"THE COASTAL FLOODS IN THE CUBAN TERRITORY, THE MOST SENSITIVE AREAS AND THE POSSIBLE IMPACT OF THE CLIMATE CHANGE"

Ida Mitrani Arenal, Rafael Pérez Parrado, Isidro Salas García, Omar García Concepción,

Maritza Ballester Pérez, Yunit Juantorena Allen, Pedro Beauballet Padrón, Ada Luisa Pérez Hernández and Carlos Rodríguez Otero.

Institute of Meteorology (INSMET), Institute of Physical Planning (IPF)

Republic of CUBA

ABSTRACT: An evaluation of the most exposed coastal areas to the effect of the mean sea level rise by the foreseen climate change was elaborated. It was considered that the greater sensibility is found in those areas that are more frequently affected by the coastal floods. The three areas that historically have received the greater damage by this phenomenon, under the influence of highly dangerous meteorological events, were chosen as study cases. The sea level variations were simulated by numerical methods in each area, in presence of the dangerous events, with the current and foreseen scenarios. Due to the absence of instrumental observations, the floods were simulated using meteorological information from the INSMET archive. A socioeconomic study of each area was carried out in order to evaluate the possible magnitude of the damage, if the mean sea level increment by climate change takes place. The obtained results are applicable in the elaboration of contingency, urban and coastal management plans. The used algorithms are also of great utility in short-term forecast of the sea surface conditions. 1. INTRODUCTION The Intergovernmental Panel of Climate Change (IPCC) evaluation has shown that a possible climate change would cause an increase of the mean sea level, the submersion of the lowest lands and the displacement of the coastal line inland. The most recent evaluation (IPCC, 1996) indicates an increase of the sea level between 15 and 95 cm for the year 2100, relative to1990, if the greenhouse gas concentration grows on planetary scale. Cuba is included among the nations that would be more affected by the possible global change, considering its insular condition, geographical configuration and the existence of low shore areas in a large part of its coastal perimeter. Most of their municipalities possess coasts and in them, important port, industrial, fishing and tourist activities are developed. More than the 10% of the population lives at a distance between 0 and 1000 m of the coastal line. There, the settlements are located fundamentally in low areas and subject to the effects of the meteorological events, that can increase their frequency and intensity due to the global climate change. Important cities, with more than 20000 inhabitants, are also potentially affected by the mean sea level rise. It was necessary to evaluate how the foreseen climate change would influence the Cuban coastal zone. For this reason, during the period 1996 - 1999, the project "Socioeconomic Impact of the Global Climate Change in the Coastal Areas of Cuba'', inside the program The Global Change and the evolution of the Cuban environment" was developed at the Institute of Meteorology (INSMET), in collaboration with the Physical Planning Institute.(IPF). The main objective was the determination of the most sensitive areas to the sea level rise, the evaluation of the possible damage and its future evolution, considering the mean sea level rise by climate change. This evaluation permitted to obtain a scientific base to design the measure plans for mitigation of possible damage. The obtained results show that the most sensitive areas are the shore track at the Havana Mole , Gulf of Batabano and Punta Maria Aguilar - Cabo Cruz, where the coastal floods for meteorological factors occur frequently.

Figurtaken

F

e 1 Flood by wave set up at the Havana Mole, during the winter storm on 13 march 1993. (Image was by specialists from the Institute of Meteorology)

igure 2 Beach Rosario, adjacent to the Gulf of Batabanó, after the passage of the hurricane " Irene " in October, 1999. (Image was taken by specialists from the Institute of Physical Planning)

2. METEOROLOGICAL EVENTS THAT GENERATE THE MOST INTENSIVE FLOODS BY SEA LEVEL RISE ON THE CUBAN COASTAL AREAS On the Cuban coastal zone, the usual wind regime is basically conformed by the combination of trade winds and sea-breeze systems. The mean speed is about 2,8 m/s. Usually, there are good weather conditions (Atlas Climático de Cuba, 1987). This normal regime, is frequently altered by the action of tropical events (hurricanes, storms, depressions, tropical waves) and continental ones (frontal systems, extratropical cyclones). Other identified causes have been the non-prefrontal hollows, the combined action of high and low pressure centers and tornados. The more dangerous events are:

!"The tropical hurricanes !"The frontal systems

!"The south winds, generated by extratropical cyclones.

2.1TROPICAL HURRICANES The Atlantic cyclonic season extends from June 1 to November 30. The most active period is August-October, although some tropical hurricanes have registered out of season. There are testimonies of more than 500 hurricanes and 400 tropical storms in the INSMET Archive, from 1888 to 1998 for the cyclongenetical areas of the Inter-American Seas. The Cuban territory is affected by the 11% of the events that are generated in the Atlantic (Fig.3).

Figure 3. Atlantic tropical storms and tropical cyclones from 1888 to 1998 (Information comes from the INSMET Archive)

The passage frequency increases from East to West. The region to the west of the 80° meridian is the most exposed to its influence, being the most frequent trajectories, those with penetration by the south and exit for the north (Vega et al, 1990).

2.2 COLD FRONTS The cold fronts that affect Cuba, are characterized by the advance of a continental dry air mass, with north winds that can be very strong (arriving occasionally to hurricane force), accompanied by rainfall and surf. The most dangerous surfs are generated by the NW winds, since in this direction the maximum geographical fetch is presented (Fig. 4). The cold fronts

season extends from October to April, although some cases have been registered in September and May. The occurrence average for each winter season is of about 20 cases, with the greatest frequency in December, January and February. Moderate intensity fronts prevail, representing 84% of the total. The occurrence frequency over the national territory diminishes from West to East (Rodríguez M., C. González, J. Valdés, 1984). In the period (1916-1993), at least six cold fronts with winds greater than 23 m/s were registered. In 77 years, there are six cases that have generated surfs higher than 6 m at the North-Western Cuban shore.

Figure 4. Cold front is affecting the Cuban territory

2.3 SOUTH WINDS, GENERATED BY EXTRATROPICAL CYCLONES. In Cuba, the strong winds from the south that precede cold fronts are known as “Sures”. They are associated to the passage of extratropical low pressure centers over the Gulf of Mexico or adjacent territories of the United States (Fig.5) and affect the Cuban South-Western coast during the cold front season, with speeds of up to 18 m/s.. The average frequency is of five cases for season, being the month of March the one with more occurrence. In the period 1916-1998, eleven cases have been registered with wind speed greater than 20 m/s (Ballester M., 1997). The “Sures” produce floods by wind setup on the wide platform areas, located at the Cuban southern coast. The most significant cases were registered at the Gulf of Batabanó.

Figure 5. The winter storm of 13 March 1993

3. SOME TRENDS OF THE CLIMATE VARIABILITY IN THE INTERAMERICAN SEAS AND THEIR CONNECTION WITH THE COASTAL FLOOD REGIME ON THE CUBAN TERRITORY. A connection between the coastal flood regime in areas of the Cuban territory and the ENOS event occurrence was detected. The increase in the intensity of the ENOS in the last two decades, coincides with an increment in frequency and intensity of the floods in winter season. In presence of the event ENOS, the extratropical cyclones moves toward smaller latitudes over the Gulf of Mexico, coming closer its area of maximum winds to the national territory. In the proximities of the Cuban shoreline, the wind and surf action are intensified, increasing the sea level significantly at the western Cuban coast (Pérez Parrado et al., 1995). The most typical example occurred in March of 1993, under the influence of the system known as "Storm of the Century." Floods took place by wind setup in the southern coast before the step of the cold front and by wave setup in the northern coast, when the winds rotated to the northwest. The flood at the Havana Mole were generated by waves of more than 6 m, causing serious economic losses and deterioration of important urban objects. With the available information at the present time, it is not possible to foresee a variation by climate change in the tropical hurricane regime. However, it is possible to notice a variational trend in the North Atlantic cyclogenesis. The hurricanes had moved away of the Cuban territory, under the influence of the cyclonal activity decrease in the Caribbean Sea (Ballester and González, 1997) and a track prevalence in more eastern longitudes (Ortiz, 1988). Between 1910 and 1944 (35 years), 9 of the 10 more intense hurricanes that affected Cuba at the XX century were generated. In a similar way, between 1844 and 1888 5 of the 6 more intense hurricanes of XIX century were registered. However, the twenties and the period 1973 - 1995 stand out for their minimum activity on the national territory (Pérez Suárez et al. 1998). The greatest storm surges were registered in 1932 and in 1944, in the town Santa Cruz del Sur and in the Gulf of Batabanó settlements respectively, by the influence of hurricanes with Vmax ≈ 70 m/s. The sea level rise was estimated in more than 6 m (Ortiz, 1980; García and Pérez Parrado, 1998). The town of Santa Cruz del Sur suffered the most terrible catastrophe, reported at the Cuban territory. The whole town disappeared under water and 25 000 people died. On the other hand, the greatest surfs also were produced by hurricanes. In 1926 and 1944 hurricanes produced waves with heights of more than 7 m at the Havana City shoreline. For such a reason, in the contingency and coastal protection plans, the tropical hurricanes regime must be taken into account in the first place. The time study series should not be confined to only some dozens of years, but it should be extended to all the available historical information. The coastal flood regime on the Cuban territory responses to the trends above exposed. In some periods, the temporary sea level rise responses to the tropical cyclones influence and then, the floods are less frequent but more intense. In others, the dependence of the coast flood regime on the extratropical cyclon and cold front action is greatest and therefore the floods are less intense but more frequent.

4. SENSIBILITY OF THE COASTAL HUMAN SETTLEMENTS TO THE MEAN SEA LEVEL RISE AND COASTAL FLOODS.

The Cuban archipelago possesses more than 5000 km of coast, without including the small islands. The accumulative low coast occupies around 5,2% of the total shore area. All the provinces and 65% of the municipalities present shore areas, where important port, industrial, fishing and tourist activities are developed The 278 coastal settlements are located among the 14 provinces and 88 municipalities (39 on the north coast and 49 on the south). More than the 10% of population lives within a strip of 1 km from the coastal line, in 245 settlements, basically located in low areas. These are occasionally subject to the action of dangerous meteorological events that may increase its frequency and intensity due to the global climate change. Of them, 93 are located below the bench mark of 1 m. There are 52 reported settlements which have undergone coastal floods in presence of “sures”, cold fronts or tropical hurricanes (Fig.6). Of them, 42 are located below the bench mark of 1 m and it represented the 45% of the total, that have reported floods by sea level rise. Sometimes, they are accompanied by pluvial floods (Moreno et al 1998).

Figure 6. Human settlements that have reported coastal floods during the XX Century (Information was taken from the archive of the Institute of Physical Planning)

The hazard maps by meteorological factors for the Cuban coastal perimeter, were elaborated by specialists from the INSMET and IPF, considering the affectation for storm surges (Moreno et at. 1998), cold fronts and “sures”. The storm surges hazard map (Fig.7) shows that the most sensitive areas for this kind of events are the Gulf of Batabano and Punta María Aguilar- Cabo Cruz shoreline track. The cold front hazard map (Fig. 8) indicates that the most sensitive areas in this case, are the Havana City and Havana Province shoreline. At last, the "Sures" hazard map (Fig.9) shows as the most sensitive area, the Gulf of Batabano shoreline track.

Figure 7. Storm surges hazard map for Cuban coastal zone

Figure 8. Cold front hazard map for Cuban coastal zone

Figure 9. South hazard map for Cuban coastal zone

The coastal area at the Havana Mole is very abrupt. This particularity favors floods by wave setup. Although the greatest surfs have been generated by hurricanes, the wave setup by cold fronts have caused more damage, because they are more frequent (Mitrani and Pérez Parrado 1998, Mitrani, 1997). The sea level rise by wind setup due to the influence of the " sures ", is observed in areas of wide platform, located at the Cuban southern coast. The most significant floods occur on the coastal track corresponding to the Gulf of Batabanó. The presence of smooth slopes in an area of shallow waters, favors this kind of floods, that according to the neighbors' testimonies, can occur at least once a year, being able to repeat up to five times a year. The previous reflections lead to the idea that the most affected settlements by coastal floods in Cuba, are the adjacent ones to the Gulf of Batabano (Fig. 10), to the tract Cabo Cruz-Punta María Aguilar (Fig. 11) and to the Havana Mole (Fig.12).

Figure 10 Human settlements that are periodically affected by coastal floods at the Gulf of Batabano shoreline.

Figure 11 Human settlements on the Cabo Cruz-Punta María Aguilar.track

Figure 12 The Havana Mole coastal zone. The coastal floods occur between “La Punta Castle ” and the “Riviera Hotel”

Coastal flooding were simulated by numerical methods for the three selected areas, applying current and future mean sea level rise scenarios from National and IPCC evaluations. National evaluation is in the order of 0.29 cm/year (29 cm in 2100). It was obtained by Blazquez and Rodríguez (1991), using mareographic registers. The current flooding regime was calculated in every case. The return functions in current conditions and simulation results are shown on Tab. 1-8. It is possible to appreciate that the mean sea level increment will produce very little variation in the vertical dimensions of each kind of flood. However, in the horizontal dimensions, an advance of the coastal line could be observed. It will be in the order of 3 -7 Km for the Batabano area and of 1 Km in the Cabo Cruz-Punta María Aguilar tract, while the reef line at the Havana Mole will bring near in more than 10 m.

Table 1. Storm surges return function, for the current scenario (δZ) and extreme foreseen of 1 m (δZ1), on the Gulf of Batabanó (study period 1891-1991).

F (case/year) δZ [m] δZ1 [m] P [hPa] VMAX [m]

1/500 9.40 9.80 888 90.90 1/333 7.70 7.90 910 82.80 1/200 6.9 7.1 920 78.08 1/100 5.3 5.5 940 68.86 1/50 3.8 3.9 960 50.19 1/25 2.2 2.3 980 45.18 1/10 0.90 0.95 988 38.60 1/5 0.70 0.75 1000 28.00

Table 2. Sea level rise by wind setup at four of the Gulf de Batabanó human settlements,

under current conditions. (V- wind speed, ∆Z- sea level rise by wind setup, S - southern wind direction, SW- south-western wind

direction )

Playa Guanimar

Surgidero de Batabanó

Playa Rosario

Playa Caimito

V S SW SW S SW SW [m/s] ∆Z [m] ∆Z [m] ∆Z [m] ∆Z [m] ∆Z [m] ∆Z [m]

10 0.34 0.19 0.25 0.27 0.59 0.30 12 0.48 0.28 0.27 0.39 0.81 0.42 13 0.56 0.32 0.35 0.45 0.94 0.49 14 0.64 0.37 0.41 0.52 1.07 0.57 15 0.73 0.43 0.47 0.59 1.20 0.65 16 0.82 0.48 0.54 0.67 1.34 0.73 17 0.91 0.54 0.62 0.75 1.49 0.81

Table 3. Sea level rise by wind setup at four of the Golfo de Batabanó human settlements, for the foreseen scenario of 1 m.

(V- wind speed, ∆Z- sea level rise by wind setup, S - southern wind direction, SW- south-western wind direction)

Playa

Guanímar Surgidero de Batabanó

Playa Rosario

Playa Caimito

S SW S SW SW SW V [m/s] ∆Z [m] ∆Z [m] ∆Z [m] ∆Z [m] ∆Z [m] ∆Z [m]

10 0.31 0.18 0.19 0.18 0.38 0.27 11 0.38 0.22 0.24 0.22 0.45 0.32 12 0.45 0.26 0.27 0.26 0.53 0.38 13 0.52 0.30 0.32 0.30 0.62 0.44 14 0.60 0.36 0.37 0.35 0.71 0.51 15 0.68 0.40 0.42 0.40 0.80 0.58 16 0.77 0.45 0.48 0.45 0.90 0.66 17 0.86 0.50 0.54 0.51 1.0 0.73

Table 4. Return Function of the quasi-stationary southern wind on the Gulf of Batabanó

V [m/s] F [case/year] 10 0.920 11 0.694 12 0.502 13 0.352 14 0.234 15 0.142 16 0.071 17 0.014

>17 0.01

Table 5. Approximate advance distances of the current shoreline at the Gulf of Bartabanó, if the mean sea level rise of 1m takes place.

Beach Majana ⇒ de 1.8 a 2 km Beach Guanimar ⇒ de 4.7 a 5 km Beach El Cajío ⇒ de 2 a 3 km Surgidero de Batabanó ⇒ de 1.3 a 1.5 km Beach Mayabeque ⇒ de 2 a 2.7 km Beach Rosario ⇒ a 1 km Beach Caimito ⇒ de 2.6 a 3 km Beach Tasajera ⇒ a 5 km

Table 6. Storm surge return function ´[F], obtained for the current scenario (δZ) and foreseen of about 1 m (δZ1), on the Cabo Cruz-Punta María Aguilar shore track. ( Study period 1891-1991).

F

¨[case/year] δZ [m] δZ1 [m] Pmin [hPa] Vmax [m/s]

1/1000 9.0 9.20 888 90.90 1/500 7.50 7.70 900 86.32 1/300 6.7 6.9 920 78.08 1/200 5.2 5.3 940 68.86 1/100 3.7 3.8 960 58.19 1/50 2.2 2.3 980 45.18 1/20 0.70 0.90 1000 36.00 1/10 0.50 0.70 1006 16.50

Table 7. Return function [F] for deep-water wave elements, at the Havana Mole

F [case /years] Períod [s] Significant height [m] 1/2 9.0 5.0 1/5 10.0 6.0

1/10 10.57 7.95 1/20 10.98 9.06 1/50 11.04 10.34 1/75 11.45 11.61

1/100 11.55 11.93 1/200 11.75 13.83

Table 8. Advanced distances of the reef area, for different scenarios of mean sea level rise by climate change.

Foreseen scenarios [m] Advance distances [m]

29 cm 3.3 50 cm 5.7 1 m 11.5

5. RESPONSE STRATEGY The obtained results from this research, have been taken as base for the mitigation measures plan of possible damage on the coastal areas. The most important problems on the Cuban coasts are presented in the following aspects: - the human habitat. - the natural ecosystems, - the changes in the distribution, density and migration of the population, - the economic activities, - lost and degradation of terrestrial waters, - the population's dissatisfaction with the public services in the study areas, - lost of the productivity of agricultural and forest soils, - degradation of the natural protection systems in the shoreline, - deterioration of the beaches and their repercussion in recreation activities and tourism. As response strategy, a mitigation measure plan with normative and legislative character has been elaborated and inserted in national and local programs, dedicated to the integrated coastal management. With the application of this plan, the sustainable development is guaranteed as form of facing the possible climate change. There are included the following recommendations: - The relocation and protection of the socioeconomic objects. - Partial or total relocation of the settlements in danger. - If the settlements are already very deteriorated, it is recommended to improve the hygienic-sanitary conditions (drainages and sewer system) and the primary attention of health, continuing with the housings and aqueduct network. - In the beach and recreation areas, it is recommended to maintain the settlements under vacation provisional condition, taking the accommodation and protection measures against the coast line setback and flooding by sea level rise. - The vacation construction should be limited exactly inside the first coast line on the sandy dune . In the Fig. 14, the application scheme of the mitigation measures on the human settlements is presented.

Figure 13. Mitigation Measures

CONCLUSIONS - There are 244 settlements in the country, with a population of 1,41 million inhabitants living within a strip of 1000 meters from shoreline. Around 48,000 inhabitants live below the bench mark of 1 meter. If the IPCC maximum scenario occurs, all these settlements would be under the sea. - The most sensitive areas to the possible mean sea level rise by climatic change are those that are more exposed to floods by meteorological facts. These areas are the coastal tracts of the Gulf of Batabanó, the Havana Mole and Cabo Cruz-Punta María Aguilar. The early elaboration of contingency plans will allow to mitigate the possible damages of the mean sea level increase by the foreseen climate change. - The mean sea level rise scenarios, included the maximum predicted by IPCC of about 1 m for the 2100 year, doesn't have great impact in the vertical dimension of the temporary sea level rise by meteorological factors on the study areas. With the scenario of 1 m, the estimate values modify among 3 –5% in the places of maximum elevation. However, it would modify the penetration inland reach in several km, including inland displacement of the current zero bench mark. BIBLIOGRAPHY. Atlas Climático de Cuba (1987), Tomo I, INSMET, ACC. Ballester M., (1997) "Los sures en la mitad occidental de Cuba: cronología actualizada, potencial de daños y tendencias" Boletín SOMETCUBA, Vol. 3, No.2, (http://www.met.inf.cu/) Ballester M., C. González (1997) Variaciones y Tendencias de la Ciclogénesis tropical en el Atlántico Norte. Boletín. SOMETCUBA, Vol. 3 No. 1, (htttp://www.met.inf.cu//) Blázquez M., J. Rodríguez (1991) "El ascenso del nivel del mar y algunas de sus posibles consecuencias para el archipiélago cubano" (Inédito) Instituto de Oceanología, La Habana, 22 pág. IPCC (1996) Segunda Evaluación Cambio Climático - 1995. Informe del grupo Intergubernamental de Expertos sobre el Cambio Climático. OMM, UNEP, PNUMA, 71pág. Mitrani I. (1997) “Application of the Meteorological Information on Coastal Management in the Havana Mole" Boletín SOMETCUBA. Vol. 3, No. 2, INSMET, La Habana. (http://www.met.inf.cu//) Mitrani I., R. Pérez Parrado (1998) ''Influencia de los ciclones tropicales del régimen de oleaje en el litoral habanero''. Conferencia Científica sobre Ciclones Tropicales "Rodríguez in Memoriam" (Memorias). WMO- SOMETCUBA- INSMET, La Habana, 138:144 Moreno A., I. Salas, R. Pérez Parrado, O. García, I. Mitrani, C. Rodríguez, A. L. Pérez, Y. Juantorena (1998) Desarrollo de la técnicas de predicción y las inundaciones costeras, prevención y reducción de su acción destructiva. Informe Técnico. PNUD., Defensa. Civil Provincia de La Habana, Editora del Instituto de Planificación Fisica. 1998, 200 pp Ortiz R. (1980) "Huracanes notables" (Inédito), INSMET, ACC, La Habana, 92 pag. Ortiz R. (1988) "Una observación sobre las trayectorias de los huracanes y perturbaciones ciclónicas" Rev. Cub. Met. Vol.1 , No. 1, 66:68 Pérez Parrado R., Rego J. García O. (1995) Efectos del evento ENOS durante la temporada invernal en Cuba. Boletín SOMETCUBA, (Publicación electrónica), Vol. 1, No.2, La Habana, Cuba. Pérez Suárez R., M. Ballester , C. González, M. Limia (1998) Los ciclones tropicales de Cuba. Variaciones y tendencias observadas. . Conferencia Científica sobre Ciclones Tropicales "Rodríguez in Memoriam" (Memorias). WMO-SOMETCUBA-INSMET, La Habana, 30:3 Rodríguez M., C. González, J. Valdés (1984) "Cronología de los frentes fríos que han afectado a Cuba desde la temporada de 1916-1917 hasta la temporada de 1982-1983" Reporte de Investigación, INSMET, ACC, 15 pag. Vega R., M. E. Sardiñas, M. E. Nieves, A. Centella (1990) "Análisis estadístico - climatológico del régimen de la velocidad máxima del viento en Cuba" Informe Final de Resultado Científico, INSMET 60 pag.