Daniel B. Stephens

Dr. StephensDaniel B. Stephens, PhD, CHg, PG

Founder, Principal Hydrologist

Albuquerque, New Mexico

Email

(505) 822-9400

Daniel B. Stephens, Ph.D., P.Hg., P.G., is DBS&A’s Founder and Principal Hydrologist. He has more than 35 years of experience in consulting, research, and academia, and is recognized internationally as an authority on vadose zone and groundwater hydrology.

Throughout his career, Dr. Stephens has been called upon to provide technical support in hydrogeology on projects of national significance. For example, he participated in a panel to review the groundwater flow and transport modeling studies for the Yucca Flat Corrective Action Unit for the Department of Energy, and he was a member of a three-person blue-ribbon panel to review the hydrogeology of Los Alamos National Laboratory. He co-chaired the Executive Committee to map research needs in vadose zone hydrology for the Department of Energy. He also participated in an expert elicitation panel to quantify natural recharge at Yucca Mountain nuclear waste repository for the Department of Energy. As a litigation expert, he has provided testimony in more than 70 depositions and trials in the field of hydrology, involving characterization of the vadose zone and site hydrogeology, numerical modeling, environmental forensic investigations, and expert testimony for dozens of cases involving contamination of soil and groundwater, more than 30 of which involved allocation of remediation costs among potentially responsible parties (PRPs).

During his academic career, Dr. Stephens was on the faculty of New Mexico Institute of Mining and Technology (NMT) for 10 years. He served as chairman of the Geoscience Department and taught graduate-level courses in subsurface hydrology, applied subsurface hydrology, field methods in hydrology, and vadose zone hydrology. He taught a pioneering course on vadose zone hydrology at NMT, covering the theory and application of vadose zone characterization and monitoring. His research in hydrogeology focused on quantification of recharge, stream-aquifer interaction, and applied numerical modeling of groundwater flow and solute transport.

Dr. Stephens published Vadose Zone Hydrology in 1995. The text illustrates the application of soil physics to practical problems relevant to the characterization and monitoring of the vadose zone and highlights new and emerging technologies for monitoring the vadose zone, particularly for the purpose of detecting contaminants.

Dr. Stephens has published papers in scientific journals extensively throughout his career and has been invited to speak on vadose zone issues to national symposia sponsored by diverse groups such as Law Seminars International; Society of Petroleum Engineers, Environmental Study Group; American Geophysical Union; Soil Science Society of America; National Groundwater Association; and New Mexico Environment Department.

Dr. Stephens has worked with a wide variety of clients, including many attorneys, law firms, mediators, Native American tribes, state and federal agencies, cities, universities and public utilities, private citizen groups, and industry. For example, in the case titled Raul Valencia Abarca, et al., v. Merck & Co., Inc. et al., Dr. Stephens opined on the local hydrogeology and fate and transport of the metals of concern in soil, surface water, and groundwater. Dr. Stephens was quoted favorably in the Findings of Fact and Conclusions of Law in the landmark cases, collectively referred to as Burlington Northern, where the United States Supreme Court issued two key rulings on cleanup costs under CERCLA. Dr. Stephens’ broad mix of clients has afforded him the opportunity to investigate sites throughout the country, including California, Arizona, Texas, Oklahoma, Louisiana, Arkansas, Florida, Virginia, Michigan, Colorado, Wyoming, and many others.

During these investigations, Dr. Stephens has dealt with multiple complex facilities, including mines and mills (copper, uranium, zinc, ARD), petroleum hydrocarbon releases at refineries and service stations (BTEX, MtBE), manufacturing operations (chlorinated solvents, 1,4-dioxane, chormium), wood treating facilities (pentachlorophenol, arsenic), hydraulic fracturing sites, deep well injection, salt water disposal, sea water intrusion, water balance studies, and sources of rising groundwater among many others. The analyses have included site investigations and remedial action under CERCLA and RCRA.

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  • Education

    Ph.D., Hydrology, University of Arizona

    M.S., Hydrology, Stanford University

    B.S., Geological Science (with honors), Pennsylvania State University

  • Registration / Certification

    Certified Professional Hydrogeologist No. 406, American Institute of Hydrology

    Certified Hydrogeologist No. HG355, California

    Professional Geologist No. 5937, California

    Professional Geologist No. 28483, Arizona

    Professional Geologist No. 936, Idaho

    Professional Geoscientist No. 1767, Texas

  • Specializations

    Hydrogeology

    Artificial recharge

    Groundwater resource evaluations

    Stream-aquifer interaction

    Applications of numerical models

    Fate and transport

    Allocation

    Remediation system effectiveness analysis

  • Affiliations

    American Institute of Hydrology

    American Society of Agronomy

    American Geophysical Union

    Arizona Hydrological Society

    Crop Science Society of America

    Geological Society of America

    Ground Water Resources Association of California

    International Association of Hydrogeologists

    National Ground Water Association

    New Mexico Geological Society

    Soil Science Society of America

  • Technical Review Boards

    U.S. Department of Energy, Technology Innovation and Development, Office of Environmental Management, Advance Simulation Capability for Environmental Management, Peer Review Team Chair, 2011

    Orange County Water District and the Orange County Sanitation District, Groundwater Replenishment System, Independent Advisory Panel, National Water Research Institute

    Yucca Mountain Project, Department of Energy Expert Elicitation on Recharge

    Westinghouse Hanford Company, Hanford, Washington: Peer Review Panelist, Site and Grout Performance Assessments

    Los Alamos National Laboratory, Los Alamos, New Mexico: Blue Ribbon Panel, Review and Hydrogeologic Data Needs for the Environmental Restoration Program at LANL

    Idaho National Engineering and Environmental Laboratory, Idaho Falls, Idaho: Executive Committee Chairman, National Roadmap for Vadose Zone Science and Technology

    Ernest Orlando Lawrence Berkeley Laboratory, Oakland, California: Earth Sciences Division Annual Review

  • Advisory Boards

    U.S. Environmental Protection Agency Technical Workshop on Case Studies to Assess Potential Impacts of Hydraulic Fracturing on Drinking Water Resources, Research Triangle Park, North Carolina, Invited Technical Expert, July 30, 2013

    Board of Directors of the National Ground Water Association—2009 to 2015

    Scientists and Engineers Division National Ground Water Association—Chair, 2006 to 2015

    The University of Arizona, Hydrology and Water Resources Department Advisory Committee, Chairman

    The University of Arizona, College of Science Dean’s Board of Advisors

    New Mexico Tech, Presidential Advisory Committee

    Altela, Inc., Technical Advisory Board, Albuquerque, New Mexico

  • Testimonials

    Vidler states that Dr. Stephens, “is a brain trust and makes the information relevant to the people he’s presenting to so it’s understandable. Extremely knowledgeable and capable.”

Select Publications and Presentations

Books and Chapters of Books

Stephens. 2008. Vadose Zone Hydrogeology: Basic Principles, Characterization, and Monitoring, Chapter 12, In Manual of Applied Field Hydrogeology, second edition, Willis Weight, editor. McGraw-Hill, New York.

Stephens, D.B. 1999. Monitoring for Groundwater Management in (Semi-) Arid Regions. Chapter 4, In Vadose Zone Monitoring Strategy to Protect Aquifers from Contamination, UNESCO, Wageningen, The Netherlands.

Stephens, D.B. 1996. Vadose Zone Hydrology. CRC Press, Boca Raton, Florida.

Stephens, D.B. 1993. Hydraulic conductivity assessment of unsaturated soils. In D.E. Daniels and S.J. Trautwein (Eds.), Hydraulic Conductivity and Waste Contaminant Transport in Soils, ASTM STP 1142, American Society for Testing and Materials, Philadelphia, Pennsylvania.

Stephens, D.B. 1992. Application of the borehole permeameter. Chapter 4 In Advances in Measurement of Soil Physical Properties: Bringing Theory into Practice. SSSA Special Publication No. 30, Soil Science Society of America, Madison, Wisconsin.

Stephens, D.B., S. Tyler, and K. Lambert. 1983. Field experiments to determine saturated hydraulic conductivity in the vadose zone. In Role of the Unsaturated Zone In Radioactive and Hazardous Waste Disposal, Eds. J.W. Mercer, P.S.C. Rao, and I.W. Marine. Ann Arbor Science/The Butterworth Group.

Journal Articles

Stephens, D. B. 2014. Analysis of the Groundwater Monitoring Controversy at the Pavillion, Wyoming Natural Gas Field. Groundwater. doi: 10.1111/gwat.12272.

Stephens, D.B., M. Miller, S.J. Moore, T. Umstot, and D.J. Salvato. 2012. Decentralized Groundwater Recharge Systems Using Roofwater and Stormwater Runoff. Journal of the American Water Resources Association 48(1):134-144. February 2012.

Simco, A., D.B. Stephens, K. Calhoun, and D.A. Stephens. 2009. Historic Irrigation and Drainage at Priestley Farm by Joseph Elkington and William Smith. Vadose Zone Journal 9:4-13.

Stephens, D.B. 2009. J.D. Mather (ed.), Book review: 200 Years of British Hydrogeology, The Geological Society, London, 2004. Hydrogeology Journal 17(7). November 2009.

Stephens, D.B. 2009. An Imminent Human Resource Crisis in Ground Water Hydrology? Ground Water 47(2): 176-183. March—April 2009.

Stephens, D.B. 2009. Also consider the recharge. Technical commentary. Ground Water 47(1):2-3. January—February 2009.

Stephens. 2008. Recent Trends in Hydrogeology and Environmental Consulting and A Perspective on the Maturing of the Hydrogeology Profession. Journal of Hydrologic Engineering 13(1):20-27.

Stephens, D.B. and D.A. Stephens. 2006. British land drainers: their place among pre-Darcy forefathers of applied hydrogeology. Hydrogeology Journal 14:1367-1376.

Stephens, D.B. and M.A. Ankeny. 2004. A missing link in the historical development of hydrogeology. Ground Water 42(2):304-309.

National Vadose Zone Science and Technology Roadmap Executive Committee, Daniel B. Stephens, Chair. 2002. Letter to the editor on a national strategy for vadose zone science and technology. Vadose Zone Journal 1(1):197-198.

Graves, B.J., D. Jordan, D. Cartron, D.B. Stephens, and M.A. Francis. 2000. Allocating responsibility for groundwater remediation costs. Trial Lawyer, 23(2):159-171.

Stephens, D.B., J.A. Kelsey, M.A. Prieksat, M.G. Piepho, C. Shan, and M.D. Ankeny. 1998. DNAPL migration through a fractured perching layer. Ground Water 26(4):605-610.

Stephens, D.B., K.C. Hsu, M.A. Prieksat, M.D. Ankeny, T.N. Blandford, T.L. Roth, J.A. Kelsey, and J.R. Whitworth. 1998. A comparison of estimated and calculated effective porosity. Hydrogeology Journal 6:156-165.

Stephens, D.B. and C. Shan. 1995. An analytical solution for vertical transport of volatile chemicals in the vadose zone. Journal of Contaminant Hydrology 18:259-277.

Shan, C. and D.B. Stephens, 1995. Steady infiltration into a two-layered soil from a circular source. Water Resources Research, 31(8):1945-1952.

Shan, C. and D.B. Stephens. 1994. Recommendation for usage of SURFER to gridding model results. Ground Water 32(3).

Stephens, D.B. 1994. A perspective on diffuse natural recharge mechanisms in areas of low precipitation. Soil Science Society of America Journal 58(1):40-48.

Stephens, D.B. and L.M. Coons. 1994. Landfill performance assessment at a semi-arid site: Modeling and validation. Ground Water Monitoring and Remediation, Winter 1994.

Shan, C. and D.B. Stephens. 1993. A borehole field method to determine unsaturated hydraulic conductivity. Water Resources Research 29(8):2763-2769.

McCord, J.T., D.B. Stephens, and J.L. Wilson. 1991. Toward validating state-dependent macroscopic anisotropy in unsaturated media: Field experiments and modeling considerations. In P.J. Wierenga (Guest Ed.), Validation of flow and transport models for the unsaturated zone. J. Contam. Hydrol. 7:147-177.

McCord, J.T., D.B. Stephens, and J.L Wilson. 1991. Hysteresis and state-dependent anisotropy in modeling unsaturated hillslope hydrologic processes. Water Resources Research 27(7):1501-1518.

McCord, J.T. and D.B. Stephens. 1988. Comment on “Effective relative permeabilities of anisotropic porous media” by Bear, Braester, and Menier. Transport in Porous Media 3:207-210.

Stephens, D.B., J. Havlena, R.G. Knowlton, Jr., E. Mattson, and W. Cox. 1988. Vadose zone characterization of low-permeable sediments using field permeameters. Ground Water Monitoring Review, Spring.

Stephens, D.B. and S.E. Heermann. 1988. Dependence of anisotropy on saturation in a stratified sand. Water Resources Research 24(5):770-778.McCord, J.T. and D.B. Stephens. 1987. Lateral moisture flow beneath a sandy hillslope without an impending layer. Hydrological Processes Journal 1:225-238.

McCord, J.T. and D.B. Stephens. 1987. Short note on “Effect of groundwater recharge on configuration of the water table beneath sand dunes and on seepage in lakes in the sandhills of Nebraska, USA” by T.C. Winter. J. Hydrology 95:365-367.

Stephens, D.B. 1987. The significance of natural ground-water recharge in site selection for mill tailings disposal. AIME Trans. 280:2064-2068.

Stephens, D.B., K. Lambert, and D. Watson. 1987. Regression models for hydraulic conductivity and field test of the borehole permeameter. Water Resources Research 23(12):2207-2214.

Stephens, D.B. and R. Knowlton, Jr. 1986. Soil water movement and recharge through sand at a semi-arid site in New Mexico. Water Resources Research 22(6):881-889.

Stephens, D.B. and K. Rehfeldt. 1985. Evaluation of closed-form analytical models to calculate unsaturated conductivity in a fine sand. Soil Sci. Soc. Am. J. 49(1):12-19.

Stephens, D.B. 1985. A field method to determine un-saturated hydraulic conductivity using flow nets. Water Resources Research 21(1):45-50.

Stephens, D.B. 1985. Comments on “A reexamination of the constant head well permeameter method for measuring saturated hydraulic conductivity” by W.D. Reynolds, E.D. Elrick, and G.C. Topp. Soil Science 139(2):190.

Hawkins, D.C. and D.B. Stephens. 1983. Ground water modeling in a southwestern alluvial basin. Groundwater 21(6):733-740.

Byers, E. and D.B. Stephens. 1983. Statistical and stochastic analysis of hydraulic conductivity and particle size in a fluvial sand. Soil Sci. Soc. Amer. Proc. 47(6):679-688.

Person, M., R. Antle, and D.B. Stephens. 1983. Evaluation of the surface impoundment assessment in New Mexico. Ground Water 21(6):679-688.

Stephens, D.B. 1983. Groundwater flow and implications for groundwater contamination north of Prewitt, New Mexico, USA. J. Hydrology 61:391-408.

Stephens, D.B. and S.P. Neuman. 1982. Vadose zone permeability tests 1: Review. ASCE J. Hydraulics Division 108 (HY5):623-639.

Stephens, D.B. and S.P. Neuman. 1982. Vadose zone permeability tests 2: Steady state. ASCE J. Hydraulics Division 108 (HY5):640-659.

Stephens, D.B. and S.P. Neuman. 1982. Vadose zone permeability tests 3: Transient case. ASCE J. Hydraulics Division 108 (HY5):660-677.

Stephens, D.B. and S.P. Neuman. 1982. Free surface and saturated-unsaturated analysis of borehole infiltration tests above the water table. Advances in Water Resources 5:111-116.

Short Courses

Stephens, D.B. 2009. Artificial Recharge by Surface Infiltration and Vadose Zone Wells. Invited short course with D. Pyne at National Ground Water Association Artificial Recharge of Ground Water. September 24-25, 2009, Baltimore, Maryland.

Stephens, D.B.. 2008. Artificial Recharge by Surface Infiltration and Vadose Zone Wells. Invited short course with D. Pyne at National Ground Water Association 2008 Ground Water Expo. December 2-5, 2008, Las Vegas, Nevada.

Stephens, D.B., J.A. Kelsey, J. Hines, J. Kay, and E. Pease. 2007. Elements of Vadose Zone Hydrology. Invited short course at National Ground Water Association 2007 Ground Water Summit. April 29, 2007, Albuquerque, New Mexico

Stephens, D.B. 1998. Principles of vadose zone hydrology. Invited presentation to the City of Tucson Office of Environmental Management, March 6, Tucson, Arizona.

Stephens, D.B. 1997. Principles of vadose zone hydrology. Invited presentation of a two-day short course presented to the New Mexico Environment Department Underground Storage Tank Bureau, October 15-16, Santa Fe, New Mexico.

Stephens, D.B., T.N. Blandford, A. Lewis. 1997. Hydrogeology short course. Invited presentation to the State of New Mexico, Environment Department, Drinking Water Bureau, April 9, Santa Fe, New Mexico.

Stephens, D.B. 1996. Principles of vadose zone hydrology. Invited presentation of a two-day short course presented to Westinghouse Savannah River Company, March 27-28, Aiken, South Carolina.

Stephens, D.B. 1995. Vadose zone processes, characterization and monitoring. Invited workshop at the National Ground Water Association Outdoor Action Conference, May 2-3, Las Vegas, Nevada.

Stephens, D.B., M.A. Ankeny, J.F. Forbes, and J.A. Havlena. 1995. Vadose zone hydrology: Processes, characterization and monitoring. Short course presented in conjunction with Environmental Education Enterprises, Inc., October 18-20, Albuquerque, New Mexico.

Stephens, D.B. 1994. Basic concepts in vadose zone hydrology. Workshop at the National Ground Water Association Outdoor Action Conference, May 23-24, Minneapolis, Minnesota.

Stephens, D.B. and R.S. Bowman. 1994. Principles of vadose zone hydrology. Short course for the National Ground Water Association, June 20-21, San Antonio, Texas.

Stephens, D.B. 1994. Vadose zone course short course. Ohio University, June 23, Athens, Ohio.

Stephens, D.B. 1994. Principles of vadose zone hydrology. Invited presentation to Bechtel Corporation, November 1-2, San Francisco, California.

Stephens, D.B. 1993. Vadose zone characterization of hydraulic properties. Invited presentation at the DOE workshop on Characterization of Glacial Tills, April 15-16, Cincinnati, Ohio.

Presentations and Articles in Symposia Proceeding

Stephens, D.B., 2017. Early Innovations in Engineering and Hydrology: Practical Applications of Land Drainage. Presented to the Society of American Military Engineers. Albuquerque, New Mexico, August 9, 2017.

Stephens, D.B. 2017. Challenging Times Ahead. Presented to New Mexico Tech Students. Socorro, New Mexico, March 2, 2017.

Stephens, D.B. 2016. Challenging Times Ahead in Hydrology. Keynote speaker at the NGWA Conference on Hydrology and Water Quality in the Southwest. Albuquerque, New Mexico. February 23-24, 2016.

Stephens, D.B. 2015. Managed aquifer recharge. Presentation at the 2015 NGWA Groundwater Expo and Annual Meeting. Las Vegas, Nevada. December 15, 2015.

Stephens, D.B. and D.A. Stephens. 2015. The Role of William Smith’s Agricultural Improvements to Prisley Farm in the Development of the Geologic Map, Session on Celebrating the Genius of William ‘Strata’ Smith: Bicentennial Anniversary of Smith’s Revolutionary Map. Presentation at the Geological Society of America 2015 Annual Meeting, Baltimore, Maryland. November 1, 2015.

Stephens, D.B. 2015. Defining Basins from a Hydrologic Perspective: What are the Boundaries? Overview of the statutory structure including SGMA provisions; how the modeling works; areas of certainty and uncertainty; tips for selecting the most cost-effective approach. Invited speaker at the The Science and Law of Water in California Law Seminars International, Santa Monica, California. September 17, 2015.

Stephens, D.B. 2015. Analysis of Groundwater Monitoring Controversy at the Pavillion, Wyoming Natural Gas Field. Invited speaker at the 2015 Multi-State Salinity Coalition Annual Salinity Summit – Understanding the Opportunities and Challenges of Fracking in an Era of Water Supply Scarcity, Las Vegas, Nevada. February 19, 2015.

Stephens, D.B. 2014. Managed Aquifer Recharge: An Overview with Examples. Invited speaker for National Ground Water Association, Groundwater Expo and Annual Meeting, Las Vegas, Nevada. December 9-12, 2014.

Stephens, D.B. 2014. Analysis of a Groundwater Monitoring Investigation for Impacts of Hydraulic Fracturing, Pavillion, Wyoming. Webinar, National Ground Water Association. November 6, 2014.

Stephens, D.B. 2014. Analysis of Groundwater Monitoring Controversy at the Pavillion, Wyoming Natural Gas Field. Presentation at the 2014 Annual Meeting of the Geological Society of America. Vancouver, British Columbia, Canada. October 19, 2014.

Stephens, D.B. 2014. Analysis of Groundwater Monitoring Controversy at the Pavillion, Wyoming Natural Gas Field. Invited speaker for Society of Petroleum Engineers, Environmental Study Group. Midland, Texas. October 16, 2014.

Stephens, D.B. 2014. Analysis of Groundwater Monitoring Controversy at the Pavillion, Wyoming Natural Gas Field. Invited speaker at the Law Seminars International 2014 Hydraulic Fracturing in California. Beverly Hills, California. August 12, 2014.

Stephens, D.B., J. Cherney, J. Kay, T. Umstot, and B. Casadevall. 2014. High Recharge at a Semi-Arid Site Explains Wide-Spread Perchlorate in Groundwater with a Deep Water Table. Presentation at the National Ground Water Association Ground Water Summit. May 7, 2014. Denver, Colorado.

Stephens, D.B. 2013. Brownfield Remediation Program in the U.S. Invited speaker at the Institute of Soil Science of the Chinese Academy of Science. Nanjing, Peoples Republic of China. December 17, 2013.

Stephens, D.B., J. Cherney, J. Kay, T. Umstot, P. Kaiser, and B. Casadevall. 2013. Unexpectedly rapid migration of perchlorate through a thick vadose zone under low rainfall conditions. Invited speaker at the National Ground Water Association Pillars of Groundwater Innovation Conference. November 7-8, Phoenix, Arizona.

Stephens, D.B. 2013. Impacts of hydraulic fracturing on water resources, water supply and water quality. Invited speaker at the New Mexico Involvement Committee—Rocky Mountain Section of the American Water Works Association and the Rocky Mountain Section of the Water Environment Association. June 20, Albuquerque, New Mexico.

Stephens, D.B. 2012. Impacts of hydraulic fracturing on water resources. Invited speaker at the 19th Annual Conference, Western Water Law. November 15-16, Las Vegas, Nevada.

Stephens, D.B., F.E. Botros, S. Helenschmidt, P. Quinlan, and D.W. Davis. 2012. Rising groundwater: unexpected consequences downgradient of a freeway expansion. Presentation at the National Ground Water Association Ground Water Summit, May 6-10, Garden Grove, California.

Stephens, D.B. and J.A. Kelsey. 2012. Overview of artificial recharge by surface infiltration. Presentation at the National Ground Water Association Ground Water Summit, May 6-10, Garden Grove, California.

Stephens, D.B. 2012. Demystifying flow in the vadose zone. Presentation at the National Ground Water Association Ground Water Summit, May 6-10, Garden Grove, California.

Stephens, D.B., F.E. Botros, S. Helenschmidt, B. Casadevall, P. Quinlan, and D. Davis. 2012. The Importance of Hydrogeologic Characterization and Analysis to Avoid Off-site Impacts in Highway Construction. Presentation given by F.E. Botros at the American Society of Civil Engineers, Geo-Congress 2012, March 25-29, Oakland, California.

Stephens, D.B., M. Miller, S. Moore, T. Umstot, and D.J. Salvato. 2011. Decentralized groundwater recharge systems using roofwater and stormwater runoff. Presentation at the American Water Resources Association Annual Water Resources Conference. November 7-10, Albuquerque, New Mexico.

Wahi, A.K. and D.B. Stephens. 2011. Is TCE from Biodegradation of PCE or a Separate Release? An Application of Compound Specific Isotope Analysis and Other Methods. Presentation given by A.K. Wahi at the Environmental Forensics in an Era of Emerging Diagnostic Methods. Ground Water Resources of California, April 12, 2011, Irvine, California.

Stephens, D.B. and S.J. Moore. 2011. A Role for Dispersed Groundwater Recharge Systems to Balance Effects of Hydro modification. Presentation at the Managed Aquifer Recharge Symposium. National Water Research Institute. January 24-26, Orange County, California.

Stephens, D.B., S.J. Moore, M.Miller, T. Umstot, and D.J. Salvato. 2010. Decentralized Artificial Recharge. Invited presentation at the 55th Annual New Mexico Water Conference: Water Needs in the Next Decade—How will institutions evolve to meet our water needs in the next decade? New Mexico State University, Las Cruces, New Mexico. December 1-3.

Stephens, D.B. and S.J. Moore. 2010. Rainwater Harvesting to Augment Groundwater Supplies. Presentation at the North American Geology in the 21st Century: Today and Tomorrow. AIPG-AGWT-FAPG-ASFE 2010 Conference, September 11-15, 2010, Orlando, Florida.

Stephens, D.B., S.J. Moore, S.J. Cullen, A. Staden, and L. Jong. 2010. Augmenting groundwater supplies using rain water harvesting. Presentation at the National Ground Water Association Ground Water Summit and Ground Water Protection Council Meeting. April 11-15, 2010, Denver, Colorado.

Stephens, D.B., S. Moore, M. Miller, and A Standen. 2009. Is There A Role for Rainwater Harvesting in New Mexico Water Resources Management? Presentation at the 2009 New Mexico Water Research Symposium. August 11, 2009, Socorro, New Mexico.

Stephens, D.B., L. Jong, A. Standen, S. Moore, and S. Cullen. 2009. Roof Water Harvesting for Artificial Recharge in the Americas. Presentation at the National Ground Water Association Groundwater for the Americas. June 8-10, 2009, Panama City, Panama.

Stephens, D.B., A. Simco, K. Calhoun, D. Stephens. 2009. Drainage work at Prisley Bog on the Bedford Estate. Presentation at the National Ground Water Association Ground Water Summit. April 19-23, 2009, Tucson, Arizona.

Stephens, D.B. 2009. Artificial Recharge, Groundwater Storage, and Recovery: An Overview. Invited presentation at the American Bar Association Section of Environment, Energy and Resources 27th Annual Water Law Conference: Change in the Midst of Constants: Adapting Water Law to Meet New Demands, February 18-20, 2009, Coronado, San Diego, California.

Stephens, D.B. 2009. Vadose Zone Monitoring Strategies for Contaminant Detection and Recharge. Invited presentation at the Groundwater Resources Association of California Groundwater Monitoring: Design Analysis, Communications & Integration with Decision Making Conference, February 25-26, 2009, Orange, California.

Stephens, D.B. and T. Umstot. 2008. Recharge Analyses in a Desert Groundwater Basin. Presentation at the American Water Resources Association Annual Water Resources Conference. November 17-20, New Orleans, Louisiana.

Umstot, T. and D.B. Stephens. 2008. Distributed parameter modeling of an arid watershed to assess net infiltration. Presentation at the American Water Resources Association Annual Water Resources Conference. November 17-20, New Orleans, Louisiana.

Stephens, D.B. 2008. A Hydrogeologist’s Perspective on Vadose Zone Modeling Challenges. Invited presentation at the Geological Society of America/Soil Science Society of America/Agronomy Society of America/Crop Society of America Joint Meeting. October 5-9, Houston, Texas.

Stephens, D.B. and T. Umstot. 2008. Recharge Analyses in a Desert Groundwater Basin. Invited presentation at the Geological Society of America/Soil Science Society of America/Agronomy Society of America/Crop Society of America Joint Meeting. October 5-9, Houston, Texas.

Stephens, D.B. and T. Umstot. 2008. Challenges in characterizing and simulating flow and transport in stony soils. Presentation at the Geological Society of America/Soil Science Society of America/Agronomy Society of America/Crop Society of America Joint Meeting. October 5-9, Houston, Texas.

Stephens, D.B. 2007. Recharge of Groundwater Aquifers in Arid Regions. Invited speaker at Kuwait-MIT Center for Natural Resources and the Environment’s Forum on Arid Zone Hydrology, January 16-17, 2007, Kuwait.

Sweetland, N.T., T.G. Umstot, J. Ayarbe, and D.B. Stephens. 2006. Processes Influencing the Transport of Perchlorate Through the Vadose Zone. Presentation at the Perchlorate 2006: Progress Toward Understanding and Cleanup Symposium, Groundwater Resources Association of California, January 26, 2006, Santa Clara, California.

Stephens, D.B., S. Moore, D. Cartron, and T.N. Blandford. 2006. Quantifying Return Flow to Groundwater: What’s in the Tool Box. Presentation at the National Ground Water Association 2006 Ground Water Summit, April 22-27, San Antonio, Texas.

Stephens, D.B. 2005. A Perspective on Science and Research in the Environmental Consulting Industry. Invited presentation at the Annual Fall Meeting of the American Geophysical Union. December 4-9, San Francisco, California.

Stephens, D.B. 2005. Overview of Artificial Recharge Projects: Planning and Implementation Challenges. Invited presentation at the Groundwater Resources Association of California’s Artificial Recharge: Nexus of Quantity and Quality in California, March 16-17, Sacramento, California.

Stephens, D.B. and T.Neil Blandford. 2004. Hydrogeologic analysis, transport and modeling for environmental litigation, a case study. Presentation at the National Ground Water Association Ground Water and Environmental Law Conference, May 5-6, 2004, Chicago, Illinois.

Stephens, D.B. 2004. Contaminant Age Dating Using Hydrogeologic Analysis. Invited speaker at the Mealey’s Water Contamination Conference, January 26-27, 2004, Pasadena, California.

Sweetland, N.T., T.G. Umstot, and D.B.Stephens. 2004. Distinguishing Operational Releases Versus Spills for Insurance Allocation. Poster presentation at the Investigation and Remediation of Dry Cleaner Release Sites, April 7, 2004, Sacramento, California.

Stephens, D.B. 2003. Impact of Hydrogeologic Variables on Contaminant Plume Migration and Forensic Modeling. Invited speaker at the International Society of Environmental Forensics Environmental Forensics: Using Science to Reconstruct Contamination Events, December 8-9, 2003, Taipei, Taiwan.

Stephens, D.B. 2003. Late eighteenth century hydrogeology: a pre-Darcy perspective. Presentation at the Geological Society of America Annual Conference, November 2-5, 2003, Seattle, Washington.

Stephens, D.B. 2003. Unexpected field observations and DOE’s Vadose Zone Roadmap. Invited speaker at the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America Annual Meetings, November 2-6, 2003, Denver, Colorado.

Stephens, D.B. 2003. Application of groundwater contaminant transport modeling in environmental forensic investigations: Tucson Airport Superfund Site. Invited speaker at the Workshop on Environmental Forensics: theory, applications and case studies, International Society of Environmental Forensics. May 19-20, 2003, Stresa, Italy.

Stephens, D.B. 2003. Subsurface considerations of artificial recharge. Invited speaker at Artificial recharge in California—technical and policy challenges, Ground Water Resources Association of California. April 30-May 1, 2003. San Jose, California.

Stephens, D.B. 2002. Principles and Case Studies of Allocation of Responsibility for Petroleum Contaminated Soil and Groundwater. Invited speaker at the Identification and Assessment of Historical Subsurface Contamination: An International Society of Environmental Forensics Workshop, July 1-2, 2002, Milan, Italy.

Stephens, D.B. and W. Cox. 2001. The Importance of the Vadose Zone in Stream-Aquifer Interaction—Field and Model Studies. Presented by Mark Ankeny on behalf of D.B. Stephens at the American Water Resources Association Annual Conference on Water Resources. November 12-15, 2001. Albuquerque, New Mexico.

Stephens, D.B. and T. Neil Blandford. 2001. Hydrogeologic Analysis, Transport and Modeling for Environmental Litigation. A Case Study. Presented by Neil Blandford on behalf of D.B. Stephens at the Arizona Hydrological Society Fourthteenth Annual Symposium. September 12-15, 2001. Tucson, Arizona.

Stephens, D.B. and T. Neil Blandford. 2001. Hydrogeologic Analysis, Transport and Modeling for Environmental Litigation. A Case Study. Presentation at the First International Congress on Petroleum Contaminated Soils, Sediments, and Water Analysis, Assessment and Remediation, August 14-17, 2001, London, United Kingdom.

Stephens, D.B. 2001. Scientific applications of volume, mass and toxicity for cost allocation modeling. Invited speaker at the University of Wisconsin-Madison, Environmental Litigation: Advanced Forensics and Legal Strategies, April 4-5, 2001, San Francisco, CA.

Stephens, D.B. and S. Kowall. 2000. The DOE Complex-Wide Science and Technology Roadmap: Characterization, Modeling and Simulation of Subsurface Contaminant Fate and Transport. Presentation at the 12th Technical Information Exchange Workshop. November 14-16, 2000. August, Georgia.

Stephens, D.B., K. Hsu, M.A. Prieksat, M.D. Ankeny, T.N. Blandford, T.L. Roth, J.A. Kelsey, and J.R. Whitworth. 2000. Review of Porosity Measurements for Water Supply and Water Quality Modeling. Presented by T. Neil Blandford on behalf of D.B. Stephens at the Southwest Focus Ground Water Conference 2000. May 17-18, 2000. Austin, Texas.

Stephens, D.B. and N.T. Nelson. 2000. Observed natural attenuation of TCA in groundwater. In Proceedings Second International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey, California, May 22-25, 2000. Battelle Press, Columbus, Ohio.

Stephens, D.B. 2000. The role of the unsaturated zone in groundwater recharge. Invited speaker at the Innovations in Artificial Recharge: Augmenting Local Groundwater Supplies for the New Millennium, May 4-5, 2000, Ontario, California.

Stephens, D.B. 2000. Observed natural attenuation of TCA in groundwater. Tenth Annual West Coast Conference on Contaminated Soils and Water, March 20-23, 2000, San Diego, CA.

Stephens, D.B. 2000. MTBE—gasoline additive in the national spotlight. Invited speaker at the Albuquerque Petroleum Association Meeting, February 28, 2000, Albuquerque, NM.

Stephens, D.B. 1999. Physical considerations in artificial recharge. Invited presentation at the 22nd Biennial Ground Water Conference, Interconnected Water Supply in California, September 20-21, San Diego, CA.

Stephens, D.B. 1999. Scientific applications of volume, mass and toxicity for allocating cleanup responsibility. Invited presentation at IBC’s Second Annual Executive Forum on Environmental Forensics, June 24-25, 1999, Washington, D.C.

Stephens, D.B. 1999. Basic theory of flow from surface impounds and dry wells used for artificial recharge. Ninth Biennial Symposium on Artificial Recharge of Groundwater, June 10-12, 1999, Tempe, AZ.

Stephens, D.B. 1999. Invited panel member of the Southwest Ground Water—critical issues and information needs, U.S. Geological Survey, Tuscon, Arizona, March 25.

Stephens, D.B. 1998. MTBE fate and transport review. Invited presentation and panel member of the 1998 New Mexico Underground Storage Tank Conference, November 17, 1998, Albuquerque, NM.

Stephens, D.B., W. Cox. 1998. The importance of vadose zone in stream-aquifer interaction: field and model studies. In Proceedings Groundwater Protection Council 1998 Annual Forum, Sacramento, California, September 19-23.

Stephens, D.B., E. Seay. 1998. Interpretations of mechanical integrity tests and groundwater monitoring data at a salt water disposal well: a case study. In Proceedings Groundwater Protection Council 1998 Annual Forum, Sacramento, California, September 19-23.

Stephens, D.B. 1998. Scientific applications of volume mass and toxicity for allocating responsibility for aquifer clean-up. Invited presentation at the National Environmental Forensic Conference: Chlorinated Solvent and Petroleum Hydrocarbons, University of Wisconsin-Madison, Department of Engineering Professional Development, Tucson, Arizona, August 27-28.

Stephens, D.B., J.R. Forbes, M.E. Miller, and J. Minier. 1998. PCE degradation near petroleum contaminated sites. In Proceedings First International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey, California, May 18-21, 1998. Battelle Press, Columbus, Ohio.

Stephens, D.B. 1997. Case studies in DNAPL delineation, technical infeasibility and remediation cost allocation. Invited keynote speaker at the International Conference on Remedial Technology and Management of Subsurface Contamination, December 1-3, Taipei, Taiwan.

Stephens, D.B., J.A. Kelsey, M.A. Prieksat, M.G. Piepho, C. Shan, and M.D. Ankeny. 1998. DNAPL migration through a fractured perching layer. Presentation at the Geological Society of America Annual Meeting, October 21, Salt Lake City, Utah.

Stephens, D.B. 1997. Infiltration modeling roles in RBCA. Invited presentation and panel member of the 1997 New Mexico Underground Storage Tank Conference, September 9-10, Ruidoso, New Mexico.

Stephens, D.B. 1996. Borehole permeameter development, applications and limitations. Presentation at American Geophysical Union Fall Meeting, December 15-19, San Francisco, California.

Stephens, D.B. 1996. Hydrogeology and contaminant transport. Invited presentation at The Who, What, Where & How of Toxic Tort Litigation, The Arizona Bar Association Continuing Legal Education, November 22, Phoenix, Arizona.

Stephens, D.B., J.A. Kelsey, M.A. Prieksat, M.G. Piepho, M.D. Ankeny, and C. Shan. 1996. DNAPL migration in a complex multi-aquifer system. Presentation at Geological Society of America Annual Meeting, October 28-31, Denver, Colorado.

Stephens, D.B., J.A. Kelsey, M.A. Prieksat, M.G. Piepho, M.D. Ankeny, and C. Shan. 1996. DNAPL migration in a complex multi-aquifer system. Presentation at HSRC/WERC Joint Conference on the Environment, May 21-23, Albuquerque, New Mexico.

Stephens, D.B. 1996. Estimating cleanup costs for purposes of mediation: Achieving finality in face of uncertainty. Invited presentation at Resolving Environmental Disputes Through Mediation conference, University of Wisconsin, May 16-17, Albuquerque, New Mexico.

Stephens, D.B., J. Minier, and M.E. Miller. 1996. Subsurface migration and transformation of PCE. Presentation at the New Mexico Conference on the Environment, March 12-14, Albuquerque, New Mexico.

Forbes, J.R. and D.B. Stephens. 1996. Natural biodegradation of subsurface hydrocarbons: Case studies from the southwest United States. Presentation at Bioremediation Technology Transfer Conference, EPA Western Region Hazardous Subresearch Center and Albuquerque Technical Vocational Institute, February 16, Albuquerque, New Mexico.

Stephens, D.B. 1995. Site characterization, remediation: Better/cheaper/faster. Invited presentation at Los Alamos Environmental Restoration Technical Session, Los Alamos National Laboratory, April 19, Los Alamos, New Mexico.

Stephens, D.B. 1995. Environmental remediation technology. Invited presentation at New Mexico Water Law Water Rights and Water Quality Issues, August 28-29, Santa Fe, New Mexico.

Stephens, D.B. 1994. The role of consultants in water rights matters. Presented at Cambridge Institute seminar on New Mexico Water Rights: Key Issues and Recent Developments, March 16, Santa Fe, New Mexico.

Stephens, D.B. 1994. The significance of saturated hydraulic conductivity and residual water content in predictions of unsaturated transport. Invited presentation at the Soil Physics Workshop on Subsurface Transport at Battelle, March 31-April 1, Richland, Washington.

Stephens, D.B. and T.N. Blandford. 1994. Hydrogeology short course. Invited presentation to the State of New Mexico, Environment Department, Drinking Water Bureau, December 6-7, Santa Fe, New Mexico.

Stephens, D.B. and J.C. Stageman. 1993. The consultant’s role in addressing environmental risks in real estate and lending. Invited presentation at the Cambridge Institute workshop on Tackling Environmental Issues in New Mexico, September 24, Albuquerque, New Mexico.

Stephens, D.B. 1993. Designing a vadose zone monitoring system for municipal and hazardous waste landfills. 16th Annual Rocky Mountain Groundwater Conference, September 13-16, Albuquerque, New Mexico.

Stephens, D.B. 1993. Unsaturated flow and recharge. Invited presentation at the 19th Annual Field Studies in Groundwater Contamination Evaluation in Three Modules, Ohio University, June 25, Athens, Ohio.

Stephens, D.B. 1993. Vadose zone processes, characterization, and monitoring. Invited presentation at the National Ground Water Association Outdoor Action Conference, Outdoor Workshops, May 25-27, Las Vegas, Nevada.

Stephens, D.B. 1992. A comparison of the calculated and measured unsaturated hydraulic conductivity of two uniform soils in New Mexico. In M.Th. van Genuchten, F.J. Leij, and L.J. Lund (eds.), Proc. International Workshop on Indirect Methods for Estimating the Hydraulic Properties of Unsaturated Soils, October 11-13, 1989, Riverside, California. University of California, Riverside, California.

Stephens, D.B. 1992. A hydrogeologist’s encounter with geologic problems in New Mexico. Guest lecture at the New Mexico Geological Society Annual Spring Meeting, April 10, Socorro, New Mexico.

Stephens, D.B. 1992. Vadose zone processes, characterization, and monitoring. Invited presentation at the National Ground Water Association Outdoor Action Conference, Indoor Workshops, May 11-13, Las Vegas, Nevada.

Stephens, D.B. 1992. Unsaturated flow and recharge. Invited presentation at the 18th Annual Field Studies in Groundwater Contamination Evaluation in Three Modules, Ohio University, June 15-July 3, Athens, Ohio.

Stephens, D.B. 1992. Encounters with geologic problems in New Mexico. Guest lecture at the AWWA-WPCA (WEA) meeting, July 28, Albuquerque, New Mexico.

Stephens, D.B. 1992. Characterizing the leaching potential of landfills. Invited presentation at the American Geophysical Union Western Pacific Geophysics Meeting, August 17-21, Hong Kong, China.

Stephens, D.B. 1992. Cost-effective remediation at UST sites. Presentation at the Cost-Effective Corrective Action session during the New Mexico Conference on the Environment, September 15, Albuquerque, New Mexico.

Stephens, D.B. 1992. Observation of the effects of heterogeneity on unsaturated flow. Invited presentation at the Remson Symposium, 1992 American Geophysical Union Fall Meeting, December 7-11, San Francisco, California.

Bowman, R.S., D.B. Jaynes, R.C. Rice, and D.B. Stephens. 1991. Field determination of solute transport parameters in “homogeneous” vs. “heterogeneous” soils. Presented at the ASA-CSSA-SSSA 83rd Annual Meeting, October 27-November 1, Denver, Colorado.

Havlena, J. and D.B. Stephens. 1991. Vadose zone characterization using field permeameters and instrumentation. In Proc. Symp. Ground Water and Vadose Zone Investigation, ASTM, January 30-February 1, San Diego, California.

Havlena, J.A. and D.B. Stephens. 1991. Vadose zone characterization using field permeameters and instrumentation. In D.M. Nielsen and M.N. Sara (ed.), Current practice in ground water and vadose zone instrumentation, ASTM STP 118, American Society for Testing Materials, Philadelphia.

Stephens, D.B. 1991. Diffuse, natural recharge calculated from field data and comparisons among semiarid sites. Presented at the ASA-CSSA-SSSA 83rd Annual Meeting, October 27-November 1, Denver, Colorado.

Stephens, D.B. 1991. Characterizing permeability to gas in the vadose zone. Invited presentation at the Symposium on Soil Venting, sponsored by the Robert S. Kerr, Environmental Research Laboratory and the National Center for Ground Water Research, April 29-May 1, Houston, Texas.

Stephens, D.B. 1991. Vadose zone characterization and monitoring. Invited presentation for the Hazardous/Radioactive Waste Management Videoconference Training Series, Program 5: Site Characterization, June 12, University of New Mexico, Albuquerque, New Mexico.

Stephens, D.B. 1991. Unsaturated flow and recharge. Invited presentation at the 17th Annual Field Studies in Water Resource and Contamination Evaluation, Ohio University, June 10-28, Athens, Ohio.

Stephens, D.B., R.S. Bowman, E. Mattson, A. Parsons, K. Flannigan, R. Schmidt-Petersen, D. Grabka, P. Arnet, and A. Stark. 1991. Long-term three-dimensional infiltration, drainage, and transport in a heterogeneous soil. Presented at the 1991 AGU Fall Meeting, December 9-13, San Francisco, California.

Stephens, D.B. 1990. Uncertainties in site characterization data. Invited paper, 12th Annual U.S. DOE Low-Level Waste Management Conference, August 28, Chicago, Illinois.

Beach, J.A., D.B. Stephens, and A.L. Gutjahr. 1989. Incorporation of spatial variability in mill tailings hydraulic properties into numerical models: Implications for uncertainty in seepage prediction and ground water protection. Ninth Annual AGU Front Range Branch Hydrology Days, April 17-21.

Bowman, R.S., D.B. Stephens, D.P. Grabka, K.G. Flanigan, and Department of Geoscience, New Mexico Institute of Mining and Technology. 1989. A multi-tracer field experiment to evaluate solute transport in variably saturated soils. Tracers in Hydrogeology: Principles, Problems, and Practical Applications, National Water Well Association Conference, October 31-November 1, Houston, Texas.

Parsons, A.M., E.D. Mattson, D.B. Stephens, K. Flanigan, and K. Black. 1988. Field simulation of waste impoundment seepage in the vadose zone. In Proc. FOCUS on Southwestern Groundwater Issues Conference, National Water Well Association, March 23-25, Albuquerque, New Mexico.

Cox, W.B. and D.B. Stephens. 1988. Field study of ephemeral stream-aquifer interaction. In Proc. FOCUS on Southwestern Groundwater Issues Conference, National Water Well Association, March 23-25, Albuquerque, New Mexico.

McCord J.T., D.B. Stephens, and J.L. Wilson. 1988a. Field experiments and numerical simulations of unsaturated flow and transport: Role of hysteresis and state-dependent anisotropy. NATO Advanced Study Institute on Recent Advances in Modeling Hydrologic Systems, July 1988, Sintra, Portugal.

McCord J.T., D.B. Stephens, and J.L. Wilson. 1988b. Field-scale unsaturated flow and transport in a sloping, uniform porous media: Field experiments and numerical simulation (Abs). International Conference and Workshop on Validation of Flow and Transport Models for the Unsaturated Zone, Poster Session, May 22-25, Ruidoso, New Mexico.

Stephens, D.B., A.M. Parsons, E.D. Mattson, K. Black, K. Flanigan, R.S. Bowman, and W.B. Cox. 1988. A field experiment of three-dimensional flow and transport in a stratified soil. p. 401-413. In P.J. Wierenga and D. Bachelet (eds.), Proc. International Conference and Workshop on Validation of Flow and Transport Models for the Unsaturated Zone, May 22-25, Ruidoso, New Mexico. New Mexico State University, Las Cruces.

Stephens, D.B., J.T. McCord, R.G. Knowlton, Jr., B. Kickham, E. Hicks, and T. Stein. 1988. Three-dimensional soil-water flow in semi-arid terrain (Abs). International Conference on Advances in Ground-Water Hydrology, November 16-18, Tampa, Florida.

McCord, J.T. and D.B. Stephens. 1987. Infiltration and recharge on a sandy hillslope in an arid climate. International Conference on Infiltration Development and Application, University of Hawaii, January 6-9. Manoa, Hawaii.

Stephens, D.B. 1987. Processes affecting the movement and fate of pesticides in soil and groundwater. New Mexico Environmental Improvement Division, May 27, Santa Fe, New Mexico.

Stephens, D.B. 1986. Saturated-unsaturated flow relationships. 15th Annual Rocky Mountain Groundwater Conference, September 13-16, Phoenix, Arizona.

Larson, M.B. and D.B. Stephens. 1985. A comparison of methods to characterize unsaturated hydraulic properties of mill tailings. In Proceedings Seventh Symposium on Management of Uranium Mill Tailings, Low-level Waste and Hazardous Waste, Colorado State University, February 6-8, Ft. Collins, Colorado.

Lewis, B. and D.B. Stephens. 1985. Analysis of infiltration through mill tailings using a bromide tracer. In Proc. Seventh Symp. on Management of Uranium Mill Tailings, Low-Level Waste and Hazardous Waste, Colorado State University, February 6-8, Ft. Collins, Colorado.

Stephens, D.B., R.G. Knowlton, Jr., M. Stanfill, and E.M. Hirtz. 1985. Field study to quantify seepage from a fluid impoundment. pp. 283-308. In Proc. NWWA Conf. on Characterization and Monitoring of the Vadose (Unsaturated) Zone, November 19-21, Denver, Colorado. NWWA, Dublin, OH.

Stephens, D.B. 1984. Groundwater flow and implications for groundwater contamination in sedimentary formations of the southern San Juan Basin, New Mexico, USA. International Groundwater Symposium on Groundwater Resources Utilization and Contaminant Hydrology, Canada Water Well Association, May 21-23, Montreal, Canada.

Stephens, D.B., K. Lambert, and D. Watson. 1983. Influence of entrapped air on field determinations of hydraulic properties in the vadose zone. In Proc. Conf. on Vadose Zone Characterization and Monitoring, December 8-10, Las Vegas, Nevada. National Water Well Association, Columbus, Ohio.

Stephens, D.B., S. Tyler, K. Lambert, and S. Yates. 1983. Field experiments to determine saturated hydraulic conductivity in the vadose zone. pp. 113-126. In J.W. Mercer et al. (ed.), Role of the unsaturated zone in radioactive and hazardous waste disposal. Ann Arbor Sci, Ann Arbor, Michigan.

Stephens, D.B. and J. Siegel. 1981. Fluid waste movement through the vadose zone. pp. 103-110. In S.G. Wells and W. Lambert (ed.) Environmental Geology and Hydrology in New Mexico. New Mexico Geological Society, Special Pub. 10.

Siegel, J. and D.B. Stephens. 1980. Numerical simulation of seepage beneath lined ponds. pp. 219-232. In Proc. Symposium on Uranium Mill Tailings Management, November 24-25, Ft. Collins, Colorado.

Stephens, D.B. and S.P. Neuman. 1980. Free surface and saturated-unsaturated analyses of borehole infiltration tests above the water table. pp. 2.229-2.238. In Third International Conference on Finite Elements in Water Resources, May 19-23, Oxford, Mississippi, USDA-ARS.

Other Publications

Stephens, D.B., P. Johnson, and J. Havlena. 1996. Estimation of infiltration and recharge for environmental site assessment. American Petroleum Institute publication number 4643.

Bowman, R.S., D.B. Stephens, P. Arnet, D.P. Grabka, R.I. Schmidt-Petersen, and A.M. Stark. 1991. Field study of multidimensional flow and transport in the vadose zone. Report No. 262, New Mexico Water Resources Research Institute, December 1991.

Stephens, D.B. and C. Spaulding. 1984. Oil-field brine contamination: A case study, Lea County, New Mexico. In W.J. Stone, Selected papers on water quality and pollution in New Mexico, Bureau of Mines and Mineral Resources, Hydrologic Report 7.