WESLEY W. WALLENDER, Professor

Ph.D., Engineering, Utah State University, 1982
Department of Land, Air and Water Resources / Biological and Agricultural Engineering
221 Veihmeyer Hall
Phone: 530-752-0688
Email: wwwallender@ucdavis.edu

Current Research

Professor Wallender focuses his research on modeling and measurement of precipitation- and irrigation-driven watersheds from meter to kilometer scales. His interests extend to water and energy conservation and to protection of the environment.

Geographic Information Systems (GIS) are being used to transfer, analyze, and display data. Complementary regional-scale hydrology models are being developed to study the time and space scale effects on predicted water flow and solute transport. Areas as diverse as a tundra region in Alaska and an irrigation district in California are under investigation. Bridging the gap in data computer structures used in GIS and the hydrology models is a related focus for the research.

The models simulate water transport from the ocean to the terminus of the watershed. Only the final leg to the ocean is missing to complete the cycle. The general purpose of this research is to link atmosphere and hydrology models, enriched by satellite data, to understand terrestrial and aquatic process from patterns, at measurement scales from 20 to 1000 m and beyond to tens of kilometers. The model will be used to prevent detrimental atmospheric, hydrologic, and ecological consequences of changes in land use and climate.

Changes in land use and climate have diverse effects on terrestrial and aquatic ecosystems including, but not limited to, changing species distributions and changing rates of water storage and movement. Landscape structure (the spatial arrangement and number of ecosystem components) and water in the atmosphere, on the surface (sheet and stream flow), in the soil, and in the groundwater change in response to changes in land use as well as climate. It is vital to simulate and, therefore, predict the consequences of change, but the simulator should be faithful to the processes and the patterns that result. Ecologists have long implied process from pattern, and hydrologists are beginning to recognize this approach as they struggle to scale up from point measurements to stream flows (associated fish populations) which represent much larger areas. Satellite data offer a new opportunity to develop and test these distributed models which rely on small scale physics. The results can then be aggregated up to scales more familiar to ecologists and atmospheric scientists to combine the wealth of information from several disciplines.

Understanding the dynamic interaction between irrigation and drainage management technologies and the quantity and quality of downstream regional groundwater is one key to developing best management practices. Toward this end, data along a transect from the coast range foothills to the trough of the valley floor are being studied to determine the effect of changing water management practices.

It is generally accepted that current and future irrigation management should focus on practices that control percolation losses and salinity. Currently irrigation practices are based on average soil characteristics for a field. By including information on spatial and temporal variability of soil infiltration characteristics, management practices could be further refined. A mathematical model is being developed that will treat soil properties as stochastic, include a surface and subsurface water flow model, and incorporate crop response to soil and water quality and quantity. Field studies and modeling efforts are targeted to reduce applied water and drainage within environmental and economic constraints.

Representative Recent Publications

Burke S. M., R. M. Adams, and W. W. Wallender. 2004. Water banks and environmental water demand: case of the Klamath basin. Water Resources Research 40, W09S02, Doi: 10.1029/2003WR002832.

Zalom, F. G., I. Werner, M. N. Oliver, L. A. Deanovic, T. S. Kimball, B. W. Wilson, J. D. Henderson, and W. W. Wallender. 2004. Organophosphate dormant spray pest control efficacy, pesticide concentration and toxicity in storm runoff. Bulletin of Environmental Contamination and Toxicology 73:299-305.

Tarboton, K. C., W. W. Wallender, and N. S. Raghuwanshi. 2004. Salinity appraisal with water reuse. Irrigation and Drainage Systems 18:255-273.

Buyuktas, D., W.W. Wallender, R. W. Soppe, and J. E. Ayars. 2004. Calibration and validation of a three-dimensional subsurface irrigation hydrology model. Irrigation and Drainage Systems 18:211-225.

Sivakumar, B., and W.W. Wallender. 2004. Deriving high-resolution sediment load data using a nonlinear deterministic model . Water Resources Research 40, Doi: 10,1029/2004WR003152.

Ito, H., W. W. Wallender, and N. S. Raghuwanshi. 2005. Optimal sample size for furrow irrigation design. Biosystems Engineering 91(2):229-237, Doi: 10.1016/j.biosystemseng.2005.02.009.

Islam, M. D., W. W. Wallender, J Mitchell, S. Wicks, and R. E. Howitt. 2005. A comprehensive experimental study with mathematical modeling to investigate the affects of cropping practices on water balance variables. Agriculture Water Management,

Mitchell, J. P., W. R. Horwath, T. K. Hartz, K. K. Klonsky, B. R. Hanson, E. M. Miyao, D. M. May, and W. W. Wallender. 2005. Recent advances in tomato production systems management in California. 6th World Congress on the Processing Tomato and the 9th International Society for Horticultural Science’s Symposium o the Processing Tomato. Melbourne.

Mitchell, J .P., K. K. Klonsky, J. B. Baker, R. L. DeMoura, W. R. Horwath, R. J. Southard, D. S. Munk, J .F. Wroble, K. J. Kembree, J. J. Veenstra, and W. W. Wallender. 2005. Transitioning cotton and tomato production to conservation tillage. California Agriculture.

Buyuktas, D., W. W. Wallender, and B. Sivakumar. 2005. Sensitivity analysis of an enhanced subsurface-surface irrigation hydrology model. Irrigation and Drainage Systems.

Sivakuma, B., W. W. Wallender, W. R. Horwath, J. P. Mitchell, S. E. Prentice, and B. A. Joyce. 2005. Rainfall dynamics at the sustainable agriculture farming systems (SAFS) project site in California’s Sacramento Valley. Hydrologic Processes.

Gao. P., G. Pasternack, K. M. Bali, and W. W. Wallender. 2005. Impact of agricultural practices on soil erosion at the field scale in the Salton Sea Watershed. Proceedings of the Third International Conference on Irrigation and Drainage. Water District Management and Governance. San Diego, CA. USCID. pp. :571-580.

Schoups, G., J. W. Hopmans, C. A. Young, J. A. Vrugt, and W. W. Wallender. 2005. Multi-criteria optimization of a regional spatially-distributed subsurface flow model. Journal of Hydrology, Doi: 10.1016/j.hydrol.2005.01.001

Membership in Professional Societies

American Society of Agricultural Engineers
American Society of Civil Engineers
American Geophysical Union

Courses Offered

SAS 5 – Geographic Information Systems & Society
EBS 189A - Fluid Mechanics
EBS/HYD 205 - Continuum Mechanics of Natural Systems
EBS 145 - Irrigation and Drainage Systems
EBS 242 - Surface Irrigation Hydraulics

Research Support

CAL FED
International Water Management Institute
Salinity Drainage Program
Division of Agriculture and Natural Resources