Karl Flessa
Professor of Geosciences | University of Arizona
Colorado River Research Group

Research Interests & Background

Karl Flessa and his students have been conducting research on the Colorado River delta since 1992. They have documented the effects of upstream water diversions on the fauna of the river鈥檚 estuary and estimated flows necessary for their restoration. Flessa directed the NSF-supported Research Coordination Network: Colorado River Delta, the environmental monitoring program for the Ci茅nega de Santa Clara during the test run of the Yuma Desalting Plant and is currently the chief scientist for the Minute 323 Monitoring Program for the Colorado River Delta. He was a distinguished visiting scientist at Australia鈥檚 CSIRO, where he studied river management in the Murray-Darling Basin. He received his undergraduate degree at Lafayette College and his Ph.D. from Brown University.

Selected Colorado River Publications & Presentations

Publications

Flessa, K., 2022.聽 A proposed Arizona Water Authority is not enough tot save us. 聽Arizona republic, April 8, 2022.听听

Zamora, H.A., Eastoe, C.J., McIntosh, J.C. and Flessa, K.W., 2021.聽 Groundwater origin and聽dynamics on the eastern flank of the Colorado River Delta, Mexico. Hydrology 2021, 8, 80.

G贸mez鈥怱apiens, M.M., Jarchow, C.J., Flessa, K.W., Shafroth, P.B., Glenn. E.P., and Nagler, P.L., 2020.Effect of an environmental flow on vegetation growth and health using ground and remote sensing metrics.聽 Hydrological Processes.聽 34: 1682-1696.

Nelson, S.M., Kendy, E., Flessa, K.W., Rodr铆guez鈥怋urgue帽o, J.E., Ram铆rez鈥怘ern谩ndez, J., Rivas鈥怱alcedo, T.E.. 2020. Channel incision by headcut migration: Reconnection of the Colorado River to its estuary and the Gulf of California during the floods of 1979鈥1988. Hydrological Processes. 34: 4156鈥 4174.

Wilder, M.O., Varady, R.G., Gerlak, A.K., Mumme, S.P., Flessa, K.W., Zuniga-Teran, A.A., Scott, C.A., Pineda Pablos, N. and Sharon B. Megdal, S.B., 2020. Hydrodiplomacy and adaptive governance at the U.S.-Mexico border: 75 years of tradition and innovation in transboundary water management. Environmental Science & Policy, 112: 89-202.

Glenn, E., Flessa, K.W., Kendy, E., Shafroth, P.B., Ramirez-Hernandez, Gomez-Sapiens, M., and Nagler, P.L., eds.聽 Environmental flows for the Colorado River Delta: Results of an experimental pulse release from the US to Mexico.聽 Ecological Engineering 106, Part B., 629-808.

Bark, R.H., Robinson, C.J. and Flessa, K.W., 2016.聽 鈥淭racking cultural ecosystem services: water chasing the Colorado River restoration pulse flow.鈥澛 Ecological Economics 127:165-172.

Flessa, K.W., E.P. Glenn, O. Hinojosa-Huerta, C.A. de la Parra-Renteria, J. Ramirez-Hernandez, J.C. Schmidt, and F. Zamora-Arroyo.聽 2013.聽 Flooding the Colorado River Delta: A landscape-scale experiment.聽 EOS 94: 485-486.聽

Presentations

Arizona Public Media, 2020 The Delta. 聽

Flessa, K.W.聽 2021.聽 Video lecture (46 minutes): Conservation paleobiology of the Colorado River Delta. 聽 Research Coordination Network for Conservation Paleobiology

鈥淧ossible Delta Solutions鈥 at the Colorado River Conversations: Integrating Science and Identifying Solutions conference. Tucson, AZ; October 29, 2019.

"Minute 319 and Minute 323 of the US-Mexico Water Treaty: When science matters and when it doesn鈥檛鈥 at the Sustainable Development for the Americas conference. Tucson, AZ; October 24, 2019.聽

鈥淓stablishing a Baseline With Science鈥 at the Desert Waters International Symposium.聽 Tucson, AZ; April 2, 2019.

鈥淟ooking back/looking forward: Minute 319/Minute 323鈥 at the Lessons Learned Workshop.聽 Mexicali, Mexico; October 24, 2018.

鈥淢inute 319 and the Colorado River delta鈥 at the Binational Water Relations at 75 Years: Retrospectives, Resilience, and U.S.-Mexico Border Water Resources Governance.聽 Tucson, AZ; October 15, 2018.

鈥淭he Sum of the Parts: A Blueprint for Lower Basin Sustainability?鈥 at the conference 鈥淔ighting Back on the Colorado River: Carving Out Progress on Multiple Fronts.鈥澛 Getches-Wilkinson Center for Natural Resources, Energy and the Environment, University of Colorado; Boulder, CO; June 8, 2017.

鈥淭ransboundary environmental flows to the Colorado River Delta: When the past matters and when it doesn't鈥 at the International Conference on Ecological Sciences. Marseille, France; October 26, 2016.聽

鈥淭wo years after the flow: Hydrologic and ecological effects of the 2014 environmental flow to the Colorado River delta鈥 at the Geological Society of America Annual Meeting. Denver, CO; Sept 26, 2016.

Presenter at the Conservation Biology Program, University of Minnesota, Twin Cities: 鈥淎 brief meeting of the waters: Science and policy of the first environmental flow to the Colorado River Delta鈥 to the Conservation Biology Program, University of Minnesota, Twin Cities; February, 2016.