Coastal Restoration in the Oceanside Littoral Cell Essay
440 Words2 Pages
Introduction to Coastal Restoration
Assessing Coastal Restoration Efforts
Coastal Restoration Issues in the Oceanside Littoral Cell
Southern California consists of beautiful sandy beaches, coastal bluffs and wetlands. The Oceanside Littoral Cell is a fifty mile stretch of California’s coast that runs from Dana Point south to La Jolla. This area is characterized by soft bluffs and sandy beaches. The coastal bluffs are seaward edges of marine terraces uplifted from the ocean floor by tectonic activity and shaped by ocean waves and currents. The erosion of these bluffs supply sand-sized sediment to beaches. It was thought, previously, that the majority of the sediment supply, some estimates as high as 90%, was provided by river discharge in Central and Southern California. However, new mineralogical studies suggest that as much as 60% of the sediment on Southern California’s beaches comes from the erosion, transportation, and deposition of coastal bluff material.
The bluffs are composed of sedimentary rocks such as shale and sandstone, which consist of grains of quartz, feldspars and micas. A type of clear quartz grains was found on coastal bluffs, whereas, river sediments and dredge material from off-shore collection sites were found to contain predominantly frosted quartz sand grains. On top of the sedimentary layers there are deposits of soft alluvial soil with sand and gravel laid down by ancient rivers and streams. These soft alluvial sediments are extremely vulnerable to the erosive power of waves. In fact, landslides and bluff retreat are a part of the natural coastal processes in Southern California. In recent decades, heavy development of the coast has increased rates of coastal erosion through the introduction of drainpipes, septic tanks and lawn irrigation. Unfortunately, development has occurred all the way to the edge of the bluffs, which are