# Cagayan River > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Cagayan_River > Markdown URL: https://mediated.wiki/source/Cagayan_River.md > Source: https://en.wikipedia.org/wiki/Cagayan_River > Source revision: 1336080563 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Longest river in the Philippines For another river, see [Cagayan River (Mindanao)](/source/Cagayan_River_(Mindanao)). Cagayan River Río Grande de Cagayán The river as it passes through Jones in Isabela Drainage area of the river and its tributaries in northeastern Luzon Cagayan River mouth Show map of Luzon Cagayan River (Philippines) Show map of Philippines Native name Bannag (Ibanag) Location Country Philippines Region Cagayan Valley, Central Luzon Province Cagayan Isabela Nueva Vizcaya Quirino Aurora Physical characteristics Source Caraballo Mountains • location Dupax del Sur, Nueva Vizcaya • coordinates 16°11′08″N 121°08′39″E / 16.18556°N 121.14417°E / 16.18556; 121.14417 • elevation 1,524 m (5,000 ft) Mouth Babuyan Channel • location Aparri, Cagayan • coordinates 18°22′N 121°37′E / 18.367°N 121.617°E / 18.367; 121.617 • elevation 0 m (0 ft) Length 505 km (314 mi)[1] Basin size 27,753 km2 (10,715 mi2)[2] Basin features Tributaries • left Chico River Magat River • right Ilagan River Pinacanauan River The **Cagayan River**, also known as the **Río Grande de Cagayán**, is the longest river[3][1] and the largest river by [discharge](/source/Discharge_(hydrology)) volume of water in the [Philippines](/source/Philippines). It has a total length of approximately 505 kilometres (314 mi) and a [drainage basin](/source/Drainage_basin) covering 27,753 square kilometres (10,715 sq mi).[2] It is located in the [Cagayan Valley](/source/Cagayan_Valley) region in northeastern part of [Luzon Island](/source/Luzon_Island) and traverses the [provinces](/source/Provinces_of_the_Philippines) of [Nueva Vizcaya](/source/Nueva_Vizcaya), [Quirino](/source/Quirino), [Isabela](/source/Isabela_(province)) and [Cagayan](/source/Cagayan); it also flows through the only [Central Luzon](/source/Central_Luzon) province of [Aurora](/source/Aurora_(province)). ## Topography **X** Topography of the *Cagayan Valley* (marked by an **X**) in northeastern Luzon. The river's [headwaters](/source/Headwaters) are at the [Caraballo Mountains](/source/Caraballo_Mountains) of the [Central Luzon](/source/Central_Luzon) at an elevation of approximately 1,524 metres (5,000 ft). The river flows north for some 505 kilometres (314 mi)[4] to its mouth at the [Babuyan Channel](/source/Babuyan_Channel) near the town of [Aparri](/source/Aparri), [Cagayan](/source/Cagayan). The river drops rapidly to 91 metres (299 ft) above sea level some 227 kilometres (141 mi) from the river mouth. Its principal [tributaries](/source/Tributaries) are the [Pinacanauan](/source/Pinacanauan_River), [Chico](/source/Chico_River_(Philippines)), [Siffu](https://en.wikipedia.org/w/index.php?title=Siffu_River&action=edit&redlink=1), [Mallig](https://en.wikipedia.org/w/index.php?title=Mallig_River&action=edit&redlink=1), [Magat](/source/Magat_River) and [Ilagan Rivers](/source/Ilagan_River). [Magat River](/source/Magat_River), is the largest tributary with an estimated annual [discharge](/source/Discharge_(hydrology)) of 9,808 million cubic meters. It lies in the southwestern portion of the [basin](/source/Drainage_basin), stretching approximately 150 kilometres (93 mi) from [Nueva Vizcaya](/source/Nueva_Vizcaya) down to its [confluence](/source/Confluence) with Cagayan River about 55 kilometres (34 mi) from the [river mouth](/source/River_mouth). Both Magat and Chico Rivers have extensive drainage areas which comprise about 1/3 of the whole basin. The Ilagan River originates from the western slopes of the [Sierra Madre](/source/Sierra_Madre_(Philippines)) and drains the eastern central portion of the Cagayan River basin with an estimated yearly discharge of 9,455 million cubic meters. It flows westward and joins the Cagayan River at [Ilagan, Isabela](/source/Ilagan%2C_Isabela), 200 kilometres (120 mi) from the mouth. The Siffu-Mallig system lies on the slope of the Central [Cordillera](/source/Cordillera_Central_(Luzon)) ranges flowing almost parallel to the Magat River. Marshes and swamps are found in some parts of its lower reaches. Cagayan River and its tributaries have deposited sediments of [Tertiary](/source/Tertiary_(period)) and [Quaternary](/source/Quaternary) origin, mostly limestone sands and clays, throughout the relatively flat Cagayan Valley which is surrounded by the [Cordillera Mountains](/source/Cordillera_Central_(Luzon)) in the west, [Sierra Madre](/source/Sierra_Madre_(Philippines)) in the east and the [Caraballo Mountains](/source/Caraballo_Mountains) in the south. The river has a drainage area of about 27,300 square kilometres (10,500 sq mi). in the provinces of [Apayao](/source/Apayao_Province), [Aurora](/source/Aurora_Province), Cagayan, [Ifugao](/source/Ifugao_Province), Isabela, [Kalinga](/source/Kalinga_Province), [Mountain Province](/source/Mountain_Province), Nueva Vizcaya, and Quirino. The estimated annual discharge is 53,943 million cubic meters[5] with a groundwater reserve of 47,895 million cubic meters. ## Flooding The Cagayan River and its tributaries are subject to extensive flooding during the [monsoon](/source/Monsoon) season in [Southeast Asia](/source/Southeast_Asia) from May to November. The average annual rainfall in 1,000 millimetres (39 in) in the northern part and 3,000 millimetres (120 in) in the southern mountains where the river's headwaters lie. Water from the mountains flow down very slowly because of surface retention over the extensive [flood plain](/source/Flood_plain), the [gorges](/source/Gorge) in the gently-sloping mountains and the meandering course of the river. [Inundations](/source/Inundation) of the Cagayan River and its tributaries have caused great loss of life and property and substantial losses to the local and national economies. The Philippine government has established several flood warning stations along the river. Experts are specifically monitoring the lower reaches from [Tuguegarao](/source/Tuguegarao) to Aparri and the [alluvial plain](/source/Alluvial_plain) from [Ilagan](/source/Ilagan) to [Tumauini, Isabela](/source/Tumauini%2C_Isabela). In November 2020, after the onslaught of [Typhoon Vamco](/source/Typhoon_Vamco_(2020)) (Ulysses), the river reached its peak level and caused floods along its vicinity due to the rainfall accumulated from the typhoon. This flooding was one of the worst floods in the river's history. The [Magat Dam](/source/Magat_Dam) also contributed to the floods along the river when its floodgates opened due to a potential overflow.[6][7] ## Flora and fauna The Cagayan River passes through one of the few remaining [primary forests](/source/Primary_forest) in the Philippines. It supports the lives of numerous endemic and endangered species, like the Luzon bleeding-heart pigeon (*[Gallicolumba luzonica](/source/Gallicolumba_luzonica)*), Philippine eagle (*[Pithecophaga jefferyi](/source/Pithecophaga_jefferyi)*) and a rare [riverine](/source/Riverine) fish, locally called *ludong* (*[Cestreaus plicatilis](/source/Lobed_river_mullet)*). The *ludong* spawns in Cagayan River's upper reaches in [Jones, Isabela](/source/Jones%2C_Isabela). In late October until mid-November, the fish travel down the river to release their eggs at the river mouth near Aparri. In February, ludong fry by the millions are again caught in fine nets as these travel upstream. Due to the dwindling number of ludong caught yearly, local governments have imposed a ban on catching the fish and its fry, but the ban has failed. ## People The river traverses four provinces: [Nueva Vizcaya](/source/Nueva_Vizcaya), [Quirino](/source/Quirino), [Isabela](/source/Isabela_(province)) and [Cagayan](/source/Cagayan). These provinces have an approximate population of two million people, mostly farmers and indigenous tribesmen. The [Ibanag people](/source/Ibanag_people) derive their tribe's name from Cagayan River's ancient name, *Bannag*. The [Gaddang tribe](/source/Gaddang_people) lived in the upper reaches of the Cagayan River and its tributaries. An old drawn geographical description of Cagayan River (Juan Luis de Acosta, Circa 1720) ## Economic importance The river drains a fertile valley that produces a variety of crops, including rice, corn, bananas, coconut, mangoes, citrus and tobacco. Fish were a plentiful source of nutrition for centuries, but in recent decades issues such as [fertilizer runoff](/source/Fertilizer_runoff), [destructive fishing methods](/source/Dynamite_fishing) and a [burgeoning human population](/source/Overpopulation) have led to a great decline in the river's fish stocks. With [worsening weather patterns](/source/Climate_change) and regular severe storms, even traditional agricultural means are insufficient to feed families although they were bountiful in the past century, leading to the more aggressive use of destructive techniques. This has been part of a vicious cycle of [environmental degradation](/source/Environmental_degradation). Families still go to the banks of the river and its tributaries to wash clothes or have picnics. Until recently, boatmen would provide ferry service. For example, the towns of [Lasam](/source/Lasam) and [Gattaran](/source/Gattaran) are directly across the river from each other. A crossing by boat was the most convenient, but emergencies could be dangerous, such as having to fetch the doctor in Gattaran during a storm at night. Now the best way is by vehicle over the [Magapit bridge](/source/Magapit_Suspension_Bridge). There are [dams](/source/Dam) in two of the river's tributaries, the Magat and [Chico Rivers](/source/Chico_River_(Philippines)), and there are also several mining concessions in the mineral-rich [Cordillera Mountains](/source/Cordillera_Central_(Luzon)) near the headwaters of the two tributary rivers. The provincial governments along the river have also developed tourism programs that offer activities on the river, particularly [whitewater rafting](/source/Whitewater_rafting). ## Crossings From mouth to source: - [Magapit Suspension Bridge](/source/Magapit_Suspension_Bridge) ( [AH 26 (N1)](/source/Pan-Philippine_Highway) ([Pan-Philippine Highway](/source/Pan-Philippine_Highway)), [Lal-lo, Cagayan](/source/Lal-lo%2C_Cagayan)) - [Buntun Bridge](/source/Buntun_Bridge) ( [N51](/source/N51_highway_(Philippines)) ([Santiago–Tuguegarao Road](/source/Santiago%E2%80%93Tuguegarao_Road)), [Tuguegarao City](/source/Tuguegarao_City) and [Solana, Cagayan](/source/Solana%2C_Cagayan)) - [Santa Maria Overflow Bridge](/source/Cabagan%E2%80%93Santa_Maria_Bridge) (Cabagan–Santa Maria Road, [Santa Maria](/source/Santa_Maria%2C_Isabela) and [Cabagan, Isabela](/source/Cabagan%2C_Isabela)) - Cansan-Bagutari Overflow Bridge (Cabagan-Santo Tomas Road, [Cabagan](/source/Cabagan%2C_Isabela) and [Santo Tomas, Isabela](/source/Santo_Tomas%2C_Isabela)) - Delfin Albano Bridge (Ilagan–Delfin Albano–Mallig Road, [Delfin Albano](/source/Delfin_Albano%2C_Isabela) and [Tumauini, Isabela](/source/Tumauini%2C_Isabela)) - Lullutan Bridge (Ilagan–Delfin Albano–Mallig Road, [Ilagan, Isabela](/source/Ilagan%2C_Isabela)) - Gamu Bridge (Gamu–Roxas Road, [Gamu, Isabela](/source/Gamu%2C_Isabela)) - Naguilian Bridge ( [AH 26 (N1)](/source/Pan-Philippine_Highway) ([Pan-Philippine Highway](/source/Pan-Philippine_Highway)), [Naguilian, Isabela](/source/Naguilian%2C_Isabela)) - Alicaocao Overflow Bridge ([Cauayan, Isabela](/source/Cauayan%2C_Isabela)) - New Pigalo Bridge (Angadanan–Alicia Road, [Angadanan, Isabela](/source/Angadanan%2C_Isabela)) - Anafunan Overflow Bridge ([Echague, Isabela](/source/Echague%2C_Isabela)) - Gucab Overflow Bridge ([Echague, Isabela](/source/Echague%2C_Isabela)) - Dalibubon Bridge (Santiago–San Agustin Road and Echague–Jones–Maddela Road, [Echague](/source/Echague) and [Jones, Isabela](/source/Jones%2C_Isabela)) - Jones II Bridge (Santiago–San Agustin Road, [Jones, Isabela](/source/Jones%2C_Isabela)) - San Pedro Bridge ([Maddela, Quirino](/source/Maddela%2C_Quirino)) - Dumabato Bridge ([Maddela, Quirino](/source/Maddela%2C_Quirino)) - Abbag Bridge (Cordon–Diffun–Maddela–Aurora Road, [Nagtipunan, Quirino](/source/Nagtipunan)) The [Pan-Philippine Highway](/source/Pan-Philippine_Highway) generally follows the course of the river from Echague until the Magapit Suspension Bridge where it continues west. ## See also - [List of rivers of the Philippines](/source/List_of_rivers_of_the_Philippines) ## References 1. ^ [***a***](#cite_ref-worldatlas_1-0) [***b***](#cite_ref-worldatlas_1-1) Kenneth Kimutai too (July 24, 2018). ["Longest Rivers In The Philippines"](https://www.worldatlas.com/articles/longest-rivers-in-the-philippines.html). *worldatlas.com*. WorldAtlas. Retrieved September 9, 2019. 1. ^ [***a***](#cite_ref-DENR_2-0) [***b***](#cite_ref-DENR_2-1) Vicente B. Tuddao Jr. (September 21, 2011). ["Water Quality Management in the Context of Basin Management: Water Quality, River Basin Management and Governance Dynamics in the Philippines"](https://web.archive.org/web/20160829035314/http://wepa-db.net/pdf/1203forum/08.pdf) (PDF). *www.wepa-db.net*. Department of Environment and Natural Resources. Archived from [the original](http://www.wepa-db.net/pdf/1203forum/08.pdf) (PDF) on August 29, 2016. Retrieved April 5, 2017. 1. **[^](#cite_ref-Taming_the_Cagayan_River_3-0)** ["Taming the Cagayan River, Inquirer.net"](http://newsinfo.inquirer.net/459953/taming-the-cagayan-river). Retrieved May 20, 2017. 1. **[^](#cite_ref-4)** "Principal River Basins of the Philippines", Published by the National Water Resources Board, October 1976 (p. 12) 1. **[^](#cite_ref-PAGASA_5-0)** ["Flood Forecasting and Warning System for River Basins; The Cagayan River Basin"](https://web.archive.org/web/20160312125930/https://web.pagasa.dost.gov.ph/index.php/flood-forecasting-and-warning-system-for-river-basins#cagayan-river-basin). *Philippine Atmospheric, Geophysical and Astronomical Services Administration*. Archived from [the original](https://web.pagasa.dost.gov.ph/index.php/flood-forecasting-and-warning-system-for-river-basins#cagayan-river-basin) on March 12, 2016. Retrieved March 12, 2016. 1. **[^](#cite_ref-6)** San Juan, Alexandria Dennise (November 13, 2020). ["Residents near Ipo, Ambuklao, Binga, and Magat dams warned of flooding as reservoirs continue to release water"](https://mb.com.ph/2020/11/13/residents-near-ipo-ambuklao-binga-and-magat-dams-warned-of-flooding-as-reservoirs-continue-to-release-water/). *[Manila Bulletin](/source/Manila_Bulletin)*. Retrieved December 22, 2020. Magat Dam in Isabela province has also released water at 5,073 cms as seven gates have been opened 24 meters. 1. **[^](#cite_ref-7)** De Vera-Ruiz, Ellalyn (November 12, 2020). ["Widespread flooding in Isabela, Cagayan feared as Magat Dam releases more water"](https://mb.com.ph/2020/11/12/widespread-flooding-in-isabela-cagayan-feared-as-magat-dam-releases-more-water/). *[Manila Bulletin](/source/Manila_Bulletin)*. Retrieved December 22, 2020. ## Further reading - Wernstedt, F. L.; J. E. Spencer (1967). [*The Philippine Island World*](https://archive.org/details/philippineisland0000wern). Berkeley and Los Angeles: University of California Press.{{[cite book](https://en.wikipedia.org/wiki/Template:Cite_book)}}: CS1 maint: publisher location ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_publisher_location)) ## External links - Media related to [Cagayan River](https://commons.wikimedia.org/wiki/Category:Cagayan_River) at Wikimedia Commons - [Philippine Atmospheric, Geophysical and Astronomical Services Administration](http://www.pagasa.dost.gov.ph) - [International Rivers](http://www.internationalrivers.org/) v t e Principal river systems of the Philippines Abra River Abulog River Agno River Agus River Agusan River Bicol River Buayan-Malungun River Cagayan River Cagayan de Oro River Davao River Ilog-Hilabangan River Jalaur River Pampanga River Panay River Pasig/Marikina basin (Pasig River and Marikina River) Rio Grande de Mindanao Tagoloan River Tagum-Libuganon River Ulot River See also: List of rivers of the Philippines Authority control databases International VIAF FAST National Israel --- Adapted from the Wikipedia article [Cagayan River](https://en.wikipedia.org/wiki/Cagayan_River) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Cagayan_River?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.