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Appendix C Agency Interest in Groundwater Fluxes The following are brief summaries of agency interest in the topics of the workshop. Bureau of Reclamation (BuRec) Due to its water management mission, BuRec is one of the federal leaders in artificial recharge of groundwater. Accurate conception and management of such projects, and of watershed management in general, requires an understanding of natural recharge and discharge rates and distribution in space and time as well. Other issues of interest include water quality and environmental benefits and impacts of underground storage and retrieval of water. U.S. Department of Agriculture (USDA) The USDA is intensely interested in soil moisture for agriculture, and the temporal and spatial distribution of soil moisture depends partially on rates of recharge and discharge. The Agricultural Re- search Service funds research on uncertainty estimates for groundwater recharge. The Natural Re- sources Conservation Service's Soil and Water Conservation Assistance program and Resource Conser- vation and Development program indirectly take recharge into account in their projects. And the Forest Service has long-standing research on understanding effects of forest and rangeland management and related human and natural disturbances on the quality and quantity of available water - including groundwater- in their watersheds. U.S. Department of Defense (DOD) The DOD's interest in groundwater fluxes arises from its responsibilities in several research areas and is not limited to a single geographic region or climate. Contaminants are frequently encountered in groundwater at Army, Navy, and Air Force facilities, where the distribution of infiltration in space and time, and fluxes of contaminants between groundwater and surface water bodies, are key questions. The Corps of Engineers' roles include permitting of wetland mitigation; discharge rates may be the key to whether a wet- land type can be recreated in a given location. Flow rates beneath and through levees and earthen dams 74

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Appendix C 75 are of obvious interest to the Corps. Finally, there are direct military applications such as predicting soil saturation levels or stream depth and velocity for planning troop movements using estimates of the timing and volume of infiltration and runoff. U.S. Department of Energy (DOE) Groundwater fluxes are also of interest to the DOE, which recently laid out a blueprint for re- search in subsurface science in which they identified a need to characterize boundary conditions (i.e., fluxes at interfaces) that control contaminant transport and fate. Quantification of recharge rates is of intense interest at the DOE's Yucca Mountain Site for spent nuclear fuel (Flint et al., 2002), and at many other contaminated sites including the Hanford Site (Washington State), Idaho National Engi- neering and Environmental Laboratory, and the Savannah River Site (South Carolina). U.S. Environmental Protection Agency (USEPA) The Environmental Protection Agency oversees the remediation of a large number of contami- nated sites. The rate of migration of dissolved contaminants in shallow soil and aquifers is a function of recharge rates. Likewise, discharge zones can either be areas of natural degradation of contaminants, or a pathway of contamination to surface water bodies. Groundwater vulnerability and the geometry of groundwater protection areas - both important topics to the USEPA- are functions of recharge rate and distribution among other factors. The USEPA and NSF's joint research initiatives on watersheds have also involved projects that measure recharge and discharge. U.S. Geological Survey USES) Quantifying groundwater recharge is a priority research area in the U.S. Geological Survey. In a summary article prepared by USGS researchers for the American Geological Institute (Reilly et al., 2000), recent advances in measuring flow between groundwater and surface water were highlighted (along with measuring land subsidence) as particularly important to sustainability of groundwater re- sources. Groundwater recharge rate estimation is one of the four priority topics for the Ground-Water Resources Program. And the National Research Program's project on "Role of Lakes in the Hydrologic System" has spent decades examining fluxes across the lake-groundwater interface. National Air and Space Administration (NASA) in general, NASA's interest in groundwater fluxes derives from: 1) the potential to measure - directly or indirectly- groundwater and its fluxes from satellite-borne remote sensing instruments; and 2) the perceived importance of groundwater as a component of the Earth system and its relationship to climate change. The Gravity Recovery and Climate Experiment (GRACE) aims to estimate changes in total terrestrial water storage with high precision. Use of laser altimetry measurements to deduce river stage, and from that baseflow (groundwater discharge) also shows promise. NASA is also interested in the consequences of climate change for life on Earth.

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76 Appendix C The following questions of interest to NASA all include a groundwater flux component: How is the global Earth system changing? How are global precipitation, evaporation, and the cycling of water changing? How are variations in local weather, precipitation, and water resources related to global cli- mate variation? And how well can long-term climatic trends be assessed or predicted? National Oceanic and Atmospheric Administration (NOAA) Near-surface groundwater fluxes are critical to NOAA modeling needs. For example, the effect near-surface fluxes have on moisture content of the lower soil layers is not well understood. In current NOAA models, the moisture content in these lower zones contributes to Tong-term base flow in streams and rivers. Thus, any groundwater fluxes across the interface with these Tower zones can impact base flow modeling. Including the groundwater surface-water interaction in these hydrologic models may have an impact on soil moisture simulations. Second, the mechanisms for determining flow paths for near surface ground water need to be understood as the National Weather Service moves towards finer scale (distributed) hydrologic model- ing. While the paths of overland flow on the surface are assumed to follow topographic slope, it is not clear if near-surface ground water can be modeled in this manner. Research needs to address the movement of near-surface soil moisture towards river channels. Finally, the effect of Tow frequency groundwater fluctua- tions on the climate needs to be evaluated. Under what conditions are the relationship between precipitation and groundwater out of phase? And does groundwater have a significant longer terns feedback effect on the climate? National Science Foundation (NSF) NSF funds research in the hydrologic sciences (groundwater, surface water, and land surface hydrology), most of which comes through the Geosciences Directorate. In addition to the Hydrologic Science program run though the Division of Earth Sciences, NSF's Atmospheric Sciences Division funds research on Climate Variability and Predictability (CLIVAR). The two divisions are collaborating on a re- search initiative called Water and Energy: Atmospheric, Vegetative and Earth Interactions (WEAVE), which includes water and energy fluxes across interfaces. Further, NSF is sponsoring the Consortium of Universi- ties for the Advancement of Hydrologic Science, Inc. (CUAHS~ (www.cuahsi.org), which has proposed a network of hydrologic observatories that could be used for research in groundwater fluxes at a fairly large scale. Nuclear Regulatory Commission (NRC) The NRC regulates civilian use of nuclear materials. As such, it is responsible for storage and disposal of nuclear materials and waste. Groundwater discharge rates and distribution in such areas are of obvious interest to the Commission. The NRC is also in charge of the license renewals of nuclear plants. These renewals require Environmental Impact Statements, which have sections on impacts on groundwater, water use, floodplains and wetlands.

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Appendix C 77 REFERENCES Flint, A. L., L. E. Flint, E. M. Kwicklis, J. Fabryka-Martin, and G. S. Bo~varsson. 2002. Estimating recharge at Yucca Mountain, Nevada, USA: comparison of methods. Hydrogeology Journal 10(~):~80-203. Reilly, T. E., K. R. Prince, and J. W. LaBaugh. 2000. Solid earth: hydrogeology. Geotimes 45 (7): 23.

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