El Portal Road Narrows Temporary River Gages Installation

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The purpose of this project is to determine the ordinary high water mark along a section of the El Portal Road. This effort will support the El Portal Road Reconstruction--Pohono Bridge to Big Oak Flat Intersection. The project involves placing three stream gages at points along the El Portal Road in the area commonly referred to as the "the Narrows". Gages will be equipped with electronic water level sensors and dataloggers. These sensors will be surveyed along with other river geometry already scheduled for survey.

The loggers will be installed inside a 1-foot long piece of 2-inch PVC pipe which will be bolted to existing rip-rap near the level of the river. In order to protect the gages from the full brunt of the flow velocity, they will, where possible, be concealed among large boulders (rip-rap). There will be no staff plates. A few rock bolts will be needed higher on the rip-rap (just below the road) from which to measure river level. The installations will remain in place through the construction phase.