Geology topics

Lee R. Watson

Publications and source records attributed to Lee R. Watson.

7 recordsLinked to original sources

USGS2007

Hydrogeology, Ground-Water-Age Dating, Water Quality, and Vulnerability of Ground Water to Contamination in a Part of the Whitewater Valley Aquifer System near Richmond, Indiana, 2002-2003

Assessments of the vulnerability to contamination of ground-water sources used by public-water systems, as mandated by the Federal Safe Drinking Water Act Amendments of 1996, commonly have involved qualitative evaluations based on existing information on the geologic and hydrologic setting. The U.S. Geological Survey National Water-Quality Assessment Program has identified ground-water-age dating; detailed water-quality analyses of nitrate, pesticides, trace elements, and wastewater-related organic compounds; and assessed natural processes that affect those constituents as potential, unique improvements to existing methods of qualitative vulnerability assessment. To evaluate the improvement from use of these methods, in 2002 and 2003, the U.S. Geological Survey, in cooperation with the City of Richmond, Indiana, compiled and interpreted hydrogeologic data and chemical analyses of water samples from seven wells in a part of the Whitewater Valley aquifer system in a former glacial valley near Richmond. This study investigated the application of ground-water-age dating, dissolved-gas analyses, and detailed water-quality analyses to quantitatively evaluate the vulnerability of ground water to contamination and to identify processes that affect the vulnerability to specific contaminants in an area of post-1972 greenfield development. The aquifer system in the study area includes an unconfined sand and gravel aquifer used for public-water supply (upper aquifer) and a confined sand and gravel aquifer (lower aquifer) separated by a till confining unit. Several hydrogeologic and cultural measures indicate that the upper aquifer is qualitatively vulnerable to contamination: the upper aquifer is unconfined and has a shallow depth to the water table (from about 4.75 to 14 feet below land surface), low-permeability sediments in the unsaturated zone are thin (less than 10 feet thick), estimated ground-water-flow rates through the upper aquifer are relatively rapid (the highest estimated rates ranged from 0.44 to about 5.0 feet per day), and potential contaminant sources were present. Ground-water-age dates indicate that ground-water samples represented recharge from about the time greenfield development began south of the ground-water-flow divide and that changes in water quality would lag changes in contaminant inputs. Estimates of ground-water age, computed with dichlorodifluoromethane (CFC-12) and trichlorotrifluoroethane (CFC-113) concentrations in water samples collected from seven observation wells in February and March 2003, indicated that water in the upper aquifer had recharged within about 13 to 30 years before sampling. Ground-water ages were youngest (from about 13 to 15 years since recharge) in water from the shallow wells along the glacial-valley margin and oldest (30 years) in water from a well at the base of the aquifer in the valley center. Ground-water ages determined for the shallow wells may be affected by mixing of recent recharge with older ground water from deeper in the aquifer, as indicated by upward hydraulic gradients between paired shallow and deep wells in the upper aquifer. Other parts of the Whitewater Valley aquifer system with similar hydrogeologic characteristics could be expected to have similarly young ground-water ages and residence times. Analyses of water samples collected from the seven observation wells in August and September 2002 indicated that concentrations of chloride, sodium, and nitrate generally were larger in ground water from the upper aquifer than in other parts of the Whitewater Valley aquifer system. Drinking-water-quality standards for Indiana were exceeded in water samples from one well for chloride concentrations, from four wells for dissolved-solids concentrations, and from one well for nitrate concentrations. Application of low-level methods for trace-element analyses determined that concentrations of aluminum, cobalt, iron, lithium, molybdenum, nickel, selenium, uranium, vanadium, and zinc were less than or equal to 8 micrograms per liter; concentrations of arsenic, cadmium, chromium, and copper were less than or equal to 1 microgram per liter. Application of low-level analytical methods to water samples enabled the detection of several pesticides and volatile, semivolatile, and wastewater-related organic compounds; concentrations of individual pesticides and volatile organic compounds were less than 0.1 microgram per liter and concentrations of individual wastewater organic compounds were less than 0.5 microgram per liter. The low-level analytical methods will provide useful data with which to compare future changes in water quality. Results of detailed water-quality analyses, ground-waterage dating, and dissolved-gas analyses indicated the vulnerability of ground water to specific types of contamination, the sequence of contaminant introduction to the aquifer relative to greenfield development, and processes that may mitigate the contamination. Concentrations of chloride and sodium and chloride/bromide weight ratios in sampled water from five wells indicated the vulnerability of the upper aquifer to roaddeicer contamination. Ground-water-age estimates from these wells indicated the onset of upgradient road-deicer use within the previous 25 years. Nitrate in the upper aquifer predates the post-1972 development, based on a ground-water-age date (30 years) and the nitrate concentration (5.12 milligrams per liter as nitrogen) in water from a deep well. Vulnerability of the aquifer to nitrate contamination is limited partially by denitrification. Detection of one to four atrazine transformation products in water samples from the upper aquifer indicated biological and hydrochemical processes that may limit the vulnerability of the ground water to atrazine contamination. Microbial processes also may limit the aquifer vulnerability to small inputs of halogenated aliphatic compounds, as indicated by microbial transformations of trichlorofluoromethane and trichlorotrifluoroethane relative to dichlorodifluoromethane. The vulnerability of ground water to contamination in other parts of the aquifer system also may be mitigated by hydrodynamic dispersion and biologically mediated transformations of nitrate, pesticides, and some organic compounds. Identification of the sequence of contamination and processes affecting the vulnerability of ground water to contamination would have been unlikely with conventional assessment methods.

Indiana, Ohio↗

USGS2007

Evaluation of ground-water and boron sources by use of boron stable-isotope ratios, tritium, and selected water-chemistry constituents near Beverly Shores, northwestern Indiana, 2004

Concentrations of boron greater than the U.S. Environmental Protection Agency (USEPA) 900 μg/L removal action level (RAL) standard were detected in water sampled by the USEPA in 2004 from three domestic wells near Beverly Shores, Indiana. The RAL regulates only human-affected concentrations of a constituent. A lack of well logs and screened depth information precluded identification of whether water from sampled wells, and their boron sources, were from human-affected or natural sources in the surficial aquifer, or associated with a previously defined natural, confined aquifer source of boron from the subtill or basal sand aquifers. A geochemically-based classification of the source of boron in ground water could potentially determine the similarity of boron to known sources or mixtures between known sources, or classify whether the relative age of the ground water predated the potential sources of contamination. The U.S. Geological Survey (USGS), in cooperation with the USEPA, investigated the use of a geochemical method that applied boron stable isotopes, and concentrations of boron, tritium, and other constituents to distinguish between natural and human-affected sources of boron in ground water and thereby determine if the RAL was applicable to the situation. Boron stable-isotope ratios and concentrations of boron in 17 ground-water samples and tritium concentrations in 9 ground-water samples collected in 2004 were used to identify geochemical differences between potential sources of boron in ground water near Beverly Shores, Indiana. Boron and δ 11 B analyses for this investigation were made on unacidified samples to assure consistency of the result with unacidified analyses of δ 11 B values from other investigations. Potential sources of boron included surficial-aquifer water affected by coal-combustion products (CCP) or domestic-wastewater, upward discharge of ground water from confined aquifers, and unaffected water from the surficial aquifer that was distant from human-affected boron sources. Boron concentrations in potential ground-water sources of boron were largest (15,700 to 24,400 μg/L) in samples of CCP-affected surficial aquifer water from four wells at a CCP landfill and smallest (27 to 63 μg/L) in three wells in the surficial aquifer that were distant from human-affected boron sources. Boron concentrations in water from the basal sand aquifer ranged from 656 μg/L to 1,800 μg/L. Boron concentrations in water from three domestic-wastewater-affected surficial aquifer wells ranged from 84 to 387 μg/L. Among the representative ground-water samples, boron concentrations from all four samples of CCP-affected surficial aquifer water and four of five samples of water from the basal sand aquifer had concentrations greater than the RAL. A comparison of boron concentrations in acid-preserved and unacidified samples indicated that boron concentrations reported for this investigation may be from about 11 to 16 percent less than would be reported in a standard analysis of an acidified sample. The stable isotope boron-11 was most enriched in comparison to boron-10 in ground water from a confined aquifer, the basal sand aquifer (δ 11 B, 24.6 to 34.0 per mil, five samples); it was most depleted in CCP-affected water from the surficial aquifer (δ 11 B, 0.1 to 6.6 per mil, four samples). Domestic-wastewater-affected water from the surficial aquifer (δ 11 B, 8.7 to 11.7 per mil, four samples) was enriched in boron-11, in comparison to individual samples of a borax detergent additive and a detergent with perborate bleach; it was intermediate in composition between basal sand aquifer water and CCP-affected water from the surficial aquifer. The similarity between a ground-water sample from the surficial aquifer and a hypothetical mixture of unaffected surficial aquifer and basal sand aquifer waters indicates the potential for long-term upward discharge of ground water into the surficial aquifer from one or more confined aquifers. Estimated δ 11 B values for acidified samples were depleted by 1.9 to 2.8 per mil in comparison to unacidified samples from the four wells sampled; those differences were small in comparison to the differences between δ 11 B values of representative sources of boron in ground water. Tritium concentrations ranged from 7.0 to 10.3 tritium units in six samples from the surficial aquifer and were less than 0.8 tritium units in three samples from the basal sand aquifer. Water from wells in the surficial aquifer represents predominantly modern, post-1972 recharge and sources of boron and other constituents. Water from the basal sand aquifer is associated with pre-1952 recharge from sources not affected by local boron inputs. Ground water from six wells (five domestic wells and one public-supply well) where the ground-water source was unknown had boron concentrations, boron isotope ratios, and tritium concentrations similar to water from the basal sand aquifer. Boron concentrations greater than the RAL were found in water from four of these six wells. The boron isotope and tritium data from these four wells indicate a natural source of boron in ground water; therefore, the RAL does not apply to boron concentrations in water from these wells. Water samples from two domestic wells where the ground-water source was unknown had boron concentrations less than the RAL and boron isotope ratios and tritium concentrations that were similar to domestic-wastewater-affected water from the surficial aquifer. The boron isotope ratio for a sample from one domestic well was similar to that of CCP-affected water from the surficial aquifer and detergent compositions; the boron concentration of that sample was less than the RAL. The classifications of differences among representative sources of boron in ground water and water samples from wells where the ground-water source was unknown generally agreed with distinctions based on strontium-87/strontium-86 ratios and concentrations of strontium, chloride, nitrate, and ammonia. This application of boron concentrations, boron isotope ratios, and tritium concentrations to classify differences in relation to potential sources of boron in ground water was able to distinguish between boron from natural sources and from human-affected sources that are subject to regulation.

Indiana↗

USGS2002

Effects of highway-deicer application on ground-water quality in a part of the Calumet Aquifer, northwestern Indiana

The effects of highway-deicer application on ground-water quality were studied at a site in northwestern Indiana using a variety of geochemical indicators. Site characteristics such as high snowfall rates; large quantities of applied deicers; presence of a high-traffic highway; a homogeneous, permeable, and unconfined aquifer; a shallow water table; a known ground-water-flow direction; and minimal potential for other sources of chloride and sodium to complicate source interpretation were used to select a study area where ground water was likely to be affected by deicer application. Forty-three monitoring wells were installed in an unconfined sand aquifer (the Calumet aquifer) near Beverly Shores in northwestern Indiana. Wells were installed along two transects that approximately paralleled groundwater flow in the Calumet aquifer and crossed US–12. US–12 is a highway that receives Indiana’s highest level of maintenance to maintain safe driving conditions. Ground-water quality and water-level data were collected from the monitoring wells, and precipitation and salt-application data were compiled from 1994 through 1997. The water-quality data indicated that chloride was the most easily traced indicator of highway deicers in ground water. Concentration ratios of chloride to iodide and chloride to bromide and Stiff diagrams of major element concentrations indicated that the principal source of chloride and sodium in ground water from the uppermost one-third to one-half of the Calumet aquifer and downgradient from US–12 was from a halite highway-deicer source. Borehole logs of relative electromagnetic conductivity defined a distinct plume of deicer-affected water in the uppermost 8 feet of aquifer at about 9 feet horizontally from the paved roadway edge and a zone of higher conductivity than background in the lower one-third of the aquifer. Chloride and sodium in the deep parts of the aquifer originated from natural sources. Chloride and sodium from highway deicers were present in the aquifer throughout the year. The highest concentrations of chloride and sodium in ground water were determined in samples collected during the spring and summer from wells open to the water table within about 9 feet of the highway. Chloride concentrations in ground water that were attributable to highway deicers also were found in tested wells about 400 feet downgradient from US–12 during the fall and winter and at greater depths than in wells closer to US–12. Chloride concentrations exceeded the U.S. Environmental Protection Agency’s (USEPA) secondary maximum contaminant level of 250 milligrams per liter for drinking water at seven wells downgradient from the highway during late winter, spring, and summer samplings. The chloride standard was exceeded only in water from wells with total depths that are less than about 10 feet below land surface. Sodium concentrations in water periodically exceeded the USEPA drinking-water equivalency level of 20 milligrams per liter in both the uppermost (deicer 2 Effects of Highway-Deicer Application on Ground-Water Quality in a Part of the Calumet Aquifer, Northwestern Indiana affected) and lower one-thirds of the aquifer. Sodium concentrations in ground water downgradient from US–12 and in the upper 5 feet of the aquifer also occasionally exceeded drinking-water standards for sodium (160 milligrams per liter) as set by the State of Florida and a standard for taste (200 milligrams per liter) as set by the World Health Organization. Dispersion was identified by analysis of aquifer-test data, isotopic dating of ground water, and water-quality data to be the process most responsible for reducing concentrations of highway deicers in the aquifer. Chemical analyses of the sand composing the aquifer indicated that cation exchange decreased the mass of deicerrelated sodium in ground water, although the sand has a limited capacity to sustain the process. Automated daily measurements of specific conductance, correlated to chloride concentrations, indicated that some deicer is retained in the aquifer near the highway throughout the entire year and acts as a continuous chloride source for ground water. Peak concentrations of deicerrelated constituents occasionally were detected by the daily, automated measurements of specific conductance that were made between the monthly samplings of ground water. Data analysis indicated that more frequent sampling than monthly intervals would be necessary if maximum chloride concentrations were to be measured. Some deicer may be retained in the aquifer and unsaturated zone between annual salt-application periods. Chloride concentrations at wells 1-DG-WT and 2-DG-WT remained greater than background through much or all of the year. The estimated masses of chloride transported in ground water past 2-DG in 1995 and 1996 were either slightly greater than (1995) or less than (1996) the masses of chloride applied to US–12 during the study.

Indiana↗

USGS1995

Use of surface and borehole geophysics to delineate the glacial-drift stratigraphy of northeastern St. Joseph County, Indiana

Inverse models of direct current electrical- resistivity sounding data and normal-resistivity and natural-gamma logs were used to assist delineation of the glacial-drift stratigraphy in a 580-square- kilometer area of northeastern St. Joseph County, Indiana. Unconsolidated deposits in the study area are composed of glacial-drift, including outwash, till, and lacustrine sediments; thicknesses range from about 15 to more than 70 meters. The glacial outwash deposits are mostly composed of sand and gravel and are the primary source of drinking water to northeastern St. Joseph County. The glacial till and glacio-lacustrine deposits contain a larger fraction of clay than the outwash deposits and may retard ground-water flow between shallow and deeper sand and gravel aquifers. Results of the geophysical measurements collected during this study indicate that glacial-drift deposits in the area north and east of the St. Joseph River are mostly composed of sand and gravel with inter-layered clay-rich deposits that are laterally discontinuous. In the area south of the St. Joseph River, the thickness of sand and gravel deposits diminishes, and clay-rich deposits dominate the stratigraphy. The presence of an electrically conductive bedrock, the Ellsworth Shale, beneath the glacial-drift deposits is identified in inverse models of direct current electrical-resistivity sounding data.

Water-Resources Investigations Report↗

USGS1995

Ground-water quality in northeastern St. Joseph County, Indiana

This report describes the ground-water quality of a 220-square-mile area in northeastern St. Joseph County, Indiana. Ground-water samples were collected from 30 monitoring wells at 20 sites during May 1992; the wells were screened in either a shallow or a deep sand and gravel aquifer. Samples were analyzed for general water-quality properties, nutrients, major ions, trace elements, industrial organic compounds, and pesticides. In general, the ground water is a slightly basic, very hard calcium bicarbonate water with a median dissolved-solids concentration of 310 milligrams per liter. The only constituent to exceed a U.S. Environmental Protection Agency Maximum Contaminant Level in the water samples was nitrate (which was exceeded in water samples from two wells). Concentrations of methylene-blue-active substances (detergent additives), chloride, and nitrate plus nitrite in the shallow aquifer were significantly higher (at the 0.05 probability level) than in the deep aquifer. The higher concentrations of these constituents in the shallow aquifer may be attributable to human activities. Concentrations of silica, ammonia, arsenic, antimony, barium, iron, and manganese in the deep aquifer were significantly higher than in the shallow aquifer; with the exception of ammonia, most or all of these constituents are probably from natural sources. No industrial organic compounds were detected in the water samples. Four pesticides - alachlor, carbofuran, metolachlor, and triazines - were detected in water samples; the highest pesticide concentration in a water sample was 1.0 microgram per liter of alachlor.

Indiana↗

USGS1993

Geohydrology and water quality of the Calumet aquifer, in the vicinity of the Grand Calumet River/Indiana Harbor Canal, northwestern Indiana

The water-table configuration of the Calumet aquifer in the vicinity of the Grand Calumet River/Indiana Harbor Canal in Lake County, northwestern Indiana, reflects the complexity of the shallow ground-water-flow system. Large depressions in the water table in sewered areas interrupt broad ground-water divides between rivers. The aquifer/stream interactions along the Grand Calumet River/ Indiana Harbor Canal are directly related to Lake Michigan water levels because of a direct connection of the Grand Calumet River/Indiana Harbor Canal to the lake. Fluctuations in lake levels and evapotranspiration result in reversals in ground-water flow near the river and canal that last from several hours to several months. Most of the water from the Calumet aquifer discharges into sewers, the Grand Calumet River/Indiana Harbor Canal, Lake Michigan, and Silurian carbonate bedrock. Model simulations of ground-water flow for the study area indicate that the Calumet aquifer discharges about 15 ft 3 /s (cubic feet per second) of ground water to sewers, about 10 ft 3 /s to the Grand Calumet River/Indiana Harbor Canal, and about 4 ft 3 /s to Lake Michigan along a 25-mile section of shoreline. Estimates of groundwater flow from the Calumet aquifer to the bedrock range from 0 to 10 ft 3 /s. Results of analyses of water samples collected from wells in five land-use types steel industry, petrochemical industry, commercial and light industry, residential, and parks were compared. The highest median concentrations of inorganic ions and the most detections of organic compounds generally occurred in water samples from wells on the steel and petrochemical land-use areas. Water samples collected from wells on the commercial and light industrial land-use areas generally had lower median chemical concentrations than the samples from the steel and petrochemical land-use areas and greater median concentrations than the samples from the residential and park land-use areas. Seven of 52 acid-extractable and base/neutralextractable organic compounds and 17 of 36 volatile organic compounds analyzed were detected in a total of 35 wells. Only 4 of the 88 organic analytes phenols, bis(2-ethylhexyl)phthalate, benzene, and toluene were detected in more than 5 of the 35 wells. A comparison of primarily inorganic-constituent data from the five land-use groups to inorganic-constituent data from sites known to be contaminated shows that constituent concentrations in ground waters from wells in the land-use areas generally are lower than those in ground water from contaminated areas. Abstract 1 Likewise, a comparison of inorganic-constituent data from the land-use groups to inorganic-constituent data from areas relatively unaffected by human presence shows that constituent concentrations in ground water from wells in the land-use areas generally are greater than those in ground water from the unaffected areas. Some documented but unaccounted for chemical loads in the Grand Calumet River are from ground water. Ground water probably contributes more than 10 percent of the total chemical load of ammonia, chromium, and cyanide to the Grand Calumet River. In comparison, about 1 to 3 percent of the total streamflow in the Grand Calumet River is from ground water. Of the four major groundwater sinks in the aquifer, the east branch of the Grand Calumet River and the Indiana Harbor Canal generally receive the greatest chemical loads from ground water, whereas Lake Michigan generally receives the smallest loads.

Indiana↗

USGS1992

Ground-water levels and directions of flow in the vicinity of a well field, Elkhart, Indiana, December 1989

Water levels were measured in 51 observation wells in the vicinity of the Elkhart Water Works Main Street well field during 5 days of normal pumping at the well field and little or no recharge to the ground water from precipitation. Water levels were measured once each day during December 18-22, 1989. Water-level altitudes were plotted and contoured on maps to determine the distribution of ground-water levels and directions of flow in the unconfined sand and gravel aquifer tapped by the well field. Measured ground-water levels ranged from about 7.5 to 30 feet below land surface. Ground-water levels were highest north and northwest of the Main Street well field and lowest at the Main Street well field and near the St. Joseph River. Regional ground-water flow is toward the south or southeast. Ground-water levels near the river are higher than the river stage, indicating that ground water discharges to the river. As a result of pumping, three cones of depression have formed in the water table in the mapped area. A small cone of depression northwest of the Main Street well field is caused by industrial pumping. Two cones of depression have formed at the Main Street well field-one in the eastern part of the well field and one in the western part of the well field. Horizontal hydraulic gradients are variable in the study area but are largest in the eastern part of the Main Street well field and near the St. Joseph River. In general, water levels measured in seven sets of paired wells do not indicate a vertical hydraulic gradient; however, a downward gradient was measured in one set of paired wells near a pumped area at the Main Street well field.

Indiana↗