The Jamma River (Amharic: ጃማ) is a river in central

Ethiopia Ethiopia, officially the Federal Democratic Republic of Ethiopia, is a landlocked country located in the Horn of Africa region of East Africa. It shares borders with Eritrea to the north, Djibouti to the northeast, Somalia to the east, Ken ...

and a tributary to the Abay (or

Blue Nile The Blue Nile is a river originating at Lake Tana in Ethiopia. It travels for approximately through Ethiopia and Sudan. Along with the White Nile, it is one of the two major Tributary, tributaries of the Nile and supplies about 85.6% of the wa ...

). It drains parts of the Semien Shewa Zones of the Amhara and Oromia Regions. The Upper Jamma flows through steep, deep canyons cut first through volcanic rock and then through the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

sandstone and shaly sandstone, with

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

limestone at the bottom."Local History in Ethiopia"
(pdf) The Nordic Africa Institute website (accessed 29 January 2008) It has a drainage area of about 15,782 square kilometers in size. Tributaries include the Wanchet. The earliest mention of this river is in the ''Gadla'' of

Tekle Haymanot Abune Tekle Haymanot ( Ge'ez: አቡነ ተክለ ሃይማኖት; known in the Coptic Church as Saint Takla Haymanot of Ethiopia; 1215–1313) was an Ethiopian saint and monk mostly venerated as a hermit. He was the Abuna of Ethiopia who fou ...

, which was written in the fourteenth century. One of the earliest European mentions is by the missionary Pedro Páez, who was the first European to see and describe the origin of the Abay. According to

Johann Ludwig Krapf Johann Ludwig Krapf (11 January 1810 – 26 November 1881) was a German missionary in East Africa, as well as an explorer, linguist, and traveler. Krapf played an important role in exploring East Africa with Johannes Rebmann. They were the firs ...

, in the 1840s the Jamma defined the boundary between Marra Biete and Moret, two districts of the former province or

Sultanate Sultan (; ', ) is a Royal and noble ranks, position with several historical meanings. Originally, it was an Arabic abstract noun meaning "strength", "authority", "rulership", derived from the verbal noun ', meaning "authority" or "power". La ...

Shewa Shewa (; ; Somali: Shawa; , ), formerly romanized as Shua, Shoa, Showa, Shuwa, is a historical region of Ethiopia which was formerly an autonomous kingdom within the Ethiopian Empire. The modern Ethiopian capital Addis Ababa is located at it ...

.''Journals of the Rev. Messrs. Isenberg and Krapf, Missionaries of the Church Missionary Society, Detailing their proceedings in the kingdom of Shoa, and journeys in other parts of Abyssinia, in the years 1839, 1840, 1841 and 1842''
(London, 1843), p. 290

Notes

External links

Ethiopia Disaster Prevention and Preparedness Agency: Administrative atlas: Oromiya region

Ethiopia Disaster Prevention and Preparedness Agency: Flood Vulnerable Areas as of August 24, 2006
Tributaries of the Blue Nile Important Bird Areas of Ethiopia {{Ethiopia-river-stub