Soil Sampling Grid Layout and Sample Depth Intervals Soil sampling will be conducted at the Trestle locations using a modified grid approach with sampling stations to be established at all grid nodes. Additional sampling stations will be placed based on localized features such as near trestle supports or at stream bank or stream sediment sampling locations. All sampling station locations will be Oak Grove Hydroelectric Project Water Pipeline Trestles- Final Sampling and Analysis Plan plotted on a site topographic map prepared for each trestle area and will be surveyed and staked prior to or subsequent to sampling activities. Except for the sampling already completed at the Canyon Creek Trestle (where 3-inch depth intervals were used), soil samples at all established sampling stations will be collected through 6-inch intervals to target the following depths: • 0 to 0.5 feet • 0.5 to 1.0 feet • 1 to 1.5 feet It is possible that refusal on hard cobble substrate may occur at sampling stations prior to achieving the full targeted sample interval depth. In such an instance, and assuming the cobble or other interference cannot be removed from the sampling location or bypassed at a new adjacent location, then the depth of sampling refusal and the actual sample interval for the sample that encountered refusal will be recorded in field sampling documentation.
