Areas of Expertise:
- Identification of climate variations and trends, and assessment of their impacts on hydrologic watershed system-behavior, soil erosion, and regional water budgets.
- Identification of drainage characteristics on digital landscape topography, and modeling of surface runoff, flood-wave propagation, and sediment transport.
- Analyses of rainfall-runoff hydrology in large mixed land use watersheds, sediment yield, and interpretation of flow and sediment records of a changing environment.
- Adaptation of a synthetic daily weather generator to determine long term impacts of climate change on water resources availability and quality.
1984 Colorado State University; Civil Engineering (Hydrology and Water Resources); Ph. D.
1981 Colorado State University; Civil Engineering (Hydraulics); M.S.
1977 Swiss Federal Institute of Technology, Zurich; Civil Engineering; Dipl. Ing. ETHZ
1996 - Present: Res. Hydr. Eng., USDA-ARS, Grazinglands Res. Lab., El Reno, OK
1988 - 1996: Res. Hydr. Eng., USDA-ARS, Nat. Ag. Water Quality Lab., Durant, OK
1986 - 1988: Res. Hydr. Eng., USDA-ARS, Hydro-Ecosystems Res. Unit, Fort Collins, CO
1985 - 1986: Assistant Prof., Dep. Civil Eng., Colorado State University, Ft. Collins, CO
1977 - 1978: Res. Associate, Institute for Road, Railway and Rock Construction
Swiss Federal Institute of Technology, ETHZ, Zurich, Switzerland
Developed a comprehensive drainage analysis methodology for digital topographies
Developed novel solutions for automated characterization of drainage networks and landscape drainage features from Digital Elevation Models. The methodologies addressed large basin applications and complex and difficult landscape features for which traditional approaches often failed. The software has been requested by private, commercial, government, consulting and research/university entities. It has been distributed nationally and internationally, and has been incorporated by third party into government and commercial watershed analysis products.
Identified decade-long precipitation variations in the Great Plains and assessed impacts
Analyzed decade-long variations in annual precipitation in the Great Plains and identified several large regions that exhibited a sustained, decade-long wet period at the end of the 20th century. Established the impact of these decade-long variations in precipitation on streamflow trends, reservoir storage, watershed sediment yield, and reservoir sedimentation. This climate information was disseminated on the web by the Oklahoma Climatological Survey, has appeared in local newspaper, and was presented at conferences and generated interest by water resources managers, agricultural producer groups, and state and federal water agencies (specifically US Geological Survey, Oklahoma Wheat Commission, Tulsa Army Corps of Engineers, Oklahoma City Bureau of Reclamation, Oklahoma Water Resources Board).
Downscaled seasonal climate forecasts tested for decision support in grazing management
Led the development and application of a methodology to downscale seasonal climate forecasts to farm and daily time scales. The seasonal climate outlooks offer the potential to reduce economic risk and increase profitability of agricultural enterprises, and the long term climate projections support the development of strategic goals in food production and natural resources conservation. The application to a livestock grazing enterprise established that strong forecasts can provide management opportunities that reduce weather-related risk and increase the probability of profit, though strong and relevant forecasts are infrequent in central Oklahoma. The proof of concept of probabilistic approach used in the application to quantify weather-related uncertainty may also provide a practical and simple approach to integrate weather-related risk into the overall decision process.
Synthetic daily weather generation for simulation of agricultural and conservation assessments
This research put forth a synthetic weather generator called SYNTOR that generates daily synthetic precipitation and air temperature for long term climate projections. Synthetic weather is often selected to determine the vulnerability of soil and water resources to climate change and to develop decision support information for effective soil and water conservation strategies that increase the capacity of agricultural landscape to resist and recover from detrimental impacts of anticipated climate change. Overall, the synthetic weather generator demonstrated good ability to generate daily precipitation and air temperature sequences that sum up properly to historical and forecast conditions, and estimate the impacts of projected climate change on regional water availability and quality, across diverse physiographic regions in the United States.
Garbrecht, J., and G. P. Fernandez. 1994. Visualization of trends and fluctuations in climatic records. Water Res. Bull., AWRA, 30(2):297-306.
Garbrecht, J., and F. Rossel. 2002. Decade-scale precipitation increase in the Great Plains at the end of the 20th century. J. Hydrol. Eng. 7(1):64-75.
Garbrecht, J. D., and X. J. Zhang. 2003. Generating representative sequences of daily precipitation for agricultural simulations. J. Applied Eng. in Agr., publ. ASAE, 19(4):423-429.
Schneider, J. M., and J. D. Garbrecht. 2003. A measure of the usefulness of seasonal precipitation forecasts for agricultural applications. Trans. ASAE. 46(2):257-267.
Garbrecht, J., M Van Liew, and G. O. Brown. 2004. Trends in precipitation, streamflow and ET in the Great Plains. J. Hydrol. Eng., 9(5):360-367.
Schneider, J. M., J. D. Garbrecht, and D. A. Unger. 2005. A heuristic method for time disaggregation of seasonal climate forecasts. Weather and Forecasting, 20(4):212-221.
Garbrecht, J. D., H. Meinke, M. V. K. Sivakumar, R. P. Motha, and M. J. Salinger. 2005. Seasonal climate forecasts and adoption by agriculture. EOS, Trans. AGU, 86(24):227.
Garbrecht, J. D., and T. C. Piechota (Eds). 2005. Climate variations, climate change, and water resources engineering. ASCE., Reston Virginia, 192 pp.
Garbrecht, J. D., P. J. Starks, and J. L. Steiner. 2006. The under-appreciated climate factor in CEAP. J. SWC, 61(4):110-112.
Garbrecht, J. D., J. M. Schneider, and M. W. Van Liew. 2006. Monthly runoff predictions based on rainfall forecasts in a small Oklahoma watershed. J. AWRA, 42(5):1285-1295.
Schneider, J. M., and J. D. Garbrecht. 2006. Dependability and effectiveness of seasonal forecasts for agricultural applications. Trans. ASABE, 49(6):1737-1753.
Garbrecht, J. D., J. L. Steiner, and C. A. Cox. 2007. Climate change impacts on soil and water conservation. EOS, Trans. AGU, 88(11):136.
Garbrecht, J. D., and J. M. Schneider. 2007. Climate forecast and prediction product dissemination for agriculture in the United States. Australian J. Agr. Res., 58(10):966-974.
Garbrecht, J.D., J.M. Schneider, and G.O. Brown. 2007. Soil water signature of the 2005-2006
drought under Tallgrass Prairie at Fort Reno, Oklahoma. Proceedings of Oklahoma Academy of Science, 87:37-44.
Garbrecht, J. D. 2008. Multi-year precipitation variations and watershed sediment yield in a CEAP Benchmark Watershed. J. SWC, 63(2):70-76.
Garbrecht, J. D. 2008. Effects of multiyear precipitation variations on watershed runoff and sediment yield. J. SWC, 63(2):52A-53A.
Garbrecht, J. D., and J. M. Schneider. 2008. Case study of multiyear precipitation variations and the hydrology of Fort Cobb Reservoir. J. Hydrol. Eng., 13(2):64-70.
Garbrecht, J. D., and P. J. Starks. 2009. Watershed sediment yield reduction through soil conservation in a West-Central Oklahoma Watershed. Ecohydrology, 2(3):313-320.
Garbrecht, J.D., X.C. Zhang, J.M. Schneider, and J.L. Steiner. 2010. Utility of seasonal climate
forecasts in management of winter-wheat grazing. Applied Eng. in Ag., 26(5):855-866.
Garbrecht, J.D. 2011. Effects of climate variations and soil conservation on sedimentation of a
West-Central Oklahoma Reservoir. Journal of Hydrologic Engineering, 16(11):899-913.
Garbrecht, J.D. 2012. Random, but uniform please: requirements for synthetic precipitation
generation for computer simulation in agriculture. Applied Eng. in Ag, 28(2):207-217.
Garbrecht, J.D., F. Mojarro, F.G. Echavarria-Chairez, C.F. Bautista-Capetillo, D. Brauer, and J. L. Steiner. 2013. Sustainable utilization of the Calera Aquifer, Zacatecas, Mexico.
Applied Engineering in Agriculture, 29(1):67-75.
Garbrecht, J.D., and X.C. Zhang. 2014. Generating synthetic daily precipitation realizations for seasonal precipitation forecasts. Journal of Hydrologic Engineering, 19(1):252-264.
Garbrecht J.D., X.C. Zhang, and J.L. Steiner. 2014. Climate change and observed climate trends in the Fort Cobb experimental Watershed.
Journal of Environmental Quality, 43:1319-1327.
Garbrecht, J.D., M.A. Nearing, F.D. Shields Jr., M.D. Tomer, E.J. Sadler, J.V. Bonta, and C. Baffaut. 2014. Impact of weather and climate scenarios on conservation assessment outcomes. Journal of Soil and Water Conservation 69(5):383-401.
Garbrecht, J.D., M.A. Nearing, J.L. Steiner, X.J. Zhang, and M.H. Nichols. 2015. Can
conservation trump impacts of climate change on soil erosion? An assessment from winter wheat cropland in the Southern Great Plains of the United States.
Weather and Climate Extremes, 10:32-39.
Garbrecht, J.D., and X.C. Zhang. 2015. Soil Erosion from winter wheat cropland under climate change in central Oklahoma. Applied Engineering in Agriculture. 31(3):439-454.
Garbrecht, J.D., M.A. Nearing, X.C. Zhang, and J.L. Steiner. 2016. Uncertainty of climate change impacts on soil erosion from cropland in central Oklahoma.
Applied Engineering in Agriculture, 32(6):823-836.
Garbrecht, J.D., R. Gyawali, R.W. Malone, and X.J. Zhang. 2017. Cascade rainfall
disaggregation application in the U.S. Central Plains. Environment and Natural Resources Research. DOI:10.5539/enrr.v7n4pxx.
Garbrecht, J. D., D. P. Brown, and X. C. J. Zhang. 2018. Repeated and random components in Oklahoma’s monthly precipitation record. International Soil and Water Conservation Research. Vol. 6, Issue 3, Pages 261-263. https//doi.org/10.1016/j.iswcr.2018.03.005
Garbrecht, Jurgen, X.C. (John) Zhang, David Brown, and Phillip Busteed. 2019. Generation of synthetic daily weather for climate change scenarios and extreme storm intensification. Environmental and Natural Resources Research, Vol. 9, No. 2, p1-15.