Using Stable Isotopes of Meteoric Water to Evaluate the Efficacy of Manmade Canals at Maintaining Lake Habitats for Salmon and Waterfowl

Author

Adrian Jimenez, Portland State UniversityFollow

Sponsor

Funded by the U.S. National Science Foundation Grant: REU Site: PSU Center for Climate and Aerosol Research, Award AGS-1659655.

First Advisor

John Bershaw

Date of Award

Spring 6-2024

Document Type

Thesis

Degree Name

Bachelor of Science (B.S.) in Geology and University Honors

Department

Geology

Language

English

Subjects

Limnology, Isotopes, Water, Restoration, Lake, Engineering

DOI

10.15760/honors.1512

Abstract

We investigated whether hydrologic restoration at Sturgeon Lake, Oregon, USA has sufficiently increased water flux and reduced stagnation, improving environmental conditions for juvenile salmon and waterfowl. This 19.2km² lake is a pivotal environmental feature in the area, providing a haven for salmon on the Columbia River before reaching the Pacific Ocean and winter habitat for hundreds of thousands of waterfowl and migratory birds on the Pacific Flyway. The Oregon Conservation Strategy names restoring natural hydrology to Sturgeon Lake as a key step toward conservation in this area. We use stable isotopes of water from the lake, surrounding water bodies, and precipitation to understand the restoration work's efficacy and whether further efforts are necessary to restore healthy habitats. Because of its importance to bird migration and salmon spawning, we focus on seasonal patterns in the hydrology of the lake. We determined that approximately 36.5% and 9.5% of water input was lost to evaporation during the summer and winter, respectively, after restoration. We estimate the residence time of water in the lake to average ~43.2 days during the study period. Based on these results, we determined that the lake habitat is being adequately maintained in the winter, when it is most valuable to local fauna, but that some stagnation and potential ecosystem degradation occurs in the summer. Neither juvenile salmonids nor migratory birds utilize the lake during the summer, therefore the restoration work is effective at maintaining habitat for these species, but further summer-focused work could be beneficial.

Comments

Other authors: John Bershaw, Mae Saslaw, Scott Gall, Emma Rahalski

Persistent Identifier

https://archives.pdx.edu/ds/psu/42111

Recommended Citation

Jimenez, Adrian, "Using Stable Isotopes of Meteoric Water to Evaluate the Efficacy of Manmade Canals at Maintaining Lake Habitats for Salmon and Waterfowl" (2024). University Honors Theses. Paper 1480.
https://doi.org/10.15760/honors.1512