CREATING A STATEWIDE LANDSLIDE HAZARD DATABASE

The goal of the hazard zonation project is to identify, describe, and map unstable landforms in forested areas to mitigate against hazards posed from these landforms. The mapping will be accomplished by applying the watershed analysis mass wasting module methodology (modified for this purpose) to specific Watershed Administrative Units. These units are identified as those forested watersheds in the state that are not dominantly federal lands, not urban lands, and those that have not had a watershed analysis conducted. As a supporting document for this project, all available landslide inventories and mass wasting map units from watershed analysis were collected. Other inventories were also gathered from agencies that have been collecting this data outside the watershed analysis arena. Once the landslide inventories and mass wasting map units were collected, it was apparent that few authors used the watershed analysis standardized format for data collection. As such, a standard data architecture needed to be developed before these inventory and unit maps could be compiled. Geologists who had completed the mass wasting module and had other landslide inventory experience were interviewed to develop the data architecture for the landslide inventory and hazard zones. After the standard architectures were developed, the extant data could be compiled. At present, the compilation of the landslide inventory data is currently underway by the WA Department of Natural Resources Forest Practices Division. While the data is being compiled, several key tasks must occur: a) The identification of unmapped or undermapped watersheds that would need to be mapped in this project. b) The amendment of the mass wasting module to fit the needs of this project, including development and testing of protocols for field and photo data collection and GIS data input and update. c) Review and potential amendment of the hazard zone data architecture, d) Discussion and decision regarding the compilation of hazard zone units that were not collected under the watershed analysis methodology. e) Hiring and training of geotechnical staff to complete the assessments. f) Prioritization of mapping work to be done. Once the data is compiled and the groundwork for data collection is established, data collection can begin.