Mariposa Grove Distributed Soil Moisture And Snow Depth Sensor Installation

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The proposed project strives to quantify the amount and location of snow accumulation in the Mariposa Grove. This component consists of installing automatic snow depth and soil moisture measurement sites within the Mariposa Grove of Giant Sequoias to capture the variability of snow depth temporally and spatially. Sequoia groves are likely critically dependent on snow fall for water and climate warming is likely to have a substantial impact on the amount of snow that falls in the grove and consequentially the available soil moisture. The proposed installations will complement similar instrumentation along the Tioga Road. Coupled with computer modeling, this instrumentation with facilitate quantification of changes in snowfall patterns now and under estimated future climate conditions.

Proposed installations would consist of ten snow depth measurement 'nodes'. Each node would consist of a ten foot long 2-inch diameter aluminum pole anchored with a U-channel post pounded into the soil. A snow depth sensor would be mounted to the end of a three foot cross piece mounted to the top of each pole. Each pole would also contain a 10 x10 inch solar panel, a 10 x 10 x 5 inch datalogger box, a 7 x 7 x 6 inch white solar shield housing for temperature and humidity sensors, and associated conduit for wiring along the pole. After consideration of cultural and visual resources, the 10 nodes would be located to effectively sample different aspects and canopy cover within a discrete area of the grove.

At three of the nodes, a four foot deep by one and a half foot square hole would be dug to insert soil moisture sensors at depths of 4, 12, 24, and 36 inches. This would allow for tracking soil moisture response to snow melt and/or rainfall. All installations would complement an existing weather tower in the Upper Mariposa Grove. Installations would remain in place for up to ten years to collect data over a range of wet and dry years. The Division of Resources Management and Science will be responsible for instrumentation removal upon completion of the project.