1.1.1.WATER RESOURCES The average annual rainfall in Bolivia is 1,124mm, which represents a contribution of 1,235km3/year. The RHTR are estimated at around 628km3. The river system is divided into three main areas: the Amazon, the La Plata river and the closed basin of Altiplano. The Amazon basin of Bolivia, bounded on the north by the Abuna river on the border with Brazil, corresponds to the upper half of the Madeira river, part of which belongs to Peru (12 per cent) and to Brazil (16 per cent). The Madeira river is formed by the confluence of four major rivers: Madre de Dios, Beni, Mamore and Itenez. The river Parapeti, originating in the Andes, flows into the Marshes of the Izozog depression where it evaporates much of its water and communicates, in times of major floods, with the San Miguel river, part of the Madeira river. Much of this contribution becomes infiltration, which recharges the basin of the Paraguay river. The basin of the River Plate in the Plurinational State of Bolivia is divided into three major subbasins. The Paraguay river itself extends into the eastern plains in the southeast, where infiltration is high. Two major tributaries of the river are located in the southeast: the Pilcomayo and the Bermejo, which includes the Rio Grande de Tarija. Two separate water systems constitute the endorheic Altiplano basin: Lake Titicaca, which drains into Lake Poopó through the Desaguadero river and communicates with the Salar de Coipasa in exceptional times of floods, and the Salar de Uyuni. The Plurinational State of Bolivia shares basins with its neighbours on its three sides, although the largest contributions come from the Madeira river basin, mainly via the Madre de Dios and Orthon from Peru and Itenez or Guaporé and Abuna from Brazil. The endorheic basin of Lake Titicaca is shared with Peru; the basins of the rivers Bermejo and Pilcomayo are shared with Argentina and Paraguay, and the Paraguay basin is shared with Brazil, although the contributions are much lower in these last basins. Regarding groundwater, in the hydrogeological basin of the Altiplano several aquifers are located with discharge to Lake Titicaca, Lake Poopó and the Uyuni Salar. Discharges into Lake Titicaca have better hydrological conditions and contain large volumes of water of good chemical quality. This quality is worse in the region of Oruro and Lake Poopó and in the area of influence of the Salar de Uyuni. In the last years, the drilling of wells for irrigation has been intensified. In the Llanos and Chaco, the potential underground is very variable. The average annual recharge through rivers and streams is estimated at between 21 and 29 million m3 and groundwater reserves are thought to be around 100 million m3. Within the endorheic Altiplano basin there is the Titicaca-Desaguadero-Poopó-Salar de Coipasa (TDPS) system, composed of the Poopó and Titicaca Lakes, the Desaguadero river (that joins the two lakes) and the Salar de Coipasa. This last represents a separate endorheic system, except in wet years, when it is connected with Lake Poopo. Lake Titicaca has a flooded area of 8,400km2, with a volume of 932km3 dammed for the average elevation of the lake (3,810m). The lake has an annual oscillation feature of around 1m, with a maximum in April and May and a minimum in December and January. Lake Poopo, at 3,686m, covers a flooded area of 1,723km2. There are five large reservoirs in the State of Bolivia, devoted primarily to the generation of electricity.

1.1.2.WATER USE In 1987, total water withdrawals were estimated at 1,240 million m3, of which 10 per cent was devoted to domestic use, 5 per cent to industry and 85 per cent to agriculture. In 1992, 40 per cent of the population lacked a water supply; the rate increased to 76 per cent in rural areas (i.e. populations of fewer than 2,000 inhabitants). For sanitation, the equivalent figures were 57 per cent and 82 per cent respectively. The low coverage of basic sanitation and potable water supply, especially in the case of the rural population, has resulted in the presence of major diseases among the population and a high infant mortality due to water-related illnesses (diarrhoea, malaria, typhoid, cholera, etc.). In large cities, and as a result of the population growth that the country has experienced in the past two decades, there is significant competition between domestic consumption and irrigation. There are also conflicts due to the pollution caused by discharges from mining and the industrial sector and the subsequent use of polluted water for household use and agriculture.

1.2.WATER QUALITY, ECOSYSTEMS AND HUMAN HEALTH The drinking water supply and sanitation in Bolivia has improved considerably since 1990, with high investments in the sector. However, the coverage remains the lowest in South America and the quality of service is low. Political and institutional instability has contributed to the weakening of water-sector institutions at both national and local levels. Two concessions to foreign private companies in two of the three largest cities of the country (Cochabamba and Great La Paz) failed in 2000 and 2006 respectively. The second largest city, Santa Cruz de la Sierra, manages its sewage system through a cooperative, which is successful in comparison with the systems of the two other major cities.