Project (GPCP) (2006) Storage capacity Artificial storage. Chile has an artificial reservoir capacity of 4.66 km3, of which 4.2 km3 is stored behind large dams. Approximately 0.5 km3 is stored behind smaller public works dams. A majority of the stored water in these reservoirs is located within three of the fifteen regions. Regions IV, VI, and VII (from table above) account for approximately 80% of Chile's artificial surface water storage. (See also List of lakes in Chile) Natural storage. Chile has a large number of natural lakes with an approximate capacity of 7 km3. The southern regions are home to numerous lakes and lagoons, some shared with Argentina. Population density is very low in southern Chile (0.1 to 0.6 persons/km2), therefore demand for water and development of the water resources is minimal. Droughts and floods In the central and most populous regions of Chile rainfall is highly variable, resulting in occasional floods and droughts. In early 2008 one of the worst droughts to hit Chile in decades forced the government to declare an emergency. 50 farming districts in central Chile were affected and farmers were forced to irrigate with dwindling groundwater. Some reservoirs for hydroelectric dams were at an all-time low. While 2008 was one of the worst droughts on record for the central regions, southern regions such as La Araucania, Biobío, and Los Rios Region also received torrential rain for more than three consecutive days in September 2008 causing severe flooding and the declaration of another emergency. Water quality In Northern regions of Chile, point source pollution from mining effluent is a problem. Because there is not much water in rivers, dilution of contaminants is greatly reduced. In Central Chile industrial pollution is an issue. Very often these discharges go untreated directly into river basins, lakes, and irrigation channels. Nonpoint source pollution from agricultural runoff including nitrates from fertilizers and untreated sewage is contaminating underground waters. The severity of the problem has yet to be thoroughly quantified. Water resources management by sector Drinking water and sanitation Excerpts drawn from: In Chile, water is safe to drink, with ~99% of water service providers complying with bacteriological and disinfection norms. In a 2006 report on water quality management in Chile, the authors reported that in 2000, 99.1 percent of the urban population and 72.3 percent of the rural population had access to drinking water. Water quality in Chile has steadily increased