Hydroclimatic variability is an increasingly important aspect of water supply planning in arid and semi-arid regions of the United States and the world. Our understanding of past processes at relevant timescales (i.e. decadal to centennial) is often derived from high resolution palaeorecords such as tree rings. This research project will use tree-ring records to quantify wet and dry episodes within the Walker River watershed in western Nevada/eastern California. Along with the collection of long tree-ring chronologies that will stretch from the present back over 1000 years, this project will establish baseline conditions at multiple study sites with respect to climate and ecology. To capture tree-ring responses to individual hydroclimatic variables, such as summertime temperatures and wintertime precipitation, the researchers will target four tree species across a range of elevations as well as multiple topographic aspects. Baseline ecological surveys will be conducted at each study site to allow for comparison of conditions among a wide range of other surveyed locations across the Great Basin region. The researchers will use in-situ, free-air temperature sensors to better interpret microsite conditions relative to modeled and regional climate data. A climate monitoring station will be installed at high elevation in an isolated portion of the watershed, which will capture not only temperature and precipitation, but also solar radiation, wind patterns, and soil conditions. Both the ecological and sensory data will aid interpretation of palaeoclimate records, as existing data for most of the conifer zones in the watershed are limited to modeling products. A primary goal of this project is to reconstruct seasonal climate variables which would serve as inputs to water balance modeling over the last 1200 years, a time period which has seen tremendous variability based on previous tree-ring and lake sediment studies. Evaluation of watershed behavior during past time periods that exceed the envelope of our modern observations will aid water managers and users in decision making and planning as we move into an uncertain future. Records of past processes show how landscapes respond to variations in climatic and energy input, and regardless of the cause of future changes in conditions, it is critical to understand watershed dynamics in arid and semi-arid environments.
This research approach will bolster knowledge in tree-ring science, increase our understanding of climatic variability at the watershed scale, and clarify relationships between tree-ring records and water budgets. Reconstruction results from the project will be of immediate use to scientists, water managers, and water users within the Walker Basin and adjacent watersheds. Climatic and ecological data acquired as a result of the project's surveys and installations will be available to a wide range of public users, with sensor data provided in real-time. By bringing together Federal, University, and Community College researchers, this project provides a unique opportunity for collaboration and outreach across diverse levels. Educational opportunities will be provided to graduate, undergraduate, and Community College students, who will be able to participate in field and laboratory work as well as scientific conferences.
