Ethiopia Geography Unit 3 PDF

UNIT - THREE TOPOGRAPHY OF ETHIOPIA AND THE HORN Instructor- Teklit G/tinsae  TOPOGRAPHY DEFINED Topography/relief refers to: The way that the earth’s surface is structured or configured; The ups and downs of the earth; The difference in altitude between places; or The way that t...

UNIT - THREE TOPOGRAPHY OF ETHIOPIA AND THE HORN Instructor- Teklit G/tinsae  TOPOGRAPHY DEFINED Topography/relief refers to: The way that the earth’s surface is structured or configured; The ups and downs of the earth; The difference in altitude between places; or The way that the earth’s surface is arranged.  Cont’d Ethiopia’s topography is highly diverse. It is consisted of:  Mountains  Hills  Plateaus  Plains  Valleys both river valleys and rift valleys  depressions Physical Map Of Ethiopia and the Horn  Cont’d Taking the 1000 m a.s.l contour line as a boundary or demarcation, Ethiopia’s relief can broadly be classified as highlands and lowlands. The highlands are characterized by the following Warm to cool/cold temperature Moderate to high mean annual rainfall Dense population distribution Mixed farming Sedentary or permanent settlement Rain fed agriculture Well vegetated Free from tropical infections The lowlands are characterized by: High mean annual temperature Low rainfall Sparse population distribution Nomadic or semi-nomadic pastoral economy Infestation by tropical infections Poorly vegetated Temporary or mobile settlement Have high irrigation potential PHYSIOGRAPHIC DOVISIONS OF ETHIOPIA Ethiopia’s topography is divided into three major physiographic regions. These are:  The Western Highlands and Lowlands;  The Southeastern Highlands and Lowlands; and  The Ethiopian Rift Valley  Physiographic Divisions of Ethiopia Taking the Ethiopian Rift Valley as a divide, Ethiopia's topography is divided into three physiographic divisions. These are: Western Ethiopia Highlands and Lowlands Southeastern (Eastern) Ethiopia Highlands and Lowlands The Ethiopian Rift Valley 1. Western Ethiopia Highlands and Lowlands  found to the west of the Ethiopian Rift Valley;  is the largest of all the physiographic regions covering 44% Ethiopia;  Highlands 76.3% and Lowlands 23.7%  further divided into two as Western Ethiopia Highlands and Western Ethiopia Lowlands.  Cont'd A. Western Ethiopia Highlands include the highlands of Tigray, Gonder, Gojjam, Wollo, Shewa, Illubabor, Wellega, Keffa, Jimma, Gamo and Gofa. is further divided into four. Theses are: Tigrian Plateau Shewan Plateau North Central Massif Southwestern Highlands  Cont'd i. The Tigrian Plateau  is the northern most part and accounts for 13% of the Hls;  is bordered by the Mereb/Gash river in the north and the Tekeze river in the souh;  most of it lies between 1000m and 2000m asl altitudes;  Mount Tsibet (3988 m asl),  Mount Ambalage (3291 m asl), and  Mount Assimba (3248 m asl) are its highest peaks;  is the source of Tekeze river. ii. The Shewan Plateau  is bordered by the Rift Valley in the east &southeast, Abay in the north and Omo in the south and west;  accounting for 11% of the Wn Highlands & Lowlands, it is the smallest of all the subdivisions of the Wn Highlands; is the most extensive plateau land in Ethiopia;  has the highest average altitude in the country with nearly 3/4th of it lying above 2000m asl;  it is drained outwards in all directions by the tributaries of the Abay, Omo and Awash rivers;  is the watershed between the Abay, Omo and Awash rivers;  Mts Abuye Meda (4000m) in Nn Shewa and Gurage (3721m) in the south are its highest peaks;  is the origin of the Awash River. iii. North Central Massifs  follows the Tekeze (north) and Abay (south) gorge;  hosts lake Tana, which is bordered by the plains of Fogera and Dembia in the north;  58% of the area is above 2000m asl making it the second most elevated in the country;  19 of the 26 mountains that are over 4000m asl are found here;  the highest mts in this subdivision include:  Mt Ras Dashen/Dejen - 4620m asl  Mt Weynobar/Ancua - 4462m asl  Mt Kidus Yared - 4453m asl  Mt Bhawit - 4437m asl iv. Southwestern Highlands  include the hls of Illubabor, Wellega, Keffa, Jima, Gamo and Gofa;  is the wettest of all the hls in Ethiopia and the most dissected as well;  is the most forested, has most of Ethiopia's untouched forests;  forests are of tropical type with hardwood trees.  Western Lowlands found between the foothills of the Western hls and the Ethio-Sudan, South Sudan, Kenya border;  are divided into four named after the major river that drain them;  Tekeze-Setit Ll  Abay-Dendir Ll  Baro Lowlands - wettest and most vegetated  Ghibe/Omo Lowlands  Southeastern Highlands and Lowlands is found to the east of the Ethiopian Rift Valley;  accounting for 37% of Ethiopia's total area, it is the second largest physiographic region in the country;  46% is Highlands and 54% is Lowlands;  is further divided into Southeastern Highlands and Southeastern Lowlands; A. Southeastern Highlands  is further divided into the Arsi-Bale-Sidama Highlands and the Hararghe Plateau; The Arsi-Bale-Sidama Highlands  found to the east of the Lakes region of the Rift Valley;  occupy the southwestern part of the physiographic region;  Makeup 28.5% of the physiographic region and 62% of the SEn Hls;  the Arsi Hls are made up of rolling uplands and dissected mountains;  Mounts Kaka (4180m), Bada (4139m) and Chilalo (4036m) asl are its highest peaks;  the Bale Hls are separated from the Arsi Hls by the Wabishebelle river;  platform looking basaltic plateaus in the North-Central part and high mountain massifs in the north dominate it;  Mounts Tulu-Dimtu (4377m) and Batu (4307m) asl are its highest peaks;  these two Hls are important grains producing areas in Ethiopia;  the Sidama Hls are separated from the Bale Hls by the Ghenale river;  The Jemjem plateau, which is an important coffee growing area in Ethiopia, is its prominent feature;  The Wabishebelle and Ghenale rivers along with their tributaries have dissected this physiographic division;  the Sof Omar Cave, formed by the Weyb river (a tributary of Ghenale) near the Bale mountains, is an important feature in the region as well as one in the world. The Hararghe Plateau  found at the northeast;  stretches from the Chercher Hls is the Southwest to Jigjiga in the East;  makes up 17.4% of the physiographic region and 38% of the SEn Hls;  has the smallest proportion of upper highlands (>2000m asl)  The left-bank tributaries of Wabishebelle drain it;  much of the trappean lava cover has been removed exposing the mesozoic sedimentary rocks to the surface;  Mount Gara-Muleta (3381m asl) is its highest peak. The southeastern Lls  accounting for 54% of the physiographic region and nearly 20% of Ethiopia's total are, they are the most extensive lowlands in the country;  Wabishebelle plains (60%) and Ghenale plains (40%) are its subdivisions;  the plains of Ogaden, Elkere and Borena are found here;  have harsh climate;  dominated by nomadic and semi-nomadic pastoral economy;  Have high irrigation potential;  have high petroleum and natural gas potential. The Ethiopian Rift Valley  separates the Ethiopian landmass into two; Western and Southeastern;  stretches from Chew Bahir in the SW to Afar Triangle in the NE for about 1500kms;  covers 18% of Ethiopia's total area;  it is funnel shaped getting widest in the NE;  altitude varies fron 125m bsl at Denakil Depression to about 2000m asl in the lakes region;  the height of the escarpments ranges from 200m to 1500m;  Climate varies from warm, hot and dry in the lowlands to moderately moist conditions in the higher lands of the Lakes region;  is divided into three as:  Afar Triangle  widest, lowest, driest, hottest, poorly vegetated;  rich in salt, irrigation along the Awash river, high geothermal potential;  pastoral economy, mobile settlement  Main Ethiopian Rift  narrowest, most elevated, wettest, densely populated and vegetated;  has many of Ethiopia's Rift Valley lakes;  has high Tourism potential  Chew Bahir Region  southern most part of the Rift Valley;  hot and dry, drained by Ghibe/Omo rivers and its tributaries;