The Agusan River is third longest river in the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

, located in the north-eastern part of

Mindanao Mindanao ( ) ( Jawi: مينداناو) is the second-largest island in the Philippines, after Luzon, and seventh-most populous island in the world. Located in the southern region of the archipelago, the island is part of an island group of ...

island, draining majority of the

Caraga Caraga, officially the Caraga Administrative Region (or simply known as Caraga Region) and designated as Region XIII, is an Regions of the Philippines, administrative region in the Philippines occupying the northeastern section of Mindanao. Th ...

region and some parts of

Davao de Oro Davao de Oro, officially the Province of Davao de Oro ( ceb, Lalawigan sa Davao de Oro; tgl, Lalawigan ng Davao de Oro), is a province in the Philippines located in the Davao Region in Mindanao. Its capital is Nabunturan. It used to be part of ...

. It is the country's third largest river (after the

Cagayan River The Cagayan River, also known as the Río Grande de Cagayán, is the longest river and the largest river by discharge volume of water in the Philippines. It has a total length of approximately and a drainage basin covering . It is located in t ...

and

Rio Grande de Mindanao The Rio Grande de Mindanao, also known as the Mindanao River, is the second-largest river system in the Philippines. Located on the southern island of Mindanao, with a total drainage area of , draining the majority of the central and eastern po ...

) with a total drainage area of and an estimated length of from its origin.

Geography

The

headwaters The headwaters of a river or stream is the farthest place in that river or stream from its estuary or downstream confluence with another river, as measured along the course of the river. It is also known as a river's source. Definition The ...

of the river are found in the mountains of

, near its border with

Davao Oriental Davao Oriental ( Cebuano: ''Sidlakang Dabaw''; tl, Silangang Davao), officially the Province of Davao Oriental, is a province in the Philippines located in the Davao Region in Mindanao. Its capital is city of Mati, and it borders the province of ...

and east of

Tagum Tagum, officially the City of Tagum ( ceb, Dakbayan sa Tagum; fil, Lungsod ng Tagum), is a 1st class component city and capital of the Davao del Norte, Philippines. According to the 2020 census, it has a population of 296,202 people making it th ...

. It flows through the wide Agusan River valley which measures from south to north and varies from in width. Plains of Mindanao It finally drains into the Butuan Bay at its mouth in

Butuan Butuan (pronounced ), officially the City of Butuan ( ceb, Dakbayan sa Butuan; Butuanon: ''Dakbayan hong Butuan''; fil, Lungsod ng Butuan), is a 1st class highly urbanized city in the region of Caraga, Philippines. It is the ''de facto'' c ...

. One of the prominent features in the Agusan River basin is the presence of the Agusan Marsh covering a total area of . The

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found a ...

serves a flood retention basin for the Agusan River, cutting the high discharge of water causing flash floods in the lower reaches of the river. Aside from that, the marsh harbors unique and pristine habitats like the

sago Sago () is a starch extracted from the pith, or spongy core tissue, of various tropical palm stems, especially those of ''Metroxylon sagu''. It is a major staple food for the lowland peoples of New Guinea and the Maluku Islands, where it is c ...

and peat swamps forest and is a home to endangered and endemic flora and fauna. As a consequence, it was designated a

wildlife sanctuary A nature reserve (also known as a wildlife refuge, wildlife sanctuary, biosphere reserve or bioreserve, natural or nature preserve, or nature conservation area) is a protected area of importance for flora, fauna, or features of geological or o ...

by then-President

Fidel V. Ramos Fidel Valdez Ramos (, ; March 18, 1928 – July 31, 2022), popularly known as FVR and Eddie Ramos, was a Filipino general and politician who served as the 12th president of the Philippines from 1992 to 1998. He was the only career military ...

in 1996.

Watershed

The Agusan River basin is divided into three sub-basins on the basis of topographic features: the upper Agusan River basin, the middle Agusan River basin, and the lower Agusan River basin. The upper Agusan River basin is the section from its

in the mountains of

Santa Josefa, Agusan del Sur Santa Josefa, officially the Municipality of Santa Josefa ( ceb, Lungsod sa Santa Josefa; tgl, Bayan ng Santa Josefa), is a 3rd class municipality in the province of Agusan del Sur, Philippines. According to the 2020 census, it has a population ...

Veruela, Agusan del Sur Veruela, officially the Municipality of Veruela ( ceb, Lungsod sa Veruela; tgl, Bayan ng Veruela), is a 2nd class municipality in the province of Agusan del Sur, Philippines. According to the 2020 census, it has a population of 39,708 people. H ...

, the middle Agusan River basin is the section of the river from Santa Josefa to Amparo,

Agusan del Sur Agusan del Sur, officially the Province of Agusan del Sur ( ceb, Habagatang Agusan; Butuanon: ''Probinsya hong Agusan del Sur''; tl, Timog Agusan), is a province in Caraga region, Mindanao, Philippines. Its capital is the municipality of Pros ...

while the lower Agusan River basin is from Amparo to its mouth at

References

External links

{{Principal Rivers of the Philippines Rivers of the Philippines Landforms of Agusan del Norte Landforms of Agusan del Sur Landforms of Davao de Oro Butuan

Geography

Watershed

See also

References

External links