LINKING EXTREME CLIMATE EVENTS AND WATERSHED LAND USE TO THE ESTUARY HEALTH OF MORRO BAY, CA

Humans modify urban and agricultural landscapes within coastal watersheds, disrupting and driving sediment downstream to critical animal habitats in estuaries. Salt marsh accretion within the Morro Bay National Estuary on the central California coast has doubled since 1897, potentially driven by agricultural practices driven by climate change. To combat this accelerated accretion and human induced erosion, the United States Environmental Protection Agency (USEPA) approved a total maximum daily load (TMDL) of sediments in Morro Bay and its watershed tributaries, Los Osos and Chorro Creeks in 2004 (USEPA, 2004). At the same time, eelgrass (Zostera marina) populations within the estuary suffered an estimated 95% decline, decreasing from 344 acres to 13 acers in 2007 and 2017, respectively (MBNEP, 2024). This study will examine land cover patterns and evidence of climate forcing events (i.e. El Niño Southern Oscillation (ENSO)) within the Morro Bay Watershed to understand how changing land use during periods of climate extremes can correlate with estuary health. To gain a better understanding of anthropogenic erosion, we link three environmental interests: 1) lateral salt marsh accretion of the Morro Bay National Estuary, 2) agricultural land cover change within the Morro Bay Watershed using remote sensing techniques of satellite imagery, and 3) extreme climate events identified by pairing ENSO events with local climate data. This research is vital for the general public, as well as the scientific community, as it will aid in developing costal policy, best management practices, and guide coastal conservation efforts.