Antelope Creek Fish Passage Improvement Project Geotechnical Investigation

Antelope Creek Fish Passage Improvement Project Geotechnical Investigation

The proposed action is necessary to develop recommendations related to the design criteria for new fish screen and a retrofit to existing diversion dam. Results of the proposed action will include written recommendations for foundation support, retaining wall design, pipe trenching and backfill and other construction activities related to constructing the new fish screen, concrete headwall structures and siphon pipeline. It is anticipated that the proposed action will require construction of approx 4-6 boreholes, 10-40 ft deep using a truck mounted drill rig with a 6-8 in diameter hollow stem auger bit and/or a coring bit, depending on site conditions. The auger and sampling tube within it will be driven into the ground using a weighted dead-fall type hammer to collect subsurface geologic materials. The approx locations in which the borehole excavation locations include a 20-ft wide buffer from the dripline of existing elderberry adn oak trees within the project area. Borehole excavations will be completed by Dec 31, 2017. Once drilled, the boreholes will be filled with either grout or the original excavated cuttings. If the boreholes are filled with grout, the cuttings will be transported offsite. Once filled, the boreholes will be smooth graded to the original grade.

Tehama