State of the Beach/State Reports/PR/Shoreline Structures
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The following discussion appears to the 2009 Puerto Rico CZM Program document:
In addition to natural causes, human activities have become a coastal erosion risk factor. This process has been aggravated by the proliferation of rigid structures along the coast in a highly mobile and changing environment. Other engineered rigid structures located on the coasts are presented as measures to protect property – like embankments and breakwaters – have the effect of accelerating the process of coastal erosion, in addition to high costs. (bolding added)
Activities which occur in watersheds’ upper parts also contribute to the processes of coastal erosion, changing the sediment supply reaching them. For example, when damming a river, sand is trapped behind the gates and starts settling, as has occurred in the La Plata and Carraízo Dams. While downstream, on route to the sea, the river picks up materials such as clay and silt. This causes less sand to reach the mouth of the rivers and beaches and, instead, the sand reaching the coast is thinner and prone to be removed more rapidly out to sea by wave action (Bush et al., 1995). These actions hinder the natural erosion process – necessary for some of the beaches that do not have coral reefs – because the sediments contribute a part of the materials needed to keep it stable.
Other actions exacerbate the erosion process, among which are: the illegal extraction of sand from river mouths, dunes and beaches; agricultural practices without proper controls; the paving and excessive urbanization and the removal of mangroves. These actions increase the amount of sediment reaching coastal waters, destroying the protective reef offshore. Although these situations represent physical and economic damage, no quantitative estimates for Puerto Rico have been inventoried.
Different types of measures can be taken to address the problem of coastal erosion. Some include: (1) protection of natural systems such as mangroves and coral reefs, which protect the coast and slow erosion; (2) redirect development outside the erosion hazard areas; (3) monitor compliance with the statutes governing the activities that can accelerate erosion, like sand extraction; (4) feeding the beaches; and (5) the construction of structures at an angle, rip raps or jacks which allow energy dissipation.
The OPP-PRLUP, establishes policy related to urban development. Objective 1.02 points to the need to "Prevent and discourage urban sprawl and the development of isolated urban centers using as criteria ... that the land where the project is located not be ... susceptible to significant erosion, landslides, and/or environmentally critical." (See policies under Objective 1.02.)
Implementing the Policy
The "Regulation for Use, Surveillance, Conservation, and Management of the Territorial Waters and Submerged Lands and the Maritime Zone", supra, states that every application for granting an authorization or concession on public property will be done by assessment of the likely impact, including cumulative impact, of the proposed activity on the public interest. To determine the suitability of uses, the regulation states that it must evaluate several factors, including erosion. This regulation also identifies areas with severe problems of erosion among the sites unsuitable for authorizations or concessions.
The "Regulations for the Extraction, Excavation, Removal and Dredging of Earth Crust Components", supra, states that a permit from the Secretary of the DNER is also required for removing material from the Earth's crust for commercial purposes. Among its evaluation criteria, this regulation states that the effects of the proposed activity on erosion of the maritime zone have to be considered when evaluating a permit application.
Moreover, the PRPB’s Coastal Zone Unit is in charge of the Federal Consistency Procedure with the PRCZMP, which seeks, among other things, to prevent inappropriate development in areas subject to coastal erosion. Also, the PRPB, empowered by the "Special Flood Hazard Areas Regulation", supra, has the power to restrict or prohibit developments which have the potential to increase flood waters or speeds resulting in increased erosion. This agency also has other laws and regulations which indirectly work with the erosion problem. RPA, meanwhile, has the responsibility of ensuring that no building on the Island is constructed, altered, eliminated, or transferred, nor any land developed or altered, unless the action has been approved by the agency in compliance with planning laws and regulations.
Moreover, in 1982 the CBRA law was passed, which is intended to discourage development in vulnerable and high risk coastal areas designated as coastal barriers, particularly those conducted with federal funds.
Areas considered as coastal barriers, being composed mainly of consolidated sediments, are highly unstable for construction and are susceptible to erosion. These form the first line of defense against the winds and tides caused by weather events and may consist of mangroves, sand bars or islets and cays.
Through the CBRA, undeveloped areas are designated to serve as protection against high winds and wave energy, in order to protect life and property from hurricane ravages, as well as the conservation of natural areas. Currently, in Puerto Rico there are 8,431 ha declared as coastal barriers (Zinn, 2003). These are located primarily in the Southwestern portion and Northeast portion of the Island.
Another measure to discourage development in areas designated as coastal barriers is their ineligibility for flood insurance through NFIP. Insurance is only available if the structure was built or the development was approved prior to the approval of this law. However, insurance will not be renewed if an existing structure is substantially rehabilitated or if it is deteriorated.
According to the report "State Coastal Program Effectiveness in Protecting Natural Beaches, Dunes, Bluffs, and Rock Shores" (T. Bernd-Cohen and M. Gordon), Coastal Management 27:187-217, 1999, permits for shoreline stabilization in Puerto Rico are administered at the local or county level.
Information on the extent of shoreline armoring in Puerto Rico was not readily available.
Some information regarding coastal armoring and Puerto Rico’s shorelines is presented on the Website of the Rincón chapter of Surfrider Foundation.
The Fiscal Year 2017 Civil Works Budget for the U.S. Army Corps of Engineers provides $4.62 billion in gross discretionary funding for the Civil Works program. This budget lists proposed projects and the associated budget justification by state.
Perception of Effectiveness
Sand replacement at tourist beaches and resort complexes has experienced limited and sometimes only short-term success. Replacement of sand after an oil spill or other contamination has shown similar short-term usefulness. Watershed disruption and coastal armoring block natural sources of sand, and with no natural sand source to replenish formerly sandy beaches, replenished shorelines often last only until the next big swell or hurricane.
Coastal developments continue to impact the dynamic and energetic Puerto Rico coast. Shoreline armoring, breakwaters, piers, port and marina infrastructure, and watershed disruption impact every region, preventing the natural flow of sand along the beaches. Sea level forecasts for Puerto Rico in 2100 are plus one meter. Expect the "World Port of the Americas" to impact major portions of the southwest corner of Puerto Rico.
A 1998 UNESCO/Puerto Rico Sea Grant report Planning for Coastline Change, Saving Our Beaches provides a nice discussion about beach erosion, beach fill, and shoreline armoring issues. The following is an excerpt from this report:
Sea Walls Serve a Few
While our coastlines were undeveloped, beach erosion happened but it went largely unnoticed. Now however, coastal development is threatened by the normal erosion process, plus what seems to be a rise in sea level throughout the region, in addition to storm-related surges of ocean water that can easily destroy million dollar buildings within a few hours time. As a result, more and more oceanfront property owners have built structures such as sea walls in order to protect luxury hotels and private homes. But these hotels, homes and other buildings are being built on land that can easily wash away. And while sea walls may protect small beachfront areas, they often lead to accelerated beach erosion by preventing the natural process of inland sand migration. Concrete sea walls also contribute to the "armoring" of once-green coastlines. This aesthetic defilement surely lowers the tourism value of our shores.
Alternatives to Concrete Armor
One "soft" alternative to sea wall construction is beach fill, which represents the deposition of massive amounts of sand, similar in weight to the original sand it replaces. Although the benefits may outweigh the cost, beach fill is a very expensive proposition, especially since its results may very well last only until the next storm. Clearly, this alternative is feasible only for a few, highly developed island beaches. A less expensive, long-term solution includes the adoption of wise policies of retreat, which dictate that new buildings be set back at a healthy distance from the ocean, that no new sea walls be constructed, and that old sea walls not be repaired.
Planning for Coastline Change
Since 1997, a project titled Planning for Coastline Change is helping the smaller Caribbean islands to plan for the future by establishing safe setbacks between new developments and the active beach zone. As part of the project, which is sponsored by UNESCO and the University of Puerto Rico (UPR) Sea Grant College Program, safe setbacks are also determined for other geological features such as the cliffs and low, rocky shores on each island.
Public Education Program
The UNESCO Publication Coping with Beach Erosion is a source of information on hurricane processes and beach erosion. It also includes information on erosion mitigation measures, and what to look for when investing in coastal property.
Surfrider Foundation's Rincón Chapter website has some great information about the the impacts of seawalls in Rincón and at all beaches.
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