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The Tijuana River (Spanish: Río Tijuana) is an intermittent river, 120 mi (195 km) long, near the Pacific coast of northern Baja California state in northwestern Mexico and Southern California in the western United States.

Tijuana River
Presa Tij 1.jpg
Dam on the Tijuana River in Mexico.
Countries  Mexico,  United States
States Baja California, California
District San Diego County (California)
Municipalities Ensenada, Tijuana, Tecate, San Ysidro (Baja California)
 - left Arroyo de las Palmas
Source Sierra de Juárez
 - location Municipality of Ensenada
 - elevation 614 ft (187 m)
Mouth Pacific Ocean
 - location Imperial Beach
 - elevation 0 ft (0 m)
Length 120 mi (193 km)
Basin 1,750 sq mi (4,532 km2)
Discharge for Nestor, San Diego
 - average 42.5 cu ft/s (1 m3/s)
 - max 33,500 cu ft/s (949 m3/s)
 - min 0 cu ft/s (0 m3/s)



The Tijuana River drains an arid area along the U.S.—Mexico border, flowing through Mexico for most its course then crossing the border into Southern California for its lower 5 mi (8 km) to empty into the ocean in an estuary on the southern edge of San Diego.

The Tijuana River has two main tributaries. One, the Arroyo de Alamar or Rio Alamar, runs in its upper reaches in the United States as Cottonwood Creek. It runs from its source in the Laguna Mountains southwestward where it is impounded by two dams, Barrett and Morena, to supply water to the city of San Diego. Cottonwood Creek is joined by the Tecate Creek before it enters Mexico where it is known as the Arroyo de Alamar from the point where it enters Mexico to its confluence with the larger tributary, the Arroyo de las Palmas, that forms the headwaters of the Tijuana River within the city.

The Arroyo de las Palmas, the main tributary of the Tijuana River, flows out of the mountains to the east into the reservoir behind the Abelardo L. Rodríguez Dam. Downstream from the Rodríguez Dam, water flows through Tijuana in a concrete channel to the international border; there it continues west through the Tijuana River Valley for a distance of about nine miles to the estuary and then to the Pacific Ocean.

Its lower reaches provide the last undeveloped coast wetlands in San Diego County amidst a highly urbanized environment at the southern city limits of Imperial Beach. The river has been the subject of great controversy in recent decades regarding pollution, flood control, and U.S. border protection.


Tijuana River seen from a pedestrian bridge in Tijuana (Mexico).

The Tijuana River rises in the Sierra de Juárez of northern Baja California, approximately 45 mi (70 km) ENE of Ensenada. It flows WNW through Tijuana, crossing the border approximately 5 mi (8 km) from the Pacific. It flows west, just skirting the international border south of the San Ysidro section of San Diego. The lower 2 mi (3 km) of the river form the broad mud flat estuary, and the Tijuana River Estuary is a rich habitat for wildlife, including over 370 species of birds.[1] It is Southern California's largest coastal wetland.[2] It is naturally prone to flooding during heavy rains. The Tijuana River enters the Pacific 10 mi (15 km) south of downtown San Diego at the southern city limits of Imperial Beach.

The river is impounded in Mexico southeast of Tijuana by the Abelardo L. Rodríguez Dam for drinking water and irrigation. Former Baja California Governor Milton Castellanos Everardo constructed concrete barriers along the riverbank to prevent flooding during his tenure.[3] The United States was supposed to build a complementary system of barriers to ensure flooding waters didn't flow back into Mexico, but instead adopted a dissipator flood control plan under the direction of the San Diego City Council, supported by ecologists, which preserved the estuary, which was then designated a wildlife sanctuary.[4]

The majority of its watershed is within Mexico, between Mesa de Otay to the east, and hills to the west.[4]



Flooding in the Tijuana River had been a concern for both the United States and Mexico because it would lead to sewage runoff and would ultimately caused property damage to the surrounding area. In 1944, the United States-Mexico Water Treaty was signed, this dealt with "utilization of waters in the Colorado and Tijuana rivers and of the Rio Grande."[5] This treaty appointed the International Boundary and Water Commission to handle several issues such as border sanitation.[6] The IBWC went on to create the Tijuana River Flood Control Project in 1966 in order to create a flood control channels along the river. Mexico had completely complied by 1976 while the U.S. implementation stalled due to opposition at the local level.[7] Despite preventive measures, flooding in 1980 caused 11 deaths and property damage in bordering cities.[8] Flooding due to high rainfall and sewage blockage continues to be a concern that endangers surrounding areas because of the wastewater pollution found in the river.[9]

Nature reservesEdit

The Tijuana River National Estuarine Research Reserve protects 2,293 acres (928 ha) and studies the Tijuana River Estuary.[10] It was established as part of the National Estuarine Research Reserve system in the United States.[11] The reserve is managed in part as a Biological Field Station by the San Diego State University (SDSU) College of Sciences, which also protects part of the estuary near the ocean within the United States.[12]

The Tijuana Slough National Wildlife Refuge is part of the San Diego National Wildlife Refuge Complex, and is also within the Estuarine Research Reserve. The Tijuana Slough Refuge protects one of southern California's largest remaining salt marshes without a road or railroad trestle running through it. Designated as a Globally Important Bird Area by the American Bird Conservancy, over 370 species of birds have been sighted on the refuge.[13]

Wastewater treatmentEdit

The river has been used as a wastewater conduit since at least the early 20th century.[14][4] As such, the issue of sewage in the Tijuana River predates other news stories about the Mexico-United States border within the San Diego–Tijuana region by several decades.[4] Raw-sewage overflows on the Mexican side, from canyons along the river, are a recurring problem despite cross-border efforts to clean it up.[14][15] In fact, they are the main source of pollution.[16] In addition to sewage, trash is carried downstream causing damage to vegetation and contributing to flooding.[17]

The first attempt to deal with sewage flowing into the Tijuana River was the creation of the International Outfall, a marine outfall, which was completed in 1939, but was proven to be inadequate as early as the late 1940s.[4] By the 1950s, there were over 4 million gallons of sewage flowing into the river each day.[4] Usage of the outfall ended in 1962 due to the completion of a pumping plant, which discharged untreated sewage into the Pacific Ocean; the pumping plant broke down in 1975.[18] During the 1970s, up to ten million gallons of sewage entered the river each day from Tijuana.[19]

Partial progress was made in the 1980s with a Clean Water Grant from the U.S. Environmental Protection Agency to improve wastewater treatment, by creating the San Diego-Tijuana Wastewater Treatment Plant to protect estuary waters.[20] In 1990, Mexico agreed to pay $41 million of the $192 million to construct the plant.[21] The plant was completed in 1997.[15] Water from the plant is discharged more than three miles offshore, but does not meet levels required by the Clean Water Act due to the lack of secondary treatment.[16] Finished in January 2011, the plant received a $93 million upgrade.[22] Other sewage that would have flowed into the Tijuana river is treated at the Punta Bandara treatment plant;[23] it handles 30 million gallons of sewage a day. However, its discharge doesn't meet Mexican water standards, sometimes causing closure of beaches as far north as Coronado.[24]

According to a 1993 report by the city of San Diego, the city had collected an average of 13 million gallons (50 million liters) per day of raw sewage, that then was treated by the Point Loma wastewater treatment plant;[20] this is down from 20 million gallons per day in 1997 being treated by the city of San Diego, which it had received from Tijuana.[4] Since 1998 the U.S. EPA has funded $42 million on sewage projects in Tijuana.[25] In 2015, the amount of sewage treated on a dry day remained the same, at 13 million gallons. However, when it rains, the amount of sewage can increase to 27 million gallons per day, and the pump which funnels water to the treatment plant is shut off so it isn't overcome.[23] In January 2017, the Punta Bandaras treatment plant, officially known as San Antonio de los Buenos plant, treated 15 million gallons of sewage a day to standards below U.S. secondary-level standards, pumping the water out into the Pacific Ocean at La Playa.[26] Due to the sewage in the river, it has been called "one of the most polluted waterways in the country".[27] This has led to a multitude of beach closures in Imperial Beach.[14] Each year the beach at Border Field State Park is closed for 233 days.[26]

In February 2017, over 143 million gallons of sewage entered the river, larger than the usual few million gallons of sewage that is routine.[28] Later, the amount of was revised upwards to over 200 million gallons.[29] However, a Mexican water official claimed the spill was only 30 million gallons.[25] The spill is the largest to occur in over ten years.[30] The sewage spill was not initially reported by Mexican officials, but was noticed by residents on the South Bay coast.[31] The impact of the spill affected waters as far north as Coronado, and was described by Imperial Beach Mayor Serge Dedina as "a tsunami of sewage",[28][32] and "deliberate".[33] According to the International Boundary Water Commission, the sewage discharge was due to a repair of a sewer pipe near Rio Alamar.[28] The sewage was first noticed in the middle of the month.[34] Repairs of the sewer pipe were completed in late February 2017, but the exact dates when the sewage began and stopped entering the river were unknown as of March 2017, leading to calls for an investigation.[35] By mid-March 2017, the California Department of Environmental Health found the water quality had returned to within health standards, opening beaches up to Coronado.[36]

In March 2018, due to sewage in the Tijuana River, Chula Vista, Imperial Beach, and the Port of San Diego sued the International Boundary Water Commission.[37]

21st century water improvement agreementsEdit

Over 30 federal, local, state, private and other interested groups want to develop bi-national long terms goals to address wastewater treatment and debris-related improvements.[38] One major initiative introduced in the United States on March 16, 2015, was Resolution R902015-0035, a Five-Year Action Plan that aimed to implement restorative projects over the span of five-years.[39] The resolution was initially introduced by the Tijuana River Valley Recovery Team (TRVRT) whose ultimate goal is to progress and implement strategies originally introduced in January 2012, under the Tijuana River Valley Recovery Strategy regulatory measures.[39] Other restorative measures across the U.S. include grants like the Community-based Marine Debris Removal Grant that brings organizations together in conjunction with community-based cleanups to remove trash and debris from the Tijuana River Valley. The debris removal grant began in 2014 and successfully removed over 400 tons of debris by 2016.[40] A bi-national discussion on July 28, 2016, established upcoming proposed projects between the Border 2020 Tijuana River Watershed Task Force and the Tijuana River Valley Recovery Team.[41] These discussions continue the national environmental resolutions agreement under the 1983 La Paz Agreement that acknowledges the environmental and social responsibility of each country near its border regions.[42] Under this treaty each country is under agreement to conserve, protect, and improve border regions for the overall well-being of the coinciding countries.[42]



The Tijuana River Valley Regional Park is located in the Tijuana River Valley district of San Diego. It protects over 1,800 acres (730 ha), including dense riparian forests along the Tijuana River. It has an extensive system of trails for walking and equestrian access.[43]


The mouth of the Tijuana River is the location of the Tijuana Sloughs big-wave surfing break, which is a mile off shore.[44] Winter waves can be as high as 12 feet or greater;[45] 20 foot high waves are not unknown to occur.[46] Surfing has been occurring at the slough since at least 1937.[47] It has been described as the "gold standard" in Southern California;[48] with surfers using it as a training ground for surf found in Hawaii.[49]

Surfing at the sloughs has impacted the evolution of surfing culture, as well as regional culture.[50] Lifeguards have watched over the area since 1939.[51] Sewage from the river impacts water quality, which can lead to surfers becoming ill;[52] one source describes that area as "virtually unsurfable due to pollution."[53]

See alsoEdit


  1. ^ Tijuana Estuary. accessed 6.16.2012
  2. ^ Barbara Zaragoza (23 June 2014). San Ysidro and The Tijuana River Valley. Arcadia Publishing Incorporated. p. 8. ISBN 978-1-4396-4592-5. 
  3. ^ Islas Parra, Victor (2011-10-11). "Murió ayer Milton Castellanos". El Mexicano. Retrieved 2011-10-25. 
  4. ^ a b c d e f g Lawrence A. Herzog (1990). Where North Meets South: Cities, Space, and Politics on the United States-Mexico Border. University of Texas Press. p. 194-201. ISBN 978-0-292-79053-7. 
  5. ^ "IBWC Treaties". International Boundary and Water Commission. Retrieved 30 November 2017. 
  6. ^ "Tijuana River Flood Control Project (TRFCP)". International Boundary and Water Commission. Retrieved November 29, 2017. 
  7. ^ Kennedy, William (1979). ""Ecology and the Border: The Case of the Tijuana Flood Control Chan". Environmental Problems Along the Bor (7): 84. 
  8. ^ Bath, Richard (1981). "Resolving Water Disputes". Proceedings of the Academy of Political Science. 34: 184. 
  9. ^ Baker, Debbi. "Tijuana River reopened after blockage kills sharks, floods streets". The San Diego Union Tribune. Retrieved 30 November 2017. 
  10. ^ TRNERR — Tijuana River National Estuarine Research Reserve at the Tijuana Estuary. accessed 6.16.2012
  11. ^ National Estuarine Research Reserve System: Tijuana River. accessed 6.16.2012
  12. ^ SDSU Field Station Archived 2007-06-08 at the Wayback Machine.
  13. ^ Refuge profile
  14. ^ a b c "Sewage History of Tijuana". San Diego Magazine. December 2007. Retrieved 24 March 2017. 
  15. ^ a b Anthony R. Turton; Johanna Hanlie Hattingh; Gillian A. Maree; Dirk J. Roux; Marius Claassen; Wilma F. Strydom (16 February 2007). Governance as a Trialogue: Government-Society-Science in Transition. Springer Science & Business Media. pp. 186–196. ISBN 978-3-540-46266-8. 
  16. ^ a b "Tijuana River National Estuarine Research Reserve Comprehensive Management Plan" (PDF). Office of Coastal Management. National Oceanic and Atmospheric Administration. August 2010. Retrieved 6 April 2017. 
  17. ^ "EPA's Border Water Program and the Tijuana River" (PDF). Committee on Environmental Safety and Toxic Materials. California State Assembly. March 2015. Retrieved 25 March 2017. 
  18. ^ International Boundary & Water Commission, United States & Mexico (1981). Proposed Recommendations for Solution of the Border Sanitation Problem at Tijuana, B.C.N. & San Diego, Cal. pp. 6–7. 
  19. ^ "HISTORY OF SAN DIEGO & TIJUANA SEWAGE SYSTEMS" (PDF). University of San Diego. Retrieved 25 March 2017. 
  20. ^ a b Saldaña, Lori (June 1994). "Tijuana River: a controversy runs through it". San Diego Earth Times. Chris Klein, Earth Media, Inc. Retrieved 24 March 2017. 
  21. ^ Mydans, Seth (22 August 1990). "U.S. and Mexico Take On a Joint Burden: Sewage". New York Times. Retrieved 25 March 2017. 
  22. ^ Davis, Rob (11 April 2012). "Sewage Flowed Freely Without Warning". Voice of San Diego. Retrieved 25 March 2017. 
  23. ^ a b Dibble, Sandra (19 December 2015). "Cross-border flows raise renewed concerns". San Diego Union-Tribune. Retrieved 24 March 2017. 
  24. ^ Dedina, Serge (10 January 2007). "Trump's Folly". Voice of San Diego. Retrieved 24 March 2017. 
  25. ^ a b Sandra Dibble; Joshua Emerson Smith (12 March 2017). "Two countries, one sewage problem: Tijuana and San Diego grapple with renegade flows". San Diego Union-Tribune. Retrieved 24 March 2017. 
  26. ^ a b Graham, Marty (19 January 2017). "Whoa, Mexico, that water clean". San Diego Reader. Retrieved 24 March 2017. 
  27. ^ Weber, Christopher (26 February 2017). "Large sewage spill in Tijuana, Mexico, flows north of border". ABC News. Associated Press. Retrieved 4 March 2017. 
  28. ^ a b c Smith, Joshua Emerson (1 March 2017). "Tijuana fouls U.S. beaches, may have been intentional". Los Angeles Times. Retrieved 4 March 2017. 
  29. ^ Rivera, Salvador (7 March 2017). "Mexican sewage spill much worse than original estimates, congressman says". KSWB. San Diego. Retrieved 24 March 2017. 
    Smith, Joshua Emerson (6 March 2017). "Huge sewage spill was perhaps far bigger: 230 million gallons?". San Diego Union-Tribune. Retrieved 24 March 2017. 
  30. ^ Rivard, Ry (16 March 2017). "Top SD Water Official Wants Tijuana to Prioritize Sewer Water Over Desal Water". Voice of San Diego. Retrieved 25 March 2017. 
  31. ^ Pat Finn; Mark Sauer (24 March 2017). "Roundtable: San Diego Encounters Trump's Budget And Tijuana's Sewage". KPBS. San Diego. Retrieved 24 March 2017. 
  32. ^ Anderson, Erik (27 February 2017). "Imperial Beach Mayor Blasts Reaction To Major Sewage Spill". KPBS. San Diego. Retrieved 4 March 2017. 
  33. ^ Gaydos, Ryan (3 March 2017). "'Tsunami of sewage spills' at Mexican border 'deliberate,' says California mayor". Fox News. Associated Press. Retrieved 4 March 2017. 
  34. ^ Graham, Marty (21 February 2017). "Tijuana River flushed hard". San Diego Reader. Retrieved 4 March 2017. 
  35. ^ Klamper, Ruth (3 March 2017). "Federal Officials to Investigate Tijuana River Sewage Spill (VIDEO)". Coronado Times. Retrieved 4 March 2017. 
  36. ^ "California Beach Reopens After Sewage Cleared". U.S. News & World Report. New York City. Associated Press. 11 March 2017. Retrieved 12 March 2017. 
  37. ^ "Study Aims To Tackle Cross-Border Sewage Spills". KPBS. San Diego. City News Service. 18 May 2018. Retrieved 6 June 2018. 
  38. ^ "Recovery Strategy Living with the Water" (PDF). January 2012. Retrieved 27 November 2017. 
  39. ^ a b California, S. O. "Tijuana River Valley Recovery Strategy". Retrieved 27 November 2017. 
  40. ^ "Tijuana River National Estuarine Research Reserve Marine Debris Cleanup and Reduction Program". OR&R's Marine Debris Program. Retrieved 27 November 2017. 
  41. ^ "U.S.-MEXICO ENVIRONMENTAL PROGRAM Summary" (PDF). Border 2020 Factsheet. 6 June 2012. Retrieved 27 November 2017. 
  42. ^ a b "La Paz Agreement" (PDF). Retrieved 27 November 2017. 
  43. ^ County of San Diego: Tijuana River Valley Regional Park. accessed 6.16.2012
  44. ^ Philip L. Fradkin; Alex Leon Fradkin (2011). The Left Coast: California on the Edge. University of California Press. p. 86. ISBN 978-0-520-25509-8. 
  45. ^ Matt Warshaw (2005). The Encyclopedia of Surfing. Houghton Mifflin Harcourt. p. 519. ISBN 0-15-603251-1. 
  46. ^ David Small; Larry Blair (2005). Wave-Finder Mexico: The Ultimate Surfer's Guide. Wavefinder Limited. p. 25. ISBN 978-0-9581726-7-7. 
  47. ^ "South Bay Historical Society Bulletin". City of Chula Vista. April 2016. Retrieved 25 March 2017. 
    "Surfhenge Surfboard Benches by Malcolm Jones". Public Art. Unified Port of San Diego. 13 June 2008. Retrieved 25 March 2017. 
  48. ^ Melekian, Brad (2 January 2007). "Huge waves at the Tijuana Sloughs are tempting, but dangerous Surfing". San Diego Union-Tribune. Archived from the original on 26 January 2009. Retrieved 25 March 2017. 
  49. ^ Wycoff, Ann (23 August 2010). "Battle for IB". San Diego Magazine. Retrieved 25 March 2017. 
  50. ^ Simon J Bronner (4 March 2015). Encyclopedia of American Folklife. Taylor & Francis. p. 3073. ISBN 978-1-317-47194-3. 
  51. ^ John C. Elwell; Jane Schmauss; California Surf Museum (4 July 2007). Surfing in San Diego. Arcadia Publishing. p. 28. ISBN 978-1-4396-3413-4. 
  52. ^ Hargrove, Dorian (12 March 2009). "Endless Bummer". San Diego Reader. Retrieved 25 March 2017. 
  53. ^ Peter J. Westwick; Peter Neushul (23 July 2013). The World in the Curl: An Unconventional History of Surfing. Crown/Archetype. p. 184. ISBN 978-0-307-71948-5. 

Further readingEdit

External linksEdit