By Leonardo Coca Palacios
There is a popular Nicaraguan song which says, "Cocibolca and Xolotlan are our two silver legends", referring to Nicaragua's two great lakes. But now Xolotlan, as the indigenous people called Lake Managua, which has calmly withstood the onslaught of nature for thousands of years, is being destroyed by sedimentation, indiscriminate deforestation and the erosion of its basin.
Nicaraguans once admired Xolotlan's beauty and drank from its clear waters. Today, however, their descendants have dedicated themselves to its destruction. The children of this guilty generation may see its charms only in their imagination as they listen to tales of how lovely it once looked, a shimmering blue-green carpet spread out before Managua.
Xolotlan dominates the landscape to the north of Managua, making it an important reference point for city residents. With 6669 square kilometres of water, it is one of Nicaragua's most important bodies of water.
At the beginning of the century, Xolotlan provided Managua with drinking water and recreation. It was also a busy passenger and freight route.
Records of its water level date back to 1927, when the capital's waste water was first channelled into it. It presently sits 38 metres above sea level and measures eight metres deep, 18 km wide and 59 km long. It reached its highest recorded point in October 1933 (43.44 metres) and its lowest in May 1979 (35.66 metres).
Several rivers and countless small streams feed into the lake. Its northern basin includes the Sebaco valley, the districts of San Francisco Libre and Las Maderas, the plains along the lake-side and in the region of Esteli, human-made Lake Apanas, and the mountains of Jinotega.
The zone covering San Francisco Libre, Las Maderas and the plains of El Jicaral and Sebaco is characterised by dry woodlands, while subtropical rainforest covers Apanas and Jinotega. Near the lake, high temperatures limit agricultural development, so the principal economic activities are commerce, livestock grazing and poultry production. Farming is more fully developed in the cooler mountainous areas.
The lake's main tributary from this northern basin is the Viejo River, which drains the 1550 sq km of the Sebaco valley. This river and others such as the Sinecapa, the Pacora and the San Antonio are important sources of water for irrigation.
Many animals and plants that have disappeared from other parts of the country can still be found in the mountains of this basin. Here there are field rats, squirrels, agoutis, raccoons, ocelots, magpies, parakeets, sparrow hawks and many other birds.
The southern basin covers the urban area and the Managua mountains; the plateau where the towns of Niquinohomo, Ticuantepe, Masatepe and San Marcos are located; El Crucero; the Masaya volcano; and the districts of Nindiri, Nagarote and Tipitapa. There are no major tributaries in the southern basin; Xolotlan is fed only by subterranean waters from the capital's volcanic lakes, Asososca, Tiscapa, Nejapa, Xiloa and Apoyeque.
The tropical rainforests of El Crucero and Las Nubes are also home to abundant wildlife: parakeets, squirrels, rabbits, agoutis, armadillos and ocelots. These cool hilly areas and the neighbouring plateau are fertile producers of coffee and horticultural products, with their volcanic soils, temperatures between 22 and 28 degrees Celsius and annual rainfall between 1100 and 1600 cubic millimetres.
The lands to the east of the lake in the districts of Nagarote and La Paz Centro (in the department of Leon) are ideally suited to the cultivation of cotton, watermelon, green squash and pitahaya fruit, as well as cattle and pig rearing.
A Ministry of Natural Resources and Environment (MARENA) study determined that "the southern basin shows more serious signs of environmental deterioration than the northern one, and accounts for more of the reduction in the quality of Lake Managua's water."
Deforestation and severe erosion in both basins, along with constant flooding, industrial waste, run-off from the capital's sewage system and the accumulation of large amounts of sediment on the lake bed, have caused serious damage to Xolotlan's ecosystem.
As the MARENA study explains, "periodic flooding, indiscriminate cutting down of trees and the inappropriate use of pesticides and insecticides have combined to upset the ecosystem in north-western Nicaragua, thus transforming the lake's ecological environment".
One committee, responsible for drawing up a plan to clean the lake, reported that "since 1950, people in rural areas have been migrating to the main urban areas, particularly the capital, which as the country's economic and social centre attracted campesinos displaced by the expansion of cotton cultivation.
"Migration continued through the '60s as the capital's industrial sector expanded. In the '80s, even more people fled to Managua from the war zones, and the city sprawled out onto the slopes at the heart of the southern basin.
"The continuing use of antiquated sewage systems, uncontrolled deforestation by an unemployed and desperate population searching for firewood to sell, the proliferation of settlements beside drainage ditches and the inappropriate use of agricultural chemicals have all contributed to severe erosion in extensive sectors of the basin. As a result, great quantities of sediment have been deposited in the lake, reducing the quality of the water and therefore possibilities for its use."
The flow of untreated waste water from the capital since 1927 has also contributed to the progressive contamination and destruction of Xolotlan.
More than 12,000 micro-industries, 1850 small and medium-sized industries and 25 large-scale chemical factories (including a fuel refinery and a factory producing chlorine and caustic soda) located along the lake's southern shore deposit industrial wastes including lead, zinc, chlorine, acetylene and cyanide into Xolotlan. In 1988, the Nicaraguan Water Authority was already report ing dangerous levels of toxins in the lake's waters.
Soil analyses indicate that 400,000 tonnes of sediment wash into Xolotlan every year from the mountains south of Managua and the El Crucero plateau.
Located at the heart of Nicaragua's most populous and developed region and adjacent to the most fertile soils in the country, a clean Xolotlan could offer innumerable concrete benefits, including the irrigation of extensive areas planted with cotton, sugarcane, and non-traditional crops such as vegetables, sesame and peanuts.
In the long term, a restored lake could provide drinking water and improve public health in Managua's lake-side neighbourhoods. New jobs and recreational activities could also be created if the city and the lake are integrated.
"These far-reaching benefits permit us to say that the restoration and development of Lake Managua would constitute the most beneficial multi-purpose project ever to have been carried out in Nicaragua, and would have a positive influence on the country's development", concluded the MARENA study.
Managua's lake is slowly dying. Helplessly waiting for the end, it is sending out a desperate SOS. Many have heard it, but will anybody respond?
[From Barricada Internacional.]