Solution of the advection-dispersion equation: Continuous load of finite duration
R.L. Runkel
1996, Journal of Environmental Engineering (122) 830-832
Field studies of solute fate and transport in streams and rivers often involve an. experimental release of solutes at an upstream boundary for a finite period of time. A review of several standard references on surface-water-quality modeling indicates that the analytical solution to the constant-parameter advection-dispersion equation for this type...
Movement of nitrate fertilizer to glacial till and runoff from a claypan soil
D. W. Blevins, D.H. Wilkison, B. P. Kelly, S. R. Silva
1996, Journal of Environmental Quality (25) 584-593
Although water from 20 to 25% of shallow farmstead wells in northern Missouri has concentrations of nitrate (NO3/-) exceeding 10 mg L-1 as nitrogen (N), many potential sources for this NO3/- are usually present. A field experiment was designed to trace and isolate the amount of a single application of...
Flow to a well in a water-table aquifer: An improved laplace transform solution
A.F. Moench
1996, Ground Water (34) 593-604
An alternative Laplace transform solution for the problem, originally solved by Neuman, of constant discharge from a partially penetrating well in a water-table aquifer was obtained. The solution differs from existing solutions in that it is simpler in form and can be numerically inverted without the need for time-consuming numerical...
A catastrophic flood caused by drainage of a caldera lake at Aniakchak Volcano, Alaska, and implications for volcanic hazards assessment
C. F. Waythomas, J. S. Walder, R. G. McGimsey, C.A. Neal
1996, Geological Society of America Bulletin (108) 861-871
Aniakchak caldera, located on the Alaska Peninsula of southwest Alaska, formerly contained a large lake (estimated volume 3.7 × 109 m3) that rapidly drained as a result of failure of the caldera rim sometime after ca. 3400 yr B.P. The peak discharge of the resulting flood was estimated using three methods:...
Effects of glacial meltwater inflows and moat freezing on mixing in an ice-covered antarctic lake as interpreted from stable isotope and tritium distributions
L.G. Miller, G. R. Aiken
1996, Limnology and Oceanography (41) 966-976
Perennially ice-covered lakes in the McMurdo Dry Valleys have risen several meters over the past two decades due to climatic warming and increased glacial meltwater inflow. To elucidate the hydrologic responses to changing climate and the effects on lake mixing processes we measured the stable isotope (??18O and ??D) and...
The influence of landscape position on lake chemical responses to drought in northern Wisconsin
K.E. Webster, T.K. Kratz, C.J. Bowser, J.J. Magnuson, W. J. Rose
1996, Limnology and Oceanography (41) 977-984
Climatic shifts to drier conditions during drought alter the hydrologic pathways of water and solute flow to aquatic ecosystems. We examined differences in drought-induced trends in the semiconservative cations, Ca+Mg, in seven northern Wisconsin lakes. These spanned the range of hydrologic settings in the region, including hydraulically mounded, groundwater flowthrough,...
Analysis of fractures intersecting Kahi Puka Well 1 and its relation to the growth of the island of Hawaii
Roger H. Morin, Frederick L. Paillet
1996, Journal of Geophysical Research B: Solid Earth (101) 11695-11699
As part of the Hawaii Scientific Drilling Project, Kahi Puka Well 1 penetrated about 275 m of Mauna Loa basalts overlying a sequence of Mauna Kea flow units as it was drilled and cored to a total depth of 1053 m below land surface. A borehole televiewer (BHTV) was run...
Hydrologic impact of Great Flood of 1993 in south-central Kansas
M. Sophocleous, A.J. Stern, S.P. Perkins
1996, Journal of Irrigation and Drainage Engineering (122) 203-210
The writers analyze the hydrologic budget and quantify the ground-water recharge impact of the Great Flood of 1993 on the Great Bend Prairie aquifer of south-central Kansas. During the summer of 1993, rainfall totals exceeded normal levels by 200% in the northern portion of the study area, while air temperature...
Occurrence and accumulation of pesticides and organic contaminants in river sediment, water and clam tissues from the San Joaquin River and tributaries, California
W. E. Pereira, Joseph L. Domagalski, F. D. Hostettler, L. R. Brown, J. B. Rapp
1996, Environmental Toxicology and Chemistry (15) 172-180
A study was conducted in 1992 to assess the effects of anthropogenic activities and land use on the water quality of the San Joaquin River and its major tributaries. This study focused on pesticides and organic contaminants, looking at distributions of contaminants in water, bed and suspended sediment, and the...
Controls on surface water chemistry in the upper Merced River basin, Yosemite National Park, California
D. W. Clow, M.A. Mast, K. Campbell
1996, Hydrological Processes (10) 727-746
Surface water draining granitic bedrock in Yosemite National Park exhibits considerable variability in chemical composition, despite the relative homogeneity of bedrock chemistry. Other geological factors, including the jointing and distribution of glacial till, appear to exert strong controls on water composition. Chemical data from...
Reactive solute transport in acidic streams
R. E. Broshears
1996, Water, Air, & Soil Pollution (90) 195-204
Spatial and temporal profiles of Ph and concentrations of toxic metals in streams affected by acid mine drainage are the result of the interplay of physical and biogeochemical processes. This paper describes a reactive solute transport model that provides a physically and thermodynamically quantitative interpretation of these profiles. The model...
Climate change and northern prairie wetlands: Simulations of long-term dynamics
Karen A. Poiani, W. Carter Johnson, George A. Swanson, Thomas C. Winter
1996, Limnology and Oceanography (41) 871-881
A mathematical model (WETSIM 2.0) was used to simulate wetland hydrology and vegetation dynamics over a 32-yr period (1961–1992) in a North Dakota prairie wetland. A hydrology component of the model calculated changes in water storage based on precipitation, evapotranspiration, snowpack, surface runoff, and subsurface inflow. A spatially explicit vegetation...
The use of streambed temperature profiles to estimate the depth, duration, and rate of percolation beneath arroyos
James Constantz, Carole L. Thomas
1996, Water Resources Research (32) 3597-3602
Temporal variations in a streambed temperature profile between 30 and 300 cm beneath Tijeras Arroyo, New Mexico, were analyzed at 30-min intervals for 1990 to estimate the depth, duration, and rate of percolation during streamflows. The depth of percolation was clearly documented by the rapid response of the streambed temperature...
Modeling impact of small Kansas landfills on underlying aquifers
M. Sophocleous, N.G. Stadnyk, M. Stotts
1996, Journal of Environmental Engineering (122) 1067-1077
Small landfills are exempt from compliance with Resource Conservation and Recovery Act Subtitle D standards for liner and leachate collection. We investigate the ramifications of this exemption under western Kansas semiarid environments and explore the conditions under which naturally occurring geologic settings provide sufficient protection against ground-water contamination. The methodology...
Episodic acidification of a coastal plain stream in Virginia
A. K. O’Brien, K.N. Eshleman
1996, Water, Air, & Soil Pollution (89) 291-316
This study investigates the episodic acidification of Reedy Creek, a wetland-influenced coastal plain stream near Richmond, Virginia. Primary objectives of the study were to quantify the episodic variability of acid- base chemistry in Reedy Creek, to examine the seasonal variability in episodic response and to explain the hydrological and geochemical...
Evaluating the reliability of the stream tracer approach to characterize stream-subsurface water exchange
Judson W. Harvey, Brian J. Wagner, Kenneth E. Bencala
1996, Water Resources Research (32) 2441-2451
Stream water was locally recharged into shallow groundwater flow paths that returned to the stream (hyporheic exchange) in St. Kevin Gulch, a Rocky Mountain stream in Colorado contaminated by acid mine drainage. Two approaches were used to characterize hyporheic exchange: sub-reach-scale measurement of hydraulic heads and hydraulic conductivity to compute...
Environmental gradients and identification of wetlands in north-central Florida
M.M. Davis, S.W. Sprecher, J.S. Wakeley, G.R. Best
1996, Wetlands (16) 512-523
Vegetation composition, soil morphology, and hydrology were characterized along wetland-to-upland gradients at six forested sites in north-central Florida to compare results of Federal wetland delineation methods with 3–5 yr of hydrologic data. Wetland and non-wetland identifications were supported by hydrology data in eight of nine plant communities. Lack of hydric...
Inferring shallow groundwater flow in saprolite and fractured rock using environmental tracers
P.G. Cook, D. K. Solomon, W. E. Sanford, E. Busenberg, Niel Plummer, R.J. Poreda
1996, Water Resources Research (32) 1501-1509
The Ridge and Valley Province of eastern Tennessee is characterized by (1) substantial topographic relief, (2) folded and highly fractured rocks of various lithologies that have low primary permeability and porosity, and (3) a shallow residuum of medium permeability and high total porosity. Conceptual models of shallow groundwater flow and...
Integrated borehole logging methods for wellhead protection applications
Frederick L. Paillet, W.H. Pedler
1996, Engineering Geology (42) 155-165
Modeling of ground water infiltration and movement in the wellhead area is a critical part of an effective wellhead protection program. Such models depend on an accurate description of the aquifer in the wellhead area so that reliable estimates of contaminant travel times can be used in defining a protection...
Properties and variability of soil and trench fill at an arid waste-burial site
Brian J. Andraski
1996, Soil Science Society of America Journal (60) 54-66
Arid sites commonly are assumed to be ideal for long-term isolation of wastes. Information on properties and variability of desert soils is limited, however, and little is known about how the natural site environment is altered by installation of a waste facility. During fall construction of two test trenches next...
Reactive solute transport in an acidic stream: Experimental pH increase and simulation of controls on pH, aluminum, and iron
R. E. Broshears, R.L. Runkel, B. A. Kimball, Diane M. McKnight, K.E. Bencala
1996, Environmental Science & Technology (30) 3016-3024
Solute transport simulations quantitatively constrained hydrologic and geochemical hypotheses about field observations of a pH modification in an acid mine drainage stream. Carbonate chemistry, the formation of solid phases, and buffering interactions with the stream bed were important factors in explaining the behavior of pH, aluminum, and iron. The precipitation...
Denitrification and mixing in a stream-aquifer system: Effects on nitrate loading to surface water
P.B. McMahon, J.K. Böhlke
1996, Journal of Hydrology (186) 105-128
Ground water in terrace deposits of the South Platte River alluvial aquifer near Greeley, Colorado, USA, had a median nitrate concentration of 1857 μmol l−1. Median nitrate concentrations in ground water from adjacent floodplain deposits (468 μmol l−1) and riverbed sediments (461 μmol...
Chloride mass-balance method for estimating ground water recharge in arid areas: Examples from western Saudi Arabia
A.S. Bazuhair, W.W. Wood
1996, Journal of Hydrology (186) 153-159
The chloride mass-balance method, which integrates time and aerial distribution of ground water recharge, was applied to small alluvial aquifers in the wadi systems of the Asir and Hijaz mountains in western Saudi Arabia. This application is an extension of the method shown to be suitable for estimating recharge in...
Multiport well design for sampling of ground water at closely spaced vertical intervals
G. N. Delin, M.K. Landon
1996, Ground Water (34) 1098-1104
Detailed vertical sampling is useful in aquifers where vertical mixing is limited and steep vertical gradients in chemical concentrations are expected. Samples can be collected at closely spaced vertical intervals from nested wells with short screened intervals. However, this approach may not be appropriate in all situations. An easy-to-construct and...
Deformation-induced changes in hydraulic head during ground-water withdrawal
Paul A. Hsieh
1996, Ground Water (34) 1082-1089
Ground-water withdrawal from a confined or semiconfined aquifer causes three-dimensional deformation in the pumped aquifer and in adjacent layers (overlying and underlying aquifers and aquitards). In response to the deformation, hydraulic head in the adjacent layers could rise or fall almost immediately after the start of pumping. This deformation-induced effect...
