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IMPACT OF LAND MANAGEMENT PRACTICES ON GROUNDWATER RECHARGE: CASE OF EDO-WATERSHED IN THE ETHIOPIAN RIFT VALLEY BASIN
(Hawassa University, 2022-10-21) ASHENAFI DORA DOKAMO
Proper water resource planning requires an understanding of the availability and use of
ground water. But, there is lack of information in the Edo watershed on groundwater
availability, rate of recharge, and there is limited information on the impact of land
management on groundwater. In line with this, the objective of this study was to determine the
impact of land management practices on groundwater recharge and soil water dynamics on
conserved land and bare land at the Edo watershed in Wondogenet. In this study, the Hydrus-
1D model and water table fluctuation methods were used to estimate groundwater recharge.
Hydrus -1D model is the Richards-based vadose zone hydrological model. The
meteorological, and soil hydraulic data were used as input data to the Hydrus-1D model. Soil
hydraulic parameters were estimated from easily measured soil physical properties using
ROSETTA-derived prior information about soil hydraulic parameters. Water table data from
twenty-five wells was used to estimate the recharge. The model performance was evaluated by
comparing the observed and simulated soil water content values both on conserved land and
bare land in the study area. The high value of
0.997 and a low value of ME (0.049) for
calibration and a high value of
0.99 for Conserved land and 0.93 for bare land and low
(RMSE of 0.23-0.28, MEB of 0.057-0.23) values during validation showed that there was a
good agreement between the observed and simulated soil water content. The overall
evaluation according to the common performance evaluation techniques revealed that the
observed and simulated soil water content in conserved land was higher compared to those in
bare land. From the Hydrus -1D, the long-term average annual groundwater recharge was
3,976,409.32 m3 or 297.8896mm, which is 26.92 % of average annual rainfall, and the water
table fluctuation method 257mm, which is 23.23% of average annual rain fall. From the
result, it can conclude the conserved land was better than bare land due to storing more
water. The current observation showed that good land management practices were useful to
sustain the water resources in the watershed.
GIS-BASED SURFACE IRRIGATION POTENTIAL ASSESSMENT OF MEKI RIVER WATERSHED, CENTRAL RIFT VALLEY OF ETHIOPIA
(Hawassa University, 2023-07-16) KUFA KAFU MILO
Irrigation can contribute to food security by increasing food availability and cash income of
smallholder farmers. However, surface irrigation development in the study area is hindered
due to lack of reliable data of suitable land and available water potential. Therefore, this
study assessed the land and water resources of Meki River watershed in rift valley lakes basin
in Ethiopia using Geographic information system to identify suitable land and available water
potential for surface irrigation. Land suitability factors such as soil depth, soil texture, soil
drainage, slope and land use/cover were considered and their suitability analyzed using
ArcGis10.3. Water availability assessed using soil and water assessment tool and calibrated
and validated with observed flow. Flow duration curve from monthly simulated flow was
developed to obtain the reliable monthly flow at 80% probability. Irrigation water
requirements estimated using CROPWAT8.0 for the Maize, Onion and Tomato and compared
with dependable flow to compute the potential irrigable area. Regarding evaluation factors
the results showed that 52.31 % of slope, 89.9% % of soil depth, 75.95% of soil drainage
99.65% of soil texture and 94.73 % of land use land cover were in the range of highly to
marginally suitable, whereas 47.69 % of slope, 10.1% of soil depth, 24.1% of soil drainage,
0.35% of soil texture and 5.27 % of land use land cover restricted for surface irrigation.
Further weighted overlay results showed that 177,199 ha were in the range of highly to
marginally suitable whereas 35798 ha were unsuitable. Besides, the results revealed that
maximum and minimum dependable flow during crop growing period were 39.6 m
3
/s and
0.05 m
3
/s respectively. Moreover, the results showed that irrigation water demands vary from
crop to crop, and 4126.04 ha were obtained to be potentially suitable for the development of
surface irrigation project. This study concludes that there is huge suitable land and
insufficient water availability in the watershed. Therefore, irrigation potential of the
watershed can be increased through using water saving technology such as drip, sprinkler
and selecting other less sensitive crops, also using other water sources such as Lake Water,
ground water and rain water harvesting
URBAN WATER SUPPLY SYSTEM PERFORMANCE ASSESMENT: THE CASE OF ASSOSA TOWN, ETHIOPIA
(Hawassa University, 2022-10-23) ABEBE AMADO MENTOSEA
Intermittent water disruption is the key problem of many water authorities in developing countries
including Ethiopia. Water demand has been increasing significantly in most cities due to population
growth and other factors. As a result, town water utilities are struggling to provide customers with
adequate and reliable water supply service despite obstacles that hinder water utilities not to provide the
required service. This study assesses the performance of Assosa town water supply system based on
main performance indicators namely Demand and supply, water loss, water quality, customer
satisfaction, and. operation and maintenance. These indicators have been cited as the main factors, which
reflect the performance of many urban water supply systems. High water loss, customer complaints, and
operation and maintenance problems indicate that there are deficiencies in the quality of the service.
To conduct this research, data of water production and consumption, water supply system data were
obtained from the water utility records, other data not found in the water utility records is collected
using instruments. Hydraulic performance of the system is also evaluated by modeling the system.
Water quality tests were conducted and compared with the national and international standards.
Household interviews were made to understand customers’ satisfaction towards the water supply. There
is a frequent interruption of boreholes. The water quality test shows some parameters departed from the
standard set on the Ethiopian and WHO water quality guidelines. In addition, there is customer’s
complaint towards continuous access of water. The operation and maintenance in the town is identified
to be poor. In conclusion, the town’s water supply system is poor in managing water loss, water quality,
operation and maintenance with the worst condition of continuous generation of water from sources
continuously interruption. It is recommended that the water utility develop a strategy and work hard on
the indicated system deficiencies especially on operation and maintenance to improve the water
supply system performance and provide customers with good quality service
PERFORMANCE EVALUATION OF FIELD WATER APPLICATION ON FURROW IRRIGATION AT WONJI SHOA SUGAR ESTATE, ETHIOPIA
(Hawassa University, 2021-10-17) TSIGE MOHAMMED AHMED
Furrow irrigation is dominantly used method of surface irrigation in the large sugar cane
irrigation projects in Ethiopia. This research was conducted to evaluate the performance
of furrow irrigation with SIRMOD software by two point method and evaluate current
performance of furrow irrigation system, identify the performance gaps and recommend
means of performance improvement at Wonji Shoa Irrigation Estate. Three fields were
selected according to soil type, furrow length and workability for measurement with field
code 15, 52,108 which had furrow length of 64 m, 48 m and 32 m which was practice in
the sugar estate. Different performance indicators were used to evaluate performance of
furrow irrigation they were application efficiency, storage efficiency, application
uniformity and deep percolation ratio. The estimated and simulation result obtained from
the average application efficiency of the three selected fields (15, 52, and 108) were
74.42%, 41.19% and 64.12% and 74.39%, 50.20% and 75.18% respectively. The storage
efficiency values for three selected fields were 100% for estimation and 99.11%, 99.67%
and 99.65% for simulation respectively. The estimation and simulation average
distribution uniformity of the three selected fields were 91.86%,90.78% and 89.86% and
92.44%,91.38% and 93.26% respectively and the deep percolation ratio for estimated and
simulation were 25.35%,58.81% and 35.88% and 25.35%, 49.48% and 24.5 respectively .
From the selected fields, filed 15 and 108 had better application efficiency with furrow
length 64 and 32 respectively than the filed 52 with furrow length 48 m and the field 52
had low application efficiency and high deep percolation ratio. The result obtained from
sensitivity analysis; discharge, cutoff time and length of furrow were highly sensitive to
application efficiency and deep percolation ratio, whereas the slope of furrow had no
effect on performance indicator in this study. The amount of water applied during
irrigation event were more than the irrigation water required which indicates that large
amount of water was being wasted due to poor irrigation water management practice.
From the result of this study, it can be concluded that there were over irrigation problems
SURVEY ON FUNGAL AND AFLATOXIN CONTAMINATION OF STORED MAIZE (Zea mays) GRAINS IN SOUTHERN ETHIOPIA
(Hawassa University College of Agriculture, 2022) MEMHIRU MEKISO MADEBO
Maize (Zea mays L.) is attacked by more than sixty diseases and a number of species of insect pests and microorganisms in the field as well as in the storage. Fungi are among the principal causes of deterioration and yield loss on farmers’ maize during the storage period. Among the storage fungal pathogens Fusarium, Aspergillus, and Penicillium are the most predominant species attacked maize grain and resulting in production of harmful products of Mycotoxins. The study was conducted at the Hawassa University College of Agriculture in plant pathology laboratory. The study was aimed to study effect of storage duration and storage type on fungal contamination and assessments of aflatoxin contamination of maize grains in southern Ethiopia . A total of 165 Maize grains samples were collected from different storage type and storage duration in southern Ethiopia, in 2019/2020. A total of seven fungal genera consisting of twenty one species of fungi were isolated from maize grain by using morphological characterstics; Fusarium spp. were most frequently isolated, followed by Aspergillus spp.The fungal contaminations of maize grains were significantly different (p<0.05) increased with storage periods. At the last six months of storage, the contamination of the Fungal isolates revealed that Fusarium spp had the highest contamination of 43.6% followed by Aspergillus spp, 28.6%, then Penicillium spp 5.27%, Alternaria spp 4.12%, Rhizopus spp 3.08%,Tricoderma spp 1.65% while the least contamination of 1.22%, was Cladosporium spp. The highest contamination of Fusarium spp (44.79%) and Aspergillus spp (24.98) were recorded in storage basket whereas the minimum contamination of Fusarium spp (35 %) and Aspergillus spp (15.5%) were obtained from plastic storage. As a result of this research, the Plastic container storage was determined to be more appropriate for protecting the stored maize grains from fungal attack during the storage periods and the stored grains have low fungal contamination until initial t o six months. Therefore, storage Basket, storage Crips, storage Sacks and Gombisa storages were inadequate for protecting stored maize from fungal attacks. Total aflatoxins has quantified from the maize samples collected from different maize growing areas in southern Ethiopia by using Enzyme Linked Immune Assay (ELISA) Kit. The result reveal that the mean 32(66.7%) of 48 maize grain sample were positive for aflatoxin contamination with levels of aflatoxin concentration ranging from 0.21-18.06µg/kg. The average aflatoxin concentrations detected in the present study were below the US Food and Drug Administration (FDA), the World Health Organization (WHO) maximum limit of total aflatoxin 20μg/kg. The EU has maximum limit of 4 μg kg−1 total aflatoxin in cereal for direct human consumption. Thus, most of the samples contaminated with aflatoxins in this study are not suitable for human consumption by the EU standards.