Urban water management in Bogotá, a metropolitan area of more than 8 million inhabitants, faces three main challenges: improving the quality of the highly polluted Bogotá River, controlling floods and revitalizing riparian areas along the river. The main public entities in charge of water resources management in Bogotá are the district government, the regional environmental agency Corporación Autónoma Regional (CAR) of the department of Cundinamarca, and the water and sanitation utility Empresa de Acueducto y Alcantarillado de Bogotá (EAAB). A court mandated that these entities cooperate to improve the river's quality, a ruling that translated into an agreement signed in 2007 that defined the responsibilities of each entity and forced them to approach the water management challenges in an integrated way. The agreement prepared the ground for the expansion of the Salitre wastewater treatment plant, construction of a new one, widening and protecting of riparian zones, restoring the natural meander of the river, and hydraulically connecting the river to its flood plains. These measures are supported by the World Bank and the Inter-American Development Bank.
Geography and climate Bogotá is located on a high plateau, called Bogotá savanna, in the Eastern Ranges of the Andes at an elevation of above sea level. The extended region is known as the Altiplano Cundiboyacense, meaning "high plateau of Cundinamarca and Boyacá". The Bogotá River crosses the savanna and forms the Tequendama Falls (Salto del Tequendama) to the southwest. Tributary rivers form valleys where villages lie and whose economy is based on agriculture, livestock, and artisan production. The savanna is bordered to the east by the Eastern Hills that run north-south and contain the Guadalupe and Monserrate hills. The western city limit is formed by the Bogotá River. Going north, the Metropolitan Area of Bogotá extends over the plateau up to the towns of Chía and Sopó.
Bogota has a subtropical highland climate and the average temperature on the Bogotá savanna is , varying from . Dry and rainy seasons alternate throughout the year. The driest months are December–March with per month of precipitation; the rainiest months are April and May with approximately monthly totals, and September - November ( per month). June and July are usually rainy periods and August is sunny with high winds. Hailstorms are common during the rainy season, and can be very strong, especially in October. Throughout the year, the days are mild and cool while nights can get moderately cold due to calm winds blowing in the evening.
History During a period of approximately thirty years from the early 1970s through the 1990s Bogotá's water management focused heavily on improving coverage and quality of water supply sanitation services (WSS) while also improving financial and technical sustainability. As a result, the water and sewage company of Bogotá (EAAB) provides above 99 percent coverage for water, sewage and drainage services, and has transformed itself from an inefficient bankrupt company into a commercial water utility with a corporate culture based on professional responsibility and accountability.
While WSS improvements were ongoing, the traditional water management approach did not account for domestic and industrial wastewater treatment and non-point sources pollution control resulting in the environmental degradation of water bodies. These systems were viewed as separate and the management strategy did not account for treatment facilities, local streams, and overall water quality within them. The philosophy is evolving however, and water resources management practice is becoming more of an integrated approach taking into account a multi-sectoral approach looking at water supply, wastewater treatment plant (WWTP), drainage and irrigation as one entity. According to pollution control work presented by a team of researchers at the British Hydrological Society symposium in 2008, there is a need to consider the sewer system, the WWTP, and the river as one system. These developments in the Bogotá water management system offer multiple opportunities to incorporate integrated methodologies both now and in the future.
Historical legal background In the 1970s, wastewater was becoming an increasing problem. All of the city's untreated wastewater were being discharged into the Bogotá river and ultimately the reservoir behind the Muña dam. The community of Muña brought a lawsuit against EAAB, CAR, EMGESA, and the district government for negligence. The Tribunal of the Department of Cundinamarca ultimately decided for the community of Muña and further required the parties to create a review process and action plan to address the grievances brought forth by Muña. The Tribunal reserved the right to force a decision by the defendants if they did not make suitable progress on the mandate. The defendants appealed and the process went under review again. Upon further review, a judge ruled again in favor of Muña and delegated shared responsibilities to CAR, EAAB, and the District. The defendants agreed to the terms set by the court ruling and the prevailing legal document was called Convenio 171 and was signed by all parties in 2007. Convenio 171 calls for CAR to finance and construct the upgrade and expansion of the Salitre WWTP. CAR did this by creating a special account for the Bogotá wastewater program called Fondos Para Inversiones Ambientales en Bogotá (FIAB) (Funds for environmental investment in Bogotá). EAAB agreed to construct the new interceptors to the forthcoming Canoas WWTP.
Multi-stakeholder assistance The World Bank is working with CAR, EAAB, and the Government District to help refine the Sanitation Plan (Plan de Saneamiento) and establish the basis for a long-term program to improve the water ecosystem in the basin. Project cost is US$487 million and the objectives are to transform 68-km of Bogota River into an environmental asset for the Bogota metropolitan region by improving water quality, reducing flood risk, restoring riparian habitats, and creating multifunctional areas along the river that provide an ecological habitat, as well as opportunities for the public use and enjoyment of this urban river.
Additionally, the World Bank is offering assistance with an integrated urban water management strategy. The goal is to enable Bogotá to move towards a sustainable approach to improving the Bogotá river and creating an urban environmental asset. Objectives include a model project for urban river recuperation that incorporates water quality improvements, flood control, wetlands, and multifunctional parks.
The Inter-American Development Bank (IDB) is planning a US$50 million loan to support CAR in its Bogotá River cleanup efforts. The IDB also contributed a US$1.5 million grant to CAR's environmental control program. An additional US$643,000 was put up by CAR itself. The projects for the basin's protection are to be carried out in multiple stages, the first of which implements an institutional, managerial, financial and operational framework to carry out the cleanup project. With the loan, CAR plans on building aqueducts and increasing potable water supply, drainage systems and wastewater treatment for all 41 municipalities located in the Bogotá river basin. The money may also finance the design, construction and operation of wastewater treatment plants for municipalities that do have them.
Water supply and use
Surface water Water supply in the Bogotá metro area involves a system of watersheds that collect, store, and deliver water to the Bogotá River Basin. Watersheds upstream include Tibitoc with a total storage capacity of 887 Mn3, Chingaza with total storage capacity at 325 Mn3, and Tunjuelo with total storage capacity at 10.4 Mn3. Chingaza, which is Bogotá's primary source for drinking water receives its water from another watershed belonging to the inhabitants of the eastern Colombian plains. Waters from the eastern catchment are transferred to Chinzaga and then finally reach the Rio Bogotá as wastewater after passing through the Bogotá water system. Within these other water basins, there are approximately nine storage reservoirs that supply water by way of tunnel, aqueduct, or tributary to the main water system of Bogotá. Primary storage reservoirs include Chuza, Sisga, Tominé, and the Neusa.
The Bogotá River starts at an elevation of and flows before discharging into the Magdalena River at an elevation of 280 meters. The Basin covers and is divided into three parts: i) upper basin north of Bogotá; ii) middle basin in the Bogotá metropolitan area; and iii) lower basin downstream of Bogotá. While the Bogotá River passes through the middle basin and the Bogotá metro area, three sub-basins, the Salitre, Fucha, and Tunjuelo discharge their tributaries into the Bogotá River before entering the lower basin. The average flow before entering the city is 10 m3/s, and the sub-basins surrounding Bogotá discharge an additional 22 m3/s of wastewater.
Groundwater While most of the water supply for Bogotá is supplied by rivers, there does exist groundwater that could become a considerable portion of the Bogotá water portfolio. Currently, groundwater is primarily used for the irrigation of flowers. Approximately (BCM) is contained in the Guadalupe aquifer representing about 30 times the amount of water stored in all the reservoirs of the city. In the past, wells have been drilled in some areas and aquifer levels have descended causing the collapse of housing developments, roads, and some of the wells themselves.
Water use The population of Bogotá consumes per capita which is generally accepted to be an adequate amount for drinking, bathing, sanitation, and cooking. EAAB estimates per capita usage of around . In Latin America, the average water use was estimated in 2005 at about per capita.ADERASA Benchmarking report 2005, p. 22, based on a non-representative sample of 50 utilities of various sizes in 9 countries Total consumption was about , of which 85% (or ) was returned to the Bogotá River downstream. The other municipalities in the basin used about , for a total of for the whole basin. This amount increased to 23–25 m3/s by year 2000 and was expected to reach by 2010. There currently remains approximately 700,000 people in the metropolitan area and 75,000 in other nearby municipalities that are without water services.
Infrastructure
Drainage The Bogotá drainage system consists of three main sub-catchments: the Salitre, Fucha and Tunjuelo Rivers. Each one flows from east to west. The drainage system is a combination of a combined and separated system. The first drainage system developments (before 1965) were constructed in the central part of Salitre sub-catchment and the eastern part of Fucha sub-catchment and they consist of a combined system with an approximate length of while newer ones (since 1965) consist of separated systems.
Wastewater and treatment The original wastewater master plan for Bogotá was conceived in the late 1980s, and called for the construction of one wastewater treatment plant downstream of the city. In the early 1990s, however, the municipal government changed course and decided to pursue 3 medium-sized wastewater treatment plants, one for each of the three sub-catchments (introduced in the previous section) in Bogotá. In 1994, the city entered into a build-operate-transfer (BOT) concession contract with a French consortium for a 4 m3/s primary WWTP called Salitre, which is located in the northern part of Bogotá. The plant started operations in 2000, and in December 2003 the district canceled the contract, purchased the plant from the consortium, and turned over its operation to EAAB. The existing Salitre WWTP does not provide adequate treatment, therefore an expansion and upgrade to a secondary WWTP is underway and will serve the northern population in Bogota City.