Date of Award

8-2024

Document Type

Thesis

Degree Name

Master of Arts in Interdisciplinary Studies

Department

Interdisciplinary Studies

First Reader/Committee Chair

Alford, Jennifer

Abstract

Headwater streams play a significant role in overall watershed condition. These streams are critical freshwater resources and are imperative for human and ecosystem health. Seasonal variability in climate patterns is becoming increasingly more common as the effects of climate change are studied. The phenomenon known as “weather whiplash,” prolonged periods of drought followed by a sudden increase in precipitation, creates additional challenges for human and ecosystem conditions. Factors adversely impacting headwater streams include climate change, drought, wildfires, and human influence. While climate change continues to be studied, little is known about how weather whiplash patterns affect headwater streams in Southern California. This study focuses on four streams in the San Bernardino Mountains: Deep Creek, Little Bear Creek, Hooks Creek, and Orchard Creek, all headwater streams of the Mojave Watershed. Each stream exhibits a unique flow pattern that navigates through various landscapes with diverse land use and cover conditions. To better comprehend these intense shifts in climate, water samples were collected for each stream at least once a month for the hydrological years 2019-2020 and 2020-2021. Water quality parameters included stream flow rate, stream temperature (c), conductivity, dissolved oxygen (DO), pH, turbidity, ammonium (NH4+), nitrate (NO3-), total coliform (TC), E. coli, and enterococcus. Water data was analyzed as a percentage of not meeting regulatory requirements. Monthly precipitation and atmospheric temperature were also assessed to examine any relationship between climate and stream health. The NLCD was applied to stream sites to explore how land use types potentially affect water quality. Findings found that nutrients had the highest regular exceedances throughout the hydrological year. After precipitation events, the limited bacteria samples collected had high exceedance rates and were primarily concentrated in catchments with higher development concentrations. Furthermore, examining current watershed management practices allowed for assessing possible ways to manage headwater streams better.

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