16: California Coastline
- Page ID
- 20350
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- Describe the typical features and processes observed along the California coastline.
- Assess hazards associated with California’s coastline, including rip currents, erosion, and tsunamis.
- Analyze how shoreline structures, such as breakwaters and seawalls, affect the coast.
- Understand the legal issues affecting access to the coast, as part of the California Coastal Act of 1976, and frequent efforts to subvert and ignore this legislation.
Think of the idea of California, and amid palm trees and movie stars and Yosemite, you probably will picture the iconic image of shirtless surfers plying Pacific waters. The coastline of California is fundamentally part of the California experience. Whether through surfing or sunbathing or walking, or enjoying one of the many dog-friendly off-leash areas, where sloppy-tongued hounds frolic in the sun and air of a mongrel beach, the coasts are part of what it means to live in California. About 80% of California residents live within an hour’s drive of a beach (Shyong 2021).
And yet, few California residents appreciate the complex geologic processes that sculpt and create our rugged occidental boundary. Nor do many residents or visitors know the major hazard lurking just offshore–not sharks, which very rarely interact with the humans with whom they share the waters, but rip currents, which are fast movements of water that can quickly drag hapless beach swimmers far from shore. Rip currents cause the majority of beach rescues and contribute to an annual rate of 1.1 drowning deaths per 100,000 California residents (CDC 2023).
With California’s majestic Pacific sunsets, people yearn to own a home with an ocean-view, as close to the coastline as possible. However, many of these homes have simply been built too close to the shore, with little consideration for how quickly an eroding coast can retreat. El Niño Southern Oscillation (ENSO) warm events, known as El Niño, can collapse meters of shoreline in a single storm. Efforts to mitigate losses of homes by reinforcing shorelines with concrete, boulders, or other structures succeed primarily as vain demonstrations of hubris, often exacerbating the problem they attempt to solve. Climate change and rising ocean levels further contribute to the loss of shoreline; a 2023 USGS study estimated that by the year 2100, some areas of California will lose as much as 70% of the existing shoreline (Gammon 2023). Moreover, evidence suggests that climate change is creating ever larger waves along the California coast, contributing to accelerated erosion (Rott 2023).
The California Constitution (Article 10, § 4) guarantees public access to beaches, and while many enjoy California’s sandy beaches and the recreational opportunities, public access to the shoreline has eroded like shifting sands. A seemingly strong piece of legislation, today the 1976 California Coastal Act is routinely violated without serious consequence by those who carve out private areas on public beaches and prevent would-be beach visitors from accessing shorelines.
This chapter explores these connections between geologic processes, such as plate tectonics and erosion, with humans and our interactions with the vast interface of the California coast.
- 16.2: Coastal Processes
- The dynamic nature of California's coast is shaped by relentless tectonic uplift, forcing raw and rocky shorelines against the powerful erosive force of waves. Wave mechanics, influenced by factors like wind, wave depth, and the Coriolis effect, induce phenomena such as wave refraction, shaping distinctive features like arches and sea stacks, while upwelling of cold, nutrient-rich waters dictates the region's ecosystem and even impacts marine life and fishing industries.
References
- Shyong, F. (2021, July 9). The beach is there for all of us — We just have to get there. Los Angeles Times. https://www.latimes.com/california/story/2021-07-09/beach-restrictions-race
- Centers for Disease Control (2023, June 12). Drowning Data. Retrieved October 3, 2023, from https://www.cdc.gov/drowning/data/index.html
- Gammon, K. (2023, May 27). Up to 70% of California beaches could disappear by end of the century. The Guardian. https://www.theguardian.com/us-news/2023/may/27/california-beaches-erosion-2100-study
- Rott, N. (2023, August 1). Surf's up! Wave heights increase on California's coast as the climate warms. Retrieved October 5, 2023, from https://www.npr.org/2023/08/01/1191216362/surfs-up-wave-heights-increase-on-californias-coasts-as-climate-warms