Geology topics

Donald O. Whittemore

Publications and source records attributed to Donald O. Whittemore.

12 recordsLinked to original sources

USGS2017

Late-Quaternary recharge determined from chloride in shallow groundwater in the central Great Plains

An extensive suite of isotopic and geochemical tracers in groundwater has been used to provide hydrologic assessments of the hierarchy of flow systems in aquifers underlying the central Great Plains (southeastern Colorado and western Kansas) of the United States and to determine the late Pleistocene and Holocene paleotemperature and paleorecharge record. Hydrogeologic and geochemical tracer data permit classification of the samples into late Holocene, late Pleistocene-early Holocene, and much older Pleistocene groups. Paleorecharge rates calculated from the Cl concentration in the samples show that recharge rates were at least twice the late Holocene rate during late Pleistocene-early Holocene time, which is consistent with their relative depletion in 16O and D. Noble gas (Ne, Ar, Kr, Xe) temperature calculations confirm that these older samples represent a recharge environment approximately 5??C cooler than late Holocene values. These results are consistent with the global climate models that show a trend toward a warmer, more arid climate during the Holocene. (C) 2000 University of Washington.

Quaternary Research↗

USGS2009

Patterns of Tamarix water use during a record drought

During a record drought (2006) in southwest Kansas, USA, we assessed groundwater dynamics in a shallow, unconfined aquifer, along with plant water sources and physiological responses of the invasive riparian shrub Tamarix ramosissima. In early May, diel water table fluctuations indicated evapotranspirative consumption of groundwater by vegetation. During the summer drought, the water table elevation dropped past the lowest position previously recorded. Concurrent with this drop, water table fluctuations abruptly diminished at all wells at which they had previously been observed despite increasing evapotranspirative demand. Following reductions in groundwater fluctuations, volumetric water content declined corresponding to the well-specific depths of the capillary fringe in early May, suggesting a switch from primary dependence on groundwater to vadose-zone water. In at least one well, the fluctuations appear to re-intensify in August, suggesting increased groundwater uptake by Tamarix or other non-senesced species from a deeper water table later in the growing season. Our data suggest that Tamarix can rapidly shift water sources in response to declines in the water table. The use of multiple water sources by Tamarix minimized leaf-level water stress during drought periods. This study illustrates the importance of the previous hydrologic conditions experienced by site vegetation for controlling root establishment at depth and demonstrates the utility of data from high-frequency hydrologic monitoring in the interpretation of plant water sources using isotopic methods. ?? Springer-Verlag 2009.

Oecologia↗

USGS2007

A field investigation of phreatophyte‐induced fluctuations in the water table

Hydrographs from shallow wells in vegetated riparian zones frequently display a distinctive pattern of diurnal water table fluctuations produced by variations in plant water use. A multisite investigation assessed the major controls on these fluctuations and the ecohydrologic insights that can be gleaned from them. Spatial and temporal variations in the amplitude of the fluctuations are primarily a function of variations in (1) the meteorological drivers of plant water use, (2) vegetation density, type, and vitality, and (3) the specific yield of sediments in the vicinity of the water table. Past hydrologic conditions experienced by the riparian zone vegetation, either in previous years or earlier within the same growing season, are also an important control. Diurnal water table fluctuations can be considered a diagnostic indicator of groundwater consumption by phreatophytes at most sites, so the information embedded within these fluctuations should be more widely exploited in ecohydrologic studies.

Water Resources Research↗

USGS2007

Fate and identification of oil-brine contamination in different hydrogeologic settings

Past disposal of oil-field brine at the surface has caused substantial contamination of water resources in Kansas. Natural saline water occurs in and discharges from Permian bedrock in parts of the state, and other anthropogenic sources of saline water exist, requiring clear identification of different sources. Time-series analysis of Cl- concentration and streamflow relative to pre-contamination contents, and end-member mixing plots, especially for Br- and Cl-, are practical methods for source differentiation and quantification. Although regulations preventing escape of saltwater from oil wells were first passed in Kansas in 1935, much oil and gas brine was disposed on the surface through the 1940s. Hydrogeologic characteristics of the areas with past surface disposal of oil brine differ appreciably and result in large differences in the ratio of saltwater transported in streams or ground water. Much of the brine disposed during the 1910s to 1940s in an area of silty clay soils overlying shale and limestone bedrock in south-central Kansas soon ran off or was flushed from the surface by rain into streams. Chloride concentration in the rivers draining this area often exceeded 1000 mg/L after the start of oil production up to the 1950s. Chloride content in the rivers then generally declined to about 100 mg/L or less in recent low flows. Oil brine was also disposed in surface ponds overlying the unconsolidated High Plains aquifer in south-central Kansas from the latter 1920s into the 1940s. Most of the surface-disposed brine infiltrated to the underlying aquifer. Where the High Plains aquifer is thin, saltwater has migrated along the top of clay layers or the underlying shaly bedrock and either discharged into small streams or flowed into thicker parts of the aquifer. Where the aquifer is thick, surface-disposed oil brine moved downward until reaching clay lenses, migrated latterly to the edge of the clay, and again moved downward if still dense enough. Water-level declines from pumping have increased the lateral migration rate of the saltwater contamination in the aquifer towards water-supply wells. The period of flushing most of the surface-disposed saltwater from the area of shale and limestone bedrock is on the order of many decades but is at least many centuries for the deeper parts of the High Plains aquifer. ?? 2007 Elsevier Ltd. All rights reserved.

Applied Geochemistry↗

USGS2006

Inverse approaches with lithologic information for a regional groundwater system in southwest Kansas

Two practical approaches incorporating lithologic information for groundwater modeling calibration are presented to estimate distributed, cell-based hydraulic conductivity. The first approach is to estimate optimal hydraulic conductivities for geological materials by incorporating thickness distribution of materials into inverse modeling. In the second approach, residuals for the groundwater model solution are minimized according to a globalized Newton method with the aid of a Geographic Information System (GIS) to calculate a cell-wise distribution of hydraulic conductivity. Both approaches honor geologic data and were effective in characterizing the heterogeneity of a regional groundwater modeling system in southwest Kansas. ?? 2005 Elsevier Ltd All rights reserved.

Journal of Hydrology↗

USGS2006

Precipitation induced stream flow: An event based chemical and isotopic study of a small stream in the Great Plains region of the USA

A small stream in the Great Plains of USA was sampled to understand the streamflow components following intense precipitation and the influence of water storage structures in the drainage basin. Precipitation, stream, ponds, ground-water and soil moisture were sampled for determination of isotopic (D, 18O) and chemical (Cl, SO4) composition before and after two intense rain events. Following the first storm event, flow at the downstream locations was generated primarily through shallow subsurface flow and runoff whereas in the headwaters region - where a pond is located in the stream channel - shallow ground-water and pond outflow contributed to the flow. The distinct isotopic signatures of precipitation and the evaporated pond water allowed separation of the event water from the other sources that contributed to the flow. Similarly, variations in the Cl and SO4 concentrations helped identify the relative contributions of ground-water and soil moisture to the streamflow. The relationship between deuterium excess and Cl or SO4 content reveals that the early contributions from a rain event to streamflow depend upon the antecedent climatic conditions and the position along the stream channel within the watershed. The design of this study, in which data from several locations within a watershed were collected, shows that in small streams changes in relative contributions from ground water and soil moisture complicate hydrograph separation, with surface-water bodies providing additional complexity. It also demonstrates the usefulness of combined chemical and isotopic methods in hydrologic investigations, especially the utility of the deuterium excess parameter in quantifying the relative contributions of various source components to the stream flow. ?? 2006 Elsevier B.V. All rights reserved.

Journal of Hydrology↗

USGS2005

Uses of chloride/bromide ratios in studies of potable water

In natural ground water systems, both chlorine and bromine occur primarily as monovalent anions, chloride and bromide. Although dissolution or precipitation of halite, biological activity in the root zone, anion sorption, and exchange can affect chloride/bromide ratios in some settings, movement of the ions in potable ground water is most often conservative. Atmospheric precipitation will generally have mass ratios between 50 and 150; shallow ground water, between 100 and 200; domestic sewage, between 300 and 600; water affected by dissolution of halite, between 1000 and 10,000; and summer runoff from urban streets, between 10 and 100. These, and other distinctive elemental ratios, are useful in the reconstruction of the origin and movement of ground water, as illustrated by case studies investigating sources of salinity in ground water from Alberta, Kansas, and Arizona, and infiltration rates and pathways at Yucca Mountain, Nevada.

Groundwater↗

USGS2001

User interface for ground-water modeling: Arcview extension

Numerical simulation for ground-water modeling often involves handling large input and output data sets. A geographic information system (GIS) provides an integrated platform to manage, analyze, and display disparate data and can greatly facilitate modeling efforts in data compilation, model calibration, and display of model parameters and results. Furthermore, GIS can be used to generate information for decision making through spatial overlay and processing of model results. Arc View is the most widely used Windows-based GIS software that provides a robust user-friendly interface to facilitate data handling and display. An extension is an add-on program to Arc View that provides additional specialized functions. An Arc View interface for the ground-water flow and transport models MODFLOW and MT3D was built as an extension for facilitating modeling. The extension includes preprocessing of spatially distributed (point, line, and polygon) data for model input and postprocessing of model output. An object database is used for linking user dialogs and model input files. The Arc View interface utilizes the capabilities of the 3D Analyst extension. Models can be automatically calibrated through the Arc View interface by external linking to such programs as PEST. The efficient pre- and postprocessing capabilities and calibration link were demonstrated for ground-water modeling in southwest Kansas.

Journal of Hydrologic Engineering↗

USGS1991

Geochemistry of halogens in the Milk River aquifer, Alberta, Canada

Analytical data are presented for Cl, Br and I on a regional scale for the Milk River aquifer. The three halides show strikingly similar spatial distributions and are highly correlated. Concentrations are low in the freshwater portions of the aquifer but increase by as much as two orders of magnitude along the margins. However, halide ratios reach nearly constant values moving down-gradient, suggesting the dominance of a common subsurface source for these ions. Ratios of Cl/I and Cl/Br are less than those of seawater and fit an origin derived from the diagenesis of organic matter in the sediments. Halide ratios rule out leakage and/or diffusion from the underlying Colorado Group as a major influence on the chemistry; the favored hypothesis is altered connate seawater diffusing from low-permeability units within the Milk River Formation as the primary source of salts. This hypothesis of an internal source has important implications for solute sources in other aquifers affected by saline waters because it does not require the importation of a distant fluid.

Alberta↗

USGS1990

Movement and fate of atrazine and bromide in central Kansas croplands

Two flooding experiments were conducted at two sites with different soils to study the transport and fate of the commonly used herbicide atrazine and inorganic chemicals in the Great Bend Prairie croplands of south-central Kansas. The instantaneous profile method supplemented by the use of an organic (atrazine) and an inorganic (bromide) tracer chemical was used to characterize in situ the hydraulic and chemical properties of the appropriately instrumented field sites. Atrazine readily degraded to hydroxyatrazine and biodegradation by-products and was not detected deeper in the soil profile and underlying shallow aquifer. The classical processes of chemical movement based on porous media-equilibrium-diffuse flow did not fit the data well at either site. Incompletely mixed, slug flow appeared to predominate at one of the sites and preferential flow at the other. The slug movement caused 'piston-type' displacement of more saline solutions in the soil profile to the shallow water table. Recommendations for conducting related field studies based on our sampling experience are given.

Kansas↗

USGS1990

Hydrogeochemistry and stable isotopes of ground and surface waters from two adjacent closed basins, Atacama Desert, northern Chile

The geochemistry and stable isotopes of groundwaters, surface waters, and precipitation indicate different sources of some dissolved constituents, but a common source of recharge and other constituents in two adjacent closed basins in the Atacama Desert region of northern Chile (24°15′–24°45′S). Waters from artesian wells, trenches, and ephemeral streams in the Punta Negra Basin are characterized by concentrations of Na>Ca>Mg and Cl≥SO 4 ,with TDS<10 g/l. Values of δD and δ 18 O for Punta Negra Basin waters follow an evaporitic trend typical of closed basin waters in northern Chile and elsewhere. In contrast, ground waters in the Hamburgo Basin, located about 25 km NW of the Punta Negra Basin, have concentrations of Na > Mg≥Ca and SO 4 >Cl, with TDS also <10 g/l. Aqueous speciation calculations indicate that Hamburgo Basin groundwaters are close to saturation with respect to gypsum. The relatively high SO 4 and low Ca in Hamburgo Basin waters result from SO 4 influx and subsequent gypsum precipitation related to weathering at La Escondida, a large porphyry copper deposit located near to the center of the basin. Deep mine waters from 130 m below the water table at La Escondida also have Na>Mg≥Ca and SO 4 >Cl, but with TDS up to 40 g/l. The deep mine waters have pH between 3.2 and 3.9, and are high in dissolved CO 2 (δ 13 C= −4.8%PDB), indicating probable interaction with oxidizing sulfides. The deep mine waters have δ 18 O values of ≈−1.8%.compared with values < −3.5‰ for other Hamburgo Basin waters; thus the mine waters may represent a mixture of meteoric waters with deeper “metamorphic” waters, which had interacted with rocks and exchanged oxygen isotopes at elevated temperatures. Alternatively, the deep mine waters may represent fossil meteoric waters which evolved isotopically along an evaporative trend starting from values quite depleted in δ 18 O and °Dd relative to either precipitation or shallow groundwaters. High I/Br ratios in the Hamburgo Basin waters and La Escondida mine waters are consistent with regionally high I in surficial deposits in the Atacama Desert region and may represent dissolution of a wind-blown evaporite component.

Atacama Desert↗

USGS1989

Effects of variations in recharge on groundwater quality

The predominant regional effect of recharge on municipal groundwater quality in Kansas is the dilution of mineralized water in aquifers with relatively shallow water tables. The individual dissolved constituents contributing most to the water-quality variations are sulfate and chloride, and the calcium and sodium accompanying them, which are derived from the dissolution of evaporite minerals within the aquifer or from saline formation water in bedrock underlying the aquifer. The relationship between recharge and groundwater-quality variation can be quantified by associating certain climatic indices, especially the Palmer Drought Index, with quality observations. The response time of the maximum water-quality change relative to the occurrence of drought or substantial recharge ranges from a month to 3 years depending on the aquifer characteristics, and is generally proportional to the saturated thickness and specific yield. The response time is also affected by discharge to and recharge from nearby streams and by the well construction, particularly the placement of the screened interval, and pumping stress.

Journal of Hydrology↗