USGS models

A USGS model for computing the major and trace element speciation and mineral saturation for natural waters. 

A USGS model for computing the chemical evolution of the aqueous phase as the result of specified geochemical reactions. Based on an ion-pairing aqueous model,... 

Sources of tliis information include site descriptions mid data from the preliminary assessment (PA), site inspection (SI), and remedial investigation (RI) reports. Other sources include local soil sur eys, wetland maps, aerial photographs, and reports by the National Oceanograpliic and Atmospheric Association (NOAA) and tlie U.S. Geological Sur ey (USGS). One cmi also consult with appropriate tecluiical e.xperts (e.g., hydrogeologists, air modelers) as needed to cluuacterize tlie site. 

Formulation and Use of Practical Models for River-Quality Assessment, Geology Survey Circular 715-B, USGS, Reston, VA, Washington, D.C., 1975. 

Models of the above have been presented by various researchers of the U.S. Geological Survey (USGS) and the academia. The above equation has been solved principally (a) numerically over a temporal and spatial discretized domain, via finite difference or finite element mathematical techniques (e.g., 11) (b) analytically, by seeking exact solutions for simplified environmental conditions (e.g., 12) or (c) probabilistically (e.g., 13). 

Watershed attributes were determined using Arcview. Watersheds were delineated using the watershed command in ArcView on National Elevation Dataset digital elevation models (DEM) from the United States Geological Survey (USGS,... 

In our original system of partial differential equations, to obtain a pseudohomogeneous model the two energy balances can be combined by eliminating the term (Usg/Vb)(Ts — Tg), that describes the heat transfer between the solid and the gas. If the gas and solid temperatures are assumed to be equal (Ts = Tg)19 and the homogeneous gas/solid temperature is defined as T, the combined energy balance for the gas and solid becomes... 

The simulation-optimization model incorporates the USGS simulation models MODFLOW (McDonald and Harbaugh 1984) and MODPATH (Pollack 1994) to determine the system state under a set of imposed stresses. More detailed discussions of the simulation-optimization model, model parameterization, and solution characteristics are presented in Mulligan and Ahlfeld (1999a) and Mulligan (1999). 

Konikow LF, Bredehoeft JD (1978) Computer model of 2-dimensional solute transport and dispersion in groundwater. In USGS techniques of water resources investigations, book 7, chap C2. United States Geological Survey, Washington, DC... 

Modeling results are summarized in several ways. First, Fig. 13 presents iso-pleths of annual average benzene concentrations overlaid on a United States Geological Survey (USGS) topographic map of the refinery area. Each curved line... 

Foose M. P., Zientek M. L., and Klein D. P. (1995) Magmatic sulfide deposits (MODELS 1, 2b, 5a, 5b, 6a, 6b, and 7a Page, 1986a-g). http //geology.cr.usgs.gov/pub/open-file-reports/off-95-0831/CHAP4.PDF... 

Geochemical modeling of reactants in flowing mountainous stream systems can be done with the USGS codes OTIS (Runkel, 1998) and OTEQ (Runkel et al., 1996, 1999) that model solute transport and reactive transport, respectively. OTIS, or one-dimensional transport with inflow and storage, is based on the earlier work of Bencala (1983) and Bencala and Walters (1983). The OTEQ code combines the OTIS code with MEMTEQA2 for chemical reaction at each... 

Leach, D., Viets, J. G., Foley-Ayuso, N., and Klein, D. P., 1995, Mississippi VaUey-type Pb-Zn deposits in du Bray, E. A., ed.. Preliminary compilation of descriptive geoenvironmental mineral deposit models USGS Open-File Report 95-831, p. 234-243. 

Leenheer, J. A., D. M. McKnight, E. M. Thurman, and P. MacCarthy. 1989. Structural components and proposed structural models of fulvic acid from the Suwanee River. In R. C. Averett, J. A. Leenheer, D. M. McKnight, and K. A. Thorn, eds. Humic substances in the Suwanee River, Georgia interactions, properties, and proposed structures. USGS Report 87-557, Denver, CO, pp. 335-359. 

Fig. 7.13 Inset-. House Finch survey-wide population size (P, measured in counts per party hour) vs time (The North American Breeding Bird Survey. Graph of survey-wide yearly indices from CBC. USGS Patuxent Wildhfe Research Center, Laurel, Maryland, USA). In order to estimate r we used a logarithmic plot and removed points far away from the exponential phase (large times), which implied a decrease in the regression coefficient of the linear fits. Main figure House Finch annual dispersal histogram (from [457]). Note that a time interval of 1 yr, which is the value for the data shown, corresponds roughly to the time required by a newborn individual to turn into an adult, i.e., roughly to T in the RT model. Reprinted from [329]...

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