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USGS1979

Preconstruction and postconstruction ground-water levels, Lock and Dam 2, Red River Valley, Louisiana

Proposed construction of a series of locks and dams in the Red River in Louisiana will cause a permanent increase in average river stage. The potentiometric surface of the shallow alluvial aquifer and the water table in the fine-grained material confining the aquifer will be affected. The purpose of this study using digital-modeling techniques, was to predict the average postconstruction potentiometric surface (steady state) and the water table (nonsteady state) so that potential effects of the water-level changes could be evaluated. Plans for lock and dam 2 at mile 87 (kilometer 140) above the mouth of the Red River call for a pool elevation of 58 feet (17.7 meters) and will cause an average increase in river stage of 12.5 feet (3.8 meters). As a result, ground-water levels will be raised 1 foot (0.3 meter) or more within 4 miles (6.4 kilometers) of the river and will be near land surface in low areas. The potentiometric surface may be as much as 1 to 2 feet (0.3 to 0.6 meter) above land surface south of Latanier along Chatlin Lake Canal and south of the Annandale area of Alexandria. The magnitude of ground-water-level fluctuations near the river will be reduced.

Louisiana↗

USGS1979

Preconstruction and postconstruction ground-water levels, Lock and Dam 3, Red River Valley, Louisiana

Proposed construction of a series of locks and dams in the Red River in Louisiana will cause a permanent increase in average river stage. The potentiometric surface of the shallow alluvial aquifer and the water table in the fine-grained material confining the aquifer will be affected. The purpose of this study, using digital-modeling techniques, was to predict the average postconstruction potentiometric surface (steady state) and the water table (nonsteady state) so that potential effects of the water-level changes could be evaluated. Plans for lock and dam 3 at realined mile 111 (kilometer 179) above the mouth of the Red River call for a pool elevation of 87 feet (27 meters) and will cause an average increase in river stage ranging from 21 to 3.5 feet (l.4 to 1.1 meters). As a result, ground-water levels will be raised to near land surface in low areas east of the river from the damsite to Aloha and in a 0.5-mile (0.8-kilometer) strip along the west side extending 9 miles (14 kilometers) above the dam. The potentiometric surface may be above land surface locally near the dam. The magnitude of ground-water-level fluctuations near the river will be reduced to less than half the preconstruction range.

Louisiana↗

USGS1979

Preconstruction and postconstruction ground-water levels, Lock and Dam 4, Red River Valley, Louisiana

Proposed construction of a series of locks and dams in the Red River in Louisiana will cause a permanent increase in average river stage. The potentiometric surface of the shallow alluvial aquifer and the water table in the fine-grained material confining the aquifer will be affected. The purpose of this study, using digital-modeling techniques, was to predict the average postconstruction potentiometric surface (steady state) and the water table (nonsteady state) so that potential effects of the water-level changes could be evaluated. Plans for lock and dam 4 at realined mile 154 (kilometer 250) above the mouth of the Red River call for a pool elevation of 115 feet (35 meters) and will cause an average increase in river stage ranging from 24 to 4.5 feet (7 to 1.4 meters). As a result, ground-water levels will be raised 1 foot (0.3 meter) or more between the Red River and Bayou Pierre from the dam to Coushatta , and below Campti, east of the river. The potentiometric surface may be at or near land surface in low areas between the Red River and Bayou Pierre, and above land surface locally upstream from the dam. The magnitude of ground-water-level fluctuations near the river will be reduced to less than half the present range.

Louisiana↗

USGS1979

Preconstruction and postconstruction ground-water levels, Lock and Dam 5 and 6, Red River Valley, Louisiana

Proposed construction of a series of locks and dams in the Red River in Louisiana will cause a permanent increase in average river stage. The potentiometric surface of the shallow alluvial aquifer and the water table in the fine-grained material confining the aquifer will be affected. The purpose of this study, using digital-modeling techniques, was to predict the average postconstruction potentiometric surface (steady state) and the water table (nonsteady state) so that potential effects of the water-level changes could be evaluated. Plans for lock and dam 5 at mile 243 (kilometer 390) above the mouth of the Red River call for a pool elevation of 145 feet (44 meters) and will cause an average increase in river stage of 23 feet (7.0 meters). As a result, ground-water levels in the pool area will be raised to near land surface in much of the area between the river and Bayou Pierre and as much as 2 miles (3.2 kilometers) east of the river from the dam upstream to realined mile 220 (kilometer 350). Areas of Barksdale Air Force Base where levels are now near land surface would be enlarged and extend downstream along Flat River to near Curtis. The potentiometric surface may be above land surface near Howard, Anderson Island, and Dixie Gardens. (Woodard-USGS)

Louisiana↗

USGS2013

Investigating the potential impact of efflorescent mineral crusts on water quality: complementing analytical techniques with geochemical modelling

Efflorescent crusts are a common feature forming on the surface of gold mining sites and tailings storage facilities during the dry season. Their dissolution at the start of the wet sea- son releases an acidic pulse of water rich in metal pollutants. The composition of the crusts is indicative of the water from which they precipitated. This study aimed at assessing the crust formation and dissolution processes that result in episodic changes in receiving water quality. The approach involved characterising the composition of the crusts by analytical techniques (powder X-ray di2raction (PXRD)) and establishing compositional discrepancies by modelling the formation and dissolution processes.

Conference Paper↗

USGS2001

Geochemical baseline studies and relations between water quality and streamflow in the Upper Blackfoot watershed, Montana: Data for July 1997-December 1998

We used ultraclean sampling techniques to study the solute (operationally defined as <0.2 ?m) surface water geochemistry at five sites along the Upper Blackfoot River and four sites along the Landers Fork, some in more detail and more regularly than others. We collected samples also from Hogum Creek, a tributary to the Blackfoot, from Copper Creek, a tributary to the Landers Fork, and from ground water seeps contributing to the flow along the Landers Fork. To better define the physical dynamics of the hydrologic system and to determine geochemical loads, we measured streamflow at all the sites where we took samples for water quality analysis. The Upper Blackfoot River, which drains historic mines ca. 20 Km upstream of the study area, had higher trace metal concentrations than did the Landers Fork, which drains the pristine Scapegoat Wilderness area. In both rivers, many of the major elements were inversely related to streamflow, and at some sites, several show a hysteresis effect in which the concentrations were lower on the rising limb of the hydrograph than on the falling limb. However, many of the trace elements followed far more irregular trends, especially in the Blackfoot River. Elements such as As, Cu, Fe, Mn, S, and Zn exhibited complex and variable temporal patterns, which included almost no response to streamflow differences, increased concentrations following a summer storm and at the start of snowmelt in the spring, and/or increased concentrations throughout the course of spring runoff. In summary, complex interactions between the timing and magnitude of streamflow with physical and chemical processes within the watershed appeared to greatly influence the geochemistry at the sites, and streamflow values alone were not good predictors of solute concentrations in the rivers.

Montana↗

USGS2006

Ground-water/surface-water interaction in nearshore areas of Three Lakes on the Grand Portage Reservation, northeastern Minnesota, 2003-04

The U.S. Geological Survey (USGS), in cooperation with the Grand Portage Band of Chippewa Indians, applied three techniques to assess ground-water/surface-water interaction in nearshore areas of three lakes (North, Teal, and Taylor) on the Grand Portage Reservation in northeastern Minnesota. At each lake, analyses of existing aerial photographs, in-situ temperature measurements of shoreline lake sediment, and chemical analyses of surface water and pore water were conducted. Surface-water and pore-water samples were analyzed for major constituents, nutrients, and stable isotopes of oxygen and hydrogen. Bulk precipitation samples were collected and analyzed (1) for nutrient concentrations to determine nutrient input to the lakes through atmospheric deposition and (2) for stable isotope ratios of oxygen and hydrogen to determine a meteoric waterline that was needed for the stable isotope analyses of surface-water and pore-water samples. Total nitrogen concentrations in the precipitation samples ranged from 0.51 to 8.4 mg/L (milligrams per liter) as nitrogen at the North Lake precipitation station and from 0.42 to 2.3 mg/L as nitrogen at the Grand Portage precipitation station. Oxygen-18/oxygen-16 and deuterium/protium isotope ratios for the bulk precipitation samples lie relatively close to a meteoric waterline for northern Wisconsin, except for the ratios for samples collected on May 20, 2004. Analyses of existing aerial photographs, nearshore lake-sediment temperatures, and seasonal isotope ratios of surface-water and pore-water samples were the most valuable data for identifying locations of ground-water inflow and surface-water outseepage. Analyses of existing aerial photographs of the three lakes indicated the location of potential inflow channels and lineaments identifying potential ground-water inflow locations for pore-water sampling. Lake-sediment temperatures at potential ground-water inflow locations ranged from 4 to 16 ºC, varying between lakes, seasons, and climatic conditions. Major constituent chemistry was valuable at Taylor Lake, and to a limited extent at North and Teal Lakes, in confirming results from the isotope and lake-sediment temperature data. Ground-water inflow to North Lake likely occurs along the southwest and south shores, and along portions of the west, southeast, north, and northeast shores. Relatively cool lake-sediment temperatures along the southwest, south, west, and southeast shores, and in isolated beaver channels along the north and northeast shores of North Lake indicate potential ground-water inflow at these locations. Both localized ground-water inflow and surface-water outseepage occurs along portions of the north, northeast, southeast, and south shores, varying seasonally. Conflicting evidence for ground-water flow conditions exist for the northwest and north-northwest pore-water samples. Only minor differences in the major constituent concentrations were seen between the surface-water and pore-water samples from the North Lake area with the exception of iron and manganese concentrations. Ground-water inflow likely takes place along the south-southwest and north shores of Teal Lake, with a mixture of ground-water inflow and surface-water outseepage occurring in other areas of the lake. Cooler lake-sediment temperatures occurred along the south-southwest, west, and northwest shores, portions of the north shore, and in channels identified in aerial photographs throughout the lake, indicating potential ground-water inflow at those locations. Warmer lake-sediment temperatures along the northeast and portions of the southwest and northwest shores of Teal Lake indicate potential locations where surface-water outseepage or little ground- and surface-water interaction occurs. The major constituent concentrations were higher in the pore-water samples collected from the south-southwest and northeast shores of Teal Lake, indicating ground-water inflow. Cation adsorption, cation exchanges with hydrogen ions, and chelation with organic materials occurring in the fen surrounding the lake likely resulted in the low dissolved calcium, magnesium, and sodium concentrations in north, northwest, and west pore-water samples from the Teal Lake area. Pore-water samples from the south-southwest, north, and southwest shores of Teal Lake had isotopic compositions that plotted closest to the meteoric waterline, indicating that little evaporation or transpiration occurred in these samples and that ground-water inflow may be occurring at these locations. Surface-water outseepage from Teal Lake likely occurs along the northeast shore even though major constituent concentrations were high. Major constituent concentrations may be high because of a nearby beaver dam. Ground-water inflow to Taylor Lake likely occurs at the north and south pore-water sampling sites. Higher major constituent concentrations and the least evaporative isotope ratios were found in pore-water samples along the south, north, and west shores of Taylor Lake, indicating potential locations of ground-water inflow. However, a combination of warmer and cooler lake-sediment temperatures along the west lowland indicated that ground-water inflow and surface-water outseepage may occur at that location. Surface-water outseepage likely occurs from Taylor Lake along the south shore through a surface-water drainage channel to a downgradient bog. Warmer lake-sediment temperatures along portions of the south and southeast shores indicate that surface-water outseepage may occur at those locations. Both ground-water inflow and surface-water outseepage may occur along the west, southeast, and east shores of Taylor Lake, varying seasonally and with local precipitation. Knowledge of general water-flow directions in lake watersheds and how they may change seasonally can help water-quality specialists and lake managers address a variety of water-quality and aquatic habitat protection issues for lakes. Results from this study indicate that ground-water and surface-water interactions at the study lakes are complex, and the ability of the applied techniques to identify ground-water inflow and surface-water outseepage locations varied among the lakes. Measurement of lake-sediment temperatures proved to be a reliable and relatively inexpensive reconnaissance technique that lake managers may apply in complex settings to identify general areas of ground-water inflow and surface-water outseepage.

Minnesota↗

USGS1991

Techniques for computing discharge at four Navigation Dams on the Illinois and Des Plaines Rivers in Illinois

Techniques for computing discharge are developed for Brandon Road Dam on the Des Plaines River and for Dresden Island, Marseilles, and Starved Rock Dams on the Illinois River. At Brandon Road Dam, streamflow is regulated by the operation of Tainter gates and headgates. At Dresden Island, Marseilles, and Starved Rock Dams, only Tainter gates are operated to regulate streamflow. The locks at all dams are equipped with culvert valves that are used to fill and empty the lock. The techniques facilitate determination of discharge at locations along the upper Illinois Waterway where no streamflow-gaging stations exist. The techniques are also useful for computing low flows when the water-surface slope between control structures on the river approaches zero and traditional methods of determining discharge based on slope are unsatisfactory. Two techniques can be used to compute discharge at the dams--gate ratings and tailwater ratings . A gate ratingdescribes the relation between discharge, gate opening, tailwater stage, and headwater stage. A tailwater rating describes the relation between tailwater stage and discharge. Gate ratings for Tainter gates at Dresden Island, Marseilles, and Starved Rock Dams are based on a total of 78 measurements of discharge that range from 569 to 86,400 cubic feet per second. Flood hydrographs developed from the gate ratings and Lockmaster records of gate opening and stage compare closely with streamflow records published for nearby streamflow-gaging stations. Additional measurements are needed to verify gate ratings for Tainter gates and headgates at Brandon Road Dam after the dam rehabilitation is completed. Extensive leakage past deteriorated headgates and sluice gates contributed to uncertainty in the ratings developed for this dam. A useful tailwater rating is developed for Marseilles Dam. Tailwater ratings for Dresden Island Dam and Starved Rock Dam are of limited use because of varying downstream channel-storage conditions. A tailwater rating could not be developed for Brandon Road Dam because its tailwater pool is substantially affected by the headwater pool of Dresden Island Dam.

Water-Resources Investigations Report↗

USGS2007

Development and evaluation of a gas chromatographic method for the determination of triazine herbicides in natural water samples

A multi-residue method is described for the determination o triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0.1 μg/L in a 1-litre sample. Three different natural water samples were used for error analysis via evaluation of recovery efficiencies and estimation of overall method precision. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.

International Journal of Environmental Analytical ↗

USGS2011

Microphotographs of cyanobacteria documenting the effects of various cell-lysis techniques

Cyanotoxins are a group of organic compounds biosynthesized intracellularly by many species of cyanobacteria found in surface water. The United States Environmental Protection Agency has listed cyanotoxins on the Safe Drinking Water Act's Contaminant Candidate List 3 for consideration for future regulation to protect public health. Cyanotoxins also pose a risk to humans and other organisms in a variety of other exposure scenarios. Accurate and precise analytical measurements of cyanotoxins are critical to the evaluation of concentrations in surface water to address the human health and ecosystem effects. A common approach to total cyanotoxin measurement involves cell membrane disruption to release the cyanotoxins to the dissolved phase followed by filtration to remove cellular debris. Several methods have been used historically, however no standard protocols exist to ensure this process is consistent between laboratories before the dissolved phase is measured by an analytical technique for cyanotoxin identification and quantitation. No systematic evaluation has been conducted comparing the multiple laboratory sample processing techniques for physical disruption of cell membrane or cyanotoxins recovery. Surface water samples collected from lakes, reservoirs, and rivers containing mixed assemblages of organisms dominated by cyanobacteria, as well as laboratory cultures of species-specific cyanobacteria, were used as part of this study evaluating multiple laboratory cell-lysis techniques in partnership with the U.S. Environmental Protection Agency. Evaluated extraction techniques included boiling, autoclaving, sonication, chemical treatment, and freeze-thaw. Both treated and untreated samples were evaluated for cell membrane integrity microscopically via light, epifluorescence, and epifluorescence in the presence of a DNA stain. The DNA stain, which does not permeate live cells with intact membrane structures, was used as an indicator for cyanotoxin release into the dissolved phase. Of the five techniques, sonication (at 70 percent) was most effective at complete cell destruction while QuikLyse (Trademarked) was least effective. Autoclaving, boiling, and sequential freeze-thaw were moderately effective in physical destruction of colonies and filaments.

Open-File Report↗

USGS2002

Final report: Initial ecosystem response of salt marshes to ditch plugging and pool creation: Experiments at Rachel Carson National Wildlife Refuge (Maine)

This study evaluates the response of three salt marshes, associated with the Rachel Carson National Wildlife Refuge (Maine), to the practice of ditch plugging. Drainage ditches, originally dug to drain the marsh for mosquito control or to facilitate salt hay farming, are plugged with marsh peat in an effort to impound water upstream of the plug, raise water table levels in the marsh, and increase surface water habitat. At two study sites, Moody Marsh and Granite Point Road Marsh, ditch plugs were installed in spring 2000. Monitoring of hydrology, vegetation, nekton and bird utilization, and marsh development processes was conducted in 1999, before ditch plugging, and then in 2000 and 2001 (all parameters except nekton), after ditch plugging. Each study site had a control marsh that was monitored simultaneously with the plugged marsh, and thus, we employed a BACI study design (before, after, control, impact). A third site, Marshall Point Road Marsh, was plugged in 1998. Monitoring of the plugged and control sites was conducted in 1999 and 2000, with limited monitoring in 2001, thus there was no ?before? plug monitoring. With ditch plugging, water table levels increased toward the marsh surface and the areal extent of standing water increased. Responding to a wetter substrate, a vegetation change from high marsh species (e.g., Spartina patens) to those more tolerant of flooded conditions (e.g., Spartina alterniflora) was noted at two of the three ditch plugged sites. Initial response of the nekton community (fishes and decapod crustaceans) was evaluated by monitoring utilization of salt marsh pools using a 1m2 enclosure trap. In general, nekton species richness, density, and community structure remained unchanged following ditch plugging at the Moody and Granite Point sites. At Marshall Point, species richness and density (number of individuals per m2) were significantly greater in the experimental plugged marsh than the control marsh (<2% of the control marsh was open water habitat vs. 11% of the plugged marsh). The response of birds, categorized as waterfowl & waterbirds, shorebirds & wading birds, gulls & terns, and miscellaneous (raptors, passerines, other), was variable. Following ditch plugging, bird species richness increased at the Granite Point site (1999 pre-plug = 15.4, 2000 post-plug = 26.2, 2001 post-plug = 38.7). Because of a low sample size at Moody Marsh, reliable statements on species richness cannot be made. Density of birds (no. of birds per ha) remained unchanged with ditch plugging at Granite Point Marsh, although there was a strong, but not statistically significant, trend toward increased density. This study only reports on initial responses of marsh functions to ditch plugging. Monitoring should continue at these sites, and perhaps at additional sites, for the next decade or so. A monitoring plan is recommended. Long-term monitoring will include evaluation of salt marsh development processes using SET (surface elevation table) methodology. There is concern, although not confirmed, that as ditch-plugged marshes become wetter and marsh grass production declines their ability to keep pace with sea level rise could be jeopardized. It is suggested that ditch plugging should be considered an experimental marsh management technique. Additional monitoring on the physical and habitat responses of ditch-plugged marshes is required, along with assessments of other techniques aimed at restoring open water habitat to the marsh surface.

Book↗

USGS2021

Field evaluation of a compact, polarizing topo‐bathymetric lidar across a range of river conditions

This paper summarizes field trials to evaluate the performance of a prototype compact topo‐bathymetric lidar sensor for surveying rivers. The sensor uses a novel polarization technique to distinguish between laser returns from the water surface and streambed and its size and weight permit deployment from a small unmanned aerial system (sUAS) or a boat. Field testing was designed to identify the range of operational conditions under which the sensor can provide accurate information on river depths. For accuracy assessment, conventional, field‐based depth measurements were collected by wading and sonar. Additionally, optical properties of the rivers were measured in situ. Wading and lidar bathymetry comparisons in relatively shallow channels yielded observed versus predicted (OP) regression R 2 values ranging from 0.60 to 0.97. A comparison between sonar and lidar bathymetry in a deeper river resulted in an OP R 2 of 0.72. Absorption and attenuation coefficients at the 532 nm wavelength of the lidar were recorded in the field and the highest values of these inherent optical properties were at sites with the highest turbidity and highest concentrations of colored dissolved organic matter, chlorophyll, and suspended sediment. At these sites, which included both sand and gravel/cobble beds, the point density of riverbed returns was not uniform, with areas of sparse coverage occurring primarily in deeper water. However, submerged objects and slopes could be resolved in the lidar point clouds.

Arizona, Colorado↗

USGS2018

A novel high-frequency groundwater quality monitoring system

High-frequency, long-term monitoring of water quality has revolutionized the study of surface waters in recent years. However, application of these techniques to groundwater has been limited by the ability to remotely pump and analyze groundwater. This paper describes a novel autonomous groundwater quality monitoring system which samples multiple wells to evaluate temporal changes and identify trends in groundwater chemistry. The system, deployed near Fresno, California, USA, collects and transmits high-frequency data, including water temperature, specific conductance, pH, dissolved oxygen, and nitrate, from supply and monitoring wells, in real-time. The system consists of a water quality sonde and optical nitrate sensor, manifold, submersible three-phase pump, variable frequency drive, data collection platform, solar panels, and rechargeable battery bank. The manifold directs water from three wells to a single set of sensors, thereby reducing setup and operation costs associated with multi-sensor networks. Sampling multiple wells at high frequency for several years provided a means of monitoring the vertical distribution and transport of solutes in the aquifer. Initial results show short period variability of nitrate, specific conductivity, and dissolved oxygen in the shallow aquifer, while the deeper portion of the aquifer remains unchanged—observations that may be missed with traditional discrete sampling approaches. In this aquifer system, nitrate and specific conductance are increasing in the shallow aquifer, while invariant changes in deep groundwater chemistry likely reflect relatively slow groundwater flow. In contrast, systems with high groundwater velocity, such as karst aquifers, have been shown to exhibit higher-frequency groundwater chemistry changes. The stability of the deeper aquifer over the monitoring period was leveraged to develop estimates of measurement system uncertainty, which were typically lower than the manufacturer’s stated specifications, enabling the identification of subtle variability in water chemistry that may have otherwise been missed.

California↗

USGS2024

Using surficial geologic maps, vegetation, and monitoring to address erosion impacts from grazing in Channel Islands National Park, California

Employing a map-unit classification scheme based on geomorphic process and age, the U.S. Geological Survey (USGS) mapped Quaternary surficial deposits of the five islands comprising Channel Islands National Park (CHIS), California, as no such maps previously existed. Mapping was motivated through an agreement with the National Park Service (NPS) to aid natural resource assessments, including post-grazing disturbance recovery and identification of mass wasting and tectonic hazards. The resulting detailed (1:12,000 scale) maps portray areas of upland erosional transport processes and alluvial, fluvial, eolian, beach, marine terrace, mass wasting, and mixed depositional processes at a scale commensurate with the process signal on the landscape. Detailed, GPS-located observations of sedimentology, pedogenic development, landscape position, and geomorphology constrain map unit identification. In addition, map-unit boundary delineation was determined in a GIS using a variety of high-resolution (sub-meter) aerial imagery and lidar-based DEMs complemented by derivative raster products. The GIS geodatabase schema used is GeMS compliant. Resolvable map-unit widths are as small as 10-15 meter. Locational accuracy of unit boundaries is estimated to be as low as 10 m or better. Detailed mapping is at a scale allowing determination of geomorphic transport processes operating on the landscape and conveys geologic information to land managers at a resolution commensurate with park resources. Map unit ages are constrained by relative soil chronostratigraphy, vertebrate and invertebrate fossils, and materials collected for dating control using radiogenic, luminescence, and cosmogenic radionuclide techniques. Associated topical studies examined connections between geology, surface water, and vegetation distribution and restoration.

California↗

USGS1995

Quality of surface water and ground water in the proposed artificial-recharge project area, Rillito Creek basin, Tucson, Arizona, 1994

Controlled artificial recharge of surface runoff is being considered as a water-management technique to address the problem of ground-water overdraft. The planned use of recharge facilities in urban areas has caused concern about the quality of urban runoff to be recharged and the potential for ground-water contamination. The proposed recharge facility in Rillito Creek will utilize runoff entering a 1-mile reach of the Rillito Creek between Craycroft Road and Swan Road for infiltration and recharge purposes within the channel and excavated overbank areas. Physical and chemical data were collected from two surface-water and two ground-water sites in the study area in 1994. Analyses of surface-water samples were done to determine the occurrence and concentration of potential contaminants and to determine changes in quality since samples were collected during 1987-93. Analyses of ground-water samples were done to determine the variability of ground-water quality at the monitoring wells throughout the year and to determine changes in quality since samples were collected in 1989 and 1993. Surface-water samples were collected from Tanque Verde Creek at Sabino Canyon Road (streamflow-gaging station Tanque Verde Creek at Tucson, 09484500) and from Alamo Wash at Fort Lowell Road in September and May 1994, respectively. Ground-water samples were collected from monitoring wells (D- 13-14)26cbb2 and (D-13-14)26dcb2 in January, May, July, and October 1994. In surface water, calcium was the dominant cation, and bicarbonate was the dominant anion. In ground water, calcium and sodium were the dominant cations and bicarbonate was the dominant anion. Surface water in the area is soft, and ground water is moderately hard to hard. In surface water and ground water, nitrogen was found predominantly as nitrate. Concentrations of manganese in ground-water samples ranged from 60 to 230 micrograms per liter and exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level for drinking water of 50 micrograms per liter. None of the constituents in surface-water and ground-water samples exceeded the U.S. Environmental Protection Agency primary maximum contaminant levels for drinking water or State of Arizona aquifer water-quality standards. Concentrations of major ions, nutrients, and trace elements in water from the monitoring wells did not vary significantly throughout the year and were not significantly different from concentrations in samples collected in March 1989 and January and September 1993. Priority pollutants were not found in surface-water samples or ground-water samples, and organochlorine pesticides were not found in ground-water samples. Dieldrin and biphenyl polychlor were the only pesticides found in surface water and were at the minimum reporting levels in one sample from Alamo Wash.

Water-Resources Investigations Report↗

USGS2006

Unsaturated zone flow processes

Water flow in the unsaturated zone is greatly influenced by unsaturated hydrostatics (water content, energy, pressure, and retention) and by unsaturated hydrodynamics (diffuse flow and preferential flow). Important multiphase processes include the transport of gases, nonaqueous liquids, and solid particles. Numerous means are available for determination of unsaturated conditions and properties, both measurement (of moisture state, water retention, and dynamic characteristics) and through various formulas and models that are mostly empirical in nature, but in some cases incorporating insight into unsaturated‐zone physical processes. Applications to practical problems include models and techniques relating to distributions of water and energy, fluxes at the land surface, inputs, outputs, and fluxes within the unsaturated zone, all of which are frequently complicated by heterogeneity and preferential flow. Further scientific advance requires new measurement techniques and theoretical constructs that more adequately represent the important physical processes within practical modeling schemes.

Book chapter↗

USGS2012

Water quality studied in areas of unconventional oil and gas development, including areas where hydraulic fracturing techniques are used, in the United States

Domestic oil and gas production and clean water are critical for economic growth, public health, and national security of the United States. As domestic oil and gas production increases in new areas and old fields are enhanced, there is increasing public concern about the effects of energy production on surface-water and groundwater quality. To a great extent, this concern arises from the improved hydraulic fracturing techniques being used today, including horizontal drilling, for producing unconventional oil and gas in low-permeability formations. The U.S. Geological Survey (USGS) John Wesley Powell Center for Analysis and Synthesis is hosting an interdisciplinary working group of USGS scientists to conduct a temporal and spatial analysis of surface-water and groundwater quality in areas of unconventional oil and gas development. The analysis uses existing national and regional datasets to describe water quality, evaluate water-quality changes over time where there are sufficient data, and evaluate spatial and temporal data gaps.

Fact Sheet↗

USGS1982

A plan for hydrologic investigations of in situ, oil-shale retorting near Rock Springs, Wyoming

The recovery of shale oil by the in-situ retort process may cause hydrologic impacts, the most significant being ground-water contamination and possible transport of contaminants into surrounding areas. Although these impacts are site-specific, many of the techniques used to investigate each retort operation commonly will be the same. The U.S. Geological Survey has begun a study of hydrologic impacts in the area of an in-situ retort near Rock Springs, Wyoming, as a means of refining and demonstrating these techniques. Geological investigations include determining the areal extent and thickness of aquifers. Emphasis will be placed on determining lithologic variations from geophysical logging. Hydrologic investigations include mapping of potentiometric surfaces, determining rates of ground-water discharge, and estimating aquifer properties by analytical techniques. Water-quality investigations include monitoring solute migration from the retort site and evaluating sampling techniques by standard statistical procedures. A ground-water-flow and solute-transport model will be developed to predict future movement of the water plume away from the retort. (USGS)

Open-File Report↗