Groundwater flow characteristics

The regional temperature variations, rainfall, patterns, groundwater flow characteristics, explosive type, explosive concentration, presence of other contaminants, land value, and other regulatory requirements can affect the wetland s cost. Constructed wetlands may not be financially viable at aU sites (D20499J, p. 2 D20503Y, p. 30). 

The interpretation of the five pressure-related parameters can be supported by an evaluation of physico-chemical phenomena associated with gravity-induced groundwater flow and a comparison of present-day groundwater flow characteristics with theoretical flow characteristics for different hypothetical conditions and/or paleogeological and paleohydrogeological conditions. 

In many cases, microbial life in nature develops into zones within which communities are dominated by one or a few functional groups, such as aerobes, sulfate reducers, or methanogens. Distinct zoning is characteristic, for example, of microbial mats (Konhauser, 2007), hot springs (Fouke et al., 2003), marine sediments and freshwater muds (Berner, 1980), contaminated aquifers (Bekins et al., 1999), and pristine groundwater flows (Chapelle and Lovley, 1992). Communities develop as well in laboratory experiments, when microbes are cultivated in pure or mixed culture. 

This expression describes the fastest and most important mode of transport in groundwater. In fact, an important task of the hydrologist is to develop models to predict the effective velocity u (or the specific flow rate q). Like the Darcy-Weis-bach equation for rivers (Eq. 24-4), for this purpose there is an important equation for groundwater flow, Darcy s Law. In its original version, formulated by Darcy in 1856, the equation describes the one-dimensional flow through a vertical filter column. The characteristic properties of the column (i.e., of the aquifer) are described by the so-called hydraulic conductivity, Kq (units m s"1). Based on Darcy s Law, Dupuit derived an approximate equation for quasi-horizontal flow ... 

Further classification of lakes relates to their position within the regional groundwater-flow system. Terminal-lake systems are defined as lakes that function as the discharge point of the regional groundwater-flow system. For terminal lakes, water is removed by evaporation and sometimes through surface outflow. These lakes typically evolve into saline lake systems characteristic of the semiarid or arid regions of the world (32). 

When the characteristics of a groundwater flow system are adjusted to the prevailing boundary conditions and remain constant in a sedimentary basin during a certain period, the groundwater flow system is said to be in steady state. Different groundwater flow systems may coexist and interact in the same... 

Figure 2.10 Characteristic pressure-depth relations in the three subsystems of burial-induced groundwater flow.

The chemical characteristics of groundwater of meteoric origin change systematically in the direction of flow in a gravity-induced groundwater flow system (Bredehoeft et al., 1982 Collins, 1975 Herczeg et al., 1991 Tdth, 1980). The... 

The system of hydrodynamic secondary hydrocarbon migration, whether the hydrocarbons move in separate phase, in very fine suspension or in aqueous solution, is influenced by the porosity and permeability distribution in a sedimentary basin, and the magnitude and direction of the net driving force for groundwater flow. As a consequence, the different processes and associated forces that are responsible for the hydrodynamic conditions in a sedimentary basin also determine to a greater or less extent the characteristics of the hydrocarbon migration system in a hydrodynamic basin (Sections 4.3.4.1, 4.S.4.2 and4.3.4.3). 

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