Integrating climate change adaptation strategies in urban planning and landscape design of Addis Ababa City,Ethiopia

Climate change (CC) is now recognized as posing a serious threat to the sustainable development of Addis Ababa city, Ethiopia. As a consequence, city authorities are showing increasing interest in combating CC by streamlining adaptation measures into city development planning through a comprehensive and integrated approach. Nevertheless, in the past, the integration of CC adaptation into urban planning (UP) and landscape design (LD) was not given adequate consideration by planners and designers due to lack of knowledge regarding CC and the efforts that can be taken to mitigate its effects. The objective of this work is: ? To summarize the current state of knowledge of, and conceptualization of, the core elements of CC impacts and responses in Addis Ababa in terms of their implications for UP and LD in the city; ? To develop a common understanding among urban planners and related professionals of how improvements in UP and LD can contribute to CC adaptation; and ? To mainstream CC in future UP and LD endeavors. The results of this study show that integrating CC adaptation and other response options into UP and LD at the city, subcity/catchment, neighborhood, site/project, and building levels will enhance the sustainability of the city with respect to its resilience to flood risk hazards, water supply during drought periods, and urban heat island effects.     

Urban impact on ecological integrity of nearby rivers in developing countries: the Borkena River in highland Ethiopia

Accelerated pollution and eutrophication of rivers and streams because of human activity are a concern throughout the world and severe in Africa where Ethiopia is case in point. The objective of this study was to assess the urban impact on the ecological integrity of the Borkena River at the eastern escarpment of the central Ethiopian highlands. The water quality status and macroinvertebrate distribution and diversity of the river were assessed during the dry and wet seasons. Diversity indices revealed that a severe decline in the ecological integrity of the Borkena River downstream of Dessie and within Kombolcha towns in terms of macroinvertebrate abundance and composition. Clustering and ordination analysis clearly separated reference sites from urban impacted sites. At the urban-impacted sites, dissolved oxygen was also depleted to 0.5 mg/l and BOD5 values were reached to a level of above 1,000 mg/l, with extremely low biological diversity of pollution-sensitive taxa. These patterns are the result of a combination of rampant dumping of untreated wastes exacerbated by geologic, topographic, climatic and land use factors.     

Landscape-based upstream-downstream prevalence of land-use/cover change drivers in southeastern rift escarpment of Ethiopia

Characterized by high population density on a rugged topography, the Gedeo-Abaya landscape dominantly contains a multi-strata traditional agroforests showing the insight of Gedeo farmers on natural resource management practices. Currently, this area has been losing its resilience and is becoming unable to sustain its inhabitants. Based on both RS-derived and GIS-computed land-use/cover changes (LUCC) as well as socioeconomic validations, this article explored the LUCC and agroecological-based driver patterns in Gedeo-Abaya landscape from 1986 to 2015. A combination of geo-spatial technology and cross-sectional survey design were employed to detect the drivers behind these changes. The article discussed that LUCC and the prevalence of drivers are highly diverse and vary throughout agroecological zones. Except for the population, most downstream top drivers are perceived as insignificant in the upstream region and vice versa. In the downstream, land-use/cover (LUC) classes are more dynamic, diverse, and challenged by nearly all anticipated drivers than are upstream ones. Agroforestry LUC has been increasing (by 25% of its initial cover) and is becoming the predominant cover type, although socioeconomic analysis and related findings show its rapid LUC modification. A rapid reduction of woodland/shrubland (63%) occurred in the downstream, while wetland/marshy land increased threefold (158%), from 1986 to 2015 with annual change rates of -?3.7 and +?6%, respectively. Land degradation induced by changes in land use is a serious problem in Africa, especially in the densely populated sub-Saharan regions such as Ethiopia (FAO 2015). Throughout the landscape, LUCC is prominently affecting land-use system of the study landscape due to population pressure in the upstream region and drought/rainfall variability, agribusiness investment, and charcoaling in the downstream that necessitate urgent action.     

Rethinking urban water management in Addis Ababa in the face of climate change: An urgent need to transform from traditional to sustainable system

Urban water management in Addis Ababa, Ethiopia, is of significant concern to the city government owing to the growing demand for water, poor urban water management practices, insufficient and ineffective infrastructures, and climate change. The objective of this study is to review current water resources and management practices, consider the sustainability of the urban water cycle in relation to climate change, and devise a feasible strategy for a sustainable urban water management system. The results of this study show that the situation as it is now is not sustainable at current levels of demand and supply, either in terms of the systems’ management practices, or in terms of the challenges posed by climate change. An Integrated Urban Water Management strategy that covers the entire urban water cycle, including diversification of water sources, protection and conservation of water, sustainable exploitation, distribution, and consumption and wastewater management, water recycling, nutrient reuse, and safe wastewater disposal, should be implemented as soon as practicable.     

The impact of traditional coffee processing on river water quality in Ethiopia and the urgency of adopting sound environmental practices

Although waste from coffee processing is a valuable resource to make biogas, compost, and nutrient-rich animal food, it is usually dumped into nearby water courses. We carried out water quality assessment at 44 sampling sites along 18 rivers that receive untreated waste from 23 coffee pulping and processing plants in Jimma Zone, Ethiopia. Twenty upstream sampling sites free from coffee waste impact served as control, and 24 downstream sampling sites affected by coffee waste were selected for comparison. Physicochemical and biological results revealed a significant river water quality deterioration as a result of disposing untreated coffee waste into running water courses. During coffee-processing (wet) season, the highest organic load (1,900?mg/l), measured as biochemical oxygen demand, depleted dissolved oxygen (DO) to a level less than 0.01?mg/l, and thus curtailed nitrification. During off season, oxygen started to recuperate and augmented nitrification. The shift from significantly elevated organic load and reduced DO in the wet season to increased nitrate in the off season was found to be the determining factor for the difference in macroinvertebrate community structure as verified by ordination analysis. Macroinvertebrate diversity was significantly reduced in impacted sites during the wet season contrary to the off season. However, there was a significant difference in the ratio of sensitive to pollution-tolerant taxa in the off season, which remained depreciated in the longer term. This study highlights the urgency of research exploring on the feasibility of adopting appropriate pollution abatement technologies to implement ecologically sound coffee-processing systems in coffee-growing regions of Ethiopia.     

Statistical Modelling of Extreme Rainfall Indices using Multivariate Extreme Value Distributions

Environmental Modeling & Assessment - Multivariate extreme value models are used to investigate the combined behaviour of several weather variables. To investigate joint dependence of extreme...     

Modelling dependence structures of extreme wind speed using bivariate distribution: a Bayesian approach

When investigating extremes of weather variables, it is seldom that a single weather station determines the damage, and extremes may be caused from the combined behaviour of several weather stations. To investigate joint dependence of extreme wind speed, a bivariate generalised extreme value distribution (BGEVD) was considered from frequentist and Bayesian approaches to analyse the extremes of component-wise monthly maximum wind speed at selected weather stations in South Africa. In the frequentist approach, the parameters of extreme value distributions (EVDs) were estimated with maximum likelihood, whereas in the Bayesian approach the Markov Chain Monte Carlo (MCMC) technique was used with the Metropolis–Hastings algorithm. The results showed that when fitted to component-wise maxima of extreme weather variables, the BGEVD provided apparent benefits over the univariate method, which allowed information to be pooled across stations and resulted in improved precision of the estimates for the parameters and return levels of the distributions. The paper also discusses a method to construct informative priors empirically using historical data of the underlying process from weather characteristics of four pairs of surrounding weather stations at various distances. The results from the Bayesian analysis showed that posterior inference might be affected by the choice of priors that were used to formulate the informative priors. From the results, it could be inferred that the Bayesian approach provides a satisfactory estimation strategy in terms of precision, compared with the frequentist approach, because it accounts for uncertainty in parameters and return level estimations.     

Building resilience to El Niño‐related drought: experiences in early warning and early action from Nicaragua and Ethiopia

Forecast‐based drought early warning/early action has been hampered by both inadequate decision‐making frameworks and a lack of appropriate funding mechanisms. Rural communities in Nicaragua and Ethiopia that have participated in resilience‐building interventions of varying durations demonstrate the value of community‐based actions informed by early warning, forecasts and drought management advice, both before and during the agricultural season. While drought affected all crops negatively, participants were better able to mitigate impacts, were more organised in accessing relief and recovered more effectively. These results are consistent with other research on the cost/benefit of anticipatory actions, use of climate services and appropriate drought management advice. They also confirm the importance of embedding short‐term early action in long‐term resilience‐building. Despite this, formal systems, national and local, remain essentially unimplemented. Systems being developed at global level now need to be operationalised and translated into effective local drought management standard operating procedures for the most vulnerable.     

Bayesian modelling of extreme wind speed at Cape Town,South Africa

In the framework of generalized extreme value (GEV) distribution, the frequentist and Bayesian methods have been used to analyse the extremes of annual maxima wind speed recorded by automatic weather stations in Cape Town, Western Cape, South Africa. In the frequentist approach, the GEV distribution parameters were estimated using maximum likelihood, whereas in the Bayesian method the Markov Chain Monte Carlo technique with the Metropolis–Hastings algorithm was used. The results show that the GEV model with trend in the location parameter appears to be a better model for annual maxima data. The paper also discusses a method to construct informative priors empirically using historical data of the underlying process from other weather stations. The results from the Bayesian analysis show that posterior inference might be affected by the choice of priors and hence by the distance between a weather station used to formulate the priors and the point of interest.     

Mainstreaming environmental impact assessment as a tool for environmental management in Ethiopia: Current challenges and directions for future improvements

The Environmental Impact Assessment (EIA) was first entered into force in the United States of America in 1969 through the National Environmental Policy Act. Since then, the EIA was implemented in many other countries. In Ethiopia, EIA was formally introduced in 2002 by Proclamation No. 299/2002 after the establishment of the Environmental Protection Authority (EPA) in 1995 and the formulation of the Environmental Policy of Ethiopia (EPE) in 1997. This study, which is based on a document review, interviews, and the application of a survey questionnaire, analyzes the procedures and practices of the Ethiopian EIA system, seeks to clarify fundamental information regarding the EIA system and characteristics of the key elements of EIA processes, and finally, offers suggestions that could improve EIA practices in the country. The overall result of this study shows that Ethiopia adopted EIA procedures that are similar to western models; however, despite approximately 15 years of experience, its implementation is still poor to the point that the use of EIA as an instrument of environmental management could be questioned. The challenges identified by this study include institutional, organizational, and professional capacity gaps, which, in turn, have resulted in constraints ranging from improper screening, scoping, and production of EIA reports to ineffective review, monitoring, and post‐project evaluation. Additional challenges to the system include poor governance and corruption, rapid economic growth, and the mushrooming of micro‐ and small‐scale enterprises that cause pollution and environmental degradation. This article also provides comprehensive suggestions to improve EIA practices in Ethiopia.