Africa Center of Excellence for Water Management

Permanent URI for this collection

http://etd.aau.edu.et/handle/12345678/145

Browse

Browsing Africa Center of Excellence for Water Management by Issue Date

Filter results by year or month
Now showing 1 - 20 of 49
  • No Thumbnail Available
    Item
    Drinking Water Quality and Management Practices From Source to Household: The Case of Kombolcha Town, Ethiopia’
    (Addis Ababa University, 2020-06-13) Tesfaye, Bezawit; Alemayehu, Esayas (Professor); Zewge, Feleke (PhD)
    This research focuses on investigation of the existing drinking water quality of Kombolcha town from the source to points of household tap in relation to safety and acceptability for users concerning water quality parameters. The town gets its water supply from groundwater sources. A total of 45 water samples were selected and collected from boreholes, reservoirs, distribution mains and households. The pH, Turbidity, Total Dissolved Solids (TDS), Electrical Conductivity (EC), Temperature, Total hardness, free chlorine residue, Manganese, Nitrate and Iron and Microbiological (Total Coliform and fecal Coliform) parameters were determined. The result was then compared with the WHO and Ethiopian water quality standards. The results obtained show that for physical analysis except temperature the rest all parameters were within the WHO permissible limit. The results for temperature were found between the ranges of 22.5°C - 26.1°C. Based on laboratory analysis of chemical parameters the result shows that total hardness is above the permissible limit set by the guidelines. Also, all chlorine residual of the samples were found to be below the recommended values of WHO and national guidelines except seven of samples. However manganese, iron and nitrate were within the permissible limit. The result of bacteriological analyses indicated that Fecal coliform of all samples were zero meeting WHO and national guidelines. But Total coliform of nine samples were above the guideline`s limit ranging between 1-4 CFU/100ml. In summary, with regard to the Physico-chemical parameters the water is safe and there is no significant effect on the health of the users. The results of bacteriological analyses have shown that some of the sample points are at risk. To overcome these problems regular chlorination is recommended. It is also recommended that sampling and monitoring at different times is essential and analysis of additional water quality parameters should be undertaken.
  • No Thumbnail Available
    Item
    Land Use Land Cover and Climate Change Impact on Surface Hydrology in Borkena Watershed, Awash Basin, Ethiopia
    (Addis Ababa University, 2020-06-24) Abebe, Esayas; Atatnaw, Fasikaw (PhD)
    The rapid land use/land cover and continuous change of climate have direct impact on catchment hydrology. This study assessed the individual and coupled impact of land use land cover and climate change impact on hydrological components of Borkena watershed, Awash basin, Ethiopia. The land use land cover data were obtained from Land Sat image and processed by ERDAS IMAGINE 2014 software for years 1994, 2007 and 2018. The coordinated regional climate downscaling experiment (CORDEX)-Africa data outputs of ensemble average two RCMs derived from MPI-ESM-LR, and EC-EARTH under intermediate and high emission scenarios were analyzed in two-time frames: mid-century and end-century. Both time frames were analyzed using both RCP scenarios from the baseline period (1974-2004). Semi distributed physically-based hydrological (Soil and Water Assessment Tool) model in the ArcGIS interface was used to realize the purpose of assessing the impact of these changes. The highest gain in land use land covers are agriculture and urbanization, the highest losses are forest land followed by shrubland and grassland were observed in the study area. The calibration and validation were done by SWAT CUP which was evaluated using three criteria;R2, NSE, and PIAS (0.667, 0.67, and 2.2%) respectively during calibration and (0.71, 0.69 and -14.22 %) during validation, indicating that a good agreement between observed and simulated streamflow. Due to a decreased in rainfall by 14.56% (mid-century) and 16.51% (end century) under RCP4.5, The change in mean annual surface runoff is predicted to decrease. The annual decreasing change in surface runoff was 21.45% and 30.66% in MC and EC under RCP 4.5 scenario respectively, similarly under RCP8.5 the 22.45% and 30.0% in MC and EC respectively. The mean annual and seasonal surface runoff amplified with combined land use land cover and climate change response compared to climate change impact alone. On the other hand; evapotranspiration has reduced due to the expansion of agriculture and urbanization. Generally From the result, the SWAT model has the capability to simulate the rainfallrunoff for Borkena watershed and LULC change had more impact than climate change on water balance components. These changes need to be mitigated through land management and afforestation, to reduce the surface runoff and increase the availability of water for the future.
  • No Thumbnail Available
    Item
    Reservoir Operation for Optimal Water Use: A Case Study of Kabalega Reservoir in Uganda
    (Addis Ababa University, 2020-07-03) Cyrus, Chelangat; Abebe, Adane (PhD)
    Wambabya River catchment over the past years (since 2013) has been experiencing alterations in its upstream (forests cleared for agriculture) which may have resulted in seasonal variability in rainfall pattern. Temperatures have increased and thus high-water loss through evapotranspiration. River inflows into the reservoir have decreased thus affecting the power generation from Kabalega dam as evidenced by the operation below its capacity in most of the first quarter months of the year and thus being unable to meet the power demand and downstream ecological requirement. The study developed reservoir operation policies for optimal water use of Kabalega reservoir in order to meet the target demands. Australian Water Balance Model (AWBM) was used to simulate Wambabya River inflow into Kabalega reservoir. The model was calibrated with observed flow from 1990-2009 and validated with flow from 2010-2019. Nash & Sutcliff efficiency for calibration and validation is 0.758 and 0.67 respectively. HEC-ResSim model was used to optimize and develop new reservoir operating rules by calibrating and validating the model for 5 and 3 years which yielded Nash Sutcliff coefficient and correlation coefficient of 0.85 and 0.82 respectively. respectively. The reservoir system performance was further investigated by using statistical performance indices which are; reliability, vulnerability, resilience and sustainability index. Simulated releases were compared to the actual releases and generated/ simulated power compared to power demand and it was found that the system exhibits fewer deficits in terms of power supply, with minimal spill flows over the spillway found to occur compared to the original operation policy. The derived operation policies are thus recommended to serve as decision-making tools for operation of Kabalega reservoir to maximize the benefits.
  • No Thumbnail Available
    Item
    Performance of Lab- scale Filtration System for Greywater Treatment and Reuse: A Case of College of Natural and Computational Science Campus, Addis Ababa University, Ethiopia
    (Addis Ababa University, 2020-07-04) Tusiime, Anna; Zewge, Feleke (PhD); Feleke, Adey (PhD)
    Greywater management through treatment using filtration systems and reuse is one way to achieve water security in Ethiopia. The College of Natural and Computational Sciences (CNCS) campus of AAU is facing the problem of water shortage especially in the evening hours when normal water supply is cut off resulting into poor sanitation. Reusing greywater (GW) that comes from dormitories for non- potable uses is one of the options to supplement water supply. The pollution levels of GW is quite low as compared to black water. This quality allows greywater to be treated by simple treatment technology like filtration. The aim of this study was to evaluate the performance of a lab- scale filtration system for greywater treatment and reuse using sand and granular activated carbon as filter media. The specific objectives of this study were to: 1) Characterize the raw greywater generated at CNCS campus; 2) Compare the treatment efficiency of lab-scale filtration systems that use gravel + sand and gravel + sand + GAC; and 3) Evaluate willingness to use treated greywater for selected non-potable uses. Raw greywater quality was characterized by determining its physico-chemical and microbiological parameters in the laboratory. The treatment efficiency was determined by comparing the mean values before filtration and with those after filtration. The systems was examined for its efficiencies at different hydraulic retention times (HRT) (12, 24, and 36 hrs) and at different filter columns, one with gravel + sand and the other with gravel + sand + GAC operating at constant HLR (0.15m/h). The willingness to use treated greywater for selected non-potable uses was evaluated through interviews (using questionnaire). Results showed that the raw greywater was polluted and was above reuse standards except nitrates and Total phosphorus, therefore treatment was necessary. For both filter columns, the treatment efficiency of the system increased with HRT at 12 h and 24 h and later on it decreased at 36 h, except for EC and NH4-N, which decreased with increase in time. The removal of contaminants was significant higher (p < 0.05) at 24 h and with no significant different (p > 0.05) between filters except in removal of NH4-N. The pollution reduction was from 60.8 % - 100 % for selected parameters (pH, turbidity, EC, BOD, COD, NH4-N, NO3, TP, TC, and FC) in filter column B and from 47.2 % - 100 % for filter column A. The results also indicated that over 80% of the respondents were willing to use the treated greywater for selected non-portable uses, for the fact that the treated greywater was meeting the reuse standards. Thus, a filtration system is efficient and can be employed to treat GW for non-portable uses at CNCS to improve hygiene, sanitation and water shortage.
  • No Thumbnail Available
    Item
    Impact of Land Use/Cover Change on Soil Erosion and Surface Water Quality: A Case of Upper Lilongwe River Catchment, Central, Malawi.
    (Addis Ababa University, 2020-07-08) Shamsdeen, Idrissa; Legese, Gudina (PhD); Zewge, Feleke (PhD)
    Safe drinking water, hygiene and good sanitation are important for good health, human survival and development. However anthropogenic activities such as land use have affected water quality in many river catchments worldwide. The adverse effect of water pollution has attracted management attention and research interest in both developed and developing countries. However, there is very limited knowledge on the influence of land use and land cover on water quality in Malawi’s catchments. Therefore, this paper aimed at assessing the impact of Land use on Soil erosion and Water quality in upper Lilongwe river which is very important for drinking, irrigation and recreation of Malawi’s capital city. The study first assessed the land use patterns between 1989 and 2019 and results showed that forest land has decreased from 66727 ha to 33594 ha from 1989 to 2019 indicating a forest loss of 46.65%. Grass/shrubs/bare land has also declined by 11.49% and water body by 25.32% within the same period. On the other hand, cultivated land has increased by 26.06% and built up by 56.68%. The land use maps indicate that Lilongwe River catchment has experienced declines in forest land with conversion into shrubs and grasslands then cultivated and built-up. Water bodies such as wetlands have also been converted into cultivated lands. The impact has been water resources depletion and watershed degradation that include accelerated rate of soil erosion and water quality degradation. Soil erosion was assessed by using MUSLE model and revealed that about 83% of the area was classified to not have any soil erosion risk (< 1 ton/ha/yr) and 16 % light risk (1-10 tons/ha/yr). For assessment of water quality, nine water monitoring points across the upper, middle and lower catchment were sampled during the rainy season in February 2020. Turbidity, SS, TDS, EC, nitrates, phosphates, pH and faecal coliform were analysed according to standard methods and compared with MBS drinking water standards. The results showed significant (p>0.05) spatial variability of nitrates, phosphate and faecal coliform between the upper section and the middle and lower section. Furthermore, the study found a positive correlation between cultivated land, Built-up with nitrate and phosphate while forest and grassland had an inverse relationship with nitrate and phosphate. This study suggests that the implementation of integrated watershed management, promoting afforestation, enforcement of buffer zones along the river banks can assist in improving the state of the catchment and improving water quality and quantity within the catchment.
  • No Thumbnail Available
    Item
    Assessment of Drinking WaterQuality from Source to Point Use (The Case of Mojo Town, Oromia Regional State of Ethiopia)
    (Addis Ababa University, 2020-07-25) Mohammed, Fedila; Mogess, Beshah (PhD); Zewege, Feleke (PhD)
    The quality of drinking water has deteriorated due to insufficient treatment plant, direct discharge of untreated wastewater, and ineffective management of piped water distribution systems. The study was conducted on assessing drinking water quality from source to point of use in Mojo town in Oromia region. To achieve the goal of this study, fourteen water samples were collected from different sources and from a household tap, using the purposive sampling method. The pH, turbidity, total dissolved solids (TDS), iron, ammonia, residual free chlorine, fluoride, nitrates, sulfates, total hardness, and Microbiological (total coliforms and faecal coliform bacteria) parameters were determined using laboratory analysis. Laboratory results of bacteriological analysis indicated 66.67% of household tap water samples in kebele two and 60% of water samples in kebele one indicating the presence of total coliforms. On average, 25% of the total household tap shows the presence of faecal coliforms. This is due to a poorly maintained distribution network, improper waste management and broken piping materials. Based on the laboratory results, a large proportion of the community gets the ammonia concentration. 75% of household and 60% of borehole water samples were exceeding the recommended value by the World Health Organization and the national standard. The highest temperature was recorded at BH1, BH2 and BH3 (25,31,29) respectively which is 60% of the total borehole water samples. Turbidity measurements taken from tap water samples especially around kebele one namely HH4, HH5 and HH6 were found to be higher than the recommended value. In addition, a relatively high level of fluoride was observed in BH5. 21.43% of the water sample of the total Iron above WHO recommended level (0.3 mg/l). In addition, a high amount of nitrate concentration was observed in most of the household and borehole samples. All remaining physical and chemical parameters were safe and within acceptable drinking water quality range. In conclusion, poor sanitation, low level of hygiene, and uncontrolled disposal of solid and liquid waste were among the causes of water pollution in the study area. In addition, it is also recommended that the current state of the Mojo water quality system be improved, the proper management of both liquid and solid wastes, the promotion of improved sanitation practices and the constant inspection of water quality.
  • No Thumbnail Available
    Item
    Water Safety Plans Managing Drinking Water Quality for Rural Community, Dirre Tiyyara District, Eastern Ethiopia, 2020
    (Addis Ababa University, 2020-10-01) Mulatu, Gutema; Kassa, kinfe (PhD)
    Water is essential for human to survive in life and having access to safe drinking water is a basic human right. However, significant number of population in developing countries especially in rural areas still drink fecally contaminated water. Similarly in Ethiopia one point water supplies are major source of drinking water in rural areas and small community(MoWIE 2015).Thus the development of water safety plans for small systems should focus on the control of microbial quality of drinking water in particular fecal contamination. The objective of the study was to assess Water Safety Plans Managing Drinking water quality for rural community, Dire Tiyyara District, Eastern Ethiopia September, 2020. A cross-sectional study design was conducted among 180 households in rural community, Dire Tiyyara District, Eastern Ethiopia. A total of 192 Water samples (12 from different source and 180 from HH) were collected and analyzed by membrane filtration method to identify faecal contamination. In addition sanitary survey was conducted at water source and point of use. In Further Combined result of microbiological and sanitary survey was used to prioritize public health risk for intervention. Statistical analysis was performed using Poison regression to assess the association between outcome variable and independent variable. Odd Ratios along with 95% Confidence intervals were estimated to measure the strength of the association and identify association bacteriological quality and water treatment, handling and storage, and latrine availability, use and operation at household level/point of use Out of 12 sources eleven (11) water sources were found to have fecal contamination. In addition level of contamination in one source was very high, and has a major public health impact and need urgent intervention. On the other hand, the average Colony count of TTC of sample (CFU/100ml) at point of use had shown increment at every point from catchment to point of use. Thus, out of the samples analyzed at point of use 91.2% had fecal coliform above permissible level (0 CFU/100ml) for drinking water. Out of this 54.7% of the water sample from point of use had major public health impact and it is clearly priority and need urgent intervention. Furthermore Samples from HH who use water treatment found to be 2 times likely to be contaminated [AOR=1.99; 95% CI (1.89, 2.07)]. Similarly HH with low sanitary risk of water handling and storage were 8.89 less likely to be contaminated compared to household with very high risk [AOR=8.89; 95%CI (8.19, 9.86)] and household with very high sanitary risk of latrine availability, use and operation were 3.86 more likely to be contaminated than low risk [AOR=3.86; 95%CI (3.45, 4.32)]. The study showed fecal contamination of drinking water in rural community of Dirre Tiyyara was significant. As a result, an intervention focusing on improving the quality of drinking should be taken.
  • No Thumbnail Available
    Item
    Macrophyte Species Composition, Distribution and Diversity in Relation to Some Environmental Factors in Upper Awash River, Ethiopia’
    (Addis Ababa University, 2020-10-15) Tigab, Temesgen; Mengistou, Seyoum (Professor)
    Macrophytes play an important role in providing a stable habitat structure to the aquatic ecosystems. Recently Awash River has experienced some undesirable ecological changes due to invasion by exotic weed, Eichhornia crassipes (water hyacinth).With a view come up with scientific information usable in the protection of aquatic resources, this study was carried out between October2019 to April 2020 to assess macrophyte species composition and diversity in upper Awash River in relation to selected environmental factors. Macrophytes were collected manually and physicochemical parameters were measured in situ using YSI 556 multi probe system. Selected nutrients (SRP, TP, TN and Nitrate) were analyzed using standard methods of water and sediment. In Awash River, a total of Twenty six macrophyte species belonging to fifteen families were identified with relatively low species diversity (H’ = 2.56, Margalef index = 2.91). The emergent macrophytes had the highest percentage composition (92 %) and attained the highest relative frequency and density, followed by free floating (4%) and rooted floating (4%). Results of CCA indicated that Nitrate, SRP, TP and flow velocity were among the factors that had significant impact on the diversity, composition and distribution of the macrophytes in the river. Environmental factors of Awash River were recorded to relate to macrophyte distribution, with emphasis on Eichhornia crassipes density along the river bank. The coverage of Cyperus articulatus L., Echinochloa colona L., Solanum incanum L., Eichhornia crassipes, Persicaria senegalensis, Rorripa nasturtium aquaticum, Ipomoea aquatica and Phragmites mauritianus were almost restricted to sites where there was higher Nitrate, SRP and TP and Ludwigia spp., Sida schimperiana, Alternanthera sessilis, Lagarosiphon cordofanus Casp, Brachiaria mutica, Juncus effuses, Ludwigia abyssinica, Cyperus latifolius, and Cyperus papyrus to sites where there was higher DO,TN and Silt. In conclusion, the in situ and experimental data obtained indicate that 50% of the macrophytes diversity was determined by the environmental factors like total nitrogen and phosphorus, flow velocity, nitrate (water) and sediment texture and half of the unexplained environmental factors that regulate the macrophyte diversity and distribution in the Awash basin have to be investigated in future studies.
  • No Thumbnail Available
    Item
    Ecological and Socio-economic Impacts of Ecohydrological Interventions on the Wetlands along the Southeastern Shore of Lake Tana, Ethiopia
    (Addis Ababa University, 2020-10-18) Asnakew, Eshete; Mengistou, Seyoum (Professor); Wondie, Ayalew (PhD); Zerihun, Yohannes (PhD)
    Information regarding the ecological and socio-economic impacts of ecohydrology based intervention approach in the wetland ecosystem plays an indispensable role in increasing biodiversity, improve water quality and enhance ecosystem services. Although ecohydrological solutions have been proposed by various studies for immediate, nature based, management to prevent degradation from imminent developments, a comprehensive study on the impacts of ecohydrology intervention in relation to biological, physico-chemical and socio-economical aspects are limited. Such information is very important for the management of degraded shore wetlands of Lake Tana. Thus, the aim of this study was to investigate the impacts of ecohydrological intervention in relation to physical, chemical and biological attributes and assess the most common socio-economic benefits of the wetlands in Lake Tana shore. Ecological and socioeconomic impacts of ecohydrological intervention on the wetlands in the shore of Lake Tana were studied in November 2019 and April 2020. Physico-chemical data were measured on each sampling point. Sediment and water samples were measured and analyzed onsite and in the laboratory and most of the Physico-chemical parameters were significantly different (p<0.05) across the sampling sites. The quadrat/transect method was employed to collect macrophyte and macroinvertebrate data. Quantitative characteristics of macrophyte sampling were conducted using transect and quadrat method along vegetation and water depth gradients. A total of 24 quadrats of 1m×1 m size were employed using the species-area curve method for all sampling sites. A total of 12 major macrophytes species were recorded from all sampling sites. The abundance of macrophytes varied between sampling sites and season and this might be attributed to the differences in protection status, human disturbances, physico-chemical parameters and level of awareness of the community. Based on the Shannon diversity index (H' = 0), the Agid kirgna wetland could be grouped under the least diverse followed by Gedromesk wetland (H' = 1.00) and Gumetirs wetland (H' = 1.24). A total of 975 macroinvertebrate individuals belonging to 15 families were collected using a D-frame net from all sampling sites during the study period. Based on the biological indices, H' = 2.39 and HFBI=4.68, the Gumetirs wetland might be grouped under a good ecological condition. Both phytoplankton and zooplankton samples were collected using a 15μm mesh size plankton net. A total of 23 phytoplankton and 9 zooplankton taxa were collected. Numerical density and diversity of zooplankton and phytoplankton taxa varied along the sampling sites, habitats and seasons which could be linked with food availability, degree of disturbance and physico-chemical conditions. Qualitative and quantitative data were collected from 90 households head (HHDs) on several variables through structured questionnaire, interview and observation to assess the socio-economic benefits of the wetlands. Overall results of this study confirmed that biological, physico-chemical conditions and wetland benefits were associated with the intensive human activities carried out in and around the wetlands, and level of awareness of the local communities. Therefore, emphasis should be given to the factors which may lead to the degradation of wetland resources within and its catchment especially recession farming, overharvesting, overgrazing and invasion of water hyacinth. Immediate ecohydrology based intervention approaches should be implemented to conserve and minimize further degradation and ensure sustainable livelihoods of wetlands along the shore of Lake Tana.
  • No Thumbnail Available
    Item
    Impacts of Urbanization on Kicukiro Water Supply Network: Spatio-Temporal Investigation Using Geospatial Models and Watergems
    (Addis Ababa University, 2020-11-03) Victor, Jimmy; Legese, Gudina (PhD)
    In Kigali, the capital city of Rwanda, the population is growing faster than the provision of services with a strong population growth of average annual growth rate of 4.0 percent. The high population growth has led to expansion of Kigali city. Nevertheless, the expansion of the city does not have in parallel a clear viability plan of water supply, and also due to rapid urbanization, the burden on the existing Kigali water distribution network is increasing along with widening gap between supply and consumer water demand. The aim of this study was to investigate the spatio-temporal impacts of urbanization on Kicukiro water supply network and water availability in order to propose the sustainable adaptation strategies. Landsat imagery were used to examine spatiotemporal changes in urbanization. The result of accuracy showed that overall accuracy of land use/land cover (LULC) is 89.030 %, 93.715 %, 94.359 % and Kappa (K) is 85.40 %, 91.50 %, 89.80 % for 1999, 2013, 2019 respectively. The outputs showed that the total built-up land has grown by 31.52 km2 from 1999 to 2019. Therefore, it was crucial to recognize that Kicukiro has clearly experienced significant and rapid expansion. It was observed that the existing water supply system of Kicukiro does not have a wider coverage of water distribution to some parts of the area. This will lead to persistence water shortage, water scarcity and lack of accessibility to the basic need of water for residential utility. The results indicate that the population of Kicukiro district will increase from 419,209 inhabitants in 2019 up 918,538 inhabitants in 2039. The results also showed that the current daily water demand (2019) is 76,854.98 m3 and 183,707.60 m3 for 2039. It was observed that there is a large gap between demand and supply of water and there is no sign of instant relief in the near future. At the end, WaterGEMS was used to analyze the existing water supply system of Kicukiro district and it was found that the resulting pressures at all the junctions and the flows with their velocities at all pipes are not enough to provide water to the study area. The outcome of this study will be an efficient tool for water management as well as to support planning processes and formulate policies to guide or redirect spatial growth in Kicukiro district; it will also provide a foundation for a long-term plan to maintain, repair, augment, or replace a water system when necessary in parallel with the urbanization. Furthermore, the result of this research will serve as baseline for future scientific researches by applying the remote sensing and GIS techniques in investigating impacts of urbanization on water supply system and water security.
  • No Thumbnail Available
    Item
    Effects of Water Hyacinth-based (Eichhornia Crassipes) Vermicompost Tea (Aqueous Extract) Supplement on Growth Performance of Lettuce Under Non-Circulating Hydroponics and Aquaponics System
    (Addis Ababa University, 2020-11-14) Ruth, Upile; Geremew, Akewake (PhD)
    The study was conducted to determine the effects of water hyacinth-based (Eichhornia crassipes) vermicompost tea (aqueous extract) supplement on growth performance of lettuce under the non-circulating hydroponics system. Water hyacinth is nutrient-rich and can undergo vermicomposting and be used in hydroponics or aquaponics production systems. The purpose of this study was to investigate the potential use of water hyacinth-based vermicompost tea material in a hydroponics system for an improved product of lettuce and management of water hyacinth through utilization. The study used a systematic random sampling design to obtain the sample size of a total of 33 plants per unit. To compare the effect of various dilutions of water hyacinth based vermicompost tea and the growth performance of lettuce in non-circulating hydroponic and aquaponic systems leaf area, shoot length, root-shoot ratio, growth rate, moisture content analysis, were used. Ash and digesting methods were used to determine the effect of various dilutions of hyacinth-based vermicompost tea on the concentration of selected nutrients and heavy metals in lettuce. Lettuce dosed with hydroponics nutrient solution were significantly different at (P<0.05) from lettuce supplied with water hyacinth-based vermicompost extract dosed at 30%, 40% and 60%, the plants had a higher growth rate, shoot length and moisture content, large leaf area and a small root-shoot ratio. Lettuce dosed with vermicompost tea was resistant to aphid and fungi attack, while the ones dosed with synthetic solutions were attacked. Yield from hydroponics and aquaponics system was not significant. Lettuce dosed with WHBVCT were short in nutrient content in their solutions while the ones with synthetic solutions had enough nutrient supply. Lettuce dosed with WHBVCT had nutrient and heavy metal concentrations within the permissible limit, except for treatment dosed at 30% and 40% which showed a higher Pd and Zn values. WHBVCT is rich in chitinase, phenols and alcohol which digest the chitin of insects and phenol and inhibit the growth of fungus and spread of insects which made lettuce with WHBVCT more resistant than the others. Therefore, WHBCVT can be used to control aphids and fungus, but it cannot be used for lettuce production non-circulating hydroponics and trials have to be made on fruiting vegetables to observe its performance.
  • No Thumbnail Available
    Item
    Diversity, Relative Abundance and Socio-economics of Fish and Fisheries in the Western Part of Lake Tana, Ethiopia
    (Addis Ababa University, 2020-11-15) Tegegne, Sewunet; Getahun, Abebe (Professor)
    The fishery resource in Lake Tana has significant socio-economic contribution through generating income, employment and used as a cheap protein source for local people. However, diversity, relative abundance and socio economics of fisheries in the western part of Lake Tana were not well studied. So the aim of this study was to investigate diversity, relative abundance and socio economic value of fisheries in the western part of Lake Tana. The study was conducted from December 2019 to August 2020. Data were generated from field sampling, fishermen catch observations, key informant interviews, focus group discussions and through questionnaires. At the sampling sites, physico-chemical parameters were measured using MPS. Fish weights were measured from the fishermen catch at the landing sites. Data were analyzed by (PAST), SPSS software and by various descriptive statistics. A total of 6118 fish specimens were collected at all sampling sites. Thirteen fish species were identified with species diversity value 1.6. The evenness value in the western part of Lake Tana was J=0.62. All the fish species were present in all sampling sites, except that L. gorgorensis was absent at the sites of Kunzila and Delgi. O. niloticus (46.24%) was the most abundant species in number and C. gariepinus (28.39%) was the second and L. gorgorensis (0.6%) the least abundant species. From the value of (% IRI), Oreochromis niloticus was the most important species during the dry season with value of 22.48 % and C. gariepinus was the most important species with the IRI value of 32.67% during the wet season. L. crassibarbis was the least important species with the IRI value of 0.23% during the dry season and L. gorgorensis was the least important species in the wet season with the IRI value of 0.31%. 18.16 % of variance was positively correlated with environmental variance with C. gariepinus, L. nedgia, L. truttiformis, L. tsanensis and O. niloticus. The total fish catch composition in the study area were O. niloticus (54.3%), C. gariepinus (23.4%) and Labeobarbus spp. (22.3%). The fishing activities in the study area were 87.8% fishing alone and 12.2% fishing in groups. The majority of fishermen were used monofilament gillnets (64%) and only 36% used multifilament gillnets. The fishermen who fished alone and those in groups had an average income of 1907.75 and 3210.42 ETB, respectively (P< 0.05). The average income who had owned modern and traditional boats were 3300.00 and 1907.75 ETB, respectively: (P<0.05). The current fishing trends in the study area and the fishery conditions were threatened. Therefore, appropriate management action should be taken especially to control monofilament fishing gears in order to sustain the fishery resources in Lake Tana.
  • No Thumbnail Available
    Item
    Groundwater Recharge Estimation and Aquifer Characterization. a Case Study of Walga Catchment Upper Gibe Basin, Central Ethiopia
    (Addis Ababa University, 2020-11-24) Wakjira, Tekalign; Azagegn, Tilahun (PhD)
    Groundwater is mainly used for irrigation and water supply in Walga catchment as other parts of the country. The main objective of this study is to quantify the amount of groundwater recharge using WetSpass model and characterization of aquifers using Aquifer test in the upper Omo-Ghibe basin of Walga catchment. Meteorological data like rainfall, wind speed, temperature, relative humidity, sunshine hours were collected from meteorological stations located within the catchment and nearby area. Potential evapotranspiration was calculated using Penman-Montieth based FAO CROPWAT software. Slope and topography map were generated from Shuttle Radar Topographic Mission elevation data while Land use land cover were prepared from Landsat OLI8 satellite images downloaded from United States Geological Earth Explorer. Parameter table (dbf data) and grid maps were prepared for WetSpass model input with the help of ArcMap 10.4. Using the model the mean annual recharge of the catchment was found to be 7.5% of the precipitation whereas surface runoff was 38.25% of the annual precipitation. The aquifer hydraulic properties were estimated from the pumping test by fitting mathematical models (type curves) to response data (water level changes) through computer software known as AQUIFER TEST. Yield or discharge of bore holes values range from 0.15 l/sec. to 61 l/sec, whereas Transmissivity ranges from 3.5 x10-4 m2/day to 290 m2/day with an average of 50.94 m2/day. Hydraulic conductivity values ranges from 0 to 16.04 m/se with mean values of 1.2 m/s. The sum of the yield from 72 boreholes is 430 l/s (119.4 m3/hr), this gives a total of 37152000 liters per day. 65.8% of Walga catchment coverage is under Satisfactory ground water potential while 0.72% is classified under very good groundwater potential. The mean descriptive statics value of groundwater quality of Walga catchment is below WHO limit and also good for irrigation water quality. The study area is characterized by lowest groundwater recharge relative to surface runoff and actual evapotranspiration due to effect of impermeable soils, morphology of the land and land use land cover of the area. The lowest transmissivity value is indicative of the poor permeability in the pyroclastic lithologic formations and low discharge to wells. It also implies that it will take a considerable time for the aquifers to replace water into wells removed during pumping.
  • No Thumbnail Available
    Item
    Assessment of the Effect of Artisanal Gold Mining on Heavy Metals Concentrations and Associated Potential Public Health Risk: The Case of May Sieley River of the Shire , Tigray, Region Ethiopia
    (Addis Ababa University, 2021-02-19) Elias, Habineza; Kifle, Demeke (PhD)
    Artisanal gold mining (AGM), in third world countries including Ethiopia has become a livelihood diversification strategy, which makes significant contribution to poverty alleviation. Although artisanal gold mining provides enormous economic benefits, the mining activities are carried out at the expense of the environment and public health due to pollution with heavy metals (HMs). The protection of public health and aquatic resources necessitates the availability of scientific information on pollution with heavy metals. The present study was, therefore, conducted to investigate the efffect of artisanal gold mining on the levels of selected heavy metals in May Sieley River (Tigray) and evaluate the potential human health risk. Surface sediment and water samples were collected from upstream, midstream and downstream sites (USS, MSS &DSS) respectively, during the dry and post-rainy periods and were analyzed for Pb, Cd, Cu, As, Cr, Hg, Ni, and Zn by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The concentrations of heavy metals in water samples were compared with WHO and Ethiopian standards for drinking water and assessment of human health risk was made following the guidelines provided by the US Environment Protection Agency. Temperature, pH and dissolved oxygen were measured insitu and were found to be within acceptable ranges and did not show large variations. The differences in HMs concentrations in water among sampling sites during both seasons were not marked except for Cu and Zinc in dry season, although Zn, Cu, Hg, Cd and Pb were higher at the MSS suggesting the association of their levels primarily with AGM. The differences in the concentrations of all HMs in water samples between seasons were marked. The concentrations of HMs in sediment samples varied markedly between the two seasons. The differences in HMs concentrations in sediments among sampling sites during dry seasons were marked for Cu, Zn, Pb and As while in post-rainy season, differences were not marked except for Ni and Pb. The concentrations of all HMs except Nickel in sediment samples of the dry season were higher at the MSS, while they were higher at USS during the post-rainy season. The present results suggest that both AGM and natural sources associated with the weathering of rocks have made contributions to the metal pollution of May Sieley River. Hg and As were above WHO and Ethiopian standards for drinking water in the dry season in all sampling sites, while Cr, Cd, Pb and As were above the same standards for drinking water in the post-rainy season in all sites, except Hg (in one sample of MSS) and Ni (in one sample of DSS). The HQ values for As, Pb, Hg and Cd for both age groups were at unacceptable non-carcinogenic potential health risk levels (HQ>1), while As and Cd for adults and As, Cd and Hg for children, are likely to have chronic effects (Q>10). The Sum of HQs (HI) of analyzed metals was far greater than 1 for both age groups, children being at greater risk. This raises concern about the non-carcinogenic adverse health effects of using the river water for drinking and other household purposes. The results of the ILCR assessment for Arsenic, Lead, Cadmium, Chromium and Nickel indicated that the carcinogenic effect associated with these metals is not acceptable. The study has revealed that the river water is not safe due to HMs pollution, AGM should be managed to reduce its contribution to the pollution of water bodies with heavy metals. The government needs to assist and empower the miners so that they can carry out their activities sustainably and in an environmentally friendly way. Further monitoring of the impact of traditional gold mining on HMs pollution by considering aquatic organisms in order to assess their biomagnification along the food chains is also recommended.
  • No Thumbnail Available
    Item
    Assessment of Municipal Solid Waste Generation Composition and Effects of Dumping Site on Water Quality at Mizan-Aman Town
    (Addis Ababa University, 2021-03-02) Barnabas, Gera; Mekonnen, Andualem (PhD)
    In Ethiopia, despite the progress that has been made to advance water supply access and the health status of the population in the last one and half decades, communicable diseases account for about 60-80% of the health problems. The existing burden of diseases is preventable and a considerable proportion is directly related to using unsafe water. Poor solid waste management systems from urban municipal dumpsites into surface and groundwater sources can be harmful to the urban population who use these water sources. Gradual accumulations of contaminants in the water sources can result in high loads of pollutants that are potentially toxic to the users. In Mizan Aman Town River Gechab, Cosakol, Shonga, Petrous, and Nimbus drain through the town and improved groundwater wells are the main sources of potable water for most residents. This study was conducted from December 2020 to April 2021, intending Assessment of Municipal Solid Waste Generation, Composition and Effects of Dumping Site on Water Quality at Mizan-Aman Town Bench Maji zone, SNNPR, Ethiopia A random research design was used in the study. The solid waste generation rate, composition, and disposal practices were assessed. The water quality of water resources around dumping sites was assessed. Water samples were collected from wells and the surface water during both the dry and the rainy seasons. The results that were found in the research were used as baseline information for a government institution to provide methods of managing solid waste disposal systems and to plan efficient collection and management of solid waste from the source of generation to disposal site. The Physic-chemical parameters measured show that other than the pH, total hardness, electrical conductivity, TDS, iron, fluoride odor, and taste, all other concentration values exceeded the Ethiopia minister of water and irrigation guidelines for drinking water and WHO guideline. The presence of a high load of bacteria in both surface and groundwater samples means that leachate is altering the water quality of water in the vicinity of the dumpsite. The bacteriological concentration of water from all sampling sites exceeded the Ethiopian minister of water and irrigation standards. Hence the surface and sub-surface water in the neighborhood of the dumpsite presents a significant threat to public health.
  • No Thumbnail Available
    Item
    Watershed Regionalization for Regional Flood Frequency Analysis in the Rift Valley Lake Basin Ethiopia
    (Addis Ababa University, 2021-03-17) Sime, Abdisa; Abebe, Adane (PhD)
    The use of regional information to predict magnitude of flow both at site and ungauged catchments are useful for planning and management of water resources. The main objective of this study was to regionalize watersheds in the Rift Valley Lake Basin (RVLB) and flood frequency analysis for the delineated homogeneous regions. In regionalization of the watersheds; Physiographic, drainage, meteorological, soil cover, land-use pattern characteristics and geographical location attributes have been used. Cluster analysis was done by Hierarchical clustering to obtain number of clusters, and final clustering by K-mean method. Accordingly four regions have been identified and checked using homogeneity tests. Using goodness of fit tests (Chi-square test, Kolmogorov–Smirnov, and Anderson–Darling), the best fit distribution models have been selected. Generalized extreme value distribution is the best fit for region I, Log-normal (2P) is selected for region II, Wakeby distribution is found to be the best for region III, and Generalized pareto is chosen for region IV. For the selected distributions efficient parameter estimation technique was selected by performing standard error analysis. Thus, method of moment (MOM) is the one with the lowest error so, selected for region I, and maximum likelihood (ML) method is found the most efficient method for the regions II to IV. For each region unique regional frequency curve is developed with standardized annual maximum flow series (AM), which is a crucial to estimate flood quantile in ungauged areas of the basin. Regional regression model was developed for all region except for region I which consists only one gauged catchment based on their R2 values. Accordingly 0.82, 0.83, and 0.79 of R2 values respectively for all the three regions. For checking performance of the model, validation of regional model was carried out by computing the relative errors, over five gauged watersheds that is representative for each region considering as pseudo ungauged. The relative errors between observed and estimated mean annual maximum flows resulted all regional model performs good having maximum of 10.6% of relative error. So, for any current and future water resources developments in the area, the developed regional model can be applied.
  • No Thumbnail Available
    Item
    Groundwater Recharge Estimation and Water Suitability Evaluation Case Study of Upper Fafem Sub Catchment in Somali Regional State of Eastern Ethiopia
    (Addis Ababa University, 2021-05-22) Ahmed, Mohamud; Ayenew, Tenalem (Professor)
    This study was conducted in upper Fafem sub catchment in Somali region which has an area of 1,300km2. Estimation of groundwater recharge and water quality for domestic and irrigation purposes of an area is very important for groundwater planning and management. There are number of methods used to estimate groundwater recharge. Wetspass model is one of the recharge estimation methods, this model simulates the recharge, run off and evapotranspiration in an annual and season bases. For estimating the recharge using wetspass, inputs of the model should be prepared in the form of digital maps using ArcGIS. The inputs of the model are long term meteorological data (precipitation, temperature, wind and potential evapotranspiration) and physical characteristics of the catchment such as soil type, slope, land use/land cover, elevation and groundwater depth. For this study, long term average annual rainfall of 660.46 mm was distributed as 616 mm (93%) of actual evapotranspiration, 23 mm (4%) of groundwater recharge and 20 mm (3%) of surface run off. Groundwater potential zones of upper Fafem sub basin were also identified using Remote sensing and GIS, the groundwater potential zones were classified as; low groundwater potential zone, moderate groundwater potential zone, high groundwater potential zone and very high groundwater potential zone. Most of the area is characterized by moderate groundwater potential, almost 52% of the area is characterized as moderate groundwater potential. For evaluating groundwater suitability for drinking and irrigation purposes, eight water samples were collected from the boreholes in the study area. The laboratory result of the water samples was compared to the WHO and MoW&I standards. As a result, the groundwater of this catchment is suitable for drinking and irrigation purposes according to the laboratory results.
  • No Thumbnail Available
    Item
    Distillery Stillage Water Pollution Control: An Integrated Approach for Efficient Treatment and Recovery
    (Addis Ababa University, 2021-05-26) Dagnew, Getachew; Alemayehu, Esayas (Professor); Chebude, Yonas (Professor); Mekonnen, Andualem (Professor)
    In spite of the increasing demand for potable and fuel ethanol, the distillery industries continue to be a major source of surface water and soil pollution, especially to developing nations, due to the release of a highly organic and complex byproduct- the stillage. Stillage contains solids, recalcitrant organics, persistent color, sulfate, chlorides, phosphorus and nitrogen, whose recovery and treatment plays a major role in environmental sustainability. In most cases, the application of single stillage treatment technology did not succeed. The objective of this study was to quantify molasses and stillage byproducts in Ethiopia and examine the feasibility of an integrated treatment approach towards sustainability. Standard methods were applied, beginning from a systematic literature review through primary data collection, stillage sampling and conducting a series of experiments. The trials were set-up based on a sound design followed by standard analytics and a statistical analysis of the results. The experiments started with determining the biochemical methane potential (BMP) test and then undertaking a mild iron oxide coated sand (IOCS) based wet air pretreatment (WAp) through anaerobic digestion (AD), adsorption and a polishing aerobic degradation. From a quantitative characterization study, Ethiopia currently produces close to 1.8 million tons of cane sugar, with the release of over 300,000 tons of molasses as a by-product. Using cane molasses as a raw material and with the release of 431,000 m3 of stillage into the environment, the potable ethanol industry in the country produces over 33,000 m3 of ethanol annually. According to the BMP test run for 45 days at mesophilic condition, molasses stillage has the potential of giving 139 NmlCH4/g-COD with 68% purity. A mild IOCS based WAp of the stillage sample at 3.5% IOCS loading, a temperature of 60 oC, which was held for four hours at atmospheric pressure brought the desirable effect in detoxification. The result observed following comparison of raw and treated stillage from E. coli incubation at 37 oC and 86 revolutions per minute of shaking demonstrated a statistically significant difference (p-value = 0.02) in toxicity. Successively, the consequence of a mild, IOCS based WAp on the methane (biogas) yield as well as the biochemical oxygen demand (BOD) and COD removal was compared with the raw counterpart using batch mesophilic (35±2 oC) AD of stillage. Further, the effect of applying scoria (a highly vesicular igneous rock) support on AD process stability and performance was assessed for the first time. Consequently, a statistically significant (p-value < 0.05) difference in the cumulative specific raw without scoria support, raw with scoria support and WAOp scoria supported stillage AD subsequently. The soluble COD (CODsol) after AD of stillage with scoria, without scoria and with scoria and WAp in mg/l was 30041.7, 30666.7, and 13375.0 respectively. With the WAOp and scoria supported stillage AD a BOD and COD reduction of ≈100% and 92% were achieved. These achievements are unique in stillage recovery and pollution remediation findings so far. Further, the biogas yield with respect to the reaction days (within 18 days) with a relatively stable process (average pH=7.7, 6.8 and 6.7 for pretreated and untreated stillage with scoria and without scoria) was hastened due to pre-treatment. Regarding the adsorption trial on stillage after the batch AD, all the significant COD removals were observed after three hours of contact time for all doses of the treated scoria adsorbent. Maximum removal rate was at 0.03 mg/ml of scoria dosing and in three hours contact time whereby the final COD of the stillage did go lower only to 7500 mg/l. In a related experiment, the effect of organic loading rate (OLR) and stillage WAp was studied in a continuous AD in scoria-packed column reactors. The removal of stillage COD was significantly better (p-value = 0.036), with an average of 13% difference, due to pre-treatment of stillage with an increased OLR to 2000 mg/L-d. In a further polishing aerobic treatment trial of the effluent from the stillage batch AD, a complete removal of the BOD and significant removal of COD, with an average effluent COD of 2278 mg/L was achieved. In fact, 68% of the COD removal occurred within eight hours of digestion. Despite the persistence of color, the removal of organics with bioenergy recovery from integrating the WAp, the batch AD and the aerobic remediations (˜99% COD and 100% BOD removals) of stillage appear to be a promising technique in its sustainable management while adhering to the regulators’ discharge limits.
  • No Thumbnail Available
    Item
    Evaluating Methods and Polarizations of S-1 Sar for Time-Series Flood Hazard Mapping Akaki Catchment
    (Addis Ababa University, 2021-06-06) Worku, Tilaye; Tamiru, Alemseged (PhD)
    Lack or absence of data is the main limiting factor for studying flood hazard and risk in many basins across the globe. The Google Earth Engine (GEE) has a potential to narrow data gaps by providing ease of access to remote sensing data and enabling automatic and rapid generation of flood inundation map for Near Real-Time monitoring. In this study, GEE was used to assess and analyze the Sentinel-1 (S-1) Synthetic Aperture Radar (SAR) dataset for flood inundation mapping in the Akaki catchment which hosts Addis Ababa city in the central part of Ethiopia. Ground Control Points were collected at the time of satellite overpass for evaluating the accuracy of the generated flood inundation maps. Change detection and Histogram thresholding methods were compared using co-polarized (VV) and cross-polarized (VH) images. A new method which is Root of Normalized Image Difference (RNID) was developed for change detection. Major flood affected roads in Addis Ababa city and Land Use Land Cover (LULC) classes were detected from April to November of 2017 to 2020. The result shows the RNID method performed better than the histogram thresholding for flood inundation mapping in the study area. The VH polarization performed better than the VV polarization to detect the lower signal backscatter intensity generated from the flooded surface. An overall accuracy of 95% and kappa coefficient 0.86 was obtained when applying the RNID method and VH polarization. In the Akaki catchment, the remote sensing mapping showed that the flood commonly starts in May and recedes in November, but flood was frequent and widespread from June to September. At the downstream of the new expressway, the riverine and pluvial flood frequently occurred in the past four years. The flood inundation map also showed that several major roads of Addis Ababa are affected by flooding. The irrigated and built-up area were the most affected land use classes with an inundation extent of 1057.05 ha (21.28% of the total irrigated land) and 544 ha (1.44% of the total urban area) respectively. The S-1 SAR was found useful for time series flood inundation mapping and the new change detection method (RNID) performed better in urban and peri-urban flood mapping, but the accuracy of the flood map varies with the flood detection method and the image polarization.
  • No Thumbnail Available
    Item
    The Impact of Hydrological Parameters and Climate Inputs on Extreme Streamflow Simulation in Upper Awash River Basin
    (Addis Ababa University, 2021-06-08) Mezgebu, Metsihet; Kidane, Hadush (PhD)
    Quantifying possible sources of uncertainty in simulations of hydrological extreme events is very important for better risk management in extreme situations and water resource planning. The main objective of this research work is to identify and address the role of input data quality and hydrological parameter sets, and uncertainty propagation in hydrological extremes estimation. This includes identifying and estimating their contribution to flood and low flow magnitude using two objective functions Nash-Sutcliffe efficiency for flood and Log Nash-Sutcliffe efficiency for low flow, 20, 000 Hydrological ByransVattenBalansa Vdelning hydrological parameter sets, and three frequency distribution models (Log-Normal, Pearson-III, and Generalized Extreme Value). The influence of uncertainty on the simulated flow is not uniform across all the selected three catchments due to different flow regimes and runoff generation mechanisms. The result shows that the uncertainty in high flow frequency modeling mainly comes from the input data quality. In the modeling of low flow frequency, the main contributor to the total uncertainty is model parameterization. The total uncertainty of QT90 (extreme peak flow quintile at 90-year return period) quintile shows that the interaction of input data and hydrological parameter sets has a significant role in the total uncertainty. In contrast, in the QT10 (extreme low flow quintile at 10-year return period) estimation, the input data quality and hydrological parameters significantly impact the total uncertainty. This implies that the main factors and their interactions may cause considerable risk in water resources management and flood and drought risk management. Therefore, neglecting these factors and their interaction in disaster risk management, water resource planning, and evaluation of environmental impact assessment is not feasible and may lead to big risk.