Mereb River
River flowing out of central Eritrea
title: "Mereb River" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["rivers-of-eritrea", "rivers-of-ethiopia", "rivers-of-sudan", "international-rivers-of-africa", "eritrea–ethiopia-border", "border-rivers"] description: "River flowing out of central Eritrea" topic_path: "general/rivers-of-eritrea" source: "https://en.wikipedia.org/wiki/Mereb_River" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary River flowing out of central Eritrea ::
::data[format=table title="Infobox river"]
| Field | Value |
|---|---|
| name | Mereb River |
| name_other | Gash or al-Qash |
| image | Kassala,Gash river.jpg |
| image_caption | The Mereb's dry riverbed at Kassala |
| map | Atbara OSM.png |
| map_size | 250 |
| map_caption | The Mereb River in the Atbara basin |
| source1_location | 15 km south-west Asmara |
| mouth_location | Dissipates in the sands of the eastern Sudanese plains |
| subdivision_type1 | Countries |
| subdivision_name1 | |
| length | 440 km |
| discharge1_avg | 21.6 m3/s |
| basin_size | 31000 km2 |
| tributaries_left | Sarana River, Balasa River, 'Engweya River, Gala River |
| tributaries_right | Obel River |
| :: |
| name = Mereb River | name_other = Gash or al-Qash | image = Kassala,Gash river.jpg | image_alt = | image_caption = The Mereb's dry riverbed at Kassala | map = Atbara OSM.png | map_size = 250 | map_alt = | map_caption = The Mereb River in the Atbara basin | source1_location = 15 km south-west Asmara | mouth_location = Dissipates in the sands of the eastern Sudanese plains | progression = | subdivision_type1 = Countries | subdivision_name1 = | location = | etymology = | length = 440 km | source1_elevation = | mouth_elevation = | discharge1_avg = 21.6 m3/s | basin_size = 31000 km2 | river_system = | tributaries_left = Sarana River, Balasa River, 'Engweya River, Gala River | tributaries_right = Obel River
The Mereb River (), also known as the Gash River (), is a river flowing out of central Eritrea. Its chief importance is defining part of the boundary between Eritrea and Ethiopia, between the point where the Mai Ambassa enters the river at to the confluence of the Balasa with the Mereb at .
Course
According to the Statistical Abstract of Ethiopia for 1967/68, the Mereb River is 440 km long. The Ethiopian Ministry of Water Resources reports its Ethiopian catchment area as 5700 km², with an annual runoff of 0.26 billion cubic meters. Other sources talking about a catchment of 21000 km² to 44000 km² over all, and a discharge of 21.6 m³/s in average over the year, and 870 m³/s in peaks. Its headwaters rise south-west of Asmara in central Eritrea. It flows south, bordering Ethiopia, then west through western Eritrea to reach the Sudanese plains near Kassala. Unlike the Setit or Takazze rivers, which flow out of Ethiopia and also forms a natural border with Eritrea, the waters of the Mereb do not usually reach the Nile but dissipate in the sands of the eastern Sudanese plains, forming an inland delta.
The Mereb is dry for much of the year, but like the Takazze is subject to sudden floods during the rainy season; only the left bank of the upper course of the Mereb is in Ethiopian territory. Its main tributaries are the Obel River on the right bank (in Eritrea) and the Sarana, Balasa, Mai Shawesh, and 'Engweya Rivers on the left (in Ethiopia).
History
The Mereb was important historically as the boundary between two separately governed regions in the area: the land of the Bahr negash (Tigrinya "kingdom of the sea", also known as Medri Bahri or "land of/by the sea") to the north of the river, and the Tigray to the south. The territories under the Bahr negash extended as far north as the Red Sea coast, and as far south (and west) as Shire and the capital was at Debarwa in modern Eritrea, about 20 mi south of Asmara.
Wildlife
The river's Eritrean floodplain was the location of a 2001 sighting of a sizable elephant herd, the first such sighting in Eritrea since 1955.
References
References
- [https://www.un.org/NewLinks/eebcarbitration/EEBC-Decision.pdf Eritrea - Ethiopia Boundary Commission Decision Regarding Delimitation of the Border...], pp. 97, 102
- [http://www.mowr.gov.et/attachmentfiles/Downloads/Water%20Sector%20Development%20Program%20Vol.2.doc "Water Sector Development Program (Vol.2)"] {{Webarchive. link. (2011-07-20 Ministry of Water Resources (accessed 21 January 2009))
- [http://www.krijnen.ch/DRAFT%20REPORT%20SUDAN.pdf ENVIRONMENTAL IMPACT ASSESSMENT KASSALA] {{webarchive. link. (2013-10-02)
- [https://earlywarning.usgs.gov/adds/pubs/Artan_et_al_2007.pdf Adequacy of satellite derived rainfall data for stream flow modeling] {{webarchive. link. (2013-10-02)
- Daniel Kendie, ''The Five Dimensions of the Eritrean Conflict 1941 – 2004: Deciphering the Geo-Political Puzzle'' (United States of America: Signature Book Printing, 2005), pp. 17–8.
- BBC Wildlife magazine, July 2003, retrieved at [https://www.bbc.co.uk/nature/animals/features/300feature1.shtml] on 28 Sept 2007
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