Regional groundwater flow systems

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). 

Batten, W. G., and Bradbury, K. R., 1996, Regional groundwater flow system between the Wolf and Fox Rivers near Green Bay, Wisconsin Wisconsin Geologic and Natural History Survey Information Circular 75, 28 p. 

Radiocarbon and tritium can be used to determine the approximate age of water masses. Three age—depth zones were deduced from the distribution of tritium and C in the groundwater. As shown in Fig. 19 B, there is an upper zone containing tritium that extends from the water table down to a depth of 6—21 m. The levels of tritium indicate that the source is probably fallout from atmospheric nuclear-fission bomb tests. Inasmuch as the testing of fission devices began in 1954, the age of water in this depth zone is probably less than 25 yr. An intermediate zone in which tritium is absent but radiocarbon is detected extends to a depth of 75m below the upper zone. If the possibility of loss of by mechanisms other than radioactive decay is neglected, a residence time of 10 —10 yr. is indicated. The deepest zone contains no detectable radiocarbon. It is in this zone that the regional groundwater flows system moves to the northeast, as previously indicated on section A—A. ... 

Toth J, Corbett T (1986) Post-Paleocene evolntion of regional groundwater flow-system and their relation to petrolenm accnmnlations, Taber area, Sonthem Alberta, Canada. Bull Can Petrol Geol 34 339-363 Tnmer G (1988) Hydrothermal flnids and argon isotopes in qnartz veins and cherts. Geochim Cosmochim Acta 52 1443-1448... 

Moreover, coupled thermal and hydraulic analysis in the far field is conducted using the homogenized parameters and the heat flux from the near field. This series of simulations shows that it is necessary to consider the effects of coupled processes in the near field on the regional groundwater flow system. 

On the other hand, the coupled processes in the far field are described in this chapter based on the results of the near field analysis. Assuming that mechanical behavior and unsaturated flow are negligible for regional groundwater flow system, only coupled thermal and hydraulic processes in saturated zone are considered. Governing equation... 

Irrigation using surface and ground water in this region has substantially altered the physical and chemical nature of the groundwater flow system and Anally the total biogeochemical food web. 

Goodfellow 2003 Gilliss et al. 2004). Interpretation of hydrology is simplified in regions dominated by porous flow in unconfined aquifers, and significantly more complicated where flow is fracture-dominated, or where significant density contrasts between different groundwater flow systems exist (Carey et al. 2003). 

Figure 1 Illustration of the development of increasingly complex flow systems as topography becomes more complex. Contours of hydraulic head are indicated by dashed lines and groundwater flow lines by solid arrows. Scale is arbitrary, but might correspond to 100 km in the horizontal direction. In (a), smooth topography produces a regional-scale flow system. In (b) and (c) increasing local topography creates a mixture of intermediate and local-scale flow systems superimposed on the regional one (Freeze and Witherspoon, 1967) (reproduced by permission of American Geophysical Union from Water Resour. Res. 1967, 3, 623-634).

Castro M. C. and Goblet P. (2003) Calibration of regional groundwater flow models working toward a better understanding of site-specific systems. Water Resour. Res. 39 (6), 1172, doi 10.1029/2002WR001653. 

After the probable depth of penetration of the regional gravity-induced groundwater flow system has been identified, it should be decided whether or not the gravity-induced flow system should be taken into accoimt in the further evaluation of the potential paths of hydrocarbon migration. 

The hydrodynamic condition in a stable subaerial region is given by the characteristics of the prevailing gravity-induced groundwater flow systems. 

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