Building capacity in two vulnerable points of the Colombian coastal area.
Although registering the highest birth and migration indexes, less than 10% of the Colombian population inhabits the coastal areas. With nearly 928.660 Km2 of submerged territory under jurisdiction, Colombia holds coast line on the Caribbean Sea and the Pacific Ocean. Both coastal zones hold a variety of developments and coastal features encompassing great challenges on coastal change issues. Sea-level rise and climate change are forecast to increase the scale and pace of these changes.
Following a “What if …” type of scenario method, the vulnerability of the coastal areas of Cartagena and San Andrés de Tumaco were identified as highly vulnerable to SLR during the first NCAP project phase (2000-2003). Adaptation opportunities of these areas were to be prioritized in this second study.
A generalized rise trend from the last 100 years of the multi-decadal tide gauges series from Panamá used to estimate mean sea- level linear variations on the Caribbean coasts confirm an equivalent ascending tendency between 1907 and 1997 of 2.01 and 3.58 mm/year. All around the coast there is evidence of consequent dramatic coastal changes, recorded in a life time range. For instance main port infrastructure along the Caribbean indicates partial flooding during annual storm surges, never observed before. Infrastructure once watching over the sea is now under the constant menace of high tides.
Groins have not been successful in halting Cartagena’s coast line retreat and may be a trigger in accelerating shore erosion. As much as one groin per two years has been built along Cartagena east Bay in the last 10 years.
Improvisation with tires, rocks and sticks is common practice south of the Bay, where sand fluxes have been dramatically reduced each year. Shore defenses are increasing and concentrating, changing important sand dune formations and giving rise to problems for other coastal users increasing the number of people exposed to flooding by storm surges and eventually sea level rise.
At the most basic level, coastal areas of Cartagena de Indias and San Andres de Tumaco are likely to continue to be impacted by a number of factors including droughts, floods and long-term sea-level rise. In the short term this means that people are likely to be hit by more and more natural disasters in the coming years. The first and most effective measure would be to improve actual disaster preparedness. Settlements established on reclaimed land in dried-up valleys or those developing very close to mangrove swamps and wetlands, are already facing up to the challenges of sea-level rise and coastal erosion. These yearly basis lessons are giving us the best chance to adapt to a long term changing coastline.
Beaches, water quality and coastal landscape are recognized to be essential resources for Cartagena tourism activity. If they are affected, the activity and its investments can be expected to have enormous losses. Moreover, the absence of sandy beaches protection services can leave the city over exposed to storms surges and hurricanes, affecting the not only the activity infrastructure but almost 65% of the inhabitants economically dependent of it. City access and thus economic trade can be seriously restrained by the presumable damages caused on the main road that communicates Cartagena and Barranquilla with inner country. Nowadays road flooding evidence has depleted pavement structure and asphaltic materials. Probably the most dramatic and unforeseen sea-level rise impact will be deeper saline wedge thru the Canal del Dique into the soils and Juan Gómez marsh waters from which the drinking water system of the city of Cartagena is connected. Tierra Bomba Island, located in the Cartagena Bay in front of the city, can continue to be affected by flooding and erosive processes caused by sea-level increase. Actual low population density can be seen as an adaptation opportunity for an early risk management Plan for the Island. Hard engineer would probably have to be seen as an option to protect between Castillogrande and El Laguito the most exposed coastal sector.
Pacific coast meso-macro tidal regime is subject to a medium to low wave energy regime associated to the trade winds influence. Tidal amplitude reaches up to 5 m in some areas, which is 10 times greater than the Caribbean. This natural condition has allowed the development of palafitic housing, dwelling built on a platform over the sea, an autonomous adaptation strategy towards sea-level changes. This proven ancient learned adaptation strategy can be used in areas where rising temperatures due to Climate Change are becoming a problem instead of using energy consuming cooling devices.
Population retreat, most workable strategy against highly risk areas, generates strong cultural resistance: Despite natural phenomena like earthquakes, subsidence and tsunamis threats people won’t leave their “palafitos” to start paying for public basic services on a continent safer house. Under a business as usual scenario the Tumaco urban population affected by flooding due to sea level rise is estimated on 19% for year 2030. Risk management should seek to advance in awareness of short term natural threats as well as long term sea-level rise. Planning to reduce sea-level rise vulnerability provides the elements for decision – making on how to organize and manage coastal territory and to specify necessary prevention, mitigation and adaptation measures and actions needed to be incorporated in to Municipal, Departmental and National Development Plans as well as in territorial organization and coastal sectorial development planning processes. National efforts to reduce green houses gases should continue to be encouraged but a strong call for attention on looking for adaptation opportunities on coastal zone is one of the Project biggest lessons learned.
Technical Report - Capacity Builinding to improve adaptability to sea level rise in two vulnerable points of the Colombian coastal areas
Vulnerability Assessment – Capacity building to improve adaptability to sea level rise in two vulnerable points of the Colombian coastal areas (Tumaco-Pacific coast and Cartagena-Caribbean coast) with special emphasis on human populations under poverty conditions.
Adaptación costera al ascenso del nivel del mar – Insumos al documento Segunda Comunicación Nacional de Colombia
Mr. Francisco Arias - Isaza
Cerra de Punta Betin, Camino del Puerto, Santa Marta
Phone: +57 5 431 2975
Email: fariasis@ invemar.org.co
For more information and other resources and links on coastal climate change and sea-level rise visit: http://www.invemar.org.co/cambioclimatico