Onilahy
Onilahy is a mapped river in the YearMaps hydrographic index. River courses organise settlement, agriculture and frontier-making more durably than any political boundary, and this reach is indexed against the dams, lakes and cities within its catchment.
- Feature Class
- River
- Coordinates
- -23.44°, 45.13°
About Onilahy
Onilahy is a river in Atsimo-Andrefana and Anosy (Toliara Province), southern Madagascar. It flows down from the hills near Betroka to the Mozambique Channel. It empties at St. Augustin (23.5666667°S 43.75°E / -23.5666667; 43.75), and into the Bay of Saint-Augustin.
Two species of cichlids are endemic to the river basin, but Ptychochromis onilahy is probably already extinct and the remaining range of Ptychochromoides betsileanus covers less than 10 square kilometres (3.9 mi2).
Encyclopedic summary adapted from Wikipedia: Onilahy River (CC BY-SA 4.0).
Onilahy in Depth
Geography
Sources of the Onilahy river are near Beadabo. It flows through Ankilimary, to Benenitra, Ehara, Bezaha and Antanimena.
The mouth of the Onilahy river is situated in the Indian Ocean at Saint Augustin, Madagascar, 35 km south of Toliara (Tuléar).
Its main affluentes from its south are Sakamena river, Evasy River, Ianapera River, Isoanala river and the Ihazofotsy River.
From the north these are Sakondry, Taheza, Sakamare and the Imatoto rivers.
Sections adapted from Wikipedia: Onilahy River (CC BY-SA 4.0).
Onilahy: Key Facts
| Length | 400 km |
|---|---|
| Drainage basin | 32,000 km² |
| Mouth | Mozambique Channel |
Facts from Wikidata Q2465863 (CC0).
Major River Dossiers
Hand-written studies of the great river systems of history.
Connected Reaches
Nearby watercourses in the same drainage network.
Water Bodies in the Catchment
Settlements Along the Reach
Hydraulic Infrastructure Nearby
Surrounding Terrain
Onilahy: Quick Answers
- Where is Onilahy?
- Onilahy is located in Madagascar, at 23.4369° S, 45.1288° E.
- Are there dams on the Onilahy?
- No dam on the Onilahy is recorded in the YearMaps dam index, which covers major structures only.