What is Coastal Erosion?
The largest erosional impact to northwestern Florida is due to hurricanes. During severe storms, large waves are present, taking away sand from dunes and the berm (the main, flat part of the beach). Often times, the storms allow sand to collect in offshore sand bars or sweep it completely away from shore. Sand naturally gets deposited to the beach from sandbars via constructive waves. Constructive waves have a low wave height and a weak backwash. However, this depositional process can take several months and even years. Many cities and towns tend to invest in beach renourishment projects to rebuild their beaches.
What is Beach Nourishment?
Due to coastal erosion and rising sea levels, many beaches need to be replenished with sand. Dredging is a common practice that is used in many reclamation projects. Dredging usually removes sand from remote areas (uninhabited bays, islands, shoals, etc.) and artificially places it on the beach. Dredging can extend beaches, enlarge sandbars, and deepen waterways. Although there are some benefits to dredging, the effects are usually short-term. However, long-term effects such as dune habitat degradation could potentially accelerate coastal erosion. Coastal dunes are a natural buffer against storm erosion. Seagrass acts as a biological anchor, holding sand in place during windy periods. Dredging could ruin these ecosystems if the sand is placed directly on these dunes. In addition, during the dredging process, newly introduced sand can lead to sediment pollution, as the ocean can quickly erode it away as the sand has a different grain size than the natural sand. In recent years, many dredging companies have chosen to use sand with a similar composition to the existing beach sand to prevent this process from occurring.
2021-2022 Panama City-Laguna Beach Renourishment Project:
The federal government is sponsoring a renourishment project to armor Laguna Beach and Panama City Beach with 2.1 cubic yards of sand. The western portion of the project stretches from Pinnacle Port to the PCB City Pier (which includes the beach at the GZ). This project utilized a hopper dredge, a type of equipment that extracts and deposits a mixture of salt water and sand onto the beach. Once the water evaporates or flows back into the ocean, the remaining dried sand is moved around by bulldozers. The hopper dredge extracts sand from local areas (Shell Island and St. Andrews Bay). In recent history, PCB and Laguna Beach have been hit by severe hurricanes, most notably Hurricane Michael, Opal, and Ivan. The large storm surge from these hurricanes left the coast with a small amount of sand.
Logging Tasks:
- On your day of visit, what were the wave conditions? Does PCB seem to have constructive waves?
- Based on what you’ve learned in the description and your observations at the GZ, are depositional processes occurring at this beach?
- Dig several inches (at least 9 inches) into the sand. Are there any differences in sand grain size or coloring? Why do you think this is?
- As of June 2019, earthcaches now contain required photo logging tasks. Please provide a photo of yourself, your GPSr, or a personal item that proves that you have visited this site. Please post this in your log.
Sources:
https://www.visitpanamacitybeach.com/things-to-do/beaches/beach-renourishment/
https://explorebeaches.msi.ucsb.edu/beach-health/beach-nourishment
https://www.usdredge.com/learn/understanding-beach-reclamation-and-sand-dredging
| We have earned GSA's highest level: |
 |
