Editing Geography of Ethiopia (section)

==Physical features==

=== Geography ===
[[File:Ethiopia Topography.png|thumb|215x215px|Ethiopia's topography]]
[[File:Ethiopia sat.png|thumb|213x213px|A satellite image of Ethiopia]]
Between the valley of the Upper [[Nile]] and Ethiopia's border with [[Sudan]] and South Sudan is a region of elevated [[plateau]]s from which rise the various tablelands and mountains that constitute the [[Ethiopian Highlands]]. On nearly every side, the walls of the plateaus rise abruptly from the [[plain]]s, constituting outer mountain chains. The highlands are thus a clearly marked geographic division. In [[Eritrea]], the eastern wall of this plateau runs parallel to the [[Red Sea]] from [[Ras Kasar]] ([[18th parallel north|18° N]]) to [[Annesley Bay]] (also known as the Bay of [[Zula]]) ([[15th parallel north|15° N]]). It then turns due south into Ethiopia and follows closely the line of [[40th meridian east|40° E]] for some {{convert|600|km|mi|0|abbr=on}}.{{sfn|Cana|1911|p=83}}

About [[9th parallel north|9° N]] there is a break in the wall, through which the [[Awash River]] flows eastward. The main range at this point trends southwest, while south of the Awash Valley, which is some {{convert|1000|m|ft|0|abbr=on}} below the level of the mountains, another [[massif]] rises in a direct line south. This second range sends a chain (the [[Ahmar Mountains]]<!-- which the EB 1911 calls the "Harar hills" -->) eastward toward the [[Gulf of Aden]].{{sfn|Cana|1911|pp=83–84}}

The two chief eastern ranges maintain a parallel course south by west, with a broad upland valley in between – in which valley are a series of lakes – to about [[3rd parallel north|3° N]], the outer (eastern) spurs of the plateau still keeping along the line of [[40th meridian east|40° E]]. The southern escarpment of the plateau is highly irregular, but has a general direction northwest and southeast from [[6th parallel north|6° N]] to [[3rd parallel north|3° N]]. It overlooks the [[Depression (geology)|depression]] in which is [[Lake Turkana]] and – east of that lake – the southern [[Debub Omo Zone]] (part of the larger [[Southern Nations, Nationalities, and Peoples Region]]).{{sfn|Cana|1911|p=84}}

The western wall of the plateau from [[6th parallel north|6° N]] to [[11th parallel north|11° N]] is well marked and precipitous. North of [[11th parallel north|11° N]] the hills turn more to the east and fall more gradually to the [[East Sudanian savanna]] plains at their base. On its northern face, the plateau falls in terraces to the level of the eastern Sudan.
[[File:Awash River Valley, Asaita, Afar, Ethiopia.JPG|thumb|Awash river valley.]]
The eastern escarpment is the best defined of these outer ranges. It has a mean height of {{convert|2100|to|2400|m|ft|0|abbr=on}}, and in many places rises almost perpendicularly from the plain. Narrow and deep clefts, through which descend mountain torrents that lose themselves in the sandy soil of the Eritrean coast, afford means of reaching the plateau, or the easier route through the [[Awash River|Awash Valley]] may be chosen. On surmounting this rocky barrier, the traveller finds that the encircling rampart rises little above the normal level of the plateau.{{sfn|Cana|1911|p=84}}

The physical aspect of the highlands is impressive. The northern portion lies mainly between [[10th parallel north|10°]] and [[15th parallel north|15° N]]. It consists of a huge mass of [[Archean|Archaean]] rocks with a mean height of {{convert|2000|to|2200|m|ft|0|abbr=on}} above sea level, and is flooded in a deep central depression by the waters of [[Lake Tana]]. Above the plateau rise several irregular and generally ill-defined mountain ranges which attain altitudes of from {{convert|3700|m|ft|0|abbr=on}} to just under {{convert|4600|m|ft|0|abbr=on}}. Many of the mountains are of unusual shape.{{sfn|Cana|1911|p=84}}

Characteristic of the country are the enormous [[canyon|fissures]] which divide it, formed over time by the [[erosion|erosive]] action of water. They are the valleys of the rivers, which rising on the uplands or mountain sides, have cut their way to the surrounding lowlands. Some of the valleys are of considerable width; in other cases the opposite walls of the gorges are but two or three hundred meters apart, and fall almost vertically thousands of meters, representing an erosion of many hundred thousands cubic metres of hard rock. One result of the action of the water has been the formation of numerous isolated flat-topped hills or small plateaus, known as ''[[amba (geology)|ambas]]'', with nearly perpendicular sides.{{sfn|Cana|1911|p=84}}

The highest peaks are found in the [[Semien Mountains|Semien]] and [[Bale Mountains|Bale]] ranges. The Semien Mountains lie northeast of Lake Tana and culminate in the snow-covered peak of [[Ras Dashen]], which has an altitude of {{convert|4550|m|ft|0|abbr=on}}. A few kilometers east and north respectively of Ras Dashen are Mounts [[Mount Biuat|Biuat]] and [[Mount Abba Yared|Abba Yared]], whose summits are less than {{convert|100|m|ft|0|sp=us}} below that of Ras Dashen.{{sfn|Cana|1911|p=84}}

The Bale Mountains are separated from the larger part of the Ethiopian highlands by the [[Great Rift Valley, Ethiopia|Great Rift Valley]], one of the longest and most profound chasms in Ethiopia. The highest peaks of that range include [[Mount Tullu Demtu|Tullu Demtu]], the second-highest mountain in Ethiopia ({{convert|4377|m|ft|0|abbr=on|disp=or}}), [[Mount Batu|Batu]] ({{convert|4307|m|ft|0|abbr=on|disp=or}}), [[Mount Chilalo|Chilalo]] ({{convert|4036|m|ft|0|abbr=on|disp=or}}) and [[Mount Kaka]] ({{convert|3820|m|ft|0|abbr=on|disp=or}}).

Parallel with the eastern escarpment are the heights of [[Mount Biala|Biala]], {{convert|3810|m|ft|0|abbr=on}}, [[Mount Abuna Yosef]], {{convert|4190|m|ft|0|abbr=on}}, and [[Kollo (mountain)|Kollo]], {{convert|4300|m|ft|0|abbr=on}}, the last-named being southwest <!-- my map shows it NE --> of [[Magdala, Ethiopia|Magdala]]. Between Lake Tana and the eastern hills are Mounts [[Mount Guna|Guna]], {{convert|4210|m|ft|0|abbr=on}}, and [[Mount Uara Sahia|Uara Sahia]], {{convert|3960|m|ft|0|abbr=on}}.{{sfn|Cana|1911|p=84}} In the [[Choqa Mountains]] of [[Misraq Gojjam Zone|Misraq Gojjam]], [[Mount Choqa]] (also known as Mount Birhan) attains a height of  {{convert|4154|m|ft|0|abbr=on}}.

Below [[10th parallel north|10° N]], the southern portion of the highlands has more open tableland than the northern portion and fewer lofty peaks. Though there are a few heights between {{convert|3000|and|4000|m|ft|0|abbr=on}}, the majority do not exceed {{convert|2400|m|ft|0|abbr=on}}, but the general character of the southern regions is the same as in the north: a much-broken hilly plateau.{{sfn|Cana|1911|p=84}}

East of the highlands towards the [[Red Sea]] there is a strip of lowland semi-desert, the [[Ethiopian xeric grasslands and shrublands]].

=== Hydrology ===
{{Further|List of rivers of Ethiopia}}
[[File:Ethiopia Hydrogeology3.png|thumb|[[Hydrogeology]] map of Ethiopia|left]]
Most of the Ethiopian uplands have a decided slope to the northwest, so that nearly all the large rivers flow in that direction to the [[Nile]], comprising some 85% of its water. Such are the [[Tekezé River]] in the north, the [[Abay River|Abay]] in the center, and the [[Sobat River|Sobat]] in the south, and about four-fifths of the entire drainage is discharged through these three arteries. Another large river is the south-flowing [[Omo River (Ethiopia)|Omo]], with 14% of the entire drainage the largest river outside the above-mentioned three main arteries discharging to the west, and by far the main feeder of the [[closed basin|endorheic]] [[Turkana Basin]] with [[Lake Turkana]]. The rest is carried off by the [[Awash River|Awash]], which runs out in the saline lacustrine district along the border with [[Djibouti]]; by the [[Shebelle River]] and the [[Jubba River|Jubba]], which flow southeast through [[Somalia]], though the Shebelle most often fails to reach the Indian Ocean.{{sfn|Cana|1911|p=84}}

The [[Tekezé River]], which is the true upper course of the [[Atbarah River]], has its headwaters in the central tableland; and falls from about {{convert|2100|to|750|m|ft|0|abbr=on}}. in the tremendous crevasse through which it sweeps west, north, forming part of the border with Eritrea, and west again down to the western terraces, where it passes from Ethiopia to Sudan. During the rains the Tekezé (i.e. the "Terrible") rises some {{convert|5|m|ft|1|abbr=on}} above its normal level, and at this time forms an impassable barrier between the northern and central regions. In its lower course, the river is known by the Arabic name [[Setit]].{{sfn|Cana|1911|p=84}}

[[File:jubbarivermap.png|thumb|223x223px|A map of the [[Jubba River]] and [[Shebelle River]] [[drainage basin]]]]In Sudan, the Setit is joined (at {{coord|14|20|N|35|51|E}}) by the Atbarah, a river formed by several streams which rise in the mountains west and northwest of [[Lake Tana]]. The Gash or [[Mareb River|Mareb]], which forms part of the border with [[Eritrea]], is the most northerly of the highland rivers which flow toward the Nile valley. Its headwaters rise on the landward side of the eastern escarpment within 80&nbsp;km of Annesley Bay on the Red Sea. It reaches the Sudanese plains near [[Kassala]], beyond which place its waters are dissipated in the sandy soil. The Mareb is dry for a great part of the year, but like the Takazze is subject to sudden freshets during the rainy season. Only the left bank of the upper course of the river is in Ethiopian territory.{{sfn|Cana|1911|p=84}}

The Abay – that is, the upper course of the Blue Nile – has its source near [[Mount Denguiza]] in the Choqa mountains, around {{coord|11|0|N|37|0|E}}. It first flows for {{convert|110|km|mi|1|abbr=on}} nearly due north to the south shore of Lake Tana. Tana, which stands {{convert|750|to|1000|m|ft|0|abbr=on}} below the normal level of the plateau, has somewhat the physical aspect of a flooded crater. It has an area of about {{convert|2800|km2|sqmi|0}}, and a depth in some parts of {{convert|75|m|ft|0|abbr=on}}. At the southeast corner the rim of the crater is, as it were, breached by a deep crevasse through which the Abay escapes, and here makes a great semicircular bend like that of the Tekezé, but in the reverse direction – east, south and north-west – down to the plains of [[Sennar (state)|Sennar]], where it takes the name of Bahr-el-Azrak or [[Blue Nile]].{{sfn|Cana|1911|p=84}}[[File:Awashrivermap.png|thumb|222x222px|A map of the [[Awash River]]]]The Abay has many tributaries. Of these, the [[Bashilo River|Bashilo]] rises near Magdala and drains eastern [[Amhara Region|Amhara]]; the [[Jamma River|Jamma]] rises near Ankober and drains northern [[Shoa, Ethiopia|Shoa]]; the [[Muger River|Muger]] rises near [[Addis Ababa]] and drains south-western [[Shoa, Ethiopia|Shoa]]; the [[Didessa River|Didessa]], the largest of the Abay's affluents, rises in the [[Kaffa (city)|Kaffa]] hills and has a generally south-to-north course; the [[Dabus River|Dabus]] runs near the western edge of the plateau escarpment. All these are perennial rivers. The right-hand tributaries, rising mostly on the western sides of the plateau, have steep slopes and are generally torrential in character. The [[Beles River|Beles]], however, is perennial, and the [[Rahad River|Rahad]] and [[Dinder River|Dinder]] are important rivers in flood-time.{{sfn|Cana|1911|p=84}}

In the mountains and plateaus of [[Gambela Region|Gambela]] and Kaffa in southwestern Ethiopia rise the [[Baro River|Baro]], [[Gelo River|Gelo]], [[Akobo River|Akobo]] and other chief affluents of the Sobat tributary of the Nile. The Akobo, in about {{coord|7|47|N|33|3|E}}, joins the [[Pibor River|Pibor]], which in about {{coord|8|30|N|33|20|E}} unites with the Baro, the river below the confluence taking the name of Sobat. These rivers descend from the mountains in great falls, and like the other Ethiopian streams are unnavigable in their upper courses. The Baro on reaching the plain becomes, however, a navigable stream affording an open waterway to the Nile. The Baro, Pibor and Akobo form for {{convert|400|km|mi|0|abbr=on}} the western and southwestern frontiers of Ethiopia.{{sfn|Cana|1911|p=84}}

The chief river of Ethiopia flowing east is the [[Awash River]] (or Awasi), which rises in the Shewan uplands and makes a semicircular bend first southeast and then northeast. It reaches the [[Afar Depression]] through a broad breach in the eastern escarpment of the plateau, beyond which it is joined on its left bank by its chief affluent, the [[Germama river|Germama]] (Kasam), and then trends round in the direction of the [[Gulf of Tadjoura]]. Here the Awash is a copious stream nearly {{convert|60|m|ft|0|abbr=on}} wide and {{convert|1.2|m|ft|2|abbr=on}} deep, even in the dry season, and during the floods rising {{convert|15|to|20|m|ft|0|abbr=on}} above low-water mark, thus inundating the plains for many kilometers along both its banks.{{sfn|Cana|1911|p=84}}
[[File:Flamants roses du Lac Abbe.JPG|thumb|[[Flamingo|Flamingos]] at Lake Abbe.]]
After a winding course of about {{convert|800|km|mi|0|abbr=on}}, the Awash River passes (in its lower reaches) through a series of badds (lagoons) to [[Lake Abbe]] (or Abhe Bid) on the border with Djibouti and some {{convert|100|to|110|km|mi|0|abbr=on}} from the head of the [[Gulf of Tadjoura]]. In this lake the Awash river is lost. This remarkable phenomenon is explained by the position of Lake Abbe in the centre of a saline lacustrine depression several hundred meters below sea level. While most of the other lagoons are highly saline, with thick incrustations of salt round their margins, Lake Abbe remains fresh throughout the year, owing to the great body of water discharged into it by the Awash.{{sfn|Cana|1911|pp=84–85}}

Another lacustrine region extends from the Shoan heights southwest to the Samburu ([[Lake Turkana]]) depression. In this chain of scenic upland lakes – some fresh, some [[brackish water|brackish]], some completely closed, others connected by short channels – the chief links in their order from north to south are: [[Lake Zway|Zway]], communicating southwards with Hara and Lamina, all in the [[Arsi Zone]]; then [[Lake Abijatta|Abijatta]] with an outlet to a smaller turn to the Baroda and Gamo areas, skirted on the west sides by grassy slopes and wooded ranges from {{convert|2000|m|ft|0|abbr=on}} to nearly {{convert|3000|m|ft|0|abbr=on}} high; lastly, [[Lake Chew Bahir]] (formerly known as Lake Stephanie) which is completely closed and falling to a level of about {{convert|550|m|ft|0|abbr=on}} above sea level.{{sfn|Cana|1911|p=85}}

To the same system belongs the neighbouring Lake Turkana, which is larger than all the rest put together. This lake receives at its northern end the waters of the Omo, which rises in the Shoan highlands and is a perennial river with many affluents. In its course of some {{convert|600|km|mi|0|abbr=on}}  it has a total fall of about {{convert|700|m|ft|0|abbr=on}}, from {{convert|1060|m|ft|0|abbr=on}} at its source to c. {{convert|360|m|ft|0|abbr=on}} at lake level, and is consequently a rapid stream, being broken by the Kokobi and other falls, and navigable only for a short distance above its mouth.{{sfn|Cana|1911|p=85}}

The chief rivers of Somalia, the Shebelle and the Jubba, rise on the southeastern slopes of the Ethiopian escarpment as the Shebelle, the [[Ganale Doria River|Ganale Doria]] and the [[Dawa River|Dawa]], and part of their course is through territory belonging to Ethiopia.{{sfn|Cana|1911|p=85}}

There are numerous [[hot spring]]s in Ethiopia, such as [[Sodere]].