Editing Cagayan River

{{Short description|Longest river in the Philippines}}
{{For|the Cagayan River in [[Mindanao]]|Cagayan River (Mindanao)}}
{{Use Philippine English|date=February 2023}}
{{Use mdy dates|date=February 2023}}
{{Infobox river
| name               = Cagayan River
| native_name        ={{native name|ibg|Bannag}}
| name_other         = ''Río Grande de Cagayán''
| name_etymology     = 
<!---------------------- IMAGE & MAP -->
| image              = Jones Isabela.JPG
| image_size         = 
| image_caption      = The river as it passes through [[Jones, Isabela|Jones]] in [[Isabela (province)|Isabela]]
| map                = Cagayan river watershed.png
| map_size           = 
| map_caption        = [[drainage basin|Drainage area]] of the river and its [[tributaries]] in northeastern [[Luzon]]
| pushpin_map        = Luzon mainland#Philippines
| pushpin_map_size   = 
| pushpin_map_caption= Cagayan River [[river mouth|mouth]]
<!---------------------- LOCATION -->
| subdivision_type1  = Country
| subdivision_name1  = {{flag|Philippines}}
| subdivision_type2  = Region
| subdivision_name2  = [[Cagayan Valley]]
| subdivision_type3  = Province
| subdivision_name3  = {{hlist|[[Cagayan]]|[[Isabela (province)|Isabela]]|[[Nueva Vizcaya]]|[[Quirino]]}}
| subdivision_type4  = <!-- City/municipality -->
| subdivision_name4  = 
| subdivision_type5  = 
| subdivision_name5  = 
<!---------------------- PHYSICAL CHARACTERISTICS -->
| length             = {{convert|505|km|mi|abbr=on}}<ref name="worldatlas"/>
| width_min          = 
| width_avg          = 
| width_max          = 
| depth_min          = 
| depth_avg          = 
| depth_max          = 
| discharge1_location= 
| discharge1_min     = 
| discharge1_avg     = 
| discharge1_max     = 
<!---------------------- BASIN FEATURES -->
| source1            = [[Caraballo Mountains]]
| source1_location   = [[Dupax del Sur]], Nueva Vizcaya
| source1_coordinates= {{coord|16|11|08|N|121|08|39|E|dim:15000_region:PH_type:river|display=inline}}
| source1_elevation  = {{convert|1524|m|ft|abbr=on}}
| mouth              = [[Babuyan Channel]]
| mouth_location     = [[Aparri, Cagayan]]
| mouth_coordinates  = {{coord|18|22|N|121|37|E|dim:15000_region:PH_type:river|display=inline,title}}
| mouth_elevation    = {{convert|0|m|ft|abbr=on}}
| progression        = 
| river_system       = 
| basin_size         = {{Convert|27753|km2|mi2|abbr=on}}<ref name=DENR>{{cite web |author1=Vicente B. Tuddao Jr. |title=Water Quality Management in the Context of Basin Management: Water Quality, River Basin Management and Governance Dynamics in the Philippines |url=http://www.wepa-db.net/pdf/1203forum/08.pdf |website=www.wepa-db.net |publisher=Department of Environment and Natural Resources |access-date=April 5, 2017 |date=September 21, 2011}}</ref>
| tributaries_left   = {{hlist|[[Chico River (Philippines)|Chico River]]|[[Magat River]]}}
| tributaries_right  = {{hlist|[[Ilagan River]]|[[Pinacanauan River]]}}
| custom_label       = 
| custom_data        = 
| extra              = {{Infobox mapframe |wikidata=yes |zoom=6 |height=250 | stroke-width=1.5}}
}}

The '''Cagayan River''', also known as the '''Río Grande de Cagayán''', is the longest river<ref name="Taming the Cagayan River">{{cite web|title=Taming the Cagayan River, Inquirer.net|url=http://newsinfo.inquirer.net/459953/taming-the-cagayan-river|access-date=May 20, 2017}}</ref><ref name="worldatlas">{{cite web |author1=Kenneth Kimutai too |title=Longest Rivers In The Philippines |url=https://www.worldatlas.com/articles/longest-rivers-in-the-philippines.html |website=worldatlas.com |publisher=WorldAtlas |access-date=September 9, 2019 |language=en |date=July 24, 2018}}</ref> and the largest river by [[discharge (hydrology)|discharge]] volume of water in the [[Philippines]]. It has a total length of approximately {{Convert|505|km}} and a [[drainage basin]] covering {{Convert|27753|km2}}.<ref name=DENR/> It is located in the [[Cagayan Valley]] region in northeastern part of [[Luzon Island]] and traverses the [[Provinces of the Philippines|provinces]] of [[Nueva Vizcaya]], [[Quirino]], [[Isabela (province)|Isabela]] and [[Cagayan]].

==Topography==
{{Annotated image
| image = Relief Map Of The Philippines.png
| image-width = 1000
| image-left = -491
| image-top = -232
| width = 120
| height = 240
| annotations = {{annotation|55|140|'''X'''|color=red}}
| caption = Topography of the ''Cagayan Valley'' <div style="font-size:xx-small;">(marked by an '''X''')</div> in northeastern Luzon.
| icon = none
| float=left
}}

The river's [[headwaters]] are at the [[Caraballo Mountains]] of the [[Central Luzon]] at an elevation of approximately {{convert|1524|m}}. The river flows north for some {{convert|505|km}}<ref>"Principal River Basins of the Philippines", Published by the National Water Resources Board, October 1976 (p. 12)</ref> to its mouth at the [[Babuyan Channel]] near the town of [[Aparri]], [[Cagayan]]. The river drops rapidly to {{convert|91|m}} above sea level some {{convert|227|km}} from the river mouth. Its principal [[tributaries]] are the [[Pinacanauan River|Pinacanauan]], [[Chico River (Philippines)|Chico]], [[Siffu River|Siffu]], [[Mallig River|Mallig]], [[Magat River|Magat]] and [[Ilagan River]]s.

[[Magat River]], is the largest tributary with an estimated annual [[discharge (hydrology)|discharge]] of 9,808 million cubic meters. It lies in the southwestern portion of the [[drainage basin|basin]], stretching approximately {{convert|150|km}} from [[Nueva Vizcaya]] down to its [[confluence]] with Cagayan River about {{convert|55|km}} from the [[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 (Philippines)|Sierra Madre]] 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]], {{convert|200|km}} from the mouth.

The Siffu-Mallig system lies on the slope of the Central [[Cordillera Central (Luzon)|Cordillera]] 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]] and [[Quaternary]] origin, mostly limestone sands and clays, throughout the relatively flat Cagayan Valley which is surrounded by the [[Cordillera Central (Luzon)|Cordillera Mountains]] in the west, [[Sierra Madre (Philippines)|Sierra Madre]] in the east and the [[Caraballo Mountains]] in the south.

The river has a drainage area of about {{convert|27300|km2}}. in the provinces of [[Apayao Province|Apayao]], [[Aurora Province|Aurora]], Cagayan, [[Ifugao Province|Ifugao]], Isabela, [[Kalinga Province|Kalinga]], [[Mountain Province]], Nueva Vizcaya, and Quirino.

The estimated annual discharge is 53,943 million cubic meters<ref name="PAGASA">{{cite web|title=Flood Forecasting and Warning System for River Basins; The Cagayan River Basin|url=https://web.pagasa.dost.gov.ph/index.php/flood-forecasting-and-warning-system-for-river-basins#cagayan-river-basin|website=Philippine Atmospheric, Geophysical and Astronomical Services Administration|access-date=March 12, 2016|archive-url=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|archive-date=March 12, 2016|url-status=dead}}</ref> 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]] season in [[Southeast Asia]] from May to November.

The average annual rainfall in {{convert|1000|mm}} in the northern part and {{convert|3000|mm}} 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]], the [[gorge]]s in the gently-sloping mountains and the meandering course of the river.

[[Inundation]]s 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]] to Aparri and the [[alluvial plain]] from [[Ilagan]] to [[Tumauini, Isabela]].

In November 2020, after the onslaught of [[Typhoon Vamco (2020)|Typhoon Vamco]] (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]] also contributed to the floods along the river when its floodgates opened due to a potential overflow.<ref>{{cite news |last1=San Juan |first1=Alexandria Dennise |title=Residents near Ipo, Ambuklao, Binga, and Magat dams warned of flooding as reservoirs continue to release water |url=https://mb.com.ph/2020/11/13/residents-near-ipo-ambuklao-binga-and-magat-dams-warned-of-flooding-as-reservoirs-continue-to-release-water/ |access-date=December 22, 2020 |work=[[Manila Bulletin]] |date=November 13, 2020 |quote=Magat Dam in Isabela province has also released water at 5,073 cms as seven gates have been opened 24 meters.}}</ref><ref>{{cite news |last1=De Vera-Ruiz |first1=Ellalyn |title=Widespread flooding in Isabela, Cagayan feared as Magat Dam releases more water |url=https://mb.com.ph/2020/11/12/widespread-flooding-in-isabela-cagayan-feared-as-magat-dam-releases-more-water/ |access-date=December 22, 2020 |work=[[Manila Bulletin]] |date=November 12, 2020}}</ref>

==Flora and fauna==
The Cagayan River passes through one of the few remaining [[primary forest]]s in the Philippines.

It supports the lives of numerous endemic and endangered species, like the Luzon bleeding-heart pigeon (''[[Gallicolumba luzonica]]''), Philippine eagle (''[[Pithecophaga jefferyi]]'') and a rare [[riverine]] fish, locally called ''ludong'' (''[[Lobed river mullet|Cestreaus plicatilis]]'').

The ''ludong'' spawns in Cagayan River's upper reaches in [[Jones, 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]], [[Quirino]], [[Isabela (province)|Isabela]] and [[Cagayan]]. These provinces have an approximate population of two million people, mostly farmers and indigenous tribesmen.

The [[Ibanag people]] derive their tribe's name from Cagayan River's ancient name, ''Bannag''. The [[Gaddang people|Gaddang tribe]] lived in the upper reaches of the Cagayan River and its tributaries.

[[File:Cagayan River 1720.png|thumb|250px|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]], [[dynamite fishing|destructive fishing methods]] and a [[overpopulation|burgeoning human population]] have led to a great decline in the river's fish stocks.  With [[climate change|worsening weather patterns]] 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]].

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]] and [[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 Suspension Bridge|Magapit bridge]].

There are [[dam]]s in two of the river's tributaries, the Magat and [[Chico River (Philippines)|Chico River]]s, and there are also several mining concessions in the mineral-rich [[Cordillera Central (Luzon)|Cordillera Mountains]] 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]].

== Crossings ==
From mouth to source:

* [[Magapit Suspension Bridge]] ({{Jct|country=PHL|AH|N1|name1=[[Pan-Philippine Highway]]}}, [[Lal-lo, Cagayan]])
* [[Buntun Bridge]] ({{Jct|country=PHL|N|51|name1=[[Santiago–Tuguegarao Road]]}}, [[Tuguegarao City]] and [[Solana, Cagayan]])
* Santa Maria Overflow Bridge (Cabagan–Santa Maria Road, [[Santa Maria, Isabela|Santa Maria]] and [[Cabagan, Isabela]])
* Cansan-Bagutari Overflow Bridge (Cabagan-Santo Tomas Road, [[Cabagan, Isabela|Cabagan]] and [[Santo Tomas, Isabela]])
* Delfin Albano Bridge (Ilagan–Delfin Albano–Mallig Road, [[Delfin Albano, Isabela|Delfin Albano]] and [[Tumauini, Isabela]])
* Lullutan Bridge (Ilagan–Delfin Albano–Mallig Road, [[Ilagan, Isabela]])
* Gamu Bridge (Gamu–Roxas Road, [[Gamu, Isabela]])
* Naguilian Bridge ({{Jct|country=PHL|AH|N1|name1=[[Pan-Philippine Highway]]}}, [[Naguilian, Isabela]])
* Alicaocao Overflow Bridge ([[Cauayan, Isabela]])
* New Pigalo Bridge (Angadanan–Alicia Road, [[Angadanan, Isabela]])
* Anafunan Overflow Bridge ([[Echague, Isabela]])
* Gucab Overflow Bridge ([[Echague, Isabela]])
* Dalibubon Bridge (Santiago–San Agustin Road and Echague–Jones–Maddela Road, [[Echague]] and [[Jones, Isabela]])
* Jones II Bridge (Santiago–San Agustin Road, [[Jones, Isabela]])
* San Pedro Bridge ([[Maddela, Quirino]])
* Dumabato Bridge ([[Maddela, Quirino]])
* Abbag Bridge (Cordon–Diffun–Maddela–Aurora Road, [[Nagtipunan|Nagtipunan, Quirino]])

The [[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]]

==References==
{{Reflist|30em}}

==Further reading==
*{{cite book |author1=Wernstedt, F. L. |author2=J. E. Spencer | title=The Philippine Island World |url=https://archive.org/details/philippineisland0000wern |url-access=registration |publisher=Berkeley and Los Angeles: University of California Press |year=1967}}

==External links==
* {{Commons category-inline}}
* [http://www.pagasa.dost.gov.ph Philippine Atmospheric, Geophysical and Astronomical Services Administration]
* [http://www.internationalrivers.org/ International Rivers]

{{Principal Rivers of the Philippines}}
{{Authority control}}

[[Category:Rivers of the Philippines]]
[[Category:Landforms of Cagayan]]
[[Category:Landforms of Isabela (province)]]
[[Category:Landforms of Nueva Vizcaya]]
[[Category:Landforms of Quirino]]