古紙微細粉体を用いた高含水粘土の地盤工学的諸特性の改良

京都大学新制・課程博士博士(工学)甲第25251号工博第5210号京都大学大学院工学研究科社会基盤工学専攻(主査)教授 安原 英明, 准教授 橋本 涼太, 准教授 澤村 康生学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

Plant Species Composition and Community Perception Towards Landscaping Work Executed at Hawassa University-Main Campus, Ethiopia

Landscaping is making visual improvements to academic institutions, urban and other private organizations with plants and attractive materials. People all over the world are attracted to green and beautiful landscapes which initiate them to be happy and creative. Especially students in higher educational institutions who spend much of their time focused on their studies need of clean, green and attractively well-designed landscape in their campus. So far data on plant species composition and perception of university towards landscape work is lacking. With this understanding, the study was conducted to investigate plant species composition and community perception towards landscaping work executed at Hawassa University’s main campus using questionnaires, interviews, observation and group discussion methods. In addition, vegetation data were collected using systematic sampling method. In the study, 221 respondents were drawn from academic staff, administrative workers and students using random sampling method. Key informants were selected using purposive sampling method. In order to identify the plant species, systematic sampling along the transect line was employed. Twelve (12), 40m X 40 m  (i.e. 1600 m2) area quadrat plots were laid and all the plants species in the quadrats were collected and identified. The distance between each transects and quadrat was 200 m and 100m, respectively. 52 plant species with 44 genera and 29 families were recorded. The study showed that, the most dominant family was Fabaceae with 9 species followed by Cupressaceae as well as Moraceae with 4 species each respectively. The results revealed that, campus landscaping work was the most significantly important and made the campus more attractive by plantation (61.1%), landscaping (27.1%) and walkways (5.7%). Plantation could also modify the micro-climate of the campus environment (94.3%) due to the plants photosynthesis process which produces O2 and takes in Co2 from the atmosphere. In general educational institutions landscaping need to be encouraged to enhance the teaching-learning process, and to make the working environment attractive. A great educational environment is guided by the most powerful teacher of all, nature itsel

Regional groundwater flow system characterization of volcanic aquifers in upper Awash using multiple approaches, central Ethiopia

Characterization of the groundwater flow systems is important for sustainable water resource management decision-making. We have used vertical profiles of electrical conductivity (EC) and water temperature taken at 2 m intervals during drilling of 109 boreholes, and samples for stable isotope analysis (δ18O, δ2H) taken from 47 boreholes to characterize groundwater recharge, flow and discharge. 222Rn measurements and piezometric evidence were used to complement results from the EC and stable isotopes. The converging evidence shows that groundwater in the study area is characterized by a mix of two different groundwater flow systems: i) the deep groundwater systems are connected to the regional groundwater flow originating from the highlands, outside the surface water basin, ii) the shallow groundwater systems get recharge from local rains. The local recharge zones are located in highly urbanized and industrialized zones posing risk to recharge reduction and pollution. Therefore, attention should be given to protect groundwater resources from contamination and increase groundwater resilience to climate change

Environmental isotopes (δ18O–δ2H, 222Rn) and electrical conductivity in backtracking sources of urban pipe water, monitoring the stability of water quality and estimating pipe water residence time

This study demonstrates the use of environmental tracers (Water isotopes-δ18O–δ2H, Radon-222Rn, and Electrical Conductivity-EC) as complementary tools for backtracking the water source, estimating pipe water residence time, and monitoring the instability of the water quality. Using the capital of Ethiopia, Addis Ababa, as a case study site, we demonstrate that water isotopes (δ18O andδ2H) effectively backtrack the tap water to its source (springs, reservoirs, shallow aquifers, or deep aquifers). 222Rn is shown to be effective for discriminating groundwater-sourced pipe networks from those that are dominated by surface waters. Our reconnaissance survey reveals that 222Rn, a tracer previously not considered to determine the pipe water residence time, can be used effectively to determine pipe water residence time in groundwater-sourced pipe networks. We recommend further research to explore the capability of 222Rn as a robust indicator of the pipe water residence time in an urban piped water network. The tracers reveal that 50% of the city obtains its water from groundwater and that the groundwater-sourced areas of the city show the highest water quality instability. The water quality in groundwater-sourced pipes varies depending on pumping stoppage owing to power interruptions. Surface water-sourced pipe water shows seasonal variations in water quality, with occasional large deviations from the normal trends following flow interruptions

Nondestructive allometric model to estimate aboveground biomass: an alternative approach to generic pan-tropical models

Nondestructive allometric model to estimate aboveground biomass: an alternative approach to generic pan-tropical modelsNondestructive allometric model to estimate aboveground biomass: an alternative approach to generic pan-tropical models-Manuscript Draft-Manuscript Number: Full Title: Nondestructive allometric model to estimate aboveground biomass: an alternative approach to generic pan-tropical modelsNondestructive allometric model to estimate aboveground biomass: an alternative approach to generic pan-tropical models Article Type: Original Article Abstract: Biomass and carbon stock analysis and estimations are performed with the use of mathematical allometric models. Developing countries in Sub-Sharan Africa such as Ethiopia lack the expensive resources to develop such costly models destructively. As a result, they are left with the only option to adopt models formulated from unrelated geographic areas which usually bears error in estimation. This study estimates the biomass of indigenous trees and develop allometric model for the Egdu Forest located Oromia region, Ethiopia. Nondestructive sampling is used to collect samples where diameter at breast height (DBH), local wood density (ρ), and tree height (H) are the estimator variable for total dry aboveground biomass (TAGB). Trees are selected based on DBH variability on the study site and located in a delineated area of quadrat plot. A set of species-specific models to relate AGB to estimator variables are fitted to the data. The allometric equation that fit the linear models has a significant p-value (P<0.000). Model comparison and selection are based on the Akaike information criterion (AIC), adjusted coefficient of determination (R2) and residual standard error (RSE) of the regression. Comparison of our results with those obtained using generalized pan-tropical model revealed differences in biomass estimations. The developed equations can be used for greater accuracy by researchers, forest managers and/or organization like REDD+ to calculate aboveground biomass and carbon stock of the studied species in Ethiopia. Abstract: Biomass and carbon stock analysis and estimations are performed with the use of mathematica

Addis Ababa’s water crisis: challenges and opportunities

Addis Ababa’s water supply is insufficient to meet current needs, leading to intermittent water supplies which are increasing inequalities in water access depending on access to household storage and finances to develop private wells. Proposals to expand surface water storage will not fully meet the growing demand from the population and expanding industries. Groundwater depletion, land for expanding reservoir storage, water quality and unreliable energy supplies limit opportunities for increasing water provision. Action is needed now to better monitor and manage groundwater use, and to improve the conjunctive use of surface and groundwater to support sustainability for Addis Ababa’s water supplies

WEAP-MODFLOW dynamic modeling approach to evaluate surface water and groundwater supply sources of Addis Ababa city

The integration between WEAP and MODFLOW models coupled via LinkKitchen helps to create a dynamic link between surface water and groundwater supply sources of Addis Ababa city. Possible impacts of natural and anthropogenic stresses on surface water reservoirs volume and groundwater storage have been assessed through water supply scenario analysis. Besides, contrary to other surface water hydrological models, the unique nature of WEAP adds water demand assessment by simulating Addis Ababa city near future water demand coverage under three population projection scenarios. The water demand projections of Addis Ababa city indicates 100% water demand coverage will not be achieved for high (4.6%), medium (3.8%) and low (2.8%) population growth rate projections, even with all the emerging and planned water supply projects start production up until 2025. Supply scenario projections indicate, as surface water reservoirs are highly sensitive to climate change and variability, the city groundwater supply sources will be noticeably affected by the emerging and planned groundwater supply expansion schemes. If groundwater abstraction continues to reach to zero unmet demand, more than 30-meter groundwater level decline can be registered in 2025. To foresee the combined effect of both natural and anthropogenic stresses on Addis Ababa city water supply sources, best case (considering conditions which improve Addis Ababa city water supply) and worst case (considering conditions stressing Addis Ababa city water supply) scenarios were tested. The best case scenario results zero unmet water demand in Addis Ababa city in most wet months of future projection years up to 2025, with likely decline of about 6 meter on the groundwater level. The worst case scenario to the contrary shows, Addis Ababa city water demand coverage will potentially be reduced to a maximum of 35% in 2025, with seasonal and annual variability. The dynamic link between surface water reservoirs and groundwater supply sources helps to gain insight into the potential consequences of continuously changing natural and anthropogenic conditions on Addis Ababa city water supply sources. Consequently, the significant predicted near future pressure on Addis Ababa city surface water and groundwater supply clearly indicate planning and developing alternative water supply sources outside of the boundary (Upper Awash basin) where the city is located should be immediately started in order to endure the pressure from the ever increasing demand. Otherwise, not only Addis will continue suffering unmet water demand for the years to come, but also the water supply sources will be severely impacted. Nonetheless, wherever the water supply sources, minimizing water loss, recycling and improving water use efficiency should be given at most priority

Education rather than age structure brings demographic dividend

The relationship between population changes and economic growth has been debated since Malthus. Initially focusing on population growth, the notion of demographic dividend has shifted the attention to changes in age structures with an assumed window of opportunity that opens when falling birth rates lead to a relatively higher proportion of the working-age population. This has become the dominant paradigm in the field of population and development, and an advocacy tool for highlighting the benefits of family planning and fertility decline. While this view acknowledges that the dividend can only be realized if associated with investments in human capital, its causal trigger is still seen in exogenous fertility decline. In contrast, unified growth theory has established human capital as a trigger of both demographic transition and economic growth. We assess the relative importance of changing age structure and increasing human capital for economic growth for a panel of 165 countries during the time period of 1980-2015. The results show a clear dominance of improving education over age structure and give evidence that the demographic dividend is driven by human capital. Declining youth dependency ratios even show negative impacts on income growth when combined with low education. Based on a multidimensional understanding of demography that considers education in addition to age, and with a view to the additional effects of education on health and general resilience, we conclude that the true demographic dividend is a human capital dividend. Global population policies should thus focus on strengthening the human resource base for sustainable development

Tracing contaminants of emerging concern in the Awash River basin, Ethiopia

Study region Awash River basin, Central Ethiopia Study focus The study focuses on characterization of Emerging Organic Contaminants (EOCs) in the Awash River basin. Characterization of the EOCs was supplemented by chemical analysis of samples from river, boreholes, tap water, and surface water reservoirs. Analyses of environmental isotopes (δ 2 H, δ 18 O, and 222Rn) were used to investigate the exchange of contaminants between surface and groundwater supply sources. New hydrological insights for the region More than 100 EOCs are identified in all water supply sources. The EOCs are linked to agricultural applications, urban, and industrial sources. Based on the analysis of chemical and environmental tracers, the deep groundwater has greater protection from contamination than the river and the shallow groundwater. The heavy metal analysis prevails the same. The shallow aquifers are affected by urban, industrial, and agricultural pollutants. Attributed to the different contaminant sources, distinct variations in terms of compound types were observed at different locations. Water supply sources located upstream are dominated by urban and industrial contaminants while compounds from agricultural applications dominate the downstream sites. Artificial infrastructures serve as attenuation points for urban and industrial sourced compounds. Characterization of EOCs showed new contaminant loads in the water supply sources, which haven’t been tested before, with potential impact on human and wider environmental health, and may necessitate a revision of the customary water quality test and monitoring practices