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Potential Future Land Loss of Small Islands of Puerto Rico and the United States Virgin Islands. Coastal Management Applications.
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Potential Future Land Loss of Small Islands of Puerto Rico and the United States Virgin Islands Coastal Management Applications
A side-looking airborne radar (SLAR) image clearly shows the physiography of the 150 x 50-km island of Puerto Rico. Several small rivers drain to the north, and the northern coastal lowlands are wide compared to the southern. Courtesy of Simulation Systems, Inc.
Coastal Compartment Management Plan Step 1: Delineate compartments Step 2: Risk assessment—evaluate hazards and vulnerability Step 3: Prioritize compartments based on natural and built environment Step 4: Develop a suite of potential mitigation alternatives Step 5: Develop final Coastal Compartment Management Plan for each compartment in cooperation with community interests (e.g., officials, planners, managers, property owners, business community)
CCMP Palo SecoSteps 1-4 finished Step 1: Delineate compartments Step 2: Risk assessment—evaluate hazards and vulnerability Step 3: Prioritize compartments based on natural and built environment [SINGLE COMPARTMENT—PALO SECO] Step 4: Develop a suite of potential mitigation alternatives Step 5: Develop final Coastal Compartment Management Plan for each compartment in cooperation with community interests (e.g., officials, planners, managers, property owners, business community) [NEXT PHASE]
Study Area Punta Salinas Isla de Cabras Palo Seco Old San Juan Ensenada de Boca Vieja San Juan Bay Levittown
Bacardi Rum Plant Power Plant (fuel oil) Río de Bayamón
Recreational, cultural, and historical site Lone access road is also main road through Palo Seco Erosion problem
We met with Palo Seco town planners and business leaders in May, 2009, to assess the problem.
Google Earth image showing location of photographs 5 4 6 3 7 2 1
Photo 2. No recreational beach. View out into Ensenada de Boca Vieja.
Photo 4. Some businesses are nearly buried in rock revetment.
Photo 5. San Juan Harbor, view north toward El Morro Fort, which is on the eastern side of the entrance to the harbor.
Photo 6. Río de Bayamón may be a source of replenishment sand. It empties into San Juan Bay.
Photo 3. There are some erosion problems along Río de Bayamón. The river water is being discharged from the Bacardi plant.
Recommendations (in increasing order of cost) 1. Do Nothing 2. Continue armoring 3. Beach replenishment 4. Seawall upgrade 5. Major seawall, boardwalk, Municipal plan
Do Nothing (Least Expensive) This is the cheapest solution, however, speaking long term, there are dire consequences, due to the constant erosion. An alternate solution must take place, because not taking action ultimately does not solve anything.
Continue to armor community with large rocks This recommendation is basically the strategy Palo Seco is doing now. As seen in the photos of the Palo Seco shoreline below. One of the situations occurring from this solution is the aesthetics. Dumping loads of rocks and concrete on the shoreline does not appeal to many citizens.
Beach replenishment The concept of beach replenishment works as a short term solution. Moving about 2 to 3 dump trucks of sand every two or so weeks might slow down the erosion process, this, however, can not be a permanent solution.
Seawall Upgrade Seawalls are never a good way to prevent erosion, due to the fact that they actually increase erosion in other areas, as shown in the photo from the USGS at Vero, Beach in Florida. If the seawall were built more sturdy and solid, then it would definitely act as a shield for vital infrastructure, such as the electricity plant.
Major seawall, boardwalk, Municipal plan (Most Expensive) Although this technique is very expensive, it can provide a long-term solution. With a sturdy seawall in place and a boardwalk to provide for the aesthetics, this concept is non-intrusive and does not involve having to tear down the road that connects Isla de Cabras to the main land.
East of San Juan, along the Boca de Cangrejos shoreline, is an example of a low-cost stabilization project with a bike trail.
The island of Vieques, off Puerto Rico’s east coast, used to be home to a U. S. Naval base and bombing range. Only the middle one-third of the island was public. The naval portions are now administered by the U. S. Fish and Wildlife Service. Villa Esperanza Along the southern shore of Vieques, the town of Villa Esperanza was suffering an erosion problem similar to Palo Seco in the late 1980’s. Their response was a seawall/boardwalk structure that was designed to not only protect the shorefront buildings but also to attract vacationers and locals to enjoy newly added amenities.
