Lake Cocibolca/Nicaragua Experience and Lessons Learned Brief Salvador Montenegro-Guillén*, Research Center for Inland Waters of Nicaragua (CIRA/UNAN), Managua, Nicaragua, [email protected] * Corresponding author 1. Introduction and foreigners who sought to grasp the geopolitical assets of the Nicaraguan freshwater inland sea and its connection to Lake Cocibolca (Figure 1), also know as Lake Nicaragua, is the Caribbean through the San Juan River. This magnifi cent the largest freshwater lake in Central America and one of the lake occupies the middle section of the tectonic valley shared largest in the Americas. The history of Nicaragua and Central with two other watersheds: Lake Xolotlán (Managua) is the America has developed linked to the interests of conquerors upper watershed, Lake Cocibolca (Nicaragua) is the middle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igure 1. The Lake Cocibolca-San Juan River Basin. watershed and the San Juan River is the lower watershed. This power in 1979. Nicaraguan alleged sympathy to leftist rebels area forms the largest international drainage basin in Central in El Salvador caused the United States to sponsor anti- America, with a total area of 41,600 km2, of which 70% or Sandinista Contra guerrillas through much of the 1980s. Free 29,000 km2 are in Nicaraguan territory and 30% or 12,600 km2 elections in 1990, 1996, and again in 2001 saw the Sandinistas in Costa Rica. defeated. The country has slowly rebuilt its economy during the 1990s, but was hard hit by Hurricane Mitch in 1998. 1.1 Background Important information on Nicaragua, which covers the majority 1.1.1 The Country of the lake basin, include the following: The Pacifi c Coast of Nicaragua was settled as a Spanish colony in the early 16th century. Independence from Spain • The economy is based on natural resources: gold, silver, was declared in 1821 and the country became an independent timber, fi sh, and agriculture; and money shipments republic in 1838. Britain occupied the Caribbean Coast in the from relatives abroad to their families remaining in the fi rst half of the 19th century, but gradually ceded control of country; the region in subsequent decades. Governments were formed with people of the higher classes belonging to two parties • Industries are based in food processing, chemicals, which successively gained power by force, weakening and machinery and metal products, textiles, clothing, impoverishing the country in a long struggle that lasted more petroleum refi ning and distribution, beverages, than three centuries. As part of a war in 1850, and in connection footwear, and wood; with the interest of the Transit Company (which carried passengers during the California Gold Rush from San Juan del • Industrial production growth rate: 4.4% (2000 est.); Norte Port in the Caribbean, through the San Juan River and Lake Cocibolca, to Port San Juan del Sur on the Pacifi c Ocean • Electricity production: 2,233 billion kWh (2000); coast), a fi libuster invaded Nicaragua, became President and destroyed the capital, Granada. After ousting him, a brief • Electricity production by source: fossil fuel (82%), calm period arrived but later foreign interventions backed a hydroelectric (9%) and other (9%) (2000); military regime which governed from 1936 until 1979. Violent opposition to governmental manipulation and corruption • Agriculture products include coffee, bananas, sugarcane, spread to all classes by 1978 and resulted in a short-lived civil cotton, rice, corn, tobacco, sesame, soy, beans; beef, war that brought the Sandinista Liberation Front guerrillas to veal, pork, poultry, and dairy products; Table 1. Demographic Statistics for Nicaragua (based on • Exports are mainly commodities such as coffee, shrimp 2002 data). and lobster, cotton, tobacco, beef, sugar, bananas and Total Population 5,023,818 people gold totaling $609.5 million (2001 est.); 0-14 years: 38.3% • Imports are fi nished goods and commodities like Age structure 15-64 years: 58.7% 65 years and over: 3% machinery and equipment, petroleum products and consumer goods totaling $1.6 billion (2001 est.); and, Population growth rate 2.09% (2002 est.) 26.98 births/1,000 Birth rate • Demography: Table 1 shows estimations based on 2002 population data. 4.76 deaths/1,000 Death rate population 32.52 deaths/1,000 live Infant mortality rate births Table 2. Physical Information on Lake Cocibolca. Life expectancy at birth 69.37 yrs Parameter Value Total fertility rate 3.09 children born/woman Total surface area 8,000 km2 at 31.40 m asl Literacy total population: 68.2% Total volume 104 km3 GDP per capita US$507 Length along major axis 160 km GDP US$2.398 billion Maximum width 70 km GDP growth 5.5% Maximum depth Approx. 45 m Infl ation 11.5% Mean depth Approx. 13 m Population under poverty Minimum historical water 47.9% (1998) 29.57 m (May 1886) line level Population under extreme Maximum historical water 17.3% (1998) 33.84 m (November 1861) poverty line level 134 Lake Cocibolca/Nicaragua Additionally, Nicaragua is extremely susceptible to natural There are thirty-two municipalities on the Nicaraguan side of hazards such as hurricanes, destructive earthquakes, the watershed and ten on the Costa Rican side of the border. volcanoes, and landslides. Slash and burn agriculture There are differences between both social and economic of subsistence not only destroys forests but also causes conditions of the two countries, which can be seen from the destruction of soils which erode and lose fertility, and is a indicators shown in Tables 4 and 5. major cause of environmental fragility. For many years, transportation on the San Juan River and Lake 1.1.2 The Watershed Cocibolca has been an important factor in the socioeconomic There are three subsystems or component basins in the larger and political development of Nicaragua. Interest in the catchment: the Lake Xolotlán (Managua) watershed (6,669 construction of an inter-oceanic route tapping the potential of km2), the Lake Cocibolca (Nicaragua) watershed (23,844 the San Juan River and Lake Cocibolca dates back to Spanish km2) and the San Juan River watershed (11,125 km2). Of the colonial times. The fi rst historical data records that the San 23,844 km2 of the Lake Cocibolca basin, 19,693 km2 (83%) Juan River and Lake Cocibolca were used to transport the are in Nicaragua and 4,151 km2 (17%) are in Costa Rica. Other riches discovered on the western coasts of South America information on the lake and its basin is given in Table 2. Table 5. Indicators of Health and Education in Lake Rainfall in the watershed varies from an average of 1,200 Cocibolca-San Juan River Basin, Costa Rican Side. mm/yr in the northwest at Malacatoya, to an average of 4,000 mm/yr at the upper watershed of Rio Frío in southeast in Costa Indicators Average Rica. The water balance for Lake Cocibolca over a 40-year Illiteracy (%) 15.37 period is given in Table 3. Birth rate (per 1000) 31.26 Mortality (general; per 1000) 3.33 Infant mortality (per 1000) 14.48 Table 3. Water Balance for Lake Cocibolca (40-year average). Neonatal (per 1000) 8.6 Quantity Type of fl ow (in m3/s) Unemployment (%) 5.77 Direct precipitation 401 Water supply Infl ow from rivers 268 Piped water (%) 71 Groundwater 196 River water (%) 25 Seepage from Lake Xolotlán 5 Rain water (%) 4 Total Infl ow 870 Sewerage Evaporation from surface (calculated) 399 Septic tanks (%) 61 Outfl ow (at San Carlos through San Juan Latrines (%) 38.5 476.6 River) Bush (%) 0.5 Total Outfl ow 875.6 Source: PROCUENA San Juan project. Table 4. Indicators of Health and Education in Lake Cocibolca-San Juan River Basin, Nicaraguan Side. Indicators Rivas Granada Masaya Boaco Chontales San Juan Total School enrollment (%) Preschool 20.1 25.1 28.1 10.85 10.9 16.8 18.2 Primary 86.7 87.3 99.6 73.7 61.6 76.0 80.4 Secondary 21.1 18.9 38.8 16.6 16.4 7.0 25.0 Technical n.a. 1.3 0.05 0.2 0.5 0.4 0.7 Health (%) Malnutrition 27.8 26.6 31.8 31.4 23.2 18.1 26.0 Sewerage (%) Urban 41 20 41 53 n.a. 1 31.2 Rural 86 64 85 69 77 17 66.3 Pipe-borne water (%) Urban 92 100 92 92 75 64 86.3 Rural 31 44 59 25 35 15 34.8 Source: PROCUENA San Juan project, based on data from SILAIS, MINSA, INIFOM, and INEC. Experience and Lessons Learned Brief 135 and shipped to Spain during the conquest of the continent.