Table Source for Ensenada Water Shortage projections
Editor’s note: Land use, planning, environmental issues and money issues have delayed Ensenada’s 2 new water projects, The Tecate to Valle de Guadalupe aqueduct and the Ensenada Lagunita Desalination Plant.
The city of Ensenada and the agricultural valleys of Maneadero and Guadalupeare located in Northern Baja California. The climate is Mediterranean, with dry summers and rains during winter. Average annual precipitation is 245 mm(CNA, 1998). In 2000, Ensenada had a population of 260,065 and the primary economic activities were commerce and manufacturing (INEGI, 2004). Ensenada’s water commission, CESPE (Comisión Estatal de Servicios Públicos de Ensenada) is in charge of both potable water supply and wastewater collection and treatment. According to CESPE, the city has more than 86,000 water supply connections, covering 99.9% of the population, with physical losses ranging between 16 and 30 percent. Wastewater collection coverage accounts for 83% or15.6 million cubic meters (Mm3) per year. All collected wastewater is treated in three wastewater treatment plants prior to ocean discharge. About 2% of treated wastewater is reused for irrigation of green areas within the city (Mendoza-Espinosaet al.2004).
Rain in the region is sporadic and no significant surface water systems exist;urban and agricultural water demands are met by local or regional aquifers. The aquifers of Maneadero, Ensenada, Guadalupe, and La Misión provide potable water for the city. The Emilio Lopez Zamora dam, now surrounded by urban development was built primarily for flood control and does not serve as storage for potable water. Although the dam has a small-capacity treatment treatment plant, it is rarely used, requiring water surpluses to be present.
Due to low rainfall, increasing urban growth and agricultural activities, the Maneadero, Ensenada, Guadalupe and La Misión aquifers are overdrawn. The Maneadero aquifer has a severe saline intrusion problems and water quality decreased dramatically in recent years (Daesslé et al.2006).
The Maneadero Valley of is an agricultural region of significant economic value for Baja California. Located 10 km South of urban Ensenada, it has an irrigation area of 5,300 ha (SAGARPA 2005). The Maneadero aquifer is the sole source of water for crop irrigation and domestic use in Maneadero (population 15,234 -INEGI 2005). The main crops in Maneadero are tomatoes, peas, onions,asparagus, and alfalfa (SAGARPA 2005). Approximately 90% of agricultural production is exported to the United States. Irrigation is mainly implemented through drip irrigation. Agricultural water uses account for 71% of total extractions, and urban uses account for 25%, other activities makeup the remaining 4%. The aquifer has an Integrated Water Management Plan (CNA2003) which identifies groundwater overdraft in Maneadero and gives an estimated natural recharge capacity of approximately 7 Mm3/yr. Overdraft of the aquifer has increased energy requirements for pumping and caused severe saline intrusion.
The Guadalupe Valley is located 12 km Northeast of the city of Ensenada. Approximately 200 l/s (6.31 Mm3/yr) of groundwater is extracted to supply Ensenada’s urban demand. The Guadalupe valley has an agricultural area of12,115 ha. Grapes and olives are the most important crops in the Guadalupe Valley, although in the last few years there has been an increase in organic produce and green house products. The aquifer is also essential for agriculture in the valley, providing for grapes and the associated wine industry, which is the most important wine region in the country (Daessléet al.2006). During 2001 wine production in the region accounted for 19.6 million liters of wine, 30% of which was exported (SAGARPA 2005). Although water quality has not deteriorated over time (Daesslé et al2006), local farmers are against the supply of water going to Ensenada, arguing that such allocations should be used for larger agricultural production in the valley.
Due to current aquifer overdraft, the city of Ensenada needs to find alternatives to guarantee water supply in years to come. Wastewater reuse is a suitable water supply for crop and landscape irrigation, aquifer recharge, and industrial uses in Ensenada and the Valleys Manuaderon and Guadalupe (Ramírez-Acosta andMendoza-Espinosa 2005). The National Water Commission (CNA) undertook a study in which members of the public were asked about their acceptance of reusing treated wastewater for urban activities (CNA, 2005). Results showed most people favoring reuse of wastewater for activities in which the public would be in indirect contact with the water, as long as its quality is closely monitored and controlled.
Unlike most cities in Mexico, Ensenada treats all the wastewater collected by its sewer infrastructure (CESPE 2005). Treatment is provided in three wastewater plants, namely El Naranjo (capacity of 500 l/s, 15.77 Mm/yr), El Gallo (capacityof 250 l/s, 7.9 Mm3/yr) and El Sauzal (capacity of 60 l/s or 1.9 Mm3/yr). All wastewater treatment plants are currently operated at slightly less than maximum capacity and their effluents meet standards for crop irrigation and have the potential for for aquifer recharge (Mendoza-Espinosa et al.2005; and2004).
The agricultural valleys of Maneadero and Guadalupe have been classified as“critical zones” due to problems arising from decreases in water quantity and quality from aquifer overdraft. The urban Ensenada also has been classified as critical due to several factors including pollution by landfills, poor drinking water quality, extensive deforestation and a drought in the region (SIDUE, 2000).
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