The purpose of the Timber Harvesting Plan (THP) Review Project is to provide technical information and advice about landslides, erosion, sedimentation and other geologic hazards to the California Department of Forestry and Fire Protection (CDF), other agencies, industries and the public that make land-use decisions on California's forested lands. CGS staff located in five northern California offices provide engineering geologic reviews of forest management documents under the following three projects: THP Enforcement Sacramento, THP Enforcement Santa Rosa, and THP Enforcement Eureka.
THP Review Sacramento
The THP Review Sacramento Project (located in the Sacramento and Redding offices) provides engineering geologic review of THPs in the Sierra Nevada and in Siskiyou, Shasta, eastern Trinity and Tehama counties. Staff also conduct statewide engineering geologic review of landslides and slope stability concerns contained in regional-scale forest management documents such as Sustained Yield Plans (SYP), Program Timberland Environmental Impact Reports (PTEIR), Habitat Conservation Plans (HCP), Option A's, Sensitive Watersheds, state and federal Forest Management Plans, and Total Maximum Daily Load (TMDL) reports. In addition, staff provide input regarding geology, slope stability, and erosion in the development of Pacific Lumber Company's HCP-required Watershed Assessments. Staff also digitize watersheds maps and develop accompanying GIS databases on geologic and landslide information.
Under contract with CDF, the THP Review Santa Rosa Project (located in the Santa Rosa and Willits offices) provides engineering geologic information and recommendations concerning slope stability, soil erosion and sedimentation problems that could result from proposed road construction and other timber harvesting activities primarily in Mendocino, Sonoma, Lake, Napa, San Mateo, Santa Cruz and Monterey counties. In addition, staff provide landslide mapping and other geologic review services in Soquel and Jackson Demonstration State Forests. Staff also serve on technical committees related to forest practices, post-fire slope and soil conditions, and development of new rules; participate in inspections associated with violations of the Forest Practice Act conduct landslide training classes for forest professionals; and provide expert witness testimony in court actions.
The THP Review Eureka Project (located in the Eureka office) ensures that geologic concerns in THPs submitted for Del Norte, Humboldt and Trinity counties are addressed and that landslide and mass wasting requirements under the Pacific Lumber Company HCP are implemented. In addition to THP review, staff review analyses of watersheds data regarding sediment sources, slope stability and fluvial geomorphology for Watershed Assessments in Pacific Lumber Company owned watersheds, provide technical advice in the development of site-specific prescriptions for each watershed, and provide ground verification of mapped landslides during the engineering geologic review of THPs.