Global Paleoflood Database. Through various international collaborations and supported by NOAA, we are developing a global database of paleoflood hydrological results. The database will be useful in assessing changes in extreme events over time scales of centuries and millennia. [K. Hirschboeck, V. Baker]
Paleoflood Hydrology of Rivers in Central and Southern India. Our studies of the Narmada, Tapi, Godavari, and Krishna Rivers are documenting the magnitude and frequency of extremely large tropical floods in relation to hydroclimatological change. The results are contributing to fundamental understanding of the nature of tropical bedrock river processes. The work has involved collaboration with The National Institute of Hydrology Roorkee, India, and with researchers at various universities, including University of Poona, Deccan College, and Anna University. Y. Enzel, Hebrew University of Jerusalem; L. Ely, Central Washington University; and A. Gupta, University of Singapore, are also collaborating in this work. [V. Baker]
SAR Investigations of Late Pleistocene Paleofloods, Paleolakes, and Paleoclimate in Central Asia. This project uses data from the RADARSAT Mission to understand the spectacular regional paleohydrological changes that occurred in Central Asia during the late Pleistocene. The study is focused on the newly discovered late Pleistocene cataclysmic flood features and associated paleolake changes in the region. [V. Baker; G. Komatsu, Lunar and Planetary Laboratory]
River Flooding and Global Climatic Change. This project, which is cooperative with the surface processes Laboratory, Dartmouth College, is a part of NASA's Earth Observing System (EOS) Program. It uses sustained multi-sensor Earth observation from space to measure various aspects of extreme floods and analyze their causation. The goal is to understand the most extreme flood phenomena in a global context. [V. Baker, K. Hirschboeck]
Paleohydrology and Paleoclimatology of Mars. Geological studies of long-term paleoenvironmental change on Mars (collaborative with R. Strom and G. Komatsu, Lunar and Planetary Laboratory) are focused on understanding, past epochs of surface-water flow, glaciation, and related paleohydrological phenomena. Calculations are also being performed to estimate paleodischarges of the ancient channelways. [V. Baker]
Desert Hydrogeomorphology. This project, supported by the U.S. Army Research Office, uses multispectral and radar remote sensing imagery to study desert hydrogeomorphology in Arizona and Australia. The project is collaborative with Dr. Melba Crawford, Center for Space Research, The University of Texas at Austin. [V. Baker, M. Crawford]
History and Philosophy of the Earth and Environmental Sciences. I have been studying the role of science education in relation to modern society, the appropriate role for models and predictions in relation to science and technology policy, the nature of scientific reasoning in the Earth Sciences and the history and development of scientific thought in relation to geomorphology. [V. Baker]
Southwest Regional Earth Science Applications Center (RESAC). The overall aims of this multi-investigator center is end-to-end demonstration of use of NASA data & technology in addressing water resources problems & other issues in the Southwest. The primary focus of the Arizona team is on use of remote sensing to map snowcover, with subsequent use of that information in making short- and long-term hydrologic forecasts. Collaborators at Berkeley National Laboratory focus on applications of regional climate modeling to Southwest water resources. Main study areas are in the Colorado River Basin, California. [Several Co-I's: ].
Alpine Hydrology and Biogeochemistry. We are using a combination of remote sensing and ground-based data in this investigation to develop a detailed understanding of the patterns and processes of the water, chemical and nutrient balances of seasonally snow-covered alpine watersheds. Field studies of snow hydrology and alpine biogeochemistry compliment the modeling efforts. Main study areas are in the Sierra Nevada, Rocky Mountains, Chilean Andes and other alpine regions. [R. Bales].
The Climate Assessment Project for the Southwest (CLIMAS). CLIMAS brings together researchers who study the processes and effects of climate on the Southwest region with individuals and organizations who need climate information to make informed decisions. The project, located within the Institute for the Study of Planet Earth is one of several initiatives that have been funded as pilot projects by the National Oceanic and Atmospheric Administration (NOAA). CLIMAS involves working with stakeholders to identify and evaluate climate information and forecast needs and products, and carry out research on climate and climate impacts in the Southwest. [Several Co-I’s].
Global Learning and Observations to Benefit the Environment (GLOBE). GLOBE is a worldwide network of students, teachers, and scientists working together to study and understand the global environment. Students and teachers from over 7,000 schools in more than 80 countries make environmental observations at or near their schools and report their data through the Internet. We provide science support to GLOBE in the area of hydrology, use the data in research and provide feedback to the students. [R. Bales; M. Conklin]
Analysis of Ice Cores for Estimating Annual Accumulation in Greenland. We are participating in studies of the role of the Greenland ice sheet in global climate, mainly focusing on historical ice sheet balance. Our work involves recovering and analyzing a set of 150-m and shallower ice cores from Greenland, and making climate interpretations of the results. This effort is part of NASA’s Program for Arctic Regional Climate Assessment (PARCA). [Co-PI: J. McConnell]
Snow-Atmosphere Transfer
Function for Reversibly Deposited Chemical Species. We are studying
the question of how hydrogen peroxide, formaldehyde, and other reactive chemical
species are incorporated into the glacial record. The aim is to invert the ice
core record to provide a record of past atmospheric oxidation capacity. It involves
field work in Greenland,
at Siple Dome in West Antarctica, at South Pole, and on the International Trans-Antarctic
Scientific Expedition (ITASE)
traverse in West Antarctica. [Co-PI: J. McConnell]
Water Rights and Transfers in the Modern Southwest. This research addresses the legal and policy consequences of water transfers from rural to urban areas in the Southwest. It specifically examines the application of water-rights doctrines to transfer proposals, the mechanisms to alleviate third-party effects and the role of institutions to rights holders and conflict managers in water transfer schemes. [M. Bradley]
Hydrologic Citizenship: Water and Equity in the "New West". This research develops the concept of hydrologic citizenship as a guide to public policy in the reallocation-era of western water resources. It generates a community-based response to the questions of water markets and transfer schemes. The public interest in water development is analyzed using the concepts of environmental ethics and social justice. [M. Bradley, H. Ingram]
The Art of the Science of Hydrology: Models, Drawings and Communications. This research examines the art of hydrology from the perspective of both semiotic and aesthetic theory. The drawing and illustrations used to understand invisible ground-water resources are analyzed as artistic statements within themselves and as communications media of great importance from the development of scientific "perspective". [M. Bradley]
Biography: Steve Reynolds, New Mexico State Engineer. A study of the life and professional accomplishments of one of the most famous and important water engineers in the modern American Southwest. It emphasizes the significance of highly ethical, technical and legal expertise in the long-range economic development of water resources in a smaller arid state. [M. Bradley]
History: Department of Hydrology and Water Resources. This project is an analytic summary of the intellectual history of HWR, from its founding under Dr. John W. Harshbarger to the present. The development of undergraduate and graduate curricula, as well as research projects and programs is the theme of this approach. Also studied are the remarkable complex of visitors, postdocs, joint faculty, and collaborating scientists, who have helped, with an outstanding internationally recognized regular faculty, to make HWR the number one program in hydrogeology for the last five consecutive years. [M. Bradley]
Effects of Nitrogen and Sulfur Deposition on Terrestrial and Aquatic Ecosystems. The last 50 years have seen an exponential increase in the emission of N and S oxides from fossil fuel combustion (although recent regulation has begun to decrease SOx) as well as agricultural use of N fertilizers. Atmospheric transport and the subsequent deposition (both wet [often termed acid rain], and dry) of these compounds have impacted both terrestrial and aquatic ecosystems. Research in this area has sought to provide an “early warning” for ecosystems at risk for future impacts as well as understanding how systems recover from past deposition. This work has been primarily centered in seasonally snow-covered catchments in the Rocky Mountains. [P. Brooks]
Biogenic Trace Gas Fluxes. Soil microbial communities may serve either as a source or sink for atmospheric gases (CH4, CO2, N2O) that are responsible for the natural greenhouse effect, and may be important in global climate change. Consequently, research designed to understand the controls on the fluxes of these gases is crucial for predicting future climate scenarios that depend on accurate estimates of atmospheric greenhouse gases. Previous work in this area has taken place in Alaska and Colorado during both summer and winter months. [P. Brooks]
Production and Export of Dissolved Organic Matter. The export of Dissolved Organic Matter (DOM) is a significant flux of carbon and nutrients from terrestrial environments as well as a major source of carbon and energy for aquatic ecosystems. However, the controls on the production of DOM are poorly understood. Research in this area ranges from laboratory experiments to field plots and catchment scale experiments. This work is crucial for understanding carbon and nutrient balance in terrestrial systems, primary productivity in aquatic systems, and water quality for human consumption. [P. Brooks]
Metal Export from Catchments Impacted by Acid Mine Drainage. Many headwater catchments in the western United States have a history of mining resulting in accelerated mineral weather and elevated metal concentrations in surface water. Population growth has increased the demand for this water, resulting in efforts to remediate these sites for both human use as well as natural values. The objective of this work has been to describe temporal patterns in metal export and relate these patterns to forcing variables (climate, land use change, etc.). [P. Brooks]
Controls on UV Penetration in Aquatic Environments: Implications for Amphibian Survival. Recent research has raised concerns that increased UV-B radiation may be responsible for the observed decline in amphibian populations. Once radiation has reached the surface of a water body, the primary control on UV-B penetration is the amount and composition of Dissolved Organic Carbon. Therefore, the objective of this work is to identify the amount, structural composition, and temporal changes in DOC in amphibian habitats (surface water) in Sequoia, Olympic, Glacier, and Rocky Mountain National Parks and relate these findings to UV penetration and amphibian populations. [P. Brooks]
Water Resources - A Factor in the Peace Process in the Middle East. The competition for the limited water resources in the Middle East is an important factor in the peace process. Possible alternative systems that could be a basis for negotiations are being developed, for governmental agencies (such as the US State Department, USAID) as well as for non-governmental organizations (e.g., The Pugwash Group for Science and Public Policy). [N. Buras]
Operation of Multiple Reservoir Storage Systems. Operation of reservoirs in series and in parallel in a dynamic setting is being studied as a complex problem in optimization. First, for any time period in a yearly cycle, optimal operation policies for each of the reservoirs in series are developed. Then, this vector of decisions is introduced into the state matrix of a multi-stage (in time) decision process. Synthetic hydrological sequences are generated and a non-linear optimization algorithm is used at each decision stage. [N. Buras; C.-S. Peng*.]
Functioning of Riparian Systems. This project is part of SAHRA. The overall objective of this research is to understand the linkages between the hydrologic cycle and the nutrient cycle in riparian systems. Initially we are focusing on the San Pedro River. Current foci: Nitrogen cycling between the banks and the stream, developing a nitrogen balance for the system and how erosion and sedimentation affects nitrogen cycling. [M. Conklin, N. Grimm (ASU), P. Brooks]
Remediating Mine Waste Products. This project is part of the campus Superfund Center. The southwest is pock-marked with abandoned mining operations. Our goal is develop passive methods to monitor metal movement off the mining sites and to use phytoremediation to remove metals from streams. [M. Conklin]
Electrochemical Remediation of Arsenic and Chromium. This project is part of the campus Superfund Center. Currently there is no inexpensive method for small water distribution systems to remove arsenic from drinking water. We are investigating zero-valent iron for arsenic and chromium removal by determining the mechanism of removal and the stability of the reaction products. [J. Farrell (ChEE) and M. Conklin]
Biogeochemical Transformation of Manganese and Toxic Metals in a Changing Riparian System. We are studying a riparian system in which a stream is receiving ground water containing high levels of Mn (II) and other toxic metals (Zn, Ni, Co and Cu), in Pinal Creek, Arizona. We are determining the biogeochemical constraints involved in the natural attenuation of Mn (II). As this system is undergoing remediation, we are also observing the system responses to lower metal concentrations. [M. Conklin, C. Fuller (USGS), J. Harvey (USGS), B. Tebo (Scripps)]
Available soon.
An Isotopic Investigation of Salinity and Water Sources in the Souss-Massa Basin, Morocco. Seawater intrusion and other processes that contribute dissolved solids to groundwater are a major threat to water quality in the heavily exploited Souss-Massa Basin nestled between the High Atlas and Anti-Atlas Mountains of Morocco. A hydrogeologic investigation using isotopes such as 18O,4He, 36Cl, and 129I is being carried out with the goal of determining the source of water, the source of salinity, and the age of the water for groundwater samples from the Souss-Massa. Information regarding the relative importance of various salinity and water sources can be used to make informed decisions about water resource allocation and possible remediation strategies.
Xenon isotopes as Tracers for Groundwater Recharge. An approach for tracing rapid recharge and groundwater movement has been applied using isotopically-enriched xenon as an artificial tracer. Xenon has nine stable isotopes to choose from to track recharge from multiple surface water sources. Noble gases are ideal tracers because they are inert and therefore pose no health concerns. Furthermore, because of their low natural abundance we can dissolve small quantities into a recharge basin and still achieve a large dynamic range during dilution with native groundwater with respect to the detection limit. The detection limit for 124Xe tracer is approximately 0.1 femtomole 124Xe per mole of water. Once xenon is dissolved in the water and remains out of contact with the atmosphere the xenon will move conservatively with the groundwater. Research areas include northern and southern California. Future research will focus on local recharge issues in Tucson.
Dating of shallow groundwater: Comparison of the transient tracers 3H-3He, CFCs, and 85Kr. Several age dating methods are employed to date groundwater that was recharged over the past several decades. The relative agreement or disagreement between different age dating methods give valuable information regarding mixing of waters of different ages, dispersion, gas loss, and sorption-desorption processes. Age dating methods will be used in future studies.
Liquid, gas, and solid transport in the vadose zone traced by 18O, Br, I, noble gases, and microspheres. This is a multi-tracer research project to study vadose zone infiltration processes. Imported water that has a composition that is distinct from the local groundwater for the tracers we studied (e.g., Br, I, 18O, 3He) was infiltrated at different rates and volumes. In addition to the natural tracers provided by the imported water, we added several artificial tracers during two separate infiltration events: LiBr, KI, and one-micron-sized mircospheres (colloid surrogates) were added. The 136Xe was artificially elevated in the vadose zone soil gas so vadose zone water and soil gas interactions could also be investigated. This study is a step toward understanding the vadose zone processes that must be incorporated into our models if we are to accurately predict the risk associated with potential releases of contaminants into the vadose zone.
Nonpoint Source MTBE Movement through the Environment: Ultra Low Level (ppt) Measurements in California. To achieve a 15 parts per trillion (ppt or 15 ng L-1) detection limit for Methyl-tert-butyl-ether (MTBE), a method was developed using a purge and trap, gas chromatographic mass spectrometer (GC/MS) operated in the selected ion monitoring mode. We traced nonpoint source MTBE in precipitation, surface water, and groundwater that would have been undetected in previous studies with typical detection limits between 0.2 to 1.0 µg L-1. MTBE is ubiquitous as a nonpoint source contaminant that persists through a variety of transport pathways at concentrations usually below current health advisory levels (i.e. 20-40 µg L-1 for drinking water).
Global climate change in the Arctic. Do dramatic changes in the Arctic Ocean detected in the 1990’s represent: 1) anthropogenic global warming, 2) a normal cycle within the cyclical climatic pattern known as the Arctic Oscillation, or 3) the superposition of these two signals? This research employs transient tracers (3H-3He), 18O, nutrients, temperature, and salinity measurements to prove that the Pacific Water/ Atlantic Water front has retreated, the Cold Halocline Layer has retreated, and the Atlantic Water core temperature near the North Pole has increased. The tracers help identify shifts in the Arctic freshwater balance, the North Atlantic Oscillation, and atmospheric forcing as causes of these observed changes. Future focus will be on quantifying the contribution to these Arctic trends from global warming.
Integration of Electromagnetic Methods of Water Content Measurement across Widely Varying Spatial Scales. This proposed study will combine numerical analyses and field measurements to improve the design of spatially distributed water content monitoring networks. Results will lead to improved ground-calibration of satellite-based remotely-sensed water content measurements.
Estimation of Recharge beneath Rillito Creek. Estimations of the contribution of recharge beneath this ephemeral surface water body are critical to the development of a water budget for the aquifer underlying the city of Tucson, AZ. In collaboration with researchers from the USGS, we will use both heat tracer and direct measurements to quantify this contribution to the groundwater reserves.
Minimizing Water Content Measurement Errors for Electromagnetic Methods in Electrically Conductive Environments. Indirect, electromagnetic measurements of the water content of porous materials have become the standard method in both soils and grains. Recent work has shown that the dielectric permittivity is dependent on the electrical conductivity, potentially giving rise to erroneous water content measurements. This proposed work will investigate the frequency-dependent response of electromagnetic instruments to water content and pore water salinity to address this issue.
Snow Moisture Measurement. There exists no accepted method of determining the unfrozen water content of snow. A research program is being developed with the aim of designing an electromagnetic method of snow moisture determination based on a spectral analysis of the dielectric properties of melting snow.
Transport of Saline Groundwater to Surface Water Bodies across Seepage Faces. Pesticides, fertilizers and naturally occurring salts transported through the subsurface impact the quality of surface water bodies. A laboratory and numerical modeling program is proposed to study the pathways of solute transport across seepage faces to assess the potential impacts on plants residing in and along streambeds and lakeshores.
Radiative Transfer Modeling Within-Leaves. In order to better understand the biogeochemical processes associated with ecosystems, within leaf radiative transfer models for photon migration are developed. The models include true photon scattering and incorporate fast and accurate theoretically based computational techniques to solve the radiative transfer equation. The models, combined with experimental measurements, are used to infer absorption profiles containing the signatures of the biochemicals in the leaf. This research is part of NASA's Mission To Planet Earth which is part of a larger effort currently underway in the Ecosystem Science and Technology Branch at NASA/Ames Research Center.
Canopy Radiative Transfer and Vegetation Canopy Dynamics. The biophysical interaction of photons with the phytoelements of vegetation canopies is modeled through the turbed medium radiative transfer equation. Special emphasis is placed on canopy architecture as characterized through leaf angle distribution included via a nested leaf orientation model. With an appropriate leaf model, canopy reflectances are estimated and compared to remotely sensed satellite data to better predict canopy efficiency and carbon gain through the fraction of photosynthetically absorbed radiation (fPAR). In this way, our understanding of canopy dynamics based on first principles is enhanced.
Subsurface Transport of Radioactive Waste Through Fractured Media. The transport of radioactive solute through fractured media is modeled as a statistical process using the Baltzmann equation for "marker particles". A fracture distribution model is incorporated as a "phase function" characterizing directional redistribution of particle flow. A numerical Fourier transform is applied to the analytical image function to obtain accurate numerical estimates of solute flow. In addition, advantage is taken of the speedup afforded by high performance parallel computation of platforms as applied to this analytical formulation.
Development of a Fine-Grid Multilayer Flow Simulation Model of the Middle San Pedro River Basin. The model replicates the stress history of that part of the basin, simulating ground water level changes as well as changes in the flow of the San Pedro River through the modeled area.
Development of a Ground-Water Flow Model in the Mesilla Basin, New Mexico to Help Determine the Ground-Water Effects on Canals, Drains, and the Rio Grande. The model was used by New Mexico to provide hydrologic information for negotiations for a settlement agreement between the city of El Paso, Texas, and the state of New Mexico.
Use of the Mesilla Basin Ground-Water Flow Model to Assess the Effects of Pumping and Canal Lining on the Hydrologic Regime of the Mesilla Basin. The model is now being integrated into Planning Processes of the Settlement Commission, an Entity Created by the Negotiated Settlement Between E. Paso and the State of New Mexico.
Development of a Boron Isotope Ratio Technique for Identifying Nitrate Contamination Sources in Ground-Waters. The methodology developed can distinguish between infiltrated effluent waters from sewage treatment, percolated irrigation return flows, and natural mountain front recharge waters, and determine their mixture quantities in a sample of ground water.
Determination of Recharge of Treated Effluent in a Natural Stream Channel. Experimental instrumentation is being employed to monitor the movement of fluid through unsaturated and saturated horizons under the stream channel.
Development of a Water Resources Management Plan for Big Bend National Park in Texas. All aspects of the park's water resources are being evaluated, from the smallest tinaja to the Rio Grande with the goal of providing the National Park Service guidance on cost and goal effective strategies to monitor, protect, and utilize the water resource of the park while striving to preserve the natural attributes of those resources.
Determination of the Quantities of Treated Effluent That are Being Recharged in the Upper Santa Cruz River Below the International Wastewater Treatment Plant at Nogales. This effort includes quantification of stream-aquifer interaction, as well as quantifying the evapotranspiration rates of the riparian vegetation.
Evaluation of Rainfall-Runoff Relationships on Experimental Watersheds Operated by the Forest Service in the Mogollon Rim Region. This effort is just starting, and the direction the research effort follows will evolve as analysis of the abundant historic data reveals interpretive opportunities.
Development of a Monitoring Program for the San Bernardino Wildlife Refuge in Black Draw. Concerns for the effects of water resource development in Mexico on the ground water system of the refuge requires the development of a monitoring program to detect any impacts as the artesian ground-water system supplies water to springs and flowing wells which in turn provide habitat for several threatened and endangered species.
An Evaluation of the Effects of Seasonal Stresses, such as Irrigation Pumpage and Stream Flow, on the Simulation of Coupled Stream-Aquifer Systems. Use of average annual values for such stresses can result in an unrealistic simulation of the actual system.
Development of an Integrated GIS and Ground Water Flow Model Using a Deformable Grid Structure. The ground water flow model incorporates both finite element and finite difference solution processes and will be compatible with the USGS MODFLOW model. The distortable grid will enable researchers to follow the sinuous geometries of coupled stream aquifer systems.
Multidisciplinary Program
in the Lower Cienega Creek Basin Southeast of Tucson. In this program that
is
nearing completion, where five M.S. Candidates developed theses in concert in
flow simulation, aquifer geometry, water policy, and water chemistry.
Multidisciplinary Program in the Upper Cienega Creek Basin Southeast of Tucson. Where six M.S. candidates developed theses in concert in flow simulation, aquifer geometry, water policy, and water chemistry.
The research I am conducting with coworkers and graduate students involves field, theoretical, and computational investigations of flow and transport through unsaturated fractured tuffs; development and application of geostatistical methods for the spatial analysis of hydrogeologic data; development and application of stochastic methods to describe mathematically fluid flow and solute transport when soil and rock properties vary randomly in space, and with the scale of observation; development of computational algorithms and computer programs to predict subsurface flow, and solute concentrations, under uncertainty, and to assess the associated prediction errors; estimation of flow and transport model parameters under uncertainty; and use of such computational models to help assess subsurface contamination, identify contaminant sources, design groundwater monitoring networks, and aid the design of remedial operations. The public in Tucson and throughout Arizona, the United States and indeed the world is deeply concerned with issues of groundwater pollution and its impact on human health and the environment. Our research provides the scientific and technical bases that are necessary if one is to approach and resolve these issues in a rational, cost-effective and timely manner.
During previous years, our group has collected extensive data of very high quality concerning the propagation of air pressure pulses between boreholes in unsaturated fractured tuffs at the Apache Leap Research Site (ALRS) near Superior, Arizona. In 1998, we developed theoretical pressure and pressure derivative type curves, as well as highly sophisticated computational simulation and parameter estimation tools, for the analysis of these data. Our analysis has provided precious new insight into the phenomenology of gas flow in unsaturated fractured porous media, the properties of such media, their variation with location, direction and scale, and the manner in which fracture connectivity affects fluid and pressure propagation through rocks. At present, water and tracer infiltration tests are being conducted at the site in collaboration with Professor Peter Wierenga of the department of Soil, Water and Environmental science.
Another exciting area of research concerns the analysis of unsaturated water flow through randomly heterogeneous soils. My students and I were able to develop two entirely new ways of solving such problems mathematically, and computationally, in a manner that is considerably more accurate than has been possible in the past. Another project is addressing the important issues of instability and fingering of dense nonaqueous liquids in randomly heterogeneous aquifers. This theoretical and experimental study is conducted in collaboration with Professor Jim Smith of McMaster University in Ontario, Canada.
We made important progress in addressing issues of scale in subsurface hydrology by showing how one can incorporate anisotropy and lacunarity in a stochastic theory we developed for this purpose in previous years. We also resolved the question how to define and predict effective parameters in a multi-scale permeability field, and how to assess their uncertainty. Issues of scale have been identified by the National Academy (Opportunities in the Hydrologic Sciences, National Academy Press, 1991) as being among the most important questions that face hydrologic science and practice in the coming decades. Our work on these topics is widely recognized as being of a fundamental and pioneering nature; in particular, we have developed entirely new paradigms for (a) the mathematical description and solution of flow and transport problems in randomly heterogeneous media under uncertainty (by means of exact, non-local conditional moment equations) which obviates the need for upscaling and Monte Carlo simulation of related problems, and (b) the scaling of random fields (by means of truncated power variograms and associated spectra) which, for the first time, explains many observed scaling phenomena in hydrogeology within a unified conceptual/theoretical framework. My students and I are continuing to work on related problems.
One of my students has
completed extensive pressure interference tests at the San Manuel mine in Arizona,
analyzed them and provided important new insight into the hydrogeology of in-situ
copper leaching. Underground leaching of copper is a relatively new and rapidly
developing mining technology which is strongly dependent on hydrogeologic input.
Our close collaboration with BHP Copper has placed us in a unique position to
contribute in a major way toward the development of this technology in Arizona
and at other sites across the world.
Our research is presently supported by the U.S. Nuclear Regulatory Commission,
the U.S. Environmental Protection Agency, the U.S. National Science Foundation,
and the U.S. Army Office of Research.
Available soon.
Aggregate Description of Heterogeneous Land-Cover in Meteorological Models. Real vegetation cover is heterogeneous at the grid scale used in meteorological models. This project is investigating methods to define effective values of vegetation-related parameters which, when they are used in one-dimensional surface models, will provide reasonable estimates or surface exchanges. [Shuttleworth, Yang, Burke, Mullen; NASA]
The Optimal Combination of Parallel Streams of Remotely Sensed Data to Document the Surface Energy Balance. There are many different streams of remotely sensed data available which contain information that should aid the documentation of surface energy exchanges (e.g. land cover class, surface radiation, vegetation vigor, surface temperature, soil moisture status). This study is concerned with developing and testing theoretical concepts to aid the simultaneous and optimum use of these data. [Shuttleworth, Lu, Burke, Lee; NASA]
Evaluating the Value of Remotely Sensed Soil Moisture. Remotely sensed soil moisture data has information content but is prone to error and only provides estimates for the uppermost layer of soil. However, they may be useful in coupled hydrological-atmospheric models via the process of four dimensional data assimilation (4DDA). This project is concerned with finding the error characteristics of area-average remotely sensed soil moisture so that it can be used in this way. [Shuttleworth, Burke; NOAA]
Representing Land-Atmosphere Exchanges in Climate and Weather Forecast Models. The representation of land surfaces in forecast models is often simplistic and does not include description of changes in the nature and vigor of the vegetation present at the surface. This project is investigating how important this defect is, how the growth and death of vegetation can best be improved, and where proposed models of these phenomena are consistent with field data. [Shuttleworth, Lu, Sen; NASA]
Exploring the Predictability of the North American Monsoon. The North American monsoon is an important hydroclimatologic phenomenon which is prone to seasonal-to-interannual variability. It would be of great social and economic benefit to understand and predict the interannual variability of summer mean rainfall, the strength of the seasonal monsoon circulation, and the date of the onset of the monsoon. This study is concerned with exploring the extent to which the North American monsoon is predictable, with a focus on understanding the importance (or otherwise) of land surface features such as antecedent snow cover, current soil moisture status and vegetation "green up". [Shuttleworth, Yang, Gochis; NASA]
Assimilating Remotely Sensed Cloud Cover to Improve Short-term Weather Forecasts. Meteorological forecast models are extremely poor at providing accurate predictions of precipitation, especially the location of hazardous convective precipitation. This project is exploring the feasibility and value of assimilating high-resolution, remotely sensed cloud cover data to improve short-term regional weather forecasts. [Shuttleworth, Yucel, Zehnder. NASA]
Application of ‘Indirect’ Data in Irrigation Management. Many irrigation schemes are proposed and operate in underdeveloped regions where the existing data required for effective management is poor or non-existent. This project is exploring whether alternative, ‘indirect’ data (from satellites and meteorological models) be used to provide a basis for management. [Shuttleworth, Garatuza-Payan, Pinker; NASA]
Evapotranspiration from Riparian and Rangeland Systems in a Semi-Arid Environment. The well being of the riparian systems that lie alongside perennial streams in semi-arid regions (e.g. those along the San Pedro River in Southern Arizona) are at risk from groundwater extraction. Models that seek to predict future change are currently limited by poor knowledge of the evapotranspiration component. This study seeks to quantify and model riparian (and other) evapotranspiration. [Shuttleworth, Scott, Sen; DOE, NASA]
The "Hydrology for Environment Life and Policy (HELP)" Initiative. Over the last 20 years there has been a distinct change in our understanding of the nature and origin of the statistics of hydrological variables as measured in an individual watershed or region. It is now realized that the locally observed statistics of hydrological variables may be significantly determined by global-scale phenomena and might be prone to long-term change. This research will investigate the value of using climate change scenarios and "modern" data capture and data transfer techniques in hydrological forecasting and design in worldwide. [Shuttleworth; UNESCO, WMO, NSF, NOAA, NASA]
Cooperative Agreement with National Weather Service. The primary objective of the cooperative agreement is to assist the National Weather Service in improving its flood forecasting services. The current focus is on rainfall-runoff models used to forecast flash floods in semi-arid regions. Distributed, physically-based models are being investigated for this purpose because of their potential for use on engaged watersheds. In addition, the impact of rainfall sampling errors on flood forecasts is being studied. [S. Sorooshian]
Evaluation of the Type and Quantity of Data Appropriate for Model Calibration: Case of Conceptual Flood Forecasting Models. The success of calibration procedures of conceptual rainfall-runoff models is ultimately dependent on the nature (quantity and quality) of the data used. In this research, methodologies which can evaluate the informativeness of data sets are being investigated within the framework of maximum likelihood approach. The relationship between the characteristics of data sets (e.g., the precipitation intensity, the interstorm time intervals, and the length of data) and the identifiability of model parameters are being studied. The National Weather Service model is being used in this project. [S. Sorooshian; H. V. Gupta]
Utilization of EOS Data in Quantifying the Processes Controlling the Hydrologic Cycle in Arid/Semi-Arid Regions. An interdisciplinary science investigation funded by NASA's Earth Observing System (EOS) program is supporting research into the utilization of remote sensing data for the study of the hydrology of arid/semi-arid regions. Current areas of our research are focused on distributed, physically based models of regional surface processes including runoff production, infiltration, evapotranspiration, water/energy balances, and scale effects. [S. Sorooshian, J. Shuttleworth, X. Gao, J. Washburne, H.V. Gupta; A. Huete, Soil, Water and Environmental Science; P. Slater, Optical Sciences; D. Goodrich, S. Moran; K. Humes, ARS]
A Novel Approach for Calibration of Hydrologic Models Using Multiobjectives and Visualization Techniques. The objective of this Small Grants for Exploratory Research project funded by NSF is to explore techniques that improve the prospects for finding preferred solutions when calibrating the emerging generation of distributed parameter and multiple-output-flux hydrologic models. The project is exploring a new calibration paradigm that involves the use of multi-objective procedures for the objective identification of the non-dominated model set and graphical procedures to facilitate the subjective procedure inherent in the selection of a reduced model set. [S. Sorooshian, H. V. Gupta]
Calibration of Hydrologic Models Using Multi-Objectives and Visualization Techniques. This NSF-funded project is an extension of the SGER project described above. The research is focused on the emerging generation of land-surface hydrologic models under consideration as viable soil-vegetation-atmosphere and transfer schemes (SVATS). It is expected that the proposed multi-objective calibration techniques will help hydrologists build more reliable and realistic models by providing insights into problems of hydrologic model identification and calibration, particularly in the areas of reliability and uniqueness. [S. Sorooshian, H. V. Gupta]
Modeling Processes Associated with Precipitation and Land Surface Hydrology in Global Circulation Models. This NOAA-funded project is to evaluate the BATS model by applying it to the Mississippi River basin. The BATS model has been applied in many special cases and also coupled with the GCMs. However, because of the lack of observation data, it is still unsure whether the process expressions and the parameters used in BATS are accurate. Because the GEWEX/GCIP program chooses the Mississippi River basin for intense study, many meteorological and hydrologic measurements will be available across the area, and a data base will be created to store the new, as well as historical, observation data. Therefore, it provides a good chance to validate the BATS at large scales. We plan to use both off-line and on-line modes to test the model. [S. Sorooshian, X. Gao, W. Hwu]
Study of Rainfall Estimation from Combined Satellite Imagery over Tropical Extratropical Regions of Pan Americas Using Artificial Neural Networks and Its Incorporation into the General Circulation Model. Microwave imagery (SSM/I) is strongly correlated with emission of cloud water drops, therefore, and is useful to estimate rainfall from space. However, the poor temporal (twice overpass per day at approximately fixed times) and spatial resolution (25 x 25 km2) of SSM/I restrict the application. On the other hand, remote sensing data from geostationary satellites (such as GOES) provide hourly and high spatial resolution images of brightness temperatures which are related to the cloud top condition. We propose to use a combination of the approaches of SSM/I and GOES to improve the estimation using an unbiased artificial neural network (ANN). The ANN model is used for function mapping. After training, the ANN model can predict the rainfall rate according to the input pixel brightness temperature and the corresponding surface information. The monthly rainfall patterns in the tropical /extratropical regions of the Pan Americas will be used to represent the precipitation distribution at the GCM subgrid scale. [S. Sorooshian, X. Gao, K. Hsu]
A Cost-effective Method for Characterizing and Monitoring the Vadose Zone and Aquifers. Knowledge of the spatial distribution of hydraulic properties, water, and contaminants in the vadose zone and aquifer is important to our management of water resources. It is therefore imperative to have a cost-effective methodology that can identify the spatial distribution of hydraulic properties and monitor the movement of water or contaminants in the vadose zone and aquifer.
In this study, a cost-effective characterization/monitoring methodology is developed, which takes advantage of the ability of electrical resistivity tomography (ERT) for monitoring changes in water content or concentration over a large volume of geological media. It then integrates the resistivity measurements with sparse point measurements of hydraulic properties, moisture content, concentration, and pressure to simultaneously identify the spatial distribution of hydraulic properties and water or contaminants in the vadose zone and aquifer. The cost-effectiveness of the method stems from the fact that the method can produce maps of subsurface heterogeneity or water and contaminant plumes at high resolutions with the minimum number of destructive samples.
The data interpretation procedure of our approach uses a new hydrological/geophysical joint inversion concept. Existing concepts have concentrated only on the use of geophysical tools for characterizing the subsurface to enhance hydrological modeling. Our joint inversion, however, recognizes that hydrological information provides useful constraints for the ERT interpretation and meanwhile the ERT can furnish a vast amount of water content and concentration information for hydrological inverse modeling. Because of the reciprocal nature of the hydrological and geophysical information and inversions, our joint inversion takes an iterative approach until given hydrological and geophysical information are fully utilized.
Finally, our approach allows us to simultaneously characterize heterogeneities and monitor distributions of moisture or tracers in both unsaturated and saturated zones in an integrated manner. The approach produces approximate conditional mean and variances of parameters, pressure head, moisture content, concentration, and resistivity fields. Thus, uncertainties associated with our characterization and monitoring can be addressed.
A State of the Art Technology for Aquifer Tests: Hydraulic Tomography. We are developing a state of the art technology, hydraulic tomography, for characterizing aquifer heterogeneity. During a hydraulic tomography experiment (i.e., a sequential aquifer test), water is sequentially pumped from or injected into an aquifer at different vertical portions or intervals of the aquifer. During each pumping or injection, hydraulic head responses of the aquifer at other intervals are monitored, yielding a set of head/discharge (or recharge) data. By sequentially pumping (or injecting) water at one interval and monitoring the steady-state head responses at others, many head/discharge (recharge) data sets are obtained.
We are developing a sequential inverse approach to interpret results of hydraulic tomography. For each set of hydraulic tomography data, an iterative geostatistical inverse approach is employed to determine the effective hydraulic conductivity of aquifers, conditioned on the head measurements. To avoid numerical difficulties associated with simultaneous inclusion of all the head data sets, a sequential conditioning approach is developed. This approach uses the estimated hydraulic conductivity field and covariances, conditioned on previous sets of head measurements, as prior information for future estimations based on a new set of pumping data. This new inverse approach allows us to delineate small-scale heterogeneity in three-dimensional geological media, which had been considered impossible.
We are designing field and laboratory equipment for conducting the hydraulic/pneumatic tomography in variably saturated porous and fractured media.
Long-term Erosion Rates From In Situ Accumulation of Cosmogenic Nuclides in Soils. We are developing two new approaches to simultaneously obtain ages and erosion rates of Quaternary landforms. The methods are based on in situ accumulation of cosmogenic nuclides in rocks and soils exposed to cosmic radiation at the surface of the earth. The nuclides used include the stable noble gases 3He and 21Ne and the radioactive isotopes 10Be, 26Al and 36Cl. [M. Zreda; D. Lal, Scripps Institution of Oceanography]
Geographic Distribution of Chlorine-36 in Post-Pleistocene Ground Water. The purpose of the project is to determine the nature of geographic variations of 36Cl in water which has entered the subsurface between 50 and 10,0000 years before the present. Information concerning geographic variations is needed for interpretation of numerous hydrologic studies of ground-water recharge in arid regions, of accumulation rates of glacial ice, of ground-water "ages", of the origin of chloride in saline lakes, of the origin of deep subsurface brines in crystalline rocks, as well as of a number of other studies related directly and indirectly to the field of hydrology. In addition to providing critical baseline information for other projects, the proposed research will include sampling of water older than 10,000 years in a few carefully selected aquifers in order to detect, and if possible to quantify, changes in past rates of natural atmospheric production of 36Cl. [S. Davis, M. Zreda]
Quaternary Glaciations
in Europe. Cosmogenic surface exposure dating is used to develop chronologies
of late Quaternary glaciations in central Europe. These chronologies will then
be compared with those at other locations worldwide (N. America, S. America,
the Arctic and Africa) to determine whether major climatic changes during the
Quaternary were synchronous.
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