Evaluating Technical Standards of Implemented
Soil and Water Conservation Technologies in
Jimma Zone, South-Western Ethiopia
Gizaw Tesfaye1*, Kalkidan Fikirie2, Yalemtsehay Debebe1 and Leta Hailu1
1 Jimma Agricultural Research Center, Ethiopia
2Melkassa Agricultural Research Center, Ethiopia
Submission: December 21, 2018, Published: January 25, 2019
*Corresponding author: Gizaw Tesfaye, Jimma Agricultural Research Center, P. O. box 192, Jimma, Ethiopia.
How to cite this article: Gizaw T, Kalkidan F, Yalemtsehay D, Leta H. Evaluating Technical Standards of Implemented Soil and Water Conservation
Technologies in Jimma Zone, South-Western Ethiopia. Agri Res& Tech: Open Access J. 2019; 19(4): 556100. DOI: 10.19080/ARTOAJ.2019.19.556100
The problems of land degradation is increasing throughout the world due to the generalized use of empirical approaches to select and apply soil and water conservation (SWC) practices. The design of SWC structures considers the extent of erosion, cause of erosion and suitability of land. The study was carried out in three selected districts (Sekoru, Gomma, and Manna) of the Jimma Zone, South Western Ethiopia, with the objective of evaluating technical standards of implemented soil and water conservation technologies. A total of 270 household heads were selected for the study using, 90 households from each district. Data were collected through a semi-structured questionnaire; focus group discussion and measurements of implemented structures. In addition, secondary data were used and analyzed with the help of SPSS version 16 and rational formulas for SWC design. The result of this study revealed SWC embankment and channel dimensions implemented didn’t follow the standards given. These dimensions were found less than the standard given while greater than the standard in some areas. Percentage of area lost per hectare due to the structure also depends on the structure dimensions. Live fence, bund stabilization grasses and shrubs were common biological measures in the area. Sekoru and Mana districts perform well by structural maintenance than Gomma district. Lack of training, extension service, lack of farm tools and skilled manpower are the major problems during SCW structures implementation. Therefore, the study suggests training and continuous follow up during and after implementation should be given by government and non-governmental organization.
Keywords: Soil erosion; Soil and water conservation; Technical standard
Abbrevations: SWC: Soil and Water Conservation; PAs: Peasant Associations; KIs: Key Informants; TLU: Tropical Livestock Unit; NGOs: Non-Governmental Organizations; FGD: Focus Group Discussion; Tc: Time of Concentration
The problem of soil and water degradation and derived effects are increasing throughout the world., this is due to a lack of appropriate identification and evaluation of the degradation processes and of the relations cause-effects of soil degradation for each specific situation and the generalized use of empirical approaches to select and apply soil and water conservation (SWC) practices. Sometimes, wrong selection and implementation of soil and water conservation practices and structures may increase land degradation processes and derived environmental impacts .
Soil and water conservation technologies are activities that maintain or enhance the productive capacity of land in areas affected by or prone to soil erosion. It includes the prevention, reduction and control of soil erosion alongside proper management of the land and water resources. Effective erosion management includes reduction of the amounts and velocity of surface runoff, maintaining good soil cover through mulching and canopy cover, conservation and retention of soil moisture, Prevention or mini
mizing the effects of raindrop impact on the soil, maintaining favorable soil structure for reducing crusting, re-shaping the slope to reduce its steepness and slope length so as to minimize runoff flows, maintenance or improvement of soil fertility, and removal of unwanted excessive runoff safely .
There are a number of technical mistakes committed by experts and farmers in almost all kinds of soil and water conservation measures. These problems become worse when it comes to drainage control structures such as graded bunds, cutoff drain and waterways. Since the design and dimensions of these structures are very much dependent on runoff rate to be generated from a particular area/watershed . Proper design of SWC structures is important for their effectiveness in protecting the soil from raindrop impact and hydraulic forces of runoff. The design of SWC structures considers severity and extent of erosion damage or risks, the factors causing erosion, as well as the suitability of land to the identified intervention. Planning and implementing land use properly lead to fewer degradation problems, achieving both short-term and long-term benefits . Soil and water conservation
are the most important part of land-use planning and must
be inserted into the whole context of land-use planning for land
development. Soil and water conservation programs must be seen
as the development and application of land use systems that preserve
or enhance soil productivity.
In high rainfall areas a common objective of implementing soil
and water conservation structures is to lead unavoidable surface
run-off safely off the land using drains and ditches. In semi-arid
regions the objective is more likely to be to slow down the run-off
to non- scouring velocities and to encourage infiltration or deposition
of silt, without diverting the run-off. There are always strong
links between measures for soil conservation and measures for
water conservation. Many measures are directed primarily to one
or the other, but most contain an element of both. Reduction of
surface run-off by structures or by changes in land management
will also help to reduce erosion. Similarly, reducing erosion will
usually involve preventing splash erosion, or formation of crusts,
or breakdown of structure, all of which will increase infiltration,
and so help the water conservation.
The Ethiopian government has been made a lot of efforts to
overcome the problem of Continuous land degradation resulted
in a loss of fertile topsoil leading to low agricultural productivity
and soil erosion. Soil conservation in Ethiopia is considered today
to be of top priority, not only to maintain and improve agricultural
production but also to achieve food self-sufficiency, which is the
long-term objective of the agricultural development programme.
Therefore, a massive effort is being made in soil conservation by
the Ministry of Agriculture. The Community of Forests and Soil
Conservation Development Department has already implemented
soil conservation measures on over more than 1 million hectares
in the last ten years in the country .
However, mass mobilization approaches lead to the implementation
of soil and water conservation structures with inappropriate
design, and consequently, soil conservation activities
have had a lesser impact than expected and resulted with gully
formation in many parts of the country. Such a problem may be
due to a technical gap and lack of trained manpower. The technical
gap causes failure of implemented SWC technologies which in
turn causes serious land degradation. In the study area also, the
failure of implemented structures was observed and reported repeatedly
in most parts of the country that could be due to wrong
SWC structures design specification. Because of this, the study was
aimed to assess and evaluate technical standards of implemented
SWC structures using Community-Based Participatory Watershed
Development guideline prepared by Desta, et al.  and empirical
equations given for soil and water conservation structures specification
The study was undertaken in three selected districts namely
Sekoru, Gomma and Manna of Jimma Zones (Figure 1). Jimma
Zone is located 350km away from Addis Ababa the Capital City of
Ethiopia. It is geographically located between 360 50’ E longitudes
and 7040’ N latitude and the altitude of the zone ranges from 880
to 3340m.a.s.l .
The study was carried out in Jimma zone, comprised 18
districts. Of these, ten districts were classified under lowlands
agro-climatic zone, while the remaining 8 districts in the highland
agro-climatic zone . Most of the soil and water conservation
technologies implemented in lowland agro-climatic zone. Therefore,
attention was given to the lowland districts of the zone and
samples were also selected from those. To select representative
districts, the first consultation was held with the zonal council
members (administrators) and then three districts were selected
purposively by considering the agro-climatic zone of the district.
Then after, three peasant associations (PAs) selected from each
sample districts purposively again based on the agro-climatic condition
of the PAs.
In this study, key informants (KIs) are referred as the elder or
a knowledgeable person who has deeper knowledge on local issues
like on environmental degradation, soil and water conservation
technologies and livelihood systems and lived in the area for
long period of time. Thus, the selections of key-informants were
done with the help of the PA administrators. Therefore, five individuals
were reasonably picked from each selected PAs. In general,
45 KIs were selected from 9 sample PAs. The number of respondent’s
sample size was determined using the formula developed
by Israel. A formula used for sample size determination:
Where: n= number of sample size; N= is population size; e= is
the level of precision (5%, 7% and 10%), but 8% precision level
was used for this study). Accordingly, the sample size required (n)
in the study was about, 267HHs from the population but a total of
270 households (HH) were used. Because of a homogeneous type
of HH population in terms of their livelihood and conservation
technologies implementation, households were selected randomly.
As a result, 90 households selected from each sample districts
The study was carried out through both quantitative and qualitative
research methods. The data was obtained from primary
and secondary sources. The main primary sources of data were
KIs Interview, FGD, and household survey. Secondary data were
from published and unpublished data sources.
KIs were individually interviewed on the perception of soil
and water conservation technologies, soil erosion, land degradation
and natural resource conservation practices. The interview
was based on open-ended questionnaires. FGD, where a group of
people having similar concern and experience regarding a subject
is encouraged to participate in a facilitated discussion, was
conducted. Therefore, one FGD was carried out in each sample
PA with the selected KIs. It was undertaken to have clarity in
the area of ambiguity and to gather detailed information in the
areas of perception of soil and water conservation technologies,
climate-related events and land management practices. A total of
nine discussions were held in the nine sample PAs.
The formal HH survey was undertaken with HHs selected randomly
from the list of HHs to get information on the areas of livelihood
activities, demographic and socio-economic characteristics,
SWC technologies perception, impacts, natural resource conservation
and vulnerability reduction practices. In the process of
formal HH survey, four stages were involved: preparation of questionnaires,
recruitment, and training of field-assistants, pre-testing
questionnaire and feedback, and finally the administration of
actual fieldwork. The survey was undertaken based on open and
Dimensions of implemented soil and conservation structures
were measured from a 9 kebeles of three selected woredas of
Jima Zone. During this measurement slope of the land (by clinometer),
type of implemented structure, embankment and channel
dimensions were seriously measured. Using these collected basic
data and corrected structures dimensions were calculated and
designed to be compared with the implemented one. During the
design of these structures peak discharge that will be generated,
vertical interval, spacing, gradient and structure dimensions were
calculated for structures implemented in the selected areas.
Is the spacing between two consecutive graded bunds in meter
(it is the difference in height or elevation between two points
on a slope). Ramser’s Formula was used:
Where: V. I. = Vertical interval between consecutive bunds and
S = Land slope (%).
Horizontal spacing: Is the horizontal ground distance or cultivable
strip in meter between the successive bunds and calculated
using the following formula:
Where: HD=Horizontal distance of the bund (m); VI = Vertical
Interval (m) and S = Slope (%)
Channel gradient: The gradient of graded bunds varies with
the soil type of an area. Accordingly, for erodible soils (silt and fine
sandy soil) grade of 0.25%, for moderately erodible soil (loam)
0.5%, for less erodible soil (clay soil and gravel) 1% and for gravel
and stones a gradient >1% was used for this study.
Peak discharge: Rational method was used to calculate the
peak discharge that can be generated from the catchment area (for
cutoff drain and waterway design) and from between two consecutive
bunds for bund design.
Where: C = Runoff coefficient; I = Maximum average rate of
rainfall over entire area which may occur during time of concentration,
cm/hr; A = contributing area, ha; Q = Design peak runoff
rate, m3 sec-1. Since there is rainfall intensity data scarcity in Ethiopia,
time of concentration (Tc) which is equivalent to duration
and IDF curve developed for the area  were used to calculate
intensity(I). Time of concentration was calculated as:
Where: Tc = Time of concentration, min.; L = Maximum length
of travel, m; S = Average land slope, m/m.
Dimension of graded bunds: Bund height, top width, bottom
width and side slope of the are the major dimensions of the bund.
In stable soils the embankment will have side slopes of 1:1 (horizontal:
vertical) but in unstable soils a 1.5-2:1 side slope is preferable,
Height of the bund will depend on the land slope, expected
maximum rainfall intensity of the area and vertical spacing used,
To allow for compaction a 20% freeboard and a 15% settlement
clearance increase on height and a berm of 10 to 25cm was left
between the embankment and the edge of the channel to prevent
the soil from sliding back. One Height of bund was determined
the bottom width and top width of the bund can be derived using
bund side slope and seepage line slope as:
Base width to accommodate the seepage line (B1): B1= h
*Slope of seepage line
Base width to suite side slope (B2): B2 = h *side slope of
Total base width (Bt): Bt = B1 +B2
Top width (T): T= Bt – 2ht *side slope of bund
Capacity of the designed bund was checked by calculating hydraulic
radius, mean velocity and then discharge capacity as:
Hydraulic radius (R): R = A / P
Where: A= area of water spread due to bund; P = Perimeter
Where: S = gradient (m/m); n= manning’s coefficient
Discharge capacity (Q): Discharge capacity of the structure
should exceed the peak discharge to withstand the generated runoff
and estimated as:
The quantitative data was summarized, tallied and coded by
using Microsoft Excel 2007 and then entered to SPSS software
version 16. The analysis of HH demographic and socio-economic
characteristics was undertaken by using appropriate statistical
tools such as one way ANOVA, chi-square and descriptive statistics:
frequencies, percentages, SD, and graphs. Qualitative data
were analyzed and described through opinion interpretations after
organized and categorized.
The total sample of the study is composed of Sekoru 97.8%,
Gomma 94.4% and Manna district 93.3% male-headed households
while the remaining 2.2%, 5.5% and 6.6% of female-headed
households from Sekoru, Gomma, and Manna district, respectively.
This shows that statistically there is an insignificant difference
between districts with regard to sex (P>0.05).
The mean age of sampled households is 44 with minimum and
maximum age of 21 and 73 respectively. More than half of respondents
from three districts are in the middle age group (31-55) and
the proportion of younger household heads is higher in Manna
district (Table 2). On the other hand, the proportion of younger
household heads is much smaller in Gomma district compared to
Sekoru and Manna. The age difference between the three districts,
however, is found to be statistically insignificant suggesting age
has to influence the implementation of SWC structures (P>0.05).
The average family size for three districts Sekoru, Gomma,
and Manna was 7.4 which are higher than the national average
family size of 6.4 people per household. The result of one-way
ANOVA confirms that statistically there is no significant difference
(P>0.05) in family size with regard to Sekoru, Gomma and Manna districts. Therefore, from this result and personal judgment during
data collection, it’s possible to conclude and suggest that labor
availability is a major factor influencing households’ decision to
implement soil and water conservation structures their own land.
Hence, the availability of labor force directly influences the implementation
of soil and water conservation structures in the study
area. Concerning the marital status of respondents, about 93.3%
in Sekoru and 83.3% in Gomma district are married, while 91.1%
of respondents in Mana were married (Table 3).
Educational level: Education is an important factor that plays
a major role in a household decision in adopting new technology. It
helps much in creating awareness on new technologies and its applications.
The study showed that most of the sample households
are found to be read and write (1-4) and the remaining elementary
school (5-8) (Table 4). The result also found that the number
of uneducated households was higher in Gomma and Manna than
Sekoru district. From the total sample respondents, only a few respondents
have completed their high school. In general, the result
shows that respondents in Sekoru district have a better educational
opportunity than the two districts. Furthermore, the statistical
test indicates that there is a significant difference among district
of household heads in their educational achievement (P<0.05).
Household livestock ownership: In order to standardize
the size of livestock, the livestock of each household is converted
into Tropical Livestock Unit (TLU) by using the conversion factors
suggested by Stock et al. . Accordingly, the average TLU owned
by the respondents in Sekoru, Gomma and Manna were 4.3, 3.0
and 5.3, respectively. More than half of respondents from the three
districts that constitute 6-10 TLU and only Manna district-owned
lower TLU (Table 5).
Implemented Soil and Water Conservation Structures:
In the study area, different physical soil and water conservation
structures were implemented. However, soil bund and cutoff
drain are the most dominant one in the three districts; soil bund
constructed 76.9% by Manna district, 53.9% of Sokoru 75.7% by
Gomma district (Table 6). In the same manner, Manna and Gomma
districts were highly constructed cutoff drain in the area.
On the other hand, biological soil and water conservation
structures were implemented due to fragile topographic nature
of the area. Accordingly, live fence biological structure is the most
dominant conservation practice in Gomma district next to Manna
(Table 7). Similarly, bund stabilization with vetiver grass is widely
implemented in the study area. In general, the result shows that
three districts were implemented in different physical and biological
soil and water conservation structures in the area.
The statistical test result shows that there is an insignificant
difference between districts with regard to soil and water conservation
structures implementation (P>0.05). This is because the
contribution of different non-governmental organizations (NGOs)
are higher in terms of giving training, extension services, experience
sharing and visiting demonstration sites. During focus group
discussion, discussants responded that in the study area, households
widely implemented different physical and biological soil
and water conservation structures individually since the area is
fragile and mountainous.
The assessment was made on which soil and water conservation
structures on the bases of difficultness and easiness to construct/
implement. According to the respondents’ soil and water
conservation measures easy to implement were more preferable.
Easiness is measured in the study area in terms of labor intensiveness
and material (soil or stone). Most of the interviewed farmers
45.7% from Manna, (65.2% from sokoru and 31.2% from Gomma
stated that Check dam was difficult to construct. But only 10%
from Manna, 19% from Sokoru and 14.5% from Gomma believed
that soil bund was difficult to construct and implement. This result
implies that bund (soil or stone bund) is the most preferable structure
to implement in the study area as shown in Figure 2 below.
According to the survey result, almost all sample districts
implemented different SWC structures in the area. However, the
performances of the structures are very low. Accordingly, about
26.6% of Sekoru respondents maintained the implemented conservation
structures, Manna 21.1% while the remaining 12.2% of
Gomma were maintained the implemented structures (Figure 3).
The statistical test result shows that there is a significant difference
(P<0.05) between districts via structures maintenance. This
indicated that sekoru and manna district have better performance
by structures maintenance than Gomma district.
This is because of in Sekoru and manna district different
NGOs were involved with conservation structures application and
maintenance. According to FGD, GIZ and SLM NOGs were highly
supported by the local households as related to natural resource
conservation. Therefore, respondents in Sekoru and manna district
have better awareness about the conservation activities and
other related issues compared to Gomma district. In addition to
this, both districts; Sekou and manna have different access like incentive,
farm materials provided by different NGOs
Training: Training on soil and water conservation technologies
is one of the important factors that influence the involvement
of farmers in natural resource conservation. Accordingly, about
65.6% of Sekoru, 67.8% of Manna and 34.4% of Gomma respondents
have access to training (Table 8). The statistical test result
confirmed that there was a significant relationship between districts
concerning training participation in soil and water conservation
(P<0.05). Comparatively, Gomma had less opportunity or
access to training. This is because of the availability of different
non-governmental organization in Sekoru and manna districts.
Hence, during FGD discussants responded that most of the time
training was often given by different NGOs like GTZ and SLM in
both districts. On the other hand, in Gomma district, farmers got
training access often from government bodies including political
leaders. The more the local farmers get soil and water conservation
training, more likely that they acquire the relevant information
about soil and water conservation technologies.
Extension Services: The household survey result indicated
that 43.3% of Sekoru, 37.8% of Gomma and 54.4% of Manna
respondents got better extension service. The chi-square test
shows that there is the insignificant difference between districts
with regard to extension service in the study areas (P>0.05)
(Table 8). Agricultural extension services are fundamental for
the development of natural resource conservation, providing
training, accessing the supply of inputs timely and giving various
information that ranges from production to marketing. Moreover,
it represents local farmers’ frequency of contact with DAs and
frequency of participation in extension planning, training, field
day, on-farm trial and demonstration regarding agriculture and
livestock production. Thus, extension service has a positive impact
on enhancing natural resource management.
Farm Material: Farm materials are one of the most important
factors whether to implement soil and water conservation technologies
or not. It was identified that the about 46.7% of Sekorus’
and 61.1 of Manas’ respondents have sufficient farm tools to implement
SWC technologies. On the other hand, in Gomma district,
only 21.1% of respondents have access to farm tools. And also, statistically
significant difference was observed in owning farm tool
between districts (P<0.05) (Table 8). Most of the time manna and
Sekoru district have better access to work with different NGOs, as
a result, Gomma district farmers own fewer farm tools to implement
Manpower: 51.1% of Sekoru respondents and 61.1% of Manna
respondents have adequate manpower while the remaining
44.4% of Gomma respondents have the better manpower (Table
8) to implement soil and water conservation structures. The statistical
analysis showed that there was no significant difference
between districts with regard to man power (P>0.05).
Note: **significant at P<0.05 and NS= insignificant P<0.05
Graded soil bund embankment and spacing dimensions:
In Manna and Gomma districts implemented soil bund spacing
and embankment dimensions (top width, height and bottom
width) were less than the standard or calculated specification.
Implemented structure lacks ability to hold the peak discharge
that can be generated in between two consecutive bunds when the
implemented structure embankment dimensions are less than the
standard. This may cause serious damage to the field via initiating
rill and gully erosion. Spacing of soil bund was less than the
standard in some areas while it was implemented with more than
the recommended bund spacing in other places as indicated in Table 9. When mechanical soil and water conservation structures
is implemented with less spacing large area of land can be lost and
farmers are not interested to implement the structure, and when it
was implemented with large spacing more runoff can be generated
causing over topping. Due to this over toping serious problems
like rill or gully erosion could be initiated which requires more
labor and budget to overcome the problem.
Graded soil bund channel dimensions: Implemented bund
channel depth in Manna and Gomma districts were less than
the calculated depth to hold the peak discharge generated and
to remove the excess runoff at a non-erosive velocity (Table 10).
This can also be a cause for overtopping and hard to reverse the
problem. The width of the soil bund channel was a little bit greater
than the calculated width which was resulted with more the area
of land lost by bunds and requires more labor.
Stone bund spacing and embankment dimensions: Stone
bund was implemented in Sokoru district and when the dimensions
were compared with the standard, the spacing, height, top width
and bottom width dimensions were less than the standard. Since
it was implemented with less spacing which makes more area to
be lost due to the implemented structure. In addition, it could be
labor intensive when applied with small spacing (Table 11).
Graded fanyajuu embankment dimensions: From assessed
graded fanyajuu spacing and embankment dimensions at six PAs
of three districts, the spacing of the implemented fanyajuu has
deviated negatively in most PAs from the standard which means
the implemented spacing was less than the standard/calculated
spacing. As a result, the area lost by the structures increases and
makes farmers resistant in the adoption of SWC structures. Height
and top width of the structure have also deviated negatively from
the standard. But the bottom width of the structure deviates
negatively at many areas and also deviates positively at some
places from the calculated graded fanyajuu dimensions (Table 12).
Graded fanyajuu channel dimensions: Similar to soil bund
depth implemented graded fanyajuu channel depth was less
than the standard depth at all assessed PAs, while the width of
the channel was greater than the standard dimension. These
standardized dimensions were made to hold the peak discharge
that could be generated from between the consecutive bund
spacing (Table 13).
Percentage of area lost: The mean percentage of area lost
per hectare due to the standardized bottom width on the bases of
land slope and vertical interval 12% of land per hectare was lost
and while it was about 10% due to the implemented graded soil
bund in the area on average. And when graded fanyajuu was done
according to the standard about 16% of land area per hectare will
be occupied by bund dimensions and about 15% of land area per
hectare was already lost due to currently implemented graded
fanyajuu dimensions. Similarly, 12.5% of the land would be lost
if the stone bund was implemented according to the standard in
the assessed districts and PAs. But due to the implemented stone
bund, about 7% of the land was lost currently in the area.
These results implied that the area lost due to soil bund and
fanyajuu had no great difference in between the standardized and
implemented dimensions in almost all areas. The standardized dimensions
were calculated to make the structure dimensions capable
of holding the generated peak discharge or runoff (Table 14).
This study revealed that evaluating technical standards of
implemented soil and water conservation structures in three districts.
Hence, from this study, it can be concluded implemented
structures composited the area lost due to structures stabilization
work by forage trees and different grasses. Stability of the embankment,
soil bund depends on the dimensions of the structures
like side slope, seepage line slope in addition to a land slope. Once
the height of the structure is determined the left dimensions can
be derived from the height using empirical formulas. If the top
width and bottom width do not fit with the seepage line and side
slope embankment failure happens. Due to this runoff generated
over tops causing rill and gully erosion which is difficult to control
To sum up, in the study area, different SWC structures implemented
by community mobilization are not standardized due to
lack of awareness and shortage of training. Consequently, it is difficult
to manage the watershed in different areas. Every year SWC
structures have been implemented via community mobilization
on the same lands. Furthermore, major constraints during SWC
structures implemented, knowledge and skill gap, lack of sufficient
materials, trained manpower and so on.
Based on the above findings, the following recommendation
can be drawn for further consideration and improvement of SWC
structures in the study area in particular and in the country in general.
a. Well organized training should be given for experts at different
levels to fill the technical gap on their skill
b. Extension services like demonstration should be held for all
stakeholders before implementing the structures.
c. Soil and water conservation structures should be planned by
experts at PA and district level rather than planning at a zonal
or regional level for its quality and effectiveness.