Table of Contents
| June to August 2024 Edition Evaluating Potential for Managed Aquifer Recharge on the Manastash Creek Alluvial Fan By Elif Myers – Graduate student at Central Washington University Located west of Ellensburg, Washington, Manastash Creek Alluvial fan is a developing region with rich agricultural roots. In recent years, changing irrigation practices and farmland diversion have affected subsurface water levels within shallow aquifers. With some wells low on water supply and others overflowing from neighboring irrigation, there is a need to characterize aquifers and the water within. Supported by The Yakima Basin Integrated Plan and Central Washington University Department of Geological Sciences, this research aims to provide an understanding of underlying lithologic and hydrologic properties of the Manastash Creek Alluvial Fan. Research methods will include the following: Site Characterization: Application of aerial imagery, LiDAR, soil maps, parcel layers, and field visit observations will result in a comprehensive map of the research site identifying hydrologic features, tectonic activity, soil classifications, and parcel boundaries. Subsurface analysis: Washington State Department of Ecology well log data will be used to create stratigraphic representations of underlying lithology and aquifer characteristics. Hydrologic analysis: Water samples collected from wells, creeks, rivers, springs, and canals will be geochemically analyzed to identify major ions and stable isotope ratios providing context for groundwater sources, mixing, and barriers to flow. Pressure transducers will be installed in two wells to track water level changes in fifteen-minute increments. Results from this study will support the Yakima Basin Integrated Plan Groundwater Committee in determining the potential for Managed Aquifer Recharge within the Manastash Creek Alluvial Fan. Suitability will be determined based on surface infiltration properties, seasonal groundwater levels, and residence time within shallow aquifers. Bio: Elif Myers is a current graduate student at Central Washington University, co-president of the AWRA-CWU Student Chapter, and a recipient of a 2024 AWRA-WA Fellowship Award. She is conducting thesis research through the Department of Geological Sciences at CWU. |