Principal Hydrologic Consultant

Professional Profile
Dr. Guymon has over 30 years of experience as a geohydrologist/water resources engineer with the State of California, Department of Water Resources; University of Alaska; and University of California (Irvine). He has also provided specialized consulting services to public agencies as well as private consulting engineering firms throughout the western United States.

Since receiving his Ph.D., he has specialized in modeling hydrologic systems, particularly groundwater. He is Professor Emeritus of Civil Engineering at University of California, Irvine.

Ph.D., Civil Engineering, University of California, Davis,1970
M.S., Civil Engineering, University of California, Davis,1967
B.S., Civil Engineering, University of California, Davis, 1966

Professional Civil Engineer, California
Professional Civil Engineer, Alaska

Relevant Experience
  • San Juan Basin Authority: Technical advice on runoff processes and original of natural and man-influenced water to the groundwater basin.

  • Old Woman Springs: Water supply potential and assessment of marketing potential.

  • Groundwater availability to a San Bernardino County development and relationship to a containment plume.

  • Modeled groundwater resources in the lower Owens Valley (Olancha area)
    for the Western Water Company. The MODFLOW model was used for this purpose.

  • Irvine Ranch Water District: Assisted in developing water system master plan. Involved in early planning for reuse and management of reclaimed water. Evaluated the use of Rattlesnake and Sand Canyon Reservoirs for storage of reclaimed water. Developed several subarea master plans for water supply facilities. Designed the Sand Canyon Reservoir controlled outlet facilities. Conducted geohydrological studies on the Irvine Basin.

  • Pacific Company: Exploration of groundwaters in the Santa Ana River/Yorba Linda area and development of two water supply wells.

  • Maricopa County Flood Control, Arizona: Evaluated scour and sedimentation hydraulics for the Agua Fria River north of Interstate 10. Developed and applied the two-dimensional hydrodynamic model to dam break flood potential for several dams local to Phoenix. Assisted in East Cave Creek flood control project which involved incorporation of aesthetic and equestrian amenities. Consulted on the Dysart Drain flood improvements.

  • San Diego County and Vicinity: Evaluated proposed reclaimed water disposal irrigation for the Otay area. Decanso groundwater investigation for increased pump age. Campo investigation on the impact on groundwaters from increased percolation of treated wastewaters.

  • Lusk Company: Performed a feasibility study of well recharge of reclaimed water and groundwater extraction for Menifee Basin, Riverside County, California. This study included geophysical exploration, field well canvassing, and groundwater modeling.

  • City of San Clemente: Developed original master plan of drainage and updated master plan of drainage. This study involved applying the Orange County Hydrology Manual, the rational method and the unit hydrograph method.

  • Tri-Cities Municipal Water District: Investigated the use of the lower San Mateo Basin for conjunctive use and water banking. This study involved geological exploration, geophysical exploration, hydrogeology, groundwater modeling and negotiations between the client and the US Marine Corps.

  • San Juan Basin Authority: Assisted in a groundwater basin management and facility plan. Primary responsibility consisted of geohydrology and groundwater modeling using the UCI model which Dr. Guymon developed. He developed the concept of increasing the sustained yield of coastal basins by inducing seawater intrusion that requires desalination to produce potable water.

  • Eastern Municipal Water District: Investigated impacts associated with discharging highly treated reclaimed water to the Santa Margarita River and groundwaters, developed a cascaded lumped cell model for this work.

  • Navy: Assessed groundwater and water quality impacts associated with wastewater disposal ponds at the Naval Air Station, Lemoore.

  • Valley Center Municipal Water District: Developed a comprehensive mathematical model of the Moosa Canyon Basin, San Diego County, to evaluate reclaimed water recharge effects on groundwaters.

  • Rand Communities Water District: Evaluated increased pumpage effects on the Fremont Basin, Kern County .

  • Moulton Niguel Water District and El Toro Water District: Evaluated groundwater availability in the Aliso Creek Basin area.

  • Over the years assisted in water resources studies and modeled numerous groundwater basins and areas in San Diego County. These include the Santa Margarita River, tributaries of the San Luis Rey, the Valley Center area, Descanso area, National City area, Otay Mesa area, and Campo area.

  • San Bernardino County Flood Control District: Assisted in developing their hydrology manual which is based upon the SCS-Corps of Engineers unit hydrograph theory, rational method and modified Pul's method of flood routing. Assisted in the flood drainage master plan for Twentynine Palms.

  • Fluor Daniel: Modeled pipeline stream crossings associated with the proposed trans-Alaskan chilled gas pipeline.

  • Corps of Engineers: Developed a coupled heat and moisture flow model for algid soils including ice segregation.

  • AMV AC Chemical: Expert witness and investigated the fate and movement of DBCP in soils associated with EP A hearings and litigation in the Central Valley, California.

  • Williamson and Schmidt: Geotechnical investigations and mathematical modeling of seepage from a retention basin located in Chino Basin.

  • Exponent: Assisted in modeling complex unsaturated flow phenomena near a sewer break that devastated numerous structures.


Books and Chapters of Books

1. "Application of the Finite-Element Method to Regional Water Transport Phenomena," (with I.P. King), Sparse Matrices and Their Applications, Edited by D.J. Rose and R.A. Willoughby, Plenum Press, 1972.

2. "The Finite-Element Method," Drainage for Agriculture (Van Schilfgaarde, J., editor), American Society of Agronomy, Monograph No.17, 1974, pp. 587-602.

3. "Modeling of Groundwater Response to Artificial Recharge," (with T .v. Hromadka), Chapter in "Groundwater Recharge," Ed. by T. Asano, Butterworth Pub., 1985, pp, 129-149.

4. G.L. Guymon, Unsaturated Zone Hydrology, Prentice-Hall, 1994.


1. "A Finite Element Solution of the One-Dimensional Diffusion-Convection Equation," Water Resources Research, 6(1), 1970, pp.204-210.

2. "A General Numerical Solution of the Two-Dimensional Diffusion-Convection Equation by the Finite-Element Method," (with V .H. Scott and L.R. Herrmann), Water Resources Research, 6(6), 1970, pp. 1611-1617.

3. "Note on the Finite-Element Solution of the Diffusion Convection Equation," Water Resources Research, 8(5), 1972, pp.1357-1360.

4. "Finite Element Solution for General Fluid Motion," Journal of the Hydraulics Div., A.S.C.E., 99(Hyd.6), 1973, pp. 913-919.

5. "Regional Sediment Yields Analysis of Alaska Streams," Journal of the Hydraulics Div., A.S.C.E., 100(HYl), 1974, pp. 41-51.

6. "A Coupled Heat and Moisture Transport Model for Arctic Soils," (with J.N. Luthin), Water Resources Research, 10(5), 1974, pp. 995-1001.

7. "Soil Moisture – Vegetation - Temperature Relationships in Central Alaska," (with J.N. Luthin), Journal of Hydrology ,23, 1974, pp. 233-246.

8. "Soil Moisture-Temperature for Alaskan Lowland," Journal of Irrigation and Drainage Division, A.S.C.E., 101(IR3), 1975, pp, 187-199.

9. "Thermal Analysis of Manmade Frozen Embankment Islands," (with G.R. Bafus), Journal on Waterways, Harbors and Coastal Engineering Div., A.S.C.E., 102(WW2), 1976, pp.1123-1139.

10. "Summer Moisture- Temperature for Arctic Tundra," Journal of Irrigation and Drainage Div., A.S.C.E., 102(IR4), 1976, pp. 403- 411.

11. "Some Effects of Linearizing the Unsaturated Soil-Moisture Transfer Diffusion Model," (with T.V. Hromadka), Water Resources Research, 16(4), 1980, pp. 643-650.

12. "A One-Dimensional Frost Heave Model Based Upon Simulation of Simultaneous Heat and Water Flux," (with R.L. Berg and T.V. Hromadka), Cold Regions Science and Technology, Vol. 3, Nos. 2 and 3, 1980, pp. 253-262.

13. "Frost Heave in an Instrumented Soil Column," (with R.L. Berg and J. Ingersoll), Cold Regions Science and Technology, Vol. 3, Nos. 2 and 3, 1980, pp. 211-221.

14. "Numerical Mass Balance for Soil-Moisture Transport Problems," (with T.V. Hromadka), Advances in Water Resources, Vol. 3, 1980, pp. 107-114.

15. "A Note on Time Integration of Unsaturated Soil Moisture Transport," (with T.V. Hromadka), Advances in Water Resources, Vol. 3, December 1980, pp. 181-186.

16. "Some Approaches to Modeling Phase Change in Freezing Soils," (with T.V. Hromadka and R.L. Berg), Cold Regions Science and Technology, Vol. 4, 1981, pp.137-145.

17. "Subdomain Integration Model of Ground-Water Flow," (with T.V. Hromadka), Journal of the Irrigation and Drainage Div., A.S.C.E. 107 (IR2), June 1981, pp. 187-196.

18. "Improved Linear Trial Function Finite Element Model of Soil Moisture Transport," (with T.V. Hromadka), Water Resources Research, 17(3), 1981, pp. 504-521.

19. "Results from a Mathematical Model of Frost Heave," (with R.L. Berg, T.C. Johnson and T.V. Hromadka), Transportation Research Record, 809, 1981, pp. 2-6.

20. "Nodal Domain Integration Model of Two-Dimensional Unsaturated Soil-Water Flow: Development," (with T.V. Hromadka and G.C. Pardoen), Water Resources Research, 17(5), 1981, pp. 1425-1430.

21. A Probabilistic-Deterministic Analysis of One-Dimensional Ice Segregating in a Freezing Soil Column," (with M.E. Harr, R.L. Berg and T.V. Hromadka), Cold Regions Science and Technology, Vol. 5, 1981, pp. 127-140.

22. "Nodal Domain Integration Model of One-Dimensional Advection-Diffusion," (with T.V. Hromadka), Advances in Water Resources, Vol. 5, 1982, pp. 9-16.

23. "A Note on Numerical Approximation of Linear Two- Dimensional Advection-Diffusion Process in Rectangular Spatial Domains," (with T.V. Hromadka), Advances in Water Resources, Vol. 5, 1982, pp. 56-60.

24. "Sensitivity of a Frost Heave Model to Numerical Method," (with T.V. Hromadka and R.L. Berg), Cold Regions Science and Technology, Vol. 6, 1982, pp.1-10.

25. "A Note on Approximation of One-Dimensional Heat Transfer With and Without Phase Change," (with T.V. Hromadka), Numerical Heat Transfer, Vol. 5, 1982, pp. 223-232.

26. "Application of a Boundary Integral Equation to Prediction of Freezing Fronts in Soil," (with T.V. Hromadka), Cold Regions Science and Technology, Vol. 6, 1982, pp. 115-121.

27. "Guidelines for Interactive Computer Software in Water Resources Engineering," (with T.V. Hromadka and J. Clemens), Water Resources Bulletin, Vol. 19, No.1, 1983, pp. 91-96.

28. "Mass Lumping Models of the Linear Diffusion Equation," (with T.V. Hromadka), Advances in Water Resources, Vol. 6, 1983, pp. 79-87.

29. "Complex Polynomial Approximation of the Laplace Equation," (with T.V. Hromadka), Journal of the Hydraulics Division, A.S.C.E., Vol. 110, No.3, 1984, pp. 329-339.

30. "Two-Dimensional Model of Coupled Heat and Moisture Transport in Frost Heaving Soils," (with T.V. Hromadka and R.L. Berg), A.S.M.E., Journal of Energy Resources Technology, Vol. 106, 1984, pp. 336-343.

31. Model Heat and Soil Water Flow I" (with T.V. Hromadka), Trans. A.S.M.E., Journal of Energy Resources Technology, Vol.106, 1984, pp. 515-520.

32. "Reducing Relative Error from the CVBEM by Proper Treatment of the Known Boundary Conditions," (with T.V. Hromadka), International Journal of Numerical Methods in Engineering, Vol. 20, 1984, pp. 2113-2120.

33. "A Complex Variable Boundary Element Method: Development," (with T.V. Hromadka), International Journal of Numerical Methods in Engineering, Vol. 20, 1984, pp. 25-37.

34. "An Algorithm to Reduce Approximation Error from the Complex-Variable Boundary-Element Method Applied to Soil Freezing," (with T.V. Hromadka II), Numerical Heat Transfer, Vol. 8, 1985, pp. 115-130.

35. "A Two-Dimensional Dam-Break Flood Plan Model" (with T.V. Hromadka II, C.E. Berenbrock and J.R. Freckleton), Advances in Water Resources, Vol. 8, 1985, pp. 7-14.

36. G.L. Guymon and T.V. Hromadka II, "Two-Dimensional Diffusion-Probabilistic Model of a Slow DamBreak," Water Resources Bulletin, Vol. 22, No.2, 1986, pp. 257-265.

37. C.C. Yen and G.L. Guymon, "An Efficient Deterministic- Probabilistic Approach to Modeling Regional Groundwater Flow: Theory," Water Resources Research, Vol. 26, No.7, 1990, pp. 1559-1567.

38. G.L. Guymon and C.C. Yen, "An Efficient Deterministic-Probabilistic Approach to Modeling Regional Groundwater Flow: Application to Owens Valley , California," Water Resources Research, Vol. 26, No.7, 1990, pp.1569-1581.

39. G.L. Guymon and M.R. Welch, "Reclaimed Wastewater Storage in Groundwater Basins" A.S.C.E., Journal of Water Resources Planning and Management, Vol. 16, No.3, 1990, pp. 305-322.

40. G.L. Guymon, A.C. Bagtzoglou and M.R. Welch, "A Lumped stream-Aquifer Model to Assess Reclaimed Water Impacts," Water Resources Bulletin, Vol. 28, No.2, 1992, pp. 361-370.

41. G.M. Lit ton and G.L. Guymon, "Laboratory Experiments on the Transport and Fate of DBCP in Hanford Sandy Loam," Journal of Environmental Quality, Vol. 22, No.2, 1993, pp. 311-325.

42. A.C. Bagtzoglou, M.N. Khan, G.L. Guymon and I. R. Thornton, "Groundwater Quality Management of a Low Inertia Basin: Application to San Mateo Basin, California," Journal of Water Resources Management, Vol. 7, 1993, pp. 189- 205.

43. T.V. Hromadka, J.A. Walker and G.L. Guymon, "Solution of Parabolic Equations Using an Eigenvalue Method for Time Advancement," Advances in Engineering Software, Vol. 18, 1993, pp. 1-5.

44. S. Shigemitsu, A. Hiratsuka, G.L. Guymon and A. Murota, " Numerical Forecasting of Storm Runoff by Using Component Separation AR Method," Journal of Osaka Sanxo University, (95), 1994, pp. 37-52.

45. G.L. Guymon, M.N. Khan, M. Collins and T.V. Hromadka II, "A Diffusion Hydrodynamic Model of a Shallow Estuary," Journal of Water Resources Planning, Vol. 120, No.2, 1994, pp. 253-266.

46. "Application of the Finite-Element Method for Simulation of Surface Water Transport Problems," Institute of Water Resources, University of Alaska, Report No. IWR-21, 1972.

47. "Application of Artificial Recharge Technology for Managing Water Resources -Anchorage, Alaska," Institute of Water Resources, University of Alaska, Report No. IWR-24, 1972.

48. "Nitrates in the Upper Santa Ana River Basin in Relation to Groundwater Pollution," edited by K.S. Ayers and R.L. Branson, California Agricultural Experimental Station, Bulletin 861, 1973.

49. "Sediment Relations of Selected Alaskan Glacier-Fed Streams," Institute of Water Resources, University of Alaska, Report No. IWR-51, 1974.

50. "A Review of Snow-Soil Interaction," Proceedings Modeling of Snow Cover Runoff, U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, NH, September 1978.

51. "Environmental Engineering Investigations Along the Yukon River-Prudhoe Bay Haul Road, Alaska," (contributed a section with other authors), CRREL Report 80-19, FHWA-RD-80-097, 1980.

52. "Principles of Soil Freezing and Frost Heaving," (with D. W . Anderson, P.J. Williams and D.L. Kane), A.S.C.E. Monograph, Frost Action and its Control, 1984, pp. 1-21.

53. G.L. Guymon, "Two-Dimensional Modeling of Floodflows on Alluvial Fans," Proc. of Association of State Floodplain Managers, 1986, pp. 29-32.

54. M.R. Welch, D.P. Groenveld and G.L. Guymon, "Influence of Changes in Soil Water and Depth of Ground Water on Transpiration and Canopy of Alkaline Scrub Communities in Owens Valley , California," U .S. Geological Survey Report, 1988.

55. G.M. Litton and G.L. Guymon," Literature Review Concerning the Fate of DCE, TCE and DBCP in Agricultural Water during Irrigation and Percolation through the Soil," UCI, Department of Civil Engineering, Report No. WE88-01, 1988, 95 p.

56. G.M. Litton and G.L. Guymon, "Experimental Study Exploring the Fate of TCE and DBCP in Hanford Sandy Loam," UCI, Department of Civil Engineering, Report No. WE89-01, 1989, 53p.

57. Kimberly A. Alexander and Gary L. Guymon, "Optimal Management of Groundwater Basins of Degraded Water Quality for Conjunctive Use," UCI, Department of Civil and Environmental Engineering, Technical Completion Report, 1995, 93 p.

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