Water resources management in El Salvador is characterized by difficulties in addressing severe water pollution throughout much of the country's surface waters due to untreated discharges of agricultural, domestic and industrial run off. The river that drains the capital city of San Salvador is considered to be polluted beyond the capability of most treatment procedures.
El Salvador has ample groundwater and partly relies on these supplies for domestic purposes. Deforestation has ravaged the country to the point that very little primary forest remains. This has led to substantial difficulties in managing stormwater when hurricanes and tropical storms make landfall.
Torrential rain leads to deadly floods and mudslides that have claimed many lives in El Salvador. A growing urban population coupled with high levels of water losses in urban centers is also challenging water institutions that are not well coordinated. This leads to inefficient water resources management.
Water management challenges
Water pollution The Acelhuate River is an important drainage system for El Salvador's capital, San Salvador, and is severely contaminated with heavy metals along with domestic and industrial waste. This water is considered a biohazard, and the contamination is so severe that it is rendered untreatable by treatment methods such as reverse osmosis. Contaminated water from the Acelhuate River flows directly into the Cerron Grande reservoir.
The Cerrón Grande reservoir is overloaded with sewage and industrial waste. In a 2004 study, the El Salvador Ministry of Environment found that the waste is coming from 54 industrial plants, 55 coffee processing plants, seven sugar mills, and 29 sewer systems discharging directly into the reservoir. Cerrón Grande dam was built in 1974 to drive El Salvador's largest hydroelectric project, and the 135 km2 reservoir collects some 3,800 tones of excrement each year from the sewage pipes, as well as factory effluents consisting of heavy metals such as chromium and lead.
The sedimentation volumes in the Cerron Grande Reservoir are dangerously high also and estimated to be as high as 7 million m3 per year which gravely impacts the health of the reservoir. Many shallow aquifers are becoming contaminated from the severe surface pollution, and this is critically challenging as deeper wells are more relied upon to provide potable water.
In El Salvador, rivers and streams in the principal agricultural areas are highly polluted by pesticides, particularly by DDT in cotton cultivations in the south-eastern coastal plains. Concentrations of 3.15 mg of DDT per litre of water have been discovered in the Río Grande de San Miguel.
Flooding and stormwater El Salvador sits directly in the path of tropical storms and hurricanes as evidenced by Hurricane Mitch in 1998 causing US$400 million in damage. Hurricane Stan in 2005 caused considerable flooding throughout El Salvador, resulted in 67 deaths, and displaced more than 50,000 people. Damages from Stan were estimated at US$355 million. There was a tropical storm in 2008 that also led to major flooding and mudslides and killed 199.
Another determining factor in the severe flood waters that plague El Salvador is deforestation. El Salvador is the second most deforested country in Latin America after Haiti. Much of El Salvador's tree cover has been removed, leaving the country vulnerable to flash flooding. Only an estimated 2 per cent of the tree cover that existed before the 10-year civil war remains. Almost 85 percent of its forested cover has disappeared since the 1960s and less than 6,000 hectares are classified as primary forest.
Urbanization The urbanized population in El Salvador was 61% in 2008 with an increase of 2% each year. In the case of San Salvador, the urbanized surface of the metropolitan area has increased almost exponentially, from 6.8 km2 in 1935 to 91.5 km2 in 2000. This has mainly taken place in the largest aquifer recharge areas. Because of this, the areas with the highest rate of infiltration have been reduced, whereas the areas with a low infiltration rate of 0.05 mm/hour have increased by the same proportion.
Water resource base
It is estimated that El Salvador has 17.3 km3 of water resources per year. Approximately 67% or 11.6 km3 of this water is surface water. The remaining 5.7 km3 are found in groundwater which is heavily relied upon because surface water is generally severely polluted. Precipitation levels are the most significant in the higher elevations varying from about 2, 286 mm in the mountain ranges down to 1,448 mm in coastal plains. About 95% of the rainfall occurs from May to October with frequent and severe droughts occurring during the drier months. Around 84% of the surface runoff takes place during the rainy season (May–October) while the remaining 16% will run off during the dry season.
Groundwater and surface water resources El Salvador counts nearly 360 rivers that connect to form ten hydrographic regions. There are four primary lakes in El Salvador including the Ilopango (72 km2), Guija (44 km2), Coatepeque (24.8 km2), , Olomega ( 24.2 km2) and four reservoirs created by hydroelectric dams discussed in more detail below. El Salvador also obtains about 7.5 km3 of surface water per year from neighboring Honduras and Guatemala. The Cerrón Grande Reservoir, known locally as Lake Suchitlán, is the largest body of fresh water in El Salvador.
The Lempa River watershed dominates El Salvador covering half of the country at 10, 255 km2 and draining 6, 214 million m3. The Lempa is 422 km long and originates in the Sierra Madre and the Sierra del Merendón in southern Guatemala. The river flows in Honduras for 31 km before entering El Salvador in northwest.
Groundwater is heavily relied upon for water supply as a result of polluted surface water, and sufficient supplies of fresh groundwater are available throughout most of the country. Groundwater recharge from infiltration is estimated at 6.15 km3 per year whereby 5.97 km3 is considered base flow that serves to recharge surface waters and therefore has the possibility of being extracted. The remaining unused water passes down through the river system and discharges into the Pacific Ocean. The best aquifers are located in coastal areas and valleys of the central plateau where substantial groundwater aquifers are located at depths of 10–100 meters.
Table: Principal characteristics in hydrological regions of El Salvador. Hydrographic Region Primary rivers Surface Area (km2) Annual Runoff (million m3) Rainy season annual runoff (million m3) Dry Season annual runoff (million m3) A Lempa 10, 255 6, 214 5, 217 836 B Paz 929 466 358 107 C Sacramento, Sunza 659 369 317 51 D San Pedro, Sonsonate, Banderas 875 776 654 123 E Maridinga, Tihuapa 1,146 359 310 50 F Comalapa, Guayabo 1,717 886 804 95 G Afluentes de la Bahia de Jiquilisco 958 618 502 115 H Grande de San Miguel 2, 250 1,161 985 175 I Afluentes del Golfo de Fonseca 804 299 296 33 J Sirama y Guascorán 1,348 479 423 56 SubTotal 20,941 11,627 9.867 1,642 Total with Guatemala and Honduras runoff totals added (regions A, B, J) 31,841 17,768 15,017 2,632 Source: FAO 2000
Water resources management by sector The average per capita availability of water in El Salvador is less than 2,800 m3/year. Per capita annual extraction is 118 m3 representing about 4.3% of available supplies. Agriculture uses about 60%, domestic needs are around 24%, and industrial usage is 16%.
Water coverage and usage
Access to an improved water source in El Salvador was estimated at 76% in 2006. Urban access was 90%, including about 13% lacking a piped connection to the house. Access in rural areas in 2006 was 50%, however only 38% of this total had a piped connection to the house. Most water in rural areas is drawn from groundwater wells.
Irrigation and drainage Potential surface area for irrigation if only considering soil type is around ; however, when adequate availability of water is also considered, the potential surface area for irrigation is about . Approximately 56% of water available for irrigation is drawn from surface water while the rest is supplied from groundwater. The highest potential for irrigation is located in the coastal plains where the best groundwater is located. About 24% of the total potential area is classified as having "good" potential, while 60% is classified as having a "moderate" potential, and finally about 15% is classified as having potential with substantial limitations.
The private sector for irrigation has grown substantially since 1950 when only were under irrigation by the private sector. By 1960, there were irrigated by the private sector and in 1995, were being irrigated under private control. A concerted effort to develop the irrigation sector between 1966 and 1991 was put forth by the Ministry of Agriculture (MAG) through their General Directorate of Irrigation and Drainage. MAG enacted irrigation districts in Zapotitán (7,400 acres), and Atiocoyo (9,760 acres) with an investment of US $24.7 million and later developed the Lempa-Acahuapa district at a cost of US $21.2 million.
Since 1975, growth in private sector irrigation has stabilized where grass crops have been replaced with higher value crops with a larger profit margin. The distribution of publicly managed irrigation are located mostly in the Sonsonate, Sensunapán, Banderas, and San Pedro watersheds. Public irrigation projects are also prevalent in other areas where good water and soil are located such as the Lempa River, Titihuapa, Sucio, Torola, Grande, and Suquiapa basins. The beneficiaries of public irrigation are organized into 36 associations.
Total surface area with irrigation drainage problems was estimated at where most of this land is located in coastal plains. These coastal regions are home to many mangroves and marshes, therefore land remains saturated. There have been successful past efforts to pump off or convey excess water left behind after the rainy season. While drainage is a problem, salinity problems have not been widely detected in the soil.
Hydroelectricity
Hydroelectric potential is estimated at 1,889 MW where 1,409 MW of this potential is on the Lempa River. However, only 21% of the potential of the Lempa River is utilized. CEL (Comisión Hidroeléctrica del Río Lempa) is a public entity that generates over 90% of the hydroelectric output of El Salvador. Four projects on the Lempa River constitute all of the hydroelectricity generation in El Salvador and account for 41% of the total electricity produced in the country.
Projects include: 5 de Noviembre with 81.4 MW installed generation capacity Guajoyo with 15MW of installed generation capacity Cerrón Grande Hydroelectric Dam with 135 MW of installed generation capacity. The dam's reservoir has a surface area of 135 km2 and a capacity of 2,180 million m3. 15 de Septiembre with 156.3 MW installed generation capacity including and upgrade to 24 MW of new installed capacity
New Hydroelectric projects include: Cimarron Hydroelectric Power Project is a project whose construction is expected to begin in 2010 and will also be on the Lempa River within the upper river basin in the Santa Ana Department. Water will be diverted from the Lempa River to a power generation site near the town of Agua Caliente. Installed capacity will be 261 MW and will generate an average of 686 GWh per year. The dam will be 165 meters high and 660 meters long and create a reservoir holding 592 million m3 of water.
El Chaparral will have 66 MW of installed generation capacity
Legal and institutional framework