Postdoctoral Fellowship: EAR-PF: Feedbacks Between Controls of Stream Dry-Down Responses at the Rain-Snow Transition

Kraft, Maggi A, Boise ID

Investigators

Abstract

Dr. Maggi Kraft has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out research and professional development activities under the mentorship of Dr. Sarah Godsey at Idaho State University. The western United States relies on snow for water resources. In the same region, the majority of streams fed by snowmelt and rain are non-perennial with streamflow disappearing for at least a portion of the year. Warming global temperatures are shifting the precipitation phase from snow to rain, but the impacts of shifting snowfall fraction in non-perennial streams are not clear. This research will merge concepts of snowmelt processes, vegetation dynamics, and soil properties across three watersheds spanning the rain-snow transition to understand how precipitation phase affects stream wetting and drying. These interactions are particularly important in controlling streamflow responses across the rain-snow transition where vegetation, snow, and soils are interrelated and sensitive to changing temperatures. While these concepts have been evaluated in a piecewise manner, they have not yet been integrated to allow us to accurately predict non-perennial streamflow response to changing snow inputs. This research will advance the science of non-perennial stream ecosystems and provide relevant information for managing natural resources. Additionally, this project will develop two education and outreach opportunities via developing and leading a workshop focused on the analysis of streamflow presence-absence data and mentoring an undergraduate student to develop, implement and present an interdisciplinary research project. Non-perennial streamflow response to shifts in snow represents a fundamental gap in our understanding of hydrologic behavior. Watersheds spanning the rain-snow transition, where precipitation shifts phase between snow and rain, provide an ideal location to study streamflow response to the shifting precipitation phase. Across the rain-snow transition feedbacks between vegetation, snow, and soil are interrelated thus, evaluation of coupled observations is needed to accurately predict streamflow response to changing snow water availability. However, there is a lack of integrated studies linking daily signals of snowmelt, transpiration, and soil moisture in non-perennial watersheds. The focus of this research is to study the response of non-perennial stream dry-down and wet-up to interactions between snow, rain, vegetation, and soils. This research will be carried out in three watersheds spanning the rain-snow transition in the semi-arid western U.S. using measurements of snow depth, sap flux, stream water presence-absence, soil moisture, and high-resolution satellite imagery. The satellite-derived and ground-based snowmelt, transpiration, and soil moisture observations will be compared to the annual and diel stream wet-dry cycle response. High-resolution soil depth maps will be created to evaluate how soil water capacity, snow storage, and vegetation modulate rain or snow water inputs and non-perennial streamflow. This research will advance the science of non-perennial stream ecosystems and provide relevant information for managing natural resources. This project is jointly funded by the Division of Earth Science Postdoctoral Fellowship Program and the Established Program to Stimulate Competitive Research (EPSCoR). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.