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Managers, regulators and consultants who assess the extent and quality of episodic channels to support permitting or restoration.



Download the full conference agenda [.pdf].


UC Berkeley
California Dept of Fish & Game
Southern California Coastal Water Research Project


Matt Kondolf, UC Berkeley
Kris Vyverberg, CA DFG
Eric Stein, SCCWRP

Why This Conference?

Over 60% of California is arid or semi-arid, and episodic streams of arid regions behave like no other. Unlike rivers in humid climates or snowmelt regimes, the essential quality of rivers in dryland landscapes is the episodic nature of flow, sediment transport and channel change. Their geomorphic regime compares to life in the trenches during World War I: long periods of boredom, punctuated by brief moments of terror. Recognizing this distinctive nature is the first step towards developing and applying conservation and management strategies suited to episodic streams and their surrounding dryland landscapes.

Modification or elimination of episodic dryland streams, whether ephemeral or intermittent, can severely affect surrounding baseflows, groundwater recharge, and well-adapted biological communities. Responses to modification include invasion of exotic species over natives, concentrated flows, and increased flood intensities, sediment transport and erosion. Effects of such modifications may not manifest for years or even decades until the next flash flood; an inherent danger to episodic streams that must be recognized in planning and management ventures.

With the rapid urbanization of California's semi-arid landscapes and proposals to fast-track construction of large solar arrays on more than one million acres of California's desert landscape (part of the $37 billion Alternative Energy Investment Program funded by the Federal Economic Recovery and Stimulus Act), investments and interventions must harmonize with the specific physical, hydrologic and ecological processes of our climate and landscape in order to be sustainable, cost-effective and durable. This conference aims to develop the capacity to analyze environmental impacts and develop design guidance for modifications of our arid and semi-arid lands.

Scope of the Conference

This symposium explores the physical processes, ecological adaptations, and management challenges of episodic channels in California. While most of the examples presented are from the state’s drylands, the symposium also addresses such processes occurring on episodic streams in less-arid parts of Mediterranean-climate California (such as Napa Valley), notably alluvial fan channels, which share many characteristics of dryland streams. Important hydrologic and geomorphic attributes include:

  • Highly localized and extremely variable ephemeral and intermittent flow;
  • Flood magnitudes much larger (as a multiple of average flow) than humid-climate streams;
  • Strong interactions with shallow groundwater, notably rapid infiltration and decreasing flow downstream
  • Episodic movement of sediment, both leading to
  • Unsuitability for application of most hydraulic modeling and
  • Transient forms that confound determinations of active versus relict stream processes and conventional notions of stable and unstable channel form.

Most concepts and tools commonly used to evaluate stream behavior were developed on perennial streams in temperate regions, and their transfer to episodic channels can be problematic. For example, hydraulic models commonly assume that channel boundaries will remain relatively fixed, that bedload and suspended sediment will occur in substantially lesser amounts than the volume of water present, that water and sediment move along a channel at a more or less a steady rate, and that water losses along a channel may be considered insignificant – conditions rarely the norm in episodic channels. Thus, hydraulic models based on such characteristics have limited value as a predictive tool for the behavior and evolution of dryland streams over time.

A critical focus of the symposium is the development of resource management tools and strategies for arid stream systems. This gathering of agency and academic professionals aims to share know-how, identify challenges and collaborate on solution development.

Related Publications

Levick, L. et al, 2008. The Ecological and Hydrological Significance of Ephemeral and Intermittent Streams in Arid and Semi-Arid American Southwest, US EPA Office of Research and Development

Alluvial Fan Task Force, 2010. Alluvial Fan Fact Sheet.

Hecht, B., 1994. South of the Spotted Owl: Restoration strategies for episodic channels and riparian corridors in Central California Western Wetlands. In Kent, DM and Zentner, JJ (eds). Selected proceedings of the 1993 Conference of the Society of Wetland Scientists, 104-117.

Vyverberg, K., 2010. A Review of Stream Processes and Forms in Dryland Watersheds. California Department of Fish and Game


Aaron O. Allen is the Chief of the North Coast Branch in the Los Angeles District Regulatory Division of the Army Corps of Engineers. His 17-year Corps career has included assignments as a Senior Project Manager and as the Los Angeles District Technical Expert in Dryland Fluvial Geomorphology. The majority of his technical experience has been focused on jurisdictional issues in the arid Southwest, fluvial geomorphology, compensatory mitigation projects, and indirect/cumulative impact analysis. He completed his undergraduate degree at the University of California at Berkeley and MS and PhD at the University of California at Los Angeles. He is also a regular presenter at regional and national conferences on many issues related to wetland regulations.

Eric Berntsen is a staff environmental scientist within the State Water Resources Control Board’s Stormwater Unit. He is a registered professional hydrologist, certified floodplain manager, certified professional in erosion and sediment control, and a certified professional in storm water quality. Eric serves on the executive council of the California-Nevada Chapter of the Soil and Water Conservation Society, the board of the Laguna Creek Watershed Council, and the Sacramento Area Creeks Council. He holds a BA in environmental studies/geology from the University of Pennsylvania and an MS in water resources from the State University of New York. At the State Board, Eric provides technical support in the areas of hydromodification, erosion and sediment control, low impact development, and landscape design. Brian Bledsoe has 22 years of experience as an engineer and environmental scientist in the private and public sectors. He earned degrees from Georgia Tech, North Carolina State University, and Colorado State University. As Associate Professor and Borland Chair in Hydraulics in the Department of Civil and Environmental Engineering at Colorado State University, his research and teaching are focused on the interface between water resources engineering and river ecology, with an emphasis on linkages among land use, hydrologic processes, sedimentation, channel stability, and water quality. Prior to moving to Colorado in 1997, he served as Nonpoint Source Program Coordinator for the State of North Carolina. He is a licensed professional engineer in NC and CO and has authored over fifty publications related to stream and watershed processes, restoration and water quality

Derek B. Booth PhD PE PG is an internationally recognized expert on urban streams and stormwater, particularly the effects of runoff on channel form and function. His first peer-reviewed publication on the subject was in 1989; of his now more than 50 such journal articles and book chapters, more than half are on this topic. He worked for a decade in urban watershed management for King County, Washington, and as director of the Center for Urban Water Resources Management at the University of Washington. He is an Affiliate Full Professor at the University of Washington and a private consultant with Stillwater Sciences. He was a member of the recent National Academy of Science panel reviewing the nationwide NPDES stormwater permitting system.

Bill Christian is the Amargosa River Project Director for the California chapter of the Nature Conservancy. For the past 7 years, he has worked to acquire and protect ecologically important Mojave Desert lands, focusing particularly on aquatic and riparian systems. Prior to the Conservancy, Christian spent 30 years as an environmental lawyer, lobbyist, and project manager for the Atlantic Richfield Company, and lawyer for the State of Alaska and the US EPA. He co-teaches an annual environmental law and policy course at Claremont McKenna College.

Andy Collison’s background is in hydrology and geomorphology, with a particular emphasis on channel erosion and restoration issues. Formerly a geomorphology professor at University of London, England, he came to the US for a nine month sabbatical. That was nine years ago, and he is still has not left. After working at the USDA National Sedimentation Laboratory for two years he joined PWA in 2002, where he is now the senior geomorphologist. He led the channel vulnerability portion of the Contra Costa and San Diego Hydromodifcation Management Plans, and has developed instream mitigation for hydromodification in Los Angles County and the Bay Area.

Katherine Curtis is a research physical scientist at ERDC-CRREL's Remote Sensing and Geographic Information Systems (GIS) and Water Resources Branch in Hanover, NH. She received her bachelor's in geology from Colby College and master's in Earth Sciences from Dartmouth College, where her thesis focused on the impact of flow regulation on sediment transport competency. Katie's primary research since joining CRREL 1 1/2 years ago has been on identifying the Ordinary High Water Mark (OHWM) in western streams.

Jonathan Friedman is a plant ecologist and fluvial geomorphologist with the US Geological Survey in Boulder, Colorado. He received a BS from MIT, an MS from the University of Wisconsin-Madison and a PhD from the University of Colorado-Boulder. His research addresses interactions among streamflow, channel change and riparian vegetation across the inland western US with emphasis on floods, erosion and invasive plants.

Barry Hecht is senior geomorphologist and principal at Balance Hydrologics, Berkeley, which conducts hydrologic and geomorphic studies of watershed, channel, groundwater, and wetland dynamics in California and elsewhere, often in support of ecological restoration programs. Mr. Hecht is recognized as an authority on Mediterranean- climate river channels in the California Coast, stream-groundwater interactions, and ecological implications of human-induced changes in these episodic systems.

Deborah Hillyard is a staff environmental scientist with the California Department of Fish and Game, where she is the lead for a number of large scale, long-range conservation planning efforts on the Central Coast of California. Deb's background is in biology and rangeland management, with a particular interest in arid ecosystems, their restoration and management. She has planned and conducted assessment, management and monitoring in diverse ecosystems, including grasslands and shrublands of the Carrizo Plain, dunes and riparian systems in the Anza-Borrego Desert, maritime chaparral of the Central Coast, and coastal sage scrub of the Orange Coast, as well as a number of rare plant inventory, restoration and enhancement projects. Deb approaches her work from the perspective of a community ecologist, with a special affinity for rare natural communities.

Todd Keeler-Wolf is the Senior Vegetation Ecologist at the California Department of Fish and Game and lead’s their Vegetation Classification and Mapping Program. Todd has studied and written about vegetation of California for over 30 years and has been involved with sampling, classification, and fine-scale mapping of desert wash and riparian vegetation throughout the state. He is a principle author of the recently published second edition of A Manual of California Vegetation.

G. Mathias (Matt) Kondolf is a fluvial geomorphologist and environmental planner, specializing in environmental river management and restoration, especially Mediterranean-climate and other episodic rivers. As Professor of Environmental Planning at the University of California, Berkeley, he teaches courses in hydrology, river restoration, environmental science, and Mediterranean-climate rivers, along with shortcourses on river restoration taught in the Sierra Nevada of California and in the Rhone Valley of France. He is currently the Clarke Scholar at the Institute for Water Resources of the US Army Corps of Engineers in Washington.

Jeremy Lancaster is an engineering geologist with the California Geological Survey (Los Angeles), and serves as a technical specialist on flooding and debris flow processes as related to the geomorphology of alluvial fan systems. Recently he served as a technical consultant on the California Alluvial Fan Task Force, and assisted in developing chapters and appendices for the document titled, "The Integrated Approach For Sustainable Development On Alluvial Fans." Mr. Lancaster has published several abstracts on the topic of assessing alluvial fan flood hazards using surficial geologic maps coupled with engineering geologic investigations, and currently has three publications in press/preparation on the same topic.

Lainie Levick is a senior research specialist with the University of Arizona, and works at the USDA-ARS Southwest Watershed Research Center in Tucson, Arizona. She conducts watershed-based research and hydrologic modeling in arid and semi-arid systems in the Southwestern US. She was the lead author on the report "The Ecological and Hydrological Significance of Ephemeral and Intermittent Streams in the Arid and Semi-Arid American Southwest", which was funded by the EPA Region 9 to support their Clean Water Act jurisdictional analyses in the southwest. Currently she is working on a project to evaluate and classify ephemeral and intermittent stream systems on Department of Defense lands in the southwest region.

Laurel Marcus is a restoration ecologist and the executive director of the non-profit California Land Stewardship Institute in Napa. Laurel has worked extensively in the watersheds of northern and central California. Ms Marcus is the author of the Fish Friendly Farming (FFF) Environmental Certification Program. The FFF program uses collaboration and incentives for recovery of listed salmonid species and water quality improvements on private agricultural and rangeland in 10 watersheds in northern California and the Sierra foothills. As part of implementing stream restoration projects in these areas she has recently focused on alluvial fans and the unique challenge they pose to salmonid migration and native plant revegetation.

Sophie Parker is an Ecoregional Ecologist with The Nature Conservancy and provides science leadership to projects in the south coast and deserts of California. She has worked to ensure the protection of lands and waters along the Amargosa River and in the Coachella Valley, and is one of the authors of the Conservancy's 2010 Mojave Ecoregional Assessment. This document includes science-based information about conservation values, threats, and opportunities within the Mojave Desert that may be used to help inform future conservation and development decisions.

Ed Pert is the Regional Manager for the California Department of Fish and Game’s South Coast Region. Prior to his current appointment, Ed was the Project Manager for the Department’s Lake Davis Pike Eradication Project. Ed was also the Chief of Fisheries Programs Branch after coming to the Dept as a Fisheries Science Advisor to the Director back in late 2000. Ed was an Assistant Professor in Fisheries at the University of Arkansas at Pine Bluff. When he was actually conducting research his work focused on fisheries, primarily stream ecosystems.

Chris Solek is a biologist specializing in wetland and riverine assessment and monitoring. He received his B.S. in Wildlife Biology from U.C. Davis in 1992, a M.S. in Biological Sciences from California State Polytechnic University Pomona in 2002, and a Ph.D. in Environmental Science, Policy, and Management from U.C. Berkeley in 2008. He joined SCCWRP in April 2007 and is currently involved with developing and implementing monitoring/assessment programs for southern California wetlands. His current interests include the development of rapid assessment methodologies for arid land streams.

Tom Spittler is a senior engineering geologist with the California Geological Survey. In addition to working on geologic hazards associated with timber harvesting and other impacts in northern California, he works on geologic hazard assessments throughout the state, including those related to post-fire debris flow potential. He chaired an Association of Environmental and Engineering Geologists symposium on watershed restoration, has been on numerous California and Federal Emergency Management Agency technical committees evaluating wildfire and earthquake hazards, and was recently a technical consultant to the California Alluvial Fan Task Force where he contributed to three chapters on hazard and resource evaluations of alluvial fans.

Eric Stein is currently a principal scientist at the Southern California Coastal Water Research Project (SCCWRP), where he is head of the Biology Department. Dr. Stein oversees a variety of projects related to in-stream and coastal water quality, bioassessment, hydromodification, watershed modeling, and assessment of wetlands and other aquatic resources. His research focuses on effects of human activities on the condition of aquatic ecosystems, and on developing tools to better assess and manage those effects. He is one of the principal authors of the California Rapid Assessment Method (CRAM) and participates in many State and Federal workgroups on approaches to ecosystem assessment. Prior to joining SCCWRP, Dr. Stein spent six years as a Senior Project Manager with the Regulatory Branch of the Los Angeles District Corps of Engineers, and four years with a private consulting firm.

Kris Vyverberg is a senior engineering geologist with the California Department of Fish and Game, in which capacity she provides geomorphic and geotechnical expertise to Department staff and other State and Federal resource management agencies with whom she works to protect and restore the waters of the state. She is the principal technical consultant to Department's Lake and Stream Alteration Program on stream delineation issues, the geological and geomorphic considerations of watershed management and restoration projects, and the environmental compatibility of projects in the stream corridor.


Download a printable file [.pdf] of the full conference agenda.

Monday, November 8
Introduction and Workshop GoalsEric Stein
WelcomeEd Pert
Keynote: Physical and ecological processes in episodic channelsJonathan Friedman
Episodic channel hydrology:
Long periods of boredom, brief moments of terror
Matt Kondolf
Episodic river channel formDerek Booth
Sediment supply and the upland stream connectionBrian Bledsoe
Alluvial fans: unique forms and stream processJeremy Lancaster
Ecological & hydrological significance
of episodic streams
Lainie Levick
Development pressure of the dryland environment:
Ecological implications
Sophie Parker
South of the Spotted Owl:
Recurrence, recharge, restoration and resilience
Barry Hecht
Intermittent alluvial fan channels
in the Northern California wine country
Laurel Marcus
Optional Dinner or Networking Mixer
Tuesday, November 9
Development pressure on the dryland environment:
Regulatory and policy implications
Bill Christian
Implications of urbanization on alluvial fansTom Spittler
Large-scale renewable energy project developmentAndy Collison
Recognition of conservation & management challenges:
A first step
Kris Vyverberg
Mapping versus hydrologic modeling
of episodic channels on alluvial fans
Jeremy Lancaster
Are you in or out?
Challenges of identification and mapping
Katherine Curtis
Mapping vegetation defined and controlled
by fluvial processes
Todd Keeler-Wolf
What does it all mean?
Challenges of assessing condition
Eric Stein
12:30pBREAK OUT GROUPS (Boxed Lunch)
Physical Sciences Groups:
Recommendations for mapping & assessment
Biological Sciences Groups:
Recommendations for mapping & assessment
Summaries, Discussion, Conclusion
3:30pWRAP UP
Conclusions and Next Steps
Wednesday, November 10: Optional Field Trip
Cucamonga Fan complex
East Etiwanda Canyon, North Etiwanda Preserve
Lunch in the field, San Bernardino County