Technical Advisory Group on the Santa Cruz Geologic Hazard Investigation

Shortly after the October 17, 1989 M 6.9 Loma Preita Earthquake a Technical Advisory Group (TAG) was created to evaluate whether building permits should be issued to residemnts in the Santa Cruz Mointains underlain by “anciuent landslides,” many of which partiaally reactivated during the quake. The group was established with $1.35 million in funding from the Federal Emergency Management Agency to provide “technical input” to FEMA, operating under the auspices of the Army Corps of Engineers San Francisco District. The effort was requested by Santa Cruz County, who noted that ovber $100 million worth of properties were at-risk for landslide related issues.

The group was originally comprised of: Brian Walls, geological engineer with the Corps of Engineers (manager); Gary B. Griggs, CEG, Professor of Geology at UC Santa Cruz; David K. Keefer (report editor), Ray C. Wilson, and Edwin L. Harp of the US Geological Survey, engineering geologist Gerald E. Weber, CEG of Weber & Associates, Corps of Engineers geologist Colin C. McAneny, geologist Paia Levine with the Santa Cruz County Planning Department, and engineering geologist Thomas E. Spittler, CEG with the California Division of Mines & Geology. The group met in closed sessions, which angered many of the Santa Cruz Mountains residents, who hired their own geologist to sit in on the board meetings for a time. Because of these political pressures, Brian Walls and Ray Wilson resigned from the group, and Walls’ role as the group’s manager was assumed by Arijs Rakstins of the Corps of Engineers.

In the fall of 1991 the advisory group co-authored a 405-page report titled “Geologic Hazards in the Summit Ridge Area of the Santa Cruz Mountains, Santa Cruz County, California, evaluated in response to the October 17, 1989, Loma Prieta Earthquake: Report of the Technical Advisory Group,” prepared for FEMA and published as U.S. Geological Survey Open File Report-91-618. Other contributors to this report included John M. Andersen, Mary Ellen Hynes, and H. M. Taylor of the Corps of Engineers WES in Vicksburg, MS, and Jeffrey M. Nolan of Weber and Associates.

Independent panel chaired Dr. Gerald E. Galloway Jr., PE of the University of Maryland, Dr. John J. Boland, PE, Johns Hopkins University, Dr. Raymond J. Burby, FAICP, of the University of North Carolina-Chapel Hill, Christopher B. Groves, GE, Shannon & Wilson Inc., St. Louis, MO, Susan Lien Longville, Water Resources Institute at Cal State San Bernardino, Dr. Lewis E. Link, Jr., University of Maryland, Dr. Jeffrey F. Mount, U. C. Davis, Dr. Jeff Opperman of The Nature Conservancy, Dr. Raymond B. Seed of U. C. Berkeley, George L. Sills, PE, U.S. Army Engineer Research and Development Center-Vicksburg, James J. Smyth, PE, Smyth Water Planning Solutions, Raleigh, NC, Ronald Stork of Friends of the River, and Edward A. Thomas, Esq., Association of State Floodplain Managers.

The panel was assisted by Joseph D. Countryman, PE of MBK Engineers in Sacramento, Peter C. Wijsman of MSC, The Netherlands Water Partnership in Rotterdam, Larry Larson, PE, CFM and Doug Plasencia, PE, CFM of the Association of State Floodplain Managers, Piet T.M. Dircke, Msc of the University of Rotterdam, and three people from PBS&J: Jennifer Marcy, CFM, Senior Scientist, Michael DePue, PE, CFM, D. WRE, Senior Program Manager, William Hinsley, Associate Vice President, Senior Project Director.

This group prepared a comprehensive report titled: A California Challenge-Flooding in the Central Valley, A Report to the Department of Water Resources, State of California, dated October 15, 2007. This report was intended to serve as the blueprint for the desired provision of flood protection for California’s Central Valley Region in the 21^st Century.

In 2008 an independent review board was named by the California Department of Water Resources to provide expert review of geotechnical policies and procedures with regard to safety, performance, state-of-practice, and economy. Members are Christopher B. Groves, GE of Shannon & Wilson (Chair), Prof. Raymond B. Seed of U.C. Berkeley, and George L. Sills, PE, retired from the U.S. Army Corps of Engineers ERDC-Vicksburg.