Tuolumne Meadows Permanent River Gage Installation

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The purpose of this project is to install a permanent low-profile recording and transmitting (real-time) river gage on the Tuolumne River at Tioga Road Bridge in Tuolumne Meadows. The gage would largely replace temporary research instrumentation in place for the past 12 years and allow remote access to river stage, flow, and temperature via the internet. The gage would consist of a 10-foot long (2-inch diameter) stainless steel pipe mounted to the rock abutment facing of the bridge. An instrument box (approximately 12 " by 18" by 12") mounted to the top of the abutment or under the bridge decking would contain a datalogger, battery, and radio transmitter. The instrumentation box would be connected to water depth and temperature sensors secured at the bottom of the steel pipe. A 12" long antenna mounted to the top of the gage pipe would transmit gage data to the nearby California Department of Water Resources Tuolumne Meadows Snow Pillow site. This data would be transmitted via existing satellite communications infrastructure. The existing staff plate would remain and become part of the permanent installation. A 15-watt solar panel (18" x 12") would power the unit and be mounted either where it is currently or on top of the instrumentation box. Installation would consist of drilling four to six 3/8 inch holes into the rock facing to secure pipe mounting brackets. An additional four 3/8inch holes would be drilled into the top of the abutment to secure the instrumentation box. Total installation time would take 1-2 days.