The Subangdaku River is the largest

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of w ...

Southern Leyte Southern Leyte ( ceb, Habagatang Leyte; Kabalian language, Kabalian: ''Habagatan nga Leyte''; war, Salatan nga Leyte; tl, Timog Leyte), officially the Province of Southern Leyte, is a Provinces of the Philippines, province in the Philippines loc ...

, Philippines. It drains into the

Sogod Bay Sogod Bay is a large bay in the southern part of Leyte Island in the Philippines. An extension of the Bohol Sea, the bay is surrounded by the province of Southern Leyte, and the namesake municipality of Sogod is located at the head of the bay. P ...

at the municipality of Sogod. The river's name means "big river" or "wide river" in Cebuano. For years, following the flooding of the river, it created an issue over the province. It has been quarried and re-channeled which caused the incidents. After many attempts, the issue remained unsolved.

Formation

By description, it can be considered as a braided river composed of several channels from near areas that divide and again reunite in a certain area forming an alluvial fan with very wide

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

. As such, the river usually became hazardous during

typhoon A typhoon is a mature tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere. This region is referred to as the Northwestern Pacific Basin, and is the most active tropical cyclone basin on Earth, accounting for a ...

after a heavy rain. The river has been meandering its natural course. The occurrence is being observed by natives living along the river every time a flood occurs.

Environmental issues

The

ecology Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overl ...

of the Subangdaku River has been disturbed by human activity, such as: a) noise such as those caused by grinding of rocks during

quarry A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to reduce their envir ...

ing operations; b) fragmentation of river system preventing travel of aquatic organisms through a continuous river channel; c) silt deposited in the bay which is facilitated by rechanneling activities. The resulting fragmentation and siltation of Sogod Bay may have disturbed the life cycle of some organisms that require movement between the sea and the

freshwater ecosystem Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats ...

such as Subangdaku. For instance, the behavior of a certain crab named locally as "Kamwa", has been reported by one of the local inhabitant who followed the crab upstream and found that the path the young traveled from the sea to upstream of Subangdaku reached until Barangay San Juan about above sea level. The behavior of this crab was that the adult laid eggs in the sea and when the eggs are hatched, the baby crabs traveled upstream. Other species observed and/or reported downstream were Katang, Ulang (freshwater shrimp), a small mollusk (a gastropod) having some spines on its shell locally known as Odianga and two kinds of freshwater fishes. Quarrying activities had been frequent in the area. Several companies have exploited and extracted sand and gravel in the area that are being accumulated by the river's current every time it floods. The

extraction of sand Sand mining is the extraction of sand, mainly through an open pit (or sand pit) but sometimes mined from beaches and inland dunes or dredged from ocean and river beds. Sand is often used in manufacturing, for example as an abrasive or in concr ...

and gravel weakens the river bed and makes the river vulnerable to flood and environmental occurrences such as erosion. After a typhoon strikes the area, because it has many channels, the current of the river easily gets so strong that it becomes hazardous to nearby villages. In 2001, part of the Philippine National Road was devastated. A 1994 study by

Silliman University Silliman University (also referred to as Silliman or SU) is a private research university in Dumaguete City, Negros Oriental, the Philippines. Established in 1901 as Silliman Institute by the Presbyterian Board of Foreign Missions, it is ...

identified sand and gravel mining, rechanneling, and sand harvest near the river's mouth, as causes of degraded habitats and major water quality issues of the area. The same report mentioned mining as one of the harmful practices that Sogod Bay should be protected from, and it recommended regulating quarrying and rechanneling with competent planning based on scientific evidence and monitoring as a way to protect the Subangdaku River.

References

{{Principal River Systems of the Philippines Rivers of the Philippines Landforms of Southern Leyte