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16: California Coastline

Last updated

Mar 27, 2025
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- 15.7: Detailed Figure and Video Descriptions
- 16.1: Coastal Processes

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Introduction to California Coastlines

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.

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.

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. Moreover, evidence suggests that climate change is creating ever larger waves along the California coast, contributing to accelerated erosion.

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, the 1976 California Coastal Act is today 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.

Closeup of a surfer riding a breaking wave — Figure $\PageIndex{1}$ : The endemic California surfer. "Surf's up" by Steven Newton is licensed under CC BY-NC 4.0. Access a detailed description.

Learning Objectives

At the end of this chapter, you should be able to:

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.
Know 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.

16.1: Coastal Processes
This page discusses California's dynamic coastlines shaped by tectonic uplift and erosion, resulting in emergent shorelines. Waves, affected by wind and shallow waters, cause erosion and coastal feature formation, influenced by the Coriolis effect. Upwelling processes, boosted by the Coriolis effect and Ekman transport, bring nutrient-rich waters to the surface, sustaining marine ecosystems but are threatened by climate change and events like El Niño.
16.2: California Coastline Anatomy
This page discusses California's coastline, characterized by landforms shaped by differential erosion, tectonic uplift, and sea-level rise. It highlights features such as headlands, sea caves, and arches that evolve into sea stacks, creating areas conducive to sand accumulation and development. Wave action contributes to wave-cut platforms and marine terraces, which may contain fossil sea stacks, indicating historical geological activity.
16.3: California Coastal Hazards
This page discusses California's coastal hazards, emphasizing that shark attacks are rare, while rip currents are responsible for 80% of beach rescues. Tsunamis and coastal erosion also pose significant threats, with poor land use exacerbating these issues. In Pacifica, severe erosion led to the condemnation and demolition of homes along Esplanade Ave, resulting in evacuations of low-income residents.
16.4: Human Alteration and Mitigation
Steinbeck once said that everything that comes out of a human mouth is poison; likewise, everything humans alter at the coastline just creates more problems. Build a seawall to protect your property? The beach erodes away. Build a breakwater to calm the waves? The beach grows out to the breakwater at the expense of beaches on either side. There is no way to win when human alter coastlines.
16.5: Coastal Access
Beaches are great for recreation--but what if you cannot get to them? California allegedly has good legislation guaranteeing residents the right to go to beaches, but in reality the situation in quite different, especially when race is involved. Private interests routinely violate access laws without consequence. Shocking spoiler alert: money always wins.
16.6: The Edge of California
This page discusses California's coastline, highlighting its significance and the challenges of limited access despite legal protections. Coastal development too close to the shore leads to inadequate protective measures, increasing erosion risks for properties and beachgoers. Nonetheless, the coastline's natural beauty and geological changes enhance its value and appreciation.
16.7: Chapter Summary
A summary of the California Coastline chapter.
16.8: Detailed Figure Descriptions
Descriptions of complex images within this chapter, as well as additional guidance for users who have difficulty seeing and interpreting images.

Thumbnail: The endemic California surfer. "Surf's up" by Steven Newton is licensed under CC BY-NC 4.0.

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

Introduction to California Coastlines

Learning Objectives

References

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