The sources and fates of nutrients in the Deep Lake watershed

<p>This water quality survey determined the sources and fates of nutrients within the Deep Lake watershed located in Stevens County, WA. Deep Lake is a 191-acre exorheic lake found just below the Canadian border in northeast Washington state. It is situated at the bottom of a narrow valley with steep walls and is fed throughout the year by snowmelt from tributaries descending the mountains surrounding it. Above and to the north of the lake, the tributaries are utilized by cattle ranchers as a water source for livestock while a small community of homes surrounds the lake. Water samples, discharge, and metrics including pH, % dissolved oxygen, temperature, and conductivity were taken at 8 locations within the tributaries and outflow of the lake. The same metrics, in addition to water samples and profundal settling sediment samples were recorded in the lake at 4 locations. These data were used to determine the concentrations of nutrients moving through the various tributaries and being deposited in the lake, and how that impacted the trophic status of the lake. In addition, it was used to determine the proportion of nutrients that remain in the lake and what proportion leaves via the outflow. The results of this study showed an increase in nitrogen, phosphorus, and total suspended solids loading at study sites that received frequent cattle activity. It also helped to determine the presence of internal loading occurring in the anoxic hypolimnion that was present during the summer and late fall. These results allow for the development of better land use practices that could improve and protect water quality and health.</p>

Name thesis:degree_name

Master of Science (MS) in Biology

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biology

Year

2024

Author dc:creator

• Kenison, Kiler Austin

• Terrestrial and Aquatic Ecology
• Water Resource Management

Statement dc:rights

• Access is available to all users

Repository record dc:identifier

https://dc.ewu.edu/theses/920

OAI identifier oai:identifier

oai:dc.ewu.edu:theses-1919