URUGUAY: Protection of Uruguay's Beaches, Target of Millions,
Would Be Expensive
Some of the most valuable real estate in Uruguay lies in the
coastal zone, and the predicted loss of land from a one-meter
sea level rise would have a major impact on the vital national
and international tourist industry, target for one million visitors
each summer and generating $235 million. Fishing and shipping
are other important sectors of the coast's economy.
Beach nourishment would be the major protection cost, according
to this first assessment of the country's vulnerability to sea
level rise. While Uruguay has had very limited experience with
beach nourishment and the availability of sand is unknown, it
has had a legislative setback requirement of 250 meters since
the 1970s and also a practice of leaving dunes alone and building
a coastal boulevard seaward of the first development row, adding
another 100 - 200 meters to the setback. (However the setback
regulation is not directly related to beach recession rates, which
are not well understood.)
Uruguay has quantities of sand along its shores, including large
dunes, and sandy beaches make up 65 percent of the coastline.
Only about three percent of the total coastal zone is at risk
from erosion or inundation if seas rise, but it is some of the
most valuable land. Buildings would be destroyed or damaged in
many coastal cities, and beaches would deteriorate, threatening
the vital tourist industry. Erosion is considered the larger threat,
as wetlands, subject to inundation, are a relatively small portion
of the coast.
While there are no specific data on rates of shoreline change.
the bulk of shore erosion is under water, and there would be considerable
recession. Sandy beaches and the sandy coasts of cities would
recede from 50 to even 280 meters, and river mouths would be inundated.
In the Department of Canelones erosion extends six kilometers
offshore, and recession of up to 700 meters is predicted; some
towns would be destroyed. In the Department of Maldonado, the
beach in front of the city of Piriapolis's seawall would disappear.
Along the east coast, sandy barriers separate the ocean from interior
lagoons. During storms, the barriers are overwashed and temporarily
breached; even low sea level rise scenarios suggest there would
be rapid recession, more frequent, possibly permanent breaching.
As the oceans rise, water levels within the lagoons would rise,
causing erosion and inundation of shores. (The narrow barriers
and lagoons are presently undeveloped and such impacts have not
been evaluated.) Although no protection was assumed for the Rambla,
a major highway and coastal boulevard in Montevideo, it would
almost certainly be required.
However, the study authors recommend further investigation of
some of the shoreline threats. Is the offshore erosion overestimated?
Could accretion of sand in the Parana delta, near the border of
Argentina, offset potential erosion?
The wetlands are narrow zones backed by cliffs, precluding migration
inland. They are very vulnerable and assumed to be destroyed.
But the estimates are not based on field measurements, and possible
accretion from two major rivers could offset some damage and should
be evaluated.
Low, rocky cliffs and headlands, 1 - 2 meters above mean sea
level, occupy four percent of the coast and include industrial
zones and urban areas - notably Montevideo. They already suffer
flooding and wave run-up during storm surges. Sea level rise would
bring more frequent flooding and some permanent inundation. The
sandy lime and clay cliffs of the western coast have been eroded
by waves for up to 20 meters in the last 25 years, and the high
waters of sea level rise would increase the damage done by waves
at their base.
The number of people at risk if the oceans rise amounts to only
12,000, not a significant number compared to other coastal countries.
However, this number only considers the permanent population,
which in Punta del Este, for instance, is 7,000 but in summer
may reach 500,000.
The market value of land at risk or lost amounts to $1.8 billion.
Beach nourishment - costing about $3 billion for medium to highly
developed residential and tourist areas plus other strategic sites
- dominates the protection costs, comprising 95 percent of the
total, the major part of it for groins. However, experience with
beach nourishment is very limited, and the availability of sand
is unknown. A shortage would raise prices - and protection costs.
The $3 billion figure represents six percent of Gross National
Investment - a relatively high cost compared with the other countries
surveyed by the AVVA method - and could place a serious burden
on the nation's economy.
Because costs are based on assumption of the present level of
development, the estimates are likely to be exceeded. While there
are many uncertainties, there is already substantial pressure
on the coastal zone. The potential vulnerability is sufficient
to make it prudent to examine the long-term consequences of development
options - even without sea level rise. Uruguay could learn from
the mistakes of unplanned development and growth of the developed
countries, the authors assert, and explore management options
that would diminish vulnerability and "enhance the quality of
coastal environments and aid their sustainable use."
(Claudio R. Volonte, University of Maryland, USA, and Robert
J. Nicholls, University of Middlesex, UK)
