Yakima Integrated Plan logo
Yakima Basin Integrated Plan
Groundwater Research
Grant Information

The Effects of Channel Incision and Land Use on Surface-Water/Groundwater Interactions in the Teanaway River Basin, Washington, USA

Download

Date published: April 2022

Authors: Joseph Petralia, funded in part by the YBIP GWSC

Reference:

Petralia, Joseph. “The Effects of Channel Incision and Land Use on Surface-Water/Groundwater Interactions in the Teanaway River Basin, Washington, USA.” All Master’s Theses, 1780, Central Washington University, Spring 2022, https://digitalcommons.cwu.edu/etd/1780.

Abstract:

This study of the Teanaway Valley Family Farm, an 88-hectare parcel on the main-stem Teanaway River, provides hydrogeologic data that will inform restoration projects. Ten wells were installed within and slightly above the floodplain to determine seasonal variations in groundwater level, in part to investigate the mortality of a cottonwood grove near the Teanaway River. Well cuttings revealed that the upper third of the floodplain in this region is underlain by a thick clay deposit above the bedrock, which limits the extent of river water interaction and reduces the overall aquifer storage potential. In this study, groundwater level and temperature data from pressure transducers for a 15-month period for all ten wells is analyzed and compared to river elevations. This data showed that there were two distinct “pulses” of groundwater recharge, occurring during warm spells in January and February 2020. Water elevation within the alluvial aquifer then declines over a 4-month period towards baseflow conditions so that during the summer months, groundwater in the cottonwood grove was at least two meters below the surface. Thus, the cottonwood grove does not have access to groundwater during the dry summer months. Stable isotope analyses were performed on the groundwater, soil water, and river water in order to determine the extent of river water infiltration into the unconfined alluvial aquifer adjacent to the river. The stable isotope composition of the river and well water from the four wells closest to the stream were nearly identical, whereas groundwater from three wells further up the floodplain appears to be a mixture of river water and pre-existing groundwater. Thus, the river naturally supplies water to the cottonwood grove area throughout the year. However, the stream incision and pumping from upstream ponds for irrigation has resulted in a lower water table within the floodplain during the dry summer/early fall months. The cottonwoods likely survived the challenges of the stream incision with a supply of wa

Contact person/agency: Joseph Petralia

File Format: pdf

Associated Data:

  • none

Go Back