Tuolumne Meadows Hydrologic Alterations Impacts Study

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The purpose of this project is to analyze the surface and ground water levels and flows, soils and vegetation to produce a preliminary summary of impacts to Tuolumne Meadows. This study is being conducted in support of the Tuolumne Wild and Scenic River and the Tuolumne Meadows planning processes. The entire meadow area will be studied with particular emphasis on impacts to hydrology due to: 1) the Tioga Road, 2) the old road through the middle of the meadow and other dirt roads, such as that out to Parson's Lodge, 3) the bridge and culverts, and 4) water diversions from the Dana Fork.
Specific tasks include mapping surface water diversions, installation of 50-100 hand-augered monitoring wells along 5 transects of the meadow, and installation of staff gages and water level loggers in the Tuolumne River (see attached site map). In addition, depth of meadow sediments will be determined using ground penetrating radar. Determination of the age structure of Lodgepole pines encroaching on the meadow will be conducted in concert with the ongoing Lodgepole pine removal project. Up to 100 of the removed trees or remaining stumps will be sampled. Additionally, a climate history of the area will be created through increment boring of 200 older Lodgepole pines in the areas surrounding the meadows including in Wilderness. Maps of soil type and general vegetation type will be prepared as well.
The assembled data will be used to prepare a 2-dimensional conceptual and numerical model of groundwater flow. This model will allow the researchers to assess impacts of existing infrastructure on hydrologic processes and to make recommendations for future monitoring and restoration.
This project is currently funded as a 1-year project. However, wells and staff gages installed as a part of this project would be left in place for up to 4 additional years in order to monitor interannual variability in hydrology. This would allow further refinement of the conceptual and numerical groundwater models for the area.