Risk Analysis and ArcGIS Schematics - California Delta Levees
Track: Disaster Management and Emergency Response
Author(s): Dave Hansen

The Sacramento - San Joaquin Delta is defined by waterways confined by levees. Over 1,000 miles of levees were constructed for wetland conversion to agriculture in the late 1800's. Exposure of the rich organic soils has resulted in substantial land subsidence. There have been over 160 levee failures since 1900. The levee system is at increasing risk from sea level rise or seismic activity. Information about the levees includes failure history, elevation, and materials. Associated information includes geomorphology, soils, and amount of subsidence. Levees consist of individual networks surrounding islands. Many of these island networks are in close proximity separated by narrow sloughs. These are supporting levee networks. ArcGIS is used to integrate this information for risk analysis, and Arc Schematics is used for display of related supporting levee networks.

Dave Hansen
U.S. Bureau of Reclamation
2800 Cottage Way
Sacramento , California 95825
United States
Phone: 916-978-5268
Fax: 916-978-5290
E-mail: dhansen@mp.usbr.gov