Water-table fluctuations

Palaeo-sea (and -water-table) fluctuations. Edwards et al. (2003) describe methods used to obtain valuable information about past sea level elevations and tectonics using U-... 

Szabo BJ, Kolesar PT, Riggs AC, Winograd H, Lndwig KR (1994) Paleochmatic iirferences from a 120,000-year calcite record of water-table fluctuations in Browns Room of Devils Hole, Nevada. Qnat Res 41 59-69... 

Design of an underflow structure requires the knowledge that the water table will not drop below the bottom of the baffle system. If the seasonal water table fluctuation is not known, use another approach. 

Unconsolidated outwash gravels and sands K = 2 cm/s Annual rainfall +45 in. annual water table fluctuation typically 2 to 3 ft 8 to 12 ft... 

Rouen D, Scher H, Blunt M (1997) On the structure and flow processes in the capillary fringe of phreatic aquifers. Transp Porous Media 28 159-180 Rose CW (1993) The transport of adsorbed chemicals in eroded sediments. In Russo D, Dagan G (eds) Water flow and solute transport in soils. Springer, Heidelberg, pp 180-199 Rosenberry DO, Winter TC (1997) Dynamics of water-table fluctuations in an upland between two prairie-pothole wetlands in North Dakota. J Hydrol 191 266-289 Russo D (1997) On the estimation of parameters of log-unsaturated conductivity covariance from solute transport data. Adv Water Resour 20 191-205 Russo D, Toiber-Yasur 1, Laufer A, Yaron B (1998) Numerical analysis of field scale transport of bromacU. Adv Water Resour 21 637-647... 

Many site-specific factors can influence the cost of SVE treatment. Soil properties that can influence SVE costs include permeability, porosity, depth and stratigraphy of the contamination, site heterogeneity, and seasonal water table fluctuations. In general, the more permeable and homogenous the soil, the more efficiently SVE will operate, and the lower treatment costs will be (D22449H, p. 4-4). 

Water table fluctuations are occasionally accompanied by measurable variations in water temperature or composition, providing crucial information on mixing of different water types. Water table measurements are an important tool in tracing recharge. Three cases, reported by Winslow et al. (1965) are discussed in the following sections. 

This detailed tracing of recharge history, reflected in the water table fluctuations, is unique in its completeness and reflects direct local recharge and the lack of pumping in the Saratoga Historic Park terrain. 

Fig. 4.10 Water table fluctuations measured at wells near the Mohawk River (from Winslow et al., 1965). The wells followed a flood event with a time lag of several hours correlated with the distance from the river (insert table). The distance divided by the time lag provided the propagation velocity of the hydraulic pulse.

Kettunen A., Kaitala V., Lehtinen A., Lohila A., Aim J., Silvola J., and Martikainen P. J. (1999) Methane production and oxidation potentials in relation to water table fluctuations in two boreal mires. Soil Biol. Biochem. 31, 1741-1749. 

From the material presented above it s apparent that folia indicate the elevation of water table at the time they formed. As water table rises or falls, a trail of folia is left in its wake. The presence of well-developed folia on the ceiling of Browns Room, at least 9m above the present water table clearly demonstrates the long-term range of water table fluctuation, as... 

Irregular/nodular Carbonates or clay-rich sediments Host features preserved, simple micromorphology illuvial features absent Related to karst circulation or water table fluctuation temperate-tropical... 

The formation of humic substances in a peatland environment is a complex humification process which is principally due to certain enzymatic and microbial activities. These organic matter transformation processes are influenced by the nature of the peat-forming plants and certain physical and chemical properties within a particular peatland. In very acidic or low nutrient peatlands a very different microflora may exist than in a more eutrophic and less wet situation. In the former situation humification may be retarded and the peatland plants will be preserved and thus accumulate. On the other hand, in less acid environments with moderate amounts of nutrients and periodic water-table fluctuations humification proceeds relatively rapidly and leads to decomposed organic soils such is the case in drained and cultivated organic soils. 

Typical values for the CE-model parameters Ag and q found in several aquifers support the notion that these parameters reflect actual physical conditions during infiltration. Aeschbach-Hertig et al. (2001) found that typical values of Ag in six aquifers ranged from 0.02 to 0.04 cm STP g, indicating that a few percent of the pore space were occupied by entrapped air during infiltration, in full agreement with expectations (Payer and Hillel 1986 Holocher et al. 2002). Typical q-values were -1.2 for three temperate zone aquifers and -1.5 for three semi-arid sites. Explaining these values by hydrostatic pressure due to water table fluctuations implies typical amplitudes of 2 and 5 m, respectively. Such amplitudes of water table fluctuations are probably at the upper limit of what can be expected. 

If the excess pressure is ascribed to the hydrostatic load of infiltrating water, then ANe should be a measure of the amplitude of water table fluctuations. A verification of a direct link between water table fluctuations and ANe or q under field conditions is still missing. Experiments with sand columns (Holocher et al. 2002) support the correlation of q with the amplitude of water level changes. 

---