents the total amount of water potentially available for use by man. For the 30-year period 1931 through 1960, the annual runoff from the report area has averaged nearly 26 inches (200 billion gallons), from the entire Thames River basin above Norwich about 24 inches (530 billion gallons), and from the Pawcatuck River basin about 26 inches (130 billion gallons). A total average annual runoff of 860 billion gallons is therefore available. Although runoff indicates the total amount of water potentially available, it is usually not economically feasible for man to use all of it. On the other hand, with increased development, it is possible that some water will be reused several times. The water available may be tapped as it flows through the area or is temporarily stored in streams, lakes, and aquifers. The amounts that can be developed vary from place to place and time to time, depending on the amount of precipitation, on the size of drainage area, on the thickness, permeability, and areal extent of aquifers, and on the variations in chemical and physical quality of the water. Differences in streamflow from point to point are due primarily to differences in the proportion of stratified drift in the drainage basin above each point, which affect the timing of streamflow, and to differences in precipitation, which affect the amount of streamflow. Ground water can be obtained from wells almost anywhere in the area, but the amount obtainable at any particular point depends upon the type and water-bearing properties of the aquifers. For practical purposes, the earth materials in the report area comprise three aquifers--stratified drift, bedrock, and till. Stratified drift is the only aquifer generally capable of yielding more than 100 gpm (gallons per minute) to individual wells. It covers about 20 percent of the area and occurs chiefly in lowlands where it overlies till and bedrock. The coefficient of permeability of the coarse-grained unit of stratified drift averages about 1,500 gbd (gallons per day) per sq ft. Drilled, screened wells tapping this unit are known to yield from 4 to 88o gpm and average 146 gpm. Dug wells in coarse-grained stratified drift supply about 2 gpm per foot of drawdown over a period of a few hours. Fine-grained stratified drift has an average coefficient of permeability of about 300 gpd per sq ft and can usually yield supplies sufficient for household use to dug wells. Bedrock and till are widespread in extent but generally provide only small water supplies. Bedrock is tapped chiefly by drilled wells, about 90 percent of which will supply at least 3 gpm. Very few, however, will supply more than 50 gpm. Till is tapped in a few places by dug wells which can yield small supplies of only a few hundred gpd throughout all or most of the year. The coefficient of permeability of till ranges from about 0.2 gpd per sq ft to 120 gpd per sq ft. The amount of ground water potentially available in the report area depends upon the amount of ground-water outflow, the amount of ground water in storage, and the quantity of water available by induced infiltration from streams and lakes. From data on permeability, saturated thickness, recharge, yield from aquifer storage, well performance, and streamflow, preliminary estimates of ground-water availability can be made for any point in the report area. Long-term yields estimated for 18 areas of stratified drift especially favorable for development of large ground-water supplies ranged from 1.3 to 66 mgd. Detailed site studies to determine optimum yields, drawdowns, and spacing of individual wells are needed before major ground-water development is undertaken in these or other areas. The chemical quality of water in the report area is generally good to excellent. Samples of naturally occurring surface water collected at 24 sites contained less than 151 ppm (parts per million) of dissolved solids and less than 63 ppm of hardness. Water from wells is more highly mineralized than naturally occurring water from streams. Even so only 12 percent of the wells sampled yielded water with more than 200 ppm of dissolved solids and only 8 percent yielded water with more than 120 ppm of hardness. Even in major streams, which are used to transport industrial waste, hardness rarely exceeds 60 ppm and the dissolved mineral content is generally less than 200 ppm. At a few places in the town of Montville however, waters may contain dissolved mineral concentrations of 2,000 to 4,000 ppm. Iron and manganese in both ground water and surface water are the only constituents whose concentrations commonly exceed recommended limits for domestic and industrial use. Most wells in the report area yield clear water with little or no iron or manganese, but distributed among them are wells yielding ground water that contains enough of these dissolved constituents to be troublesome for most uses. Iron concentrations in naturally occurring stream water exceed 0.3 ppm under low-flow conditions at 33 percent of the sites sampled. Large concentrations of iron in stream water result from discharge of iron-bearing water from aquifers or from swamps where it is released largely from decaying vegetation. Ground water more than 30 feet below the land surface has a relatively constant temperature, usually between 48°F and 52°F. Water temperature in very shallow wells may fluctuate from about 38°F in February or March to about 55°F in late summer. Water temperature in the larger streams fluctuates much more widely, ranging from 32°F at least for brief periods in winter, to about 85°F occasionally during summer. The quality of suspended sediment transported by streams in the area is negligible. Turbidity in streams is generally not a problem although amounts large enough to be troublesome may occur locally at times. The total amount of water used in the report area for all purposes during 1964 was about 118,260 million gallons, of which 105,600 million gallons was estuarine water used for cooling by industry. The average per capita water use, excluding estuarine, temporary summer residence, and institutional water was equivalent to 186 gpd. Public water systems supplied the domestic needs of nearly tw0-thirds the population of the report area. All of the 19 systems, which were sampled, provided water of better quality than the U.S. Public Health Service suggests for drinking water standards.

Connecticut↗
USGS1970

Water resources inventory of Connecticut Part 4: Southwestern coastal river basins

The 44O square miles of the southwestern coastal river basins (394 square miles of which are in Connecticut) yield about 183 billion gallons, or 23.9 inches of runoff during an average year. This amount of runoff is almost entirely derived from precipitation falling on the basins, and is eventually discharged into Long Island Sound. In 1965, some streamflow originated from 5.5 billion gallons of water imported from the Housatonic River basin. Mean annual runoff is generally an index of the water potentially available for development; however, in the basins, large-scale impoundment and diversion of streamflow has preempted most of the surface water available.

Connecticut↗
USGS1974

Water resources inventory of Connecticut Part 5: lower Housatonic River basin

The 557 square miles of the lower Housatonic River basin in western Connecticut include the basins of two major tributaries, the Pomperaug and Naugatuck Rivers. Nearly all water is derived from precipitation, which averaged 47 inches per year during 1931-60, In this period an additional 570 billion gallons of water per year entered the basin in the main stem of the Housatonic River at Lake Lillinonah, and some water was imported by water-supply systems from outside the basin. Almost half the precipitation--21.6 inches--was lost from the basin by evapotranspiration. Except for small amounts exported, the remainder discharged as runoff and underflow into Long Island Sound. Variations in streamflow at 6 long-term 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 two low-flow characteristics, the 7-day annual minimum flow for 2-year and 10-year recurrence intervals, have been determined for many partial-record stations throughout the basin. Of the 37 principal lakes, ponds, and reservoirs in the basin, 6 have usable storage of more than 1 billion gallons. The “maximum safe draft rate” (described in: “Storage of Water in Lakes and Reservoirs”) of the largest of these, Thomaston Reservoir near Thomaston, is 75.6 million gallons per day for the 10-year and 20-year recurrence intervals of annual lowest mean flow. Floods have occurred during every month, at one time or another. The two greatest floods on the Naugatuck River in historical time occurred 2 months apart in 1955. The larger, in August, had a peak of 106,000 cfs (cubic feet per second) at Beacon Falls. Since then, the likelihood of major floods has been considerably reduced by a program of flood control in the basin. Water can be obtained from three aquifers under-lying the basin-stratified drift, till, and bedrock. Stratified drift covers about 16 percent of the basin, mostly in valleys and lowlands, and its saturated part generally ranges in thickness from 10 feet in small valleys to 200 feet in the Housatonic River valley. Its transmissivity ranges from 0 to 47,000 ft 2 /day (feet shared per day). Till, deposited directly by glacial ice, forms a widespread but discontinuous mantle over bedrock in most upland areas and extends beneath stratified drift in lowlands; it ranges in thickness from 0 to 200 feet. The median value of 31 published determinations of hydraulic conductivity of till in southern New England is 0.67 ft/day and ranges from 0.013 to 29 ft/day. Crystalline bedrock underlies most of the basin and is composed principally of granite, gneiss, and schist. Sedimentary volcanic bedrock underlies only the Pomperaug River basin. Regardless of rock type, water is obtained mostly from fractures. Streambed deposits are significant features of the hydrogeologic system because they affect the amount of water from streams and lakes that can be induced to infiltrate aquifers. Based on field tests, characteristic values of vertical hydraulic conductivity of streambed deposits are 0.40 ft/day for fine-grained deposits and 14 ft/day for gravelly deposits. Ground-water supplies generally range in yield from several millions of gallons per day from large well fields to 1 gpm (gallons per minute) from single wells. Large supplies, with yields of 100 gpm or more from individual wells, are most commonly obtained from stratified drift. Yields to be expected from screened wells tapping this aquifer can be calculated by use of a series of graphs in conjunction with estimates of transmissivity and aquifer thickness. The yields of 14 principal ground-water reservoirs are estimated from aquifer characteristics and also from the amount of water that can be obtained from aquifer storage, from interception or runoff, and from infiltration of streamflow at low-flow conditions, using a hypothetical well-field arrangement for each reservoir. It is assumed that induced infiltration is restricted to an amount equal to the 7-day annual minimum stream-flow for a 2-year recurrence interval. Yields range from 1.4 to 15 mgd (million gallons per day) during periods of no recharge, and from 2.0 to 17 mgd during recharge periods. Small to moderate water supplies can be obtained from any of the aquifers under suitable conditions. For example, data from 294 wells in the basin indicate that yields of a few gallons per minute can be obtained from bedrock at most sites. The likelihood of obtaining an adequate domestic supply is slightly greater in granite than in schist and also is greater where the overburden is stratified drift rather than till. Chemical analyses of precipitation samples collected monthly from five stations in the basin during a 9-month period in 1966 show that rainfall is acidic and that sulfate is the dominant anion, probably because of industrial fumes and smoke within and near the basin. Where unaffected by man’s activities, water in the basin is generally low in dissolved-solids concentration, is of the calcium magnesium bicarbonate type, and is soft to moderately hard. In general, streamflow is less mineralized than ground water, particularly when it consists largely of direct runoff. However, streamflow becomes more highly mineralized during low-flow conditions, when most of it consists of more highly mineralized water discharged from aquifers. The median value of dissolved-solids concentration of water at 22 stream sites was 51 mg/1 (milligrams per liter) during high flow, and 68 mg/1 during low flow within the study period. Iron and manganese occur naturally in objectionable concentrations in parts of the basin, particularly in streams draining swamps and in water from bedrock containing iron and manganese-bearing minerals. Man’s activities have degraded the quality of water in streams in much of the basin, except in the Pomperaug subbasin. In the Naugatuck River basin, the degradation in quality is shown by wide and erratic changes in dissolved-solids concentration, excessive amounts of certain trace elements, a low dissolved oxygen content, and abnormally high temperatures. Ground water is degraded principally by induced infiltration of stream water containing chemical wastes, by wastes stored on the ground and by effluents from septic tanks. Below its confluence with the Naugatuck River, much of the Housatonic River and adjoining marshes, wetlands, and aquifers contain salt water. Measurements of specific conductance during low-flow conditions in 1969 indicate that the dissolved-solids concentration of water in the estuary ranged from 210 mg/1 near Twomile Island to 20,000 mg/1 near Long Island Sound. The quantity and quality of water in the basin are satisfactory for a wide variety of uses, and, with suitable treatment, the water may be used for most purposes. In 1967, the total amount of water used in the basin was about 194 billion gallons. About 90 percent of this was used for industrial purposes, and 95 percent of the industrial water was obtained from surface-water sources. In the same year, 17 municipal and private water-supply systems supplied water of satisfactory quality to about three-fourths of the population.

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USGS1972

Water resources inventory of Connecticut Part 6: Upper Housatonic River basin

The upper Housatonic River basin report area has an abundant supply of water of generally good quality, which is derived from precipitation on the area and streams entering the area. Annual precipitation has averaged about 46 inches over a 30-year period. Of this, approximately 22 inches of water is returned to the atmosphere each year by evaporation and transpiration; the remainder flows overland to streams or percolates downward to the water table and ultimately flows out of the report area in the Housatonic River or in smaller streams tributary to the Hudson River. During the autumn and winter precipitation normally is sufficient to cause a substantial increase in the amount of water stored in surface reservoirs and in aquifers, whereas in the summer, losses through evaporation and transpiration result in sharply reduced streamflow and lowered ground-water levels. Mean monthly storage of water in November is 2.8 inches more than it is in June. The amount of water that flows into, through, and out of the report area represents the total amount potentially available for use ignoring reuse. For the 30-year period 1931 through 1960, the annual runoff from precipitation has averaged 24 inches (294 billion gallons). During the same period, inflows from Massachusetts and New York have averaged 220 and 64 billion gallons per year, respectively. A total average annual runoff of 578 billion gallons is therefore available. Although runoff indicates the total amount of water potentially available, it is rarely feasible to use all of it. On the other hand, with increased development, some water may be reused several times. The water availability may be tapped as it flows through the area or is temporarily stored in streams, lakes, and aquifers. The amounts that can be developed differ from place to place and time to time, depending on the amount of precipitation, on the size of drainage area, on the thickness, transmissivity, and areal extent of aquifers, and on the variations in chemical and physical quality of water. Differences in precipitation cause differences in the amount of streamflow whereas differences in the proportion of stratified drift affect its timing. Water can be obtained from wells almost anywhere in the area, but the amount obtainable at any particular point depends on the type and water-bearing properties of the aquifers tapped. Stratified-drift aquifers are the only ones generally capable of yielding more than 100 gpm (gallons per minute) to individual wells. Drilled, screened wells tapping this unit yield from 17 to 1,400 gpm, with a median yield of 200 gpm. Till and bedrock are widespread but generally provide only small supplies of water. Till is tapped in a few places by dug wells, which can yield small supplies of only a few hundred gallons per day throughout all or most of the year. Bedrock is the chief aquifer for privately owned domestic and rural supplies; it is tapped by drilled wells, about 90 percent of which will supply at least 2 gpm. Only 1 of 10 bedrock wells, however, will supply more than 30 gpm. The amount of ground water potentially available in the report area depends upon the thickness and hydraulic properties of aquifers, the amount of salvageable natural discharge of ground water, and the quantity of water available by induced infiltration from streams and lakes. From data on transmissivity, thickness, recharge, well performance, and streamflow, preliminary estimates of ground-water availability can be made for most stratified-drift aquifers in the report area. Long-term yields estimated for eight areas of stratified drift especially favorable for development of large ground-water supplies ranged from 0.6 to 5 mgd (million gallons per day). Detailed site studies are needed to verity these estimates and to determine optimum yields, drawdowns, and spacing of individual wells before major ground-water development is undertaken in these or other areas. The chemical quality of water in the report area is generally good; carbonate-bedrock units exert considerable local influence on water quality. Samples of naturally occurring surface water collected at 24 sites during low flow averaged 90 mg/l (milligrams per liter) dissolved solids and 60 mg/l hardness. Water from wells is generally more highly mineralized than naturally occurring water from streams. About 37 percent of the wells sampled yielded water with more than 200 mg/l dissolved solids and 50 percent yielded water with more than 120 mg/l hardness. These concentrations reflect the high degree of mineralization of ground water in carbonate bedrock and unconsolidated deposits derived from this bedrock. The larger streams, which transport varying amounts of industrial and domestic effluents, averaged about 150 mg/l dissolved solids and 90 mg/l hardness. Iron and manganese concentrations in both ground water and surface water at some places exceed recommended limits for domestic and industrial use. Most wells in the report area yield water with little or no iron or manganese. In certain localities however, the probability is high of encountering water with excessive concentrations of these constituents. Schists, especially the unit in the northwestern corner of the basin, are the likely sources of water with excessive iron and manganese. Iron concentrations in naturally occurring stream water exceed 0.3 mg/l under low-flow conditions at 29 percent of the sites sampled. These excessive concentrations result from discharge of iron-bearing water from aquifers or from swamps where iron is released from decaying vegetation. Water temperature in the larger streams ranges from 0°C (degrees Celsius) to about 28°C. Ground water between 30 feet and 200 feet below the land surface has a relatively constant temperature, usually between 8°C and 11°C. The quantity of suspended sediment transported by streams under natural conditions is negligible. Even in streams affected by man, turbidity is rarely a problem. The total amount of water used in the report area for all purposes during 1967 was about 6,360 million gallons, or 140 gpd per person. Public supplies furnished the domestic needs of nearly half the population of the area. All of the 14 public supplies sampled provided water that meets the drinking water standards of the U.S. Public Health Service.

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USGS1981

Water resources inventory of Connecticut Part 7: upper Connecticut River basin

The 508 square miles of the upper Connecticut River basin in north-central Connecticut include the basins of four major tributaries: the Scantic, Park, and Hockanum Rivers, and the Farmington River downstream from Tariffville. Precipitation over this area averaged 44 inches per year during 1931-60. In this period, an additional 3,800 billion gallons of water per year entered the basin in the main stem of the Connecticut River at the Massachusetts state line, about 230 billion gallons per year in the Farmington River at Tariffville, and about 10 billion gallons per year in the Seantic River at the Massachusetts state line. Some water was also imported from outside the basin by water-supply systems. About half the precipitation, 22.2 inches, was lost from the basin by evapotranspiration; the remainder flowed out of the study area in the Connecticut River at Portland. Variations in streamflow at 41 long-term 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 two low-flow characteristics: (1) the 7-day annual minimum flow for 2-year and (2) 10-year recurrence intervals, have been determined for many partial-record stations throughout the basin. Of the 30 principal lakes, ponds, and reservoirs, two have usable storage capacities of more than 1 billion gallons. The maximum safe draft rate (regulated flow) of the largest of these, Shenipsit Lake at Rockville, is 6.5 million gallons per day for the 2-year and 30-year recurrence intervals (median and lowest annual flow). Floods have occurred within each month of the year but in different years. The greatest known flood on the Connecticut River was in March 1936; it had a peak flow of 130,000 cubic feet per second at Hartford. Since then, major floods have been reduced by flood-control measures. The major aquifers underlying the basin are composed of unconsolidated materials (stratified drift and till) and bedrock. Stratified drift overlies till and bedrock in valleys and lowlands in the eastern and western parts and in most of the broad central valley. The stratified drift generally ranges in thickness from 10 feet in small valleys to more than 200 feet in the Connecticut River Valley. Bedrock underlies the entire basin and is composed of (1) interbedded sedimentary and igneous rocks and (2) crystalline rocks. Ground-water sources yield from several million gallons per day from large well fields to 1 gallon per minute from single wells. Yields of 100 gal/min or more are most commonly obtained from screened wells tapping stratified-drift aquifers; amounts can be calculated by use of a series of graphs in conjunction with estimates of aquifer transmissivity and thickness. Eighteen areas underlain by good aquifers are selected as the most favorable locations for large-scale development of ground water. Selection of these areas is based on estimates of aquifer characteristics and the amount of water potentially available from induced infiltration of streamflow at low-flow conditions. Small to moderate water supplies can generally be obtained from any of the aquifers. Wells in bedrock yield at least a few gallons per minute at most sites. The probability of obtaining an adequate yield for domestic supply is greater in sedimentary than in crystalline bedrock and is also greater in stratified-drift overburden than in till. Where unaffected by man's activities, the water is of the calcium magnesium bicarbonate type, is generally low to moderate in dissolved-solids concentration, and ranges from soft to hard. In general, streamflow is less mineralized than ground water, particularly when it consists largely of direct runoff. However, streams become more highly mineralized during low-flow conditions, when most flow consists of more highly mineralized water discharged from aquifers. The median dissolved-solids concentration in water from 25 stream sites was 113 mg/L (milligrams per liter) during high flow, and 148 mg/L during low flow within the study period. Iron and manganese occur naturally in objectionable concentrations in some streams draining swamps and in some waters draining from sedimentary bedrock which contains iron- and manganese-bearing minerals. Man's activities have affected the water quality of streams in much of the area, particularly in the Hockanum and Park River basins. The degradation in quality in these streams is shown by wide and erratic changes in dissolved-solids concentration, excessive amounts of trace elements, a low dissolved-oxygen content, and abnormally high temperatures. Ground water within this area is degraded principally by induced infiltration of surface water that contains chemical wastes, by leachate from wastes stored or disposed of on the ground, and by effluents discharged from septic tanks. The quantity and quality of water are satisfactory for a wide variety of uses, and, with suitable treatment, the water may be used for most purposes. The total amount of water used in 1968 was more than 100 billion gallons. About 80 percent of this was used for industrial purposes, and 90 percent of the industrial water was obtained from surface-water sources. About 85 percent of the population was supplied with water for domestic use by 15 major public and municipal systems and 25 private associations. Analyses of water from the 13 largest systems show generally good quality.

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USGS1978

Water resources inventory of Connecticut Part 8: Quinnipiac River basin

The Quinnipiac River basin area in southcentral Connecticut covers 363 square miles, and includes all drainage basins that enter Long Island Sound from the Branford to the Wepawaug Rivers. Its population in 1970 was estimated at 535,000. Precipitation averages 47 inches per year and provides an abundant supply of water. Twenty-one inches returns to the atmosphere as evapotranspiration; the remainder flows directly to streams or percolates to the water table and discharges to Long Island Sound. Small amounts of water are exported from the basin by the New Britain Water Department, and small amounts are imported to the basin by the New Haven Water Company. The amount of water that can be developed at a given place depends upon precipitation, variability of streamflow, hydraulic properties and areal extent of the aquifers, and hydraulic connection between the aquifers and major streams. The quality of the water is determined by the physical environment and the effects of man. Stratified drift is the only aquifer capable of large sustained yields of water to individual wells. Yields of 64 screened wells tapping stratified drift range from 17 to 2,000 gpm (gallons per minute); their median yield is 500 gpm. 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 commonly are inadequate during dry periods. Till is generally used only as an emergency or secondary source of water. Bedrock aquifers underlie the entire report area and include sedimentary, igneous, and metamorphic rock types. These aquifers supply small but reliable quantities of water to wells throughout the basin and are the chief source for many nonurban homes and farms. About 90 percent of the wells tapping bedrock yield at least 2 pgm, and much larger yields are occasionally reported. Maximum well yields of 305 gpm for sedimentary, 75 gpm for igneous, and 200 gpm for metamorphic bedrock have been reported. Water potentially available from stratified drift was estimated on the basis of hydraulic characteristics of the aquifers and evaluation of natural and induced recharge. Long-term yields estimated for 14 favorable areas of stratified drift range from 0.8 to 16.1 mgd (million gallons per day), but detailed verification studies are needed before development. The natural quality of water in the report area is good. The water is generally low in dissolved solid and is soft to moderately hard. Surface water is less mineralized than ground water, especially during high flow when it is primarily surface runoff. A median dissolved-solids concentration of 117 mg/l (milligrams per liter) and a median hardness of 58 mg/l was determined for water samples collected at 20 sites on 16 streams during high flow. A median dissolved-solids concentration of 146 mg/l and a median hardness of 82 mg/l was determined for samples collected at the same sites during low flow. In contrast water from 130 wells had a median dissolved-solids concentration of 188 mg/l and a median hardness of 110 mg/l. Iron and manganese occur in objectionable concentrations in parts of the report area, particularly in water from streams draining swamps and in water from aquifers rich in iron- and manganese-bearing minerals. Concentrations of iron in excess of 0.3 mg/l were found in 40 percent of the high-streamflow samples, 59 percent of the low-streamflow samples and 20 percent of the ground-water samples. Human activities have modified the quality of water in much of the basin. Wide and erratic fluctuations in concentration of dissolved solids in streams, high bacterial content of the Quinnipiac River, and locally high nitrate and chloride concentrations in ground water are evidence of man's influence. Streams, wetlands, and some aquifers along the southern boundary of the basin contain salty water. Overpumping has caused extensive saltwater intrusion in aquifers in the southern and eastern parts of New Haven. The total amount of fresh water used in the area during 1970 is estimated at 35,710 million gallons, or 183 gallons per day per capita. Public water-supply systems met the domestic requirements of about 90 percent of the population; all the systems supplied water that met the drinking water standards of the Connecticut Department of Health.

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