Geographical Location of Jimma Zone

Astronomically, the Zone extends between 7013’17’’N – 8o5316’’ North latitudes and 35051’07’’E -3703616’’ East longitudes. Relatively, it is locatedin the south western part of Oromiya National Regional State. It isbordered with East Wollega zone in the North,withEast shawa zone andSouthwest Shawa zone in North East, with SNNP administration in the South Eastand South part, and with   Illubabor zonein the West.

Because of geographical locations i.e. [near to the largest market centers like Finfinne and Welliso), the zone has a greatadvantage for accessing the local products to the market and creates favorable condition for the provision of the demanded commodities to the communities.

            Area:- On the basis of the recent form of the border, Jimma zone has a total surface area of 18,696.7 km2 at which  all area were under land body. The zone constitutes nearly 5.4% of the regional total surface area. Out of the total area of the Zone, about 1,801 km2 is under Tropical weather condition, about 16,134 km2 is under Sub-tropical weather condition and the remaining 761 km2 is under temperate weather condition.  Limmu Seka ,Sigmo  and Gera become to the widest districts of the zone while Botor Toley, Secka Chekorsa and  Mana   districts share the smallest areas of the zone. Limmu seka is the widest district of the zone that does have more than three- times folder than those small districts.

Thebelow  table shows the total area ofJimma Zone according to the data we have. According to the above table, LimuSeka is of the largest area in size out of the total number of Districts in ourZone which covers an area of about 1776.8 square kilometers. The second largestDistrict is Sigmo which covers an area of about 1585.51 square kilometers. Within the last four consecutive years., three new districts were separatedfrom the existing districts the first of which is Mencho which was separatedfrom Dedo. The second district was Botor Toley which was basically separated fromChora Botor and took around four administrative Rural Villages from Tiro AfetaDistrict. The third one was Omo Beyam which was separated from Omo NadaDistrict in the above specified years of our study. The separation of newdistricts from the existing one made impossible to know the exact surface area of the new Districts as well as the Original districts from which the new onewere separated. This was the big challenge we have encountered.

Summery on comparative size of Jimma zone districts with their respective numbers of PAS, areas and capital towns (1998-2000)

S.N

Name of district

Capital town

No. Of

Area

PAS

@Urban centers

Km2

%

1

C/Botor

Bage

19

1

977

5.23

2

B/Xoollayi

Waayyuu

16

2

501.2

2.68

3

Dedo

Sheeki

34

2

797.8

4.27

4

Mancho

Gariru Kedida

20

1

703.67

3.76

5

Gera

Chira

29

3

1388

7.42

6

Goma

Agaro

36

5

767

4.10

7

Gumay

Toba

14

1

544.4

2.91

8

Kersa

Serbo

30

2

1006

5.38

9

L/Kosa

Genet

40

3

1353.9

7.24

10

L/Seka

Atinago

38

3

1776.8

9.50

11

Mana

Yabu

24

2

516.9

2.76

12

Agaro Town

Agaro

0

1

8

0.04

13

Jimma Town

Jimma

0

1

51

0.27

14

Omo Nada

Nada

24

2

803.184

4.30

15

O/Beeyyam

Dalota

15

1

813.816

4.35

16

Setema

Gatira

20

3

1176

6.29

17

Seka Chokorsa

Seka

36

3

516

2.76

18

Sh/Sombo

Shabe

20

2

1191

6.37

19

Sokoru

Sekoru

38

3

876.1

4.69

20

Sigmo

Sigmo

19

2

1585.51

8.48

21

Tiro Afeta

Dimtu

25

3

979

5.24

22

Nono Benja

Alga

19

2

783.7

4.19

 

Jimma Zone

Jimma

516

48

18,696.7

100

Source:-Adopted from Statistical Abstract Data of the Zone in the year 2014EC.

     

Geology: -

Geological surveys indicated that the present land form of Jimma zone created as a result of different geological processes. The vast areas of the zone land formation had taken place during the Cenozoic era. The Central and Southern part of the zone (districts of Kersa , Nonno, Tirro Afata, Sokorru, Gomma part of Seka Chekorsa, Limmu Seka and Limmu Kossa fall to Maqdala group of tertiary volcanic. While, the Northern  and Western part of the zone that share with trap series of tertiary volcanic geological formation which includes the districts of Sigmo, Setema, Gera, part of Gomma, Omo Nada, Limmu Kossa and Limmu Seka.

The thick basaltic lava rocks of the trap series were the results of tertiary volcanic erruption of the Cenozoic era that covered the largest area of the district. It is conducive for farming activities, extraction of construction and industrial materials.

The geological formation of the zone had depicted that Jimma zone has a good potential for the development of a wide range of mineral resources. However, so far the zone mineral deposits exploitation did not deeply investigated except those in Dedo areas, but currently very essential mineral extraction is being conducted in Kersa and Gomma districts on the lignite mineral at Delbimoye that can be cited as an indicator for the availability of essential minerals. There is also information that indicates the availability of Steel mineral in Tiro Afeta District in Rural village which is around five kilometers away from the center of Ako Town. According to the information obtained from elders, the author of this profile has gathered that, steel mineral was being extracted from this village through cultural methods and brought to Omo Nada for making Niles and other materials by black smiths there during Aba Jifar First. Even though there is such information on the availability of this mineral, no one conducted further study. In different districts of the Zone including Dedo, there is also coal deposit. In some districts including Dedo, Coal is being extracted.

    Relief, Drainage and Climate :

  RELIEF- The present land configuration of Jimma zone is the result of past tectonic and denudation activities. The relief feature of the zone is dominated by undulating to mountainous. The zone does generally bordered by largest rivers namely Didesa, Gibe, and Gojeb.

       ALTITUDE/ELEVATION:  The land form of the district relief elevation ranges between 1000-3500m. Jimma zone generally lies with the altitude ranges between 1000 and 3500 meters above sea level. But the widest areas of the zone (which accounts 52%) lies between 1500 and 2000 meters above sea level. Areas lying between 1500 and 2000 meters above see level are  found    on the all area of Limmu Seka, Manna, East Kersa, Northern area of Dedo, Omo Nada, Eastern and Southern Gera, Seka Chekorsa , Sokoru & Eastern Gomma.     

All area of Sigmo, Vast area of Setema, Gera, central Seka Chekorsa, Dedo, Omo Nada, Tiro Afeta, Northern part  of Kersa, and Eastern part of Limmu Kossa districts have undulating  and intermediate plateau topography that highly ideal for  the farming which lies within altitude 2000-2500m. It accounts 34% of the zone total surface area. This high land also has bounded the mountain ranges that have 2500 and 3000 m. Other topography of the zone consists of areas that have elevation between 1000 and 1500m which includes   also the major rivers of      Dedesa, Gojeb and Gibe districts of Limmu Seka, Gomma, Seka Chekorsa, Dedo, Omonada,   Limmu Kosa and Sokoru. Only the small amounts (0.4%) of areas do have elevation that ranges between 500 and 1000m as indicated.

Altitudinal Elevation of Jimma zone:

 

No

 

 Altitudinal ranges (Elevation)

Area in

Km2

%

1

3000-3500

37

0.2

2

2500-3000

616

3.3

3

2000-2500

6356

34

4

1500-2000

9722

52.0

5

1000-1500

1888

10.1

6

500-1000

74

0.4

 

Total

18,696.7

100

Source: Adopted from Oromiya Atlas (1997) and woody Biomass Project Atlas (2007)

The highest elevation of the zone is found in the central part of Omo Nada district with the most remarkable mountain peak called Gudo mount with elevation 3344m. The lowest elevation of the zone is also found in the district mentioned above with 880m along Gibe river valley.

DRAINAGE BASINS

A drainage  basin is onearea of land drained by a river and its tributaries. Its boundary is shown by aridge of high land beyond which any precipitation drain in to adjacent basins. This boundary refers to all water shed or water parting. Jimma zone constitutes three major water sheds that separate the rivers that flow to the Omo, Gibe and Baro rivers. Ithas three drainage basins namely Omo-Gibe, Abay and Baro Rivers that characterized by the type of dendrite drainage pattern. Gibe river basin occupies the largest (16,559 Km2) surface area of the zonal drainage basin. River Gojeb, Gilgel Gibe, Kersa, Kelecha, Unta, Kewa, Anderacha, Dembi, Nada, Abbonno, Doma, Busa and Nedi are remarkable perennial rivers flowing from the Eastern and Southern part and dendrite on the lower part.

Abay river basin occupies 1846 km2 surface area of the zonal drainage basin Didesa,  Dugaji, Wama, Wabe, Bokoka, Boror, Yebu and Anisu Are perennial) rivers in the western part of the zone. Didesa River constitutes the longest volume of the river basin. Baro river basin occupies the area 1101.24 km2 that found on the top of Gera mountain range. River Gebba, Onja, Sallako, Gidecha and Bodecha are the major perennial rivers in Baro river basin. Another water body is swampy locality that highly tress to the upper Gibe river catchmentsarea, for instance, Cheleleka small lake in Limmu Kossa district does remarkable  in the zone.

Summary of known streams, river (both Seasonal And perennial) in cluding length and depth of rivers in the zone..

No

River

Tributaries

Length

Seasonal

Perennial

1

Gibe

Gojeb

Gilgel Gibe

Kersa

Kelecha

Unta

Kewe

Anderacha

Dembi

Nada

Abbonno

Busa

Nedi

16559 km2

 

2

Abay

Didesa

Dugaji

Wama

Wabe

Bokoka

Boror

Yebu

Anisu

1846 km2

 

3

Baro

Gebba

Onja

Sallako

Gidacha

Bodacha

1101.24 km2

 

Source: - Adapted from Oromia regional statistics and information center (BOFED)

Ø The above table indicates that the largest area of the zone is covered by Gibe River and that the rivers occurring in the zone is perennial and this makes the zone suitable for building irrigation projects.

Ø  Gibe River creates favorable condition for getting electric power supply for the zone. It is also being used as the main source of fishes for the communities in the Zone.

                     CLIMATE :-

One of the basic important features for human beings to live on the earth is favorable environment, which in a sense is said to be favorable if and only if the climate is favorable. Most part of  Jimma administrative zone comprises 2 of three major agro-climates. I.e. Bada dare (subtropical), bada (cool) and Gamooji (tropical). The zone has characterized by three major climates.

               ANNUAL TEMPRATURE     The vast areas of Sigmo, Setema, Northern and Western Gera, Seka Chekorsa, Kersa, central Omo Nada ,Dedo,Eastern part of Limu Kossa and western Tiro Afeta districts have mean annual temperature between 15-180c.

Central part of the zone along FinfinneJimma, Mettu road (large part of Tiro Afeta, Kersa Mana, Northen part of Omo Nada and Dedo) have mean annual temperature between 18-200c. But area along major river valley, (Didessa, Gibe and Gojeb) which consists of Goma, Mana, Limu Kossa, Sokorru, Seka Chekorsa and Limu Seka have mean annual temperature between 20-230c. Only small portion of the zone area (Gibe Valley of Sokoru district has mean annual temperature between 20-230c)

The zone is weakly bimodal rainfall with spring a small rainy season during the months of April and may while summer a long rainy season during the months of July, August and September.

The zone has four rainfall classes. The first class covers the Vast area of the zone and abundantly found in the southern and central part that is common to districts of Mana, Kersa, Seka Chekorsa, Dedo, Tiro Afeta, Omo Nada, Limmu Seka and Limmu Kossa. The annual rainfall of this class lies between 1300mm -1700mm. The second class of the rainfall lies between 1700 and 2100mm which is common to the western and northern part of the zone including Setema, Gera, Gomma, Limmu Seka and Limmu Kossa. All parts of Sigimo, part of Limmu Seka, Limmu Kossa and western part of Setema districts experience annual rainfall between 900 and 1300 mm which is restricted to Gibe river valley of Sokorru and OmoNada districts. These are the information obtained before two years, when it is compared to the current situation of the zone, some part of the districts rain fall is changed with the temperature of the area.

·        Agro- Ecological climate: - is natural regions characterized by a fair, homogenous climate, physiographic, altitude (relief) and human activities. It is delineated in terms of major climatic variables and plant growing period, which is suitable for a certain ranges of crops and cultivators. It pulls together ecological parameters significant to agriculture (growing periods soils, physiographic (altitude and relief) and land degradation and environmental conservation.

Based on the general characteristics of traditional ecology, Jimma zone consists of three major climates: bada dare (subtropical), bada(temperate) and Gamoji(Tropical or Thermal Zones) which covers an area of about 78%, 12% & 10% respectively. Gamoji (tropical) agro-climate is found in Didessa, Gibe and Gojeb river valley of Limmu Seka, Gomma ,Sokorru, Dedo and Seka Chekorsa which accounts 10% of the district agro –climate having annual temperature of 20-250c. Manna, Gumay, Aggaro, Tiro Afeta and Nono Benja have Badda daree (subtropical) agro climate that accounts 78% of the zonal total area. Sigmo, part of Setema, Gera, Omo Nada, Kersa and Limmu Seka high lands have bada (cool) agro climate that accounts 12% of the zone. The climate, to the current sense is changed, meaning the percentage of bada (cool) decreases, when that of tropical increases due to environmental degradation.   

  Soils

The major soil categories of Jimma Zone are chromic and pelvic verti soils, 2925.9Km2 (15 %), OrthicAcrisols, 9553 Km 2 (50%) and Dystric Nitosols 6827 Km2 (35%). OrthicAcrisols cover the part of the Zone’s total area (50%) Which covers the vast area of Omo Nada, Dedo, Limmu Kosa, Kersa, and Sokoru. It constitutes the larger part of the zone soils. Chromic and pellic verity soils cover the smallest area of the zone’s total area (15%). The vast area of the Limmu Seka, Kersa, Yabu, Northern Omo Nada and Dedo. It constitutes the smallest part of zone soils. Dystric Nito soils have found in Setema, Sigimo, Northern and southern, western Gomma and Limmu Kossa inpart have good agricultural potentialities but land preparations do have a difficult task. It cracks during dry season and has in fact water logged character during wet season. Those extreme cases contributed for limiting agricultural potentialities of the soil. But it is very fertile soils for crop production, from the soils encountered in Jimma Zone, Dystric Nitosols have great potential for crop production, which is found in the districts mentioned above.