Publications

The method introduced by Bredehoeft and Papadopulos (1980) for conducting a modified ‘slug’ test in tight formations does not assure the condition of approximate equilibrium necessary at the start of the test. In addition, compressibility in the shut-in well can be significantly larger than the compressibility of water, which Bredehoeft and Papadopulos indicate should be used in the calculations.

South San Francisco Bay, USA, is a shallow coastal embayment that receives large inputs of nutrients (N. P, Si) and small local inputs of freshwater. Phytoplankton dynamics are typically characterized by a spring bloom when surface chlorophyll a increases from < 5 to > 40 mg m-3. The bloom persists for 2 to 4 wk, and then dissipates. Phytoplankton biomass remains low (chlorophyll a < 5 mg m-3) fro

Mass-transfer coefficients for the volatilization of ethylene and propane were correlated with the hydraulic and geometric properties of seven streams, and predictive equations were developed. The equations were evaluated using a normalized root-mean-square error as the criterion of comparison. The two best equations were a two-variable equation containing the energy dissipated per unit mass per u

Whether dendroecological analyses could be used to detect changes in the relationship of tree growth to climate that might have resulted from chronic exposure to components of the acid rain-air pollution complex was determined. Tree-ring indices of white pine (Pinus strobus L.), eastern hemlock (Tsuga canadensis (L.) Cart.), pitch pine (Pinus rigida Mill.), and chestnut oak (Quercus prinus L.) wer

While gibbsite and kaolinite solubilities usually regulate aluminum concentrations in natural waters, the presence of sulfate can dramatically alter these solubilities under acidic conditions, where other, less soluble minerals can control the aqueous geochemistry of aluminum. The likely candidates include alunogen, Al2(SO4)3 · 17H2O, alunite, KAl3(SO4)2(OH)6, jurbanite, Al(SO4)(OH) · 5H2O, and ba

The physical, chemical, and biological processes that might affect the concentration of acetone in water were investigated in laboratory studies. Processes considered included volatilization, adsorption by sediments, photodecomposition, bacterial degradation, and absorption by algae and molds. It was concluded that volatilization and bacterial degradation were the dominant processes determining th

The particle-laden surface layer (approx 150-370 mu m) and subsurface waters of a South San Francisco Bay salt marsh were sampled over 2 tidal cycles and analyzed for particle numbers and particulate-associated and total concentrations of Pb and bacteria. Laboratory studies examined the ability of a bacterial isolate from the surface layer and a bacterial 'film-former' to sorb Pb at environmentall

In 1979, liquid waste was injected into the subsurface of Florida by 10 injection systems at an aggregate average rate of 165,000 m3/d. All the systems inject into carbonate rocks that contain salty water. Extensive precautions are taken in the construction of the injection wells and in the monitoring of their operation to provide assurance that overlying and laterally contiguous freshwater resour

The increasing public awareness and concern about the hazards of toxic chemicals contaminating aquifers has created an increased need for predictive capabilities to analyze ground-water contamination problems. Several digital models to simulate the movement and concentration of ground-water contaminants have been documented recently. Most simulate the transport and dispersion of a nonreactive solu

Undesirable salinity increases occur in both groundwater and surface water and are commonly related to agricultural practices. Groundwater recharge from precipitation or irrigation will transport and disperse residual salts concentrated by evapotranspiration, salts leached from soil and aquifer materials, as well as some dissolved fertilizers and pesticides. Where stream salinity is affected by ag

Transient pulse testing has been employed increasingly in the laboratory to measure the hydraulic properties of rock samples with low permeability. Several investigators have proposed a mathematical model in terms of an initial-boundary value problem to describe fluid flow in a transient pulse test. However, the solution of this problem has not been available. In analyzing data from the transient

In Part I a general analytical solution for the transient pulse test was presented. Part II presents a graphical method for analyzing data from a test to obtain the hydraulic properties of the sample. The general solution depends on both hydraulic conductivity and specific storage and, in theory, analysis of the data can provide values for both of these hydraulic properties. However, in practice,