Session organizer for the American Geophysical Union (2002, 2003, 2007), International Association of Hydrological Sciences (2000, 2005), American Society of Civil Engineers (2005), Western Pacific Geophysics Meeting (2006), and American Institute of Hydrology (2005, 2006).

"Environmental Analysis in a Regulatory Context," Fall Meeting, American Geophysical Union, San Francisco, California, December 10-14, 2001.

"Regional Management of Water Resources," 6th Scientific Assembly of the International Association of Hydrological Sciences, Maastricht, The Netherlands, July 19, 2001.

"Surface Water-Ground Water Interactions," Annual Spring Specialty Conference, American Water Resources Association, San Antonio, Texas, April 30-May 2, 2001.

"Integrated Water Resources Management," Fall Meeting, American Geophysical Union, San Francisco, California, December 15-19, 2000.

"Water Resources Management," Fall Meeting, American Geophysical Union, San Francisco, California, December 14, 1999.

"Capitalization," 22nd Biennial Groundwater Conference, San Diego, California, September 20-21, 1999.

"Surface and Subsurface Water Contamination: Part II," Water and Environmental Resources Conference, The Universities Council on Water Resources, Kamuela, Hawaii, June 29-July 2, 1999.

"Surface and Subsurface Water Contamination: Part I," Water and Environmental Resources Management Conference, The Universities Council on Water Resources, Kamuela, Hawaii, June 29-July 2, 1999.

"Usefulness of Research in Public Policy," The Universities Council on Water Resources, Hood River, Oregon, August 4-7, 1998.

"Decision Structures and Tools for Water Management," The Universities Council on Water Resources Conference Hood River, Oregon, August 4-7, 1998.

"Groundwater Modeling," American Institute of Hydrology, Tampa, Florida, November 16-19, 1997.

"Water Use and Conservation," (C-19), Annual Conference, American Water Resources Association, Long Beach, CA, October 13-15, 1997.

"Water Use and Conservation," (C-13), Annual Conference, American Water Resources Association, Long Beach, CA, October 13-15, 1997.

"Professional Continuing Education," AWRA·UCOWR Joint Symposium on Water Resources Education, Training and Practice: Opportunities for the Next Century, Keystone, Colorado, June 29-July 3, 1997.

"Integrated Water Resources Analysis," AWRA·UCOWR Joint Symposium on Water Resources Education, Training and Practice: Opportunities for the Next Century, Keystone, Colorado, June 29-July 3, 1997.

"Water Resources and Systems Analysis," 5th Scientific Assembly of the International Association of Hydrological Sciences, Rabat, Morocco, April 23-May 3, 1997.

"Groundwater Systems Planning and Management," 24th Annual Water Resources Planning and Management Conference, American Society of Civil Engineers, Houston, Texas, April 6-9, 1997.

"Surface Water - Ground Water Interactions II," North American Water and Environment Congress '96, American Society of Civil Engineers, Anaheim, California, June 22-28, 1996.

"Surface Water - Ground Water Interactions I," North American Water and Environment Congress '96, American Society of Civil Engineers, Anaheim, California, June 22-28, 1996.

"Ground Water Planning and Management," North American Water and Environment Congress '96, American Society of Civil Engineers, Anaheim, California, June 22-28, 1996.

"Ground Water Modeling Applications," North American Water and Environment Congress '96, American Society of Civil Engineers, Anaheim, California, June 22-28, 1996.

"Conjunctive Water Use Modeling and Management," 1995 National Conference on Water Resources Planning and Management, American Society of Civil Engineers, Boston, Massachusetts, May 7-10, 1995.

"Groundwater Management," Annual Convention, American Society of Civil Engineers, Dallas, Texas, October 25-28, 1993.

"Groundwater Modeling and Management," 20th Anniversary Conference, Water Resources Planning and Management Division, American Society of Civil Engineers, Seattle, Washington, May 3-5, 1993.

"Groundwater Systems Planning and Management," Water Forum '92, American Society of Civil Engineers, Baltimore, Maryland, August 2-5, 1992.

"Groundwater Quality Systems Analysis," 18th Annual National Conference, Water Resources Planning and Management Division, American Society of Civil Engineers, New Orleans, Louisiana, May 20-23, 1991.

"Groundwater Management: Modeling Applications," 18th Annual National Conference, Water Resources Planning and Management Division, American Society of Civil Engineers, New Orleans, Louisiana, May 20-23, 1991.

"Modeling and Investigation," A Joint Conference: Focus on Environmental Hydrology and Hydrogeology Issues in U.S.A. and Hungary, American Institute of Hydrology and Hungarian Hydrological Society, Budapest, Hungary, June 26-28, 1990.

"Groundwater Modeling," 17th Annual National Conference, Water Resources Planning and Management Division, American Society of Civil Engineers, Fort Worth, Texas, April 17-20, 1990.

"Groundwater Management," National Water Conference and LIFE Symposium, Irrigation and Drainage Division and Water Resources Planning and Management Division, American Society of Civil Engineers, Newark, Delaware, July 17-20, 1989.

"Groundwater Quality," National Water Conference and LIFE Symposium, Irrigation and Drainage Division and Water Resources Planning and Management Division, American Society of Civil Engineers, Newark, Delaware, July 17-20, 1989.

"Surface Water-Groundwater Systems," 16th Annual National Conference, Water Resources Planning and Management Division, American Society of Civil Engineers, Sacramento, California, May 21-25, 1989.

"Design and Operation of Water Storage and Delivery Systems," 16th Annual National Conference, Water Resources Planning and Management Division, American Society of Civil Engineers, Sacramento, California, May 21-25, 1989.

"Groundwater Management and Modeling," 15th Annual Conference, Water Resources Planning and Management Division, American Society of Civil Engineers, Norfolk, Virginia, June 3-5, 1988.

"Land and Water Management," Research Conference, Instituto Nacional de Investigaciones Forestales y Agropecuarias/University of California, Guadalajara, Mexico, March 28-30, 1988.

"Groundwater Modeling," 14th Annual National Conference, Water Resources Planning and Management Division, American Society of Civil Engineers, Kansas City, Missouri, March 16-18, 1987.

"Special Studies in Infiltration," International Conference on Infiltration Development and Application, Honolulu, Hawaii, January 6-9, 1987.

"Advances in Parameter Estimation in Groundwater Modeling," Water Forum '86, World Water Issues in Evolution, American Society of Civil Engineers, Long Beach, California, August 4-6, 1986.

"Contaminant Transport and Modeling," International Symposium on Management of Hazardous Chemical Waste Sites, Winston-Salem, North Carolina, October 9-10, 1985.

"Numerical Models and Parameters Identification in Groundwater," Computer Applications in Water Resources, Water Resources Planning and Management Division, American Society of Civil Engineers, Buffalo, New York, June 10-12, 1985.

"Combined Sewer Overflows and Stormwater Management," Water Resources Planning and Management Division, American Society of Civil Engineers, Baltimore, Maryland, May 28-31, 1984.

"Water for Food Production," Third World Congress on Water Resources, International Water Resources Association, Mexico City, Mexico, April 23, 1979.

"Salinity Problems in Groundwater," Fall Annual Meeting, American Geophysical Union, San Francisco, California, December 4, 1978.

"Groundwater Storage Considerations: Alternative Courses of Action," 11th Biennial Conference on Groundwater, U.C. Water Resources Center and California Department of Water Resources, Fresno, California, September 15, 1977.

"Groundwater-Surface Water Interactions," Water Resources Symposium, American Water Resources Association, Las Croabas, Puerto Rico, November 1974.