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played a major role in formalizing research support for hydrology as a separate discipline through establishing a separate National Science Foundation (NSF) program focused on hydrology. Distribution of chlorine-36 in the unsaturated zone at Yucca Mountain: An indicator of fast transport paths. 58–68 in Proceedings of FOCUS '93: Topical Meeting on Site Characteristics and Model Validation.
Ironically, this recognition was achieved just as internal pressure (i.e., the level of competition for research funding) rose to new highs and as the national rationale for funding scientific research was called into question as a result of ending the Cold War and of increased international economic competition.
They are studied mainly for the information they give about the ground water flow regime rather than the nature of the chemical activity in the ground water system.
Such tracers have assumed new prominence in the past decade as a result of the refocusing of attention in applied ground water hydrology from questions of ground water supply, which are somewhat independent of the details of the flow path, to questions of ground water contamination, for which understanding the flow path and the nature of solute transport along it are central.
The goal is to elucidate how interactions with the "scientific infrastructure'' affected the development of these problems and how characteristics particular to environmental tracer research influenced those interactions. Investigations of Structural Controls and Mineralogic Associations of Chlorine-36 Fast Pathways in the ESF.
One major trend in vadose zone hydrology has been a new interest in the behavior of water in arid-region vadose zones, mostly as a result of the need to predict contaminant transport at waste disposal sites.
The recharge rates are calculated from the slope of the line and the total chloride accumulation times (in parentheses) from the chloride inventory. Chloride inventories with depth are commonly used to estimate net infiltration rates (see Figure 1), and increases in concentration are used to estimate evapotranspiration (Allison et al., 1994).
Figure 1 Cumulative water volume as a function of cumulative chloride mass (both per unit area) for three boreholes in the Pasco Basin, Washington. One frequently used tracer in this situation is also one of the simplest—chloride.
Nevertheless, no expansion of funding for research on hydrologic tracers has resulted from this change in emphasis.
Another reaction to the changing circumstances has been to reevaluate some of the basic assumptions that have served as a rationale for national funding of basic research for the past 40 years.
How can the scientific research establishment promote the transfer of basic research results into applications?
Many recent writers on this topic have attempted to generalize answers to these questions.