1.1.1.WATER RESOURCES We can distinguish two major basins in Paraguay that are integrated into the main basin of the River Plate. a)First, the Paraguay River Basin (353,752km2), which includes the Pilcomayo River which flows into the first in the vicinity of Asunción. The entire Chaco (246,845km2) with about two thirds of the Eastern Region (106,907km2) belongs to this basin, accounting for 87 per cent of the country. The Paraguay River is the major means of communication and national integration. It is navigable for much of its route, from its confluence with the Paraná to 2,300km further north, but only to Asuncion for big ships. Its main tributaries (Apa border with Brazil, Aquidabán, Ypané, Jejuí and Tebicuari) flow on its left, i.e. from the eastern part of the country. The Pilcomayo River, the most important water course across the Chaco region, is born in the Andes and flows eastward into the Paraguay River, after passing through an area that becomes groundwater flow, called the Estero Patiño. The Pilcomayo is the natural border between Paraguay and Argentina for a length of 835km.. Other important rivers of the Chaco Region are: Green, Monte Lindo and Confused, all tributaries of the Paraguay River on its right bank. b)The rest of the country's land belongs to the Paraná Basin (52,998km3). These two rivers merge in the south. Tributaries of the Paraná River, arising in Paraguay that deserve to be mentioned for their importance are Acaray, Monday, Piratiy and Carapa, all with an important hydroelectric potential. The Itaipu Dam, located on the Parana River on the border between Brazil and Paraguay, has a storage capacity of 29km3, with a maximum seawall .height of 225m It has the largest installed hydroelectric capacity in the world with 12’600MW with an annual production of nearly 75 million MWh and supplies 78 per cent of the total power in Paraguay. Additionally, the reservoir Yacyretá also on the Paraná River on the border with Argentina, floods some 1,690km2 and stores about 81km3. The electrical energy generated by this dam, with an initial capacity of 2,100MW installed but expected to reach 3,100MW, is intended primarily to supply Argentina.

1.1.2.WATER USE Total water withdrawal in Paraguay amounts to 0.4km3. Withdrawals (as a per cent of total) are agriculture (78 per cent), industry (7 per cent) and domestic (15 per cent).

1.2.WATER QUALITY, ECOSYSTEMS AND HUMAN HEALTH Major environmental problems are deforestation; water pollution; inadequate means for waste disposal which poses health risks for many urban residents; and loss of wetlands. The Pantanal of South America is one of the largest, untouched and biologically rich environments on the planet. Often referred to as the world’s largest freshwater wetland system, it extends through millions of hectares of central-western Brazil, eastern Bolivia and eastern Paraguay. However, both untreated, domestic sewage and garbage are discharged into the Pantanal's rivers and wetlands, adding to the organic loading and sediment and chemical contamination. Much of this comes from rapidly growing domestic centres in the highlands outside of the Pantanal, and particularly in the northern Pantanal. One infamous example is Cuiabá, the capital of Mato Grosso. Cuiabá is located in the watershed of the Cuiabá River and lacks waste treatment facilities. The domestic waste from this major metropolitan area is discharged into the Cuiabá River, one of the major tributaries of the Paraguay River. Overall, the two million plus inhabitants of the Upper Paraguay River Basin contribute millions of gallons everyday of untreated wastewater to the Pantanal, and this situation will become increasingly serious as the population of the basin is projected to double by 2025.

(Water Risk Filter)