Water Supply and Environmental Engineering

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Browsing Water Supply and Environmental Engineering by Subject "Addis Ababa"

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    Assessment of Solid Waste Collection Capacity in Addis Ababa, Ethiopia
    (Addis Ababa University, 2019-06) Solyana, Aweke; Alemtsehay, Gebremeskel (PhD)
    Waste collection and transportation is one of the crucial functional elements of municipal solid waste management. Available information about this matter is therefore essential for successful municipal solid waste management. The main objective of this study is to assess the solid waste collection practice in Addis Ababa. For the purpose of the study, 250 pre collector groups were selected for field survey of the primary solid waste collection. Background information was gathered using semi structured interviews with the pre collector groups and the respective cleansing management agency officers. To examine the secondary solid waste collection, field observation on the trucks and interviews with truck drivers and with waste agency officers of the city was carried out. From the study, the productivity of primary and secondary waste collection was determined; the collection capacity of the city was estimated and factors influencing the system were identified. For primary collection, three different collection methods were identified: push cart method, pushcart–collector method and truck collection method with average productivity of 2.12 m 3 /hr respectively. For secondary waste collection, the trucks productivity were determined to be 6.29 m / worker/day and 2.81m 3 / worker/day and 4.2m 3 /hr for container truck, 18.29 m 3 3 /hr for compactor (40 m 3 3 ) and 39.7 m /hr for compactor (80 m 3 ). The solid waste collection capacity was determined to be 3,192,868.8 m /year for the primary collection and 2,579,183.22 m 3 /year for the secondary collection. The solid waste generation rate of the city is determined to be 4, 157469.12m3/year. This shows that, on average, only 76% of the waste generated in the city was collected by primary collectors, and 80% was collected by the secondary collectors. The result indicates that the current collection system doesn’t cope with the solid waste generation rate of the city. 3 The role of solid waste transfer station in solid waste management is great. This study includes the basis of design and conceptual layout for a new facility of a pilot service area. This design and operational plan details the features and operational procedures for a municipal solid waste transfer station to ensure a safe, operationally efficient facility that meets the waste needs of the given service area.
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    Impact of Built Environment on Hydrological Regimes of Addis Ababa
    (Addis Ababa University, 2011-09) Getahun, Habtamu; Semu, Ayalew (PhD)
    Urbanization takes place takes place in Ethiopia early 1900‟s. The rate is different from place to place; this is mainly due to social and economic influences. Among the big cities of Africa Addis Ababa is the one with high population low planned urbanization influence. This lack of proper settlement plan of the city influences its hydrological regimes due to influence on main streams of the city The built environment of Addis Ababa includes Asphalt roads, paved roads, residential areas, commercial and industrial areas and other big infrastructures. The purpose of this study was to show the impact of built environment on hydrological regimes of Addis Ababa through defining hydrological parameters by using SCS (soil conservation Service) method to evaluate surface runoff generated as result of rainfall and it is impact on streams. The study focused on the city of Addis Ababa without considering the entire Akaki watershed. Three periods of land use maps were considered in the analysis. The land use periods are 1984, 1986 and 2002, the first two maps was obtained from Ethiopian mapping agency and the 2002 one is from Addis Ababa city Administration which developed by City master plan office. The land use maps were digitized using GIS. Based on the three periods the land uses types categorized as Asphalt, Agriculture, Forest, Paved, Built and Park and Cemetery. Using parameter,curve number for each land use types surface runoff was calculated. Accordingly it was found out that since 1984 the runoff potential has changed from 0.28 in 1984to 0.45 in 2002. This is due to the expansion of the city and increasing of built environment, which was expressed by composite Curve Number and Soil Retention. The composite curve number has changed from 84.6 in 1984 to 91.1 in 2002. This change has been also observed when we delineated twelve sub catchments using ARC SWAT and GIS . Based on the analysis we found change of surface runoff was observed. The characteristics of streams which found in the delineated sub catchments also changed .The time of concentration for streams in delineated sub catchments reduced by twenty seven percent in small streams (intermittent). Therefore it is important to consider the impact of land use change in planning and design of urban infrastructure.
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    Investigation on Storm Drainage Problem of Addis Ababa (Case Study at Gotera – Wollo Sefer, Saris - Gotera And Ring Road)
    (Addis Ababa University, 2011-07) Desalegn, Getachew; Yilma, Seleshi (PhD)
    Proper drainage system is required in developing urban areas. In Addis Ababa, drainage problem become an issue during rainy season. This study deals with investigation of storm drainage problem of Addis Ababa and a possible mitigation measure to overcome the problem. Despite there are many places in the city facing storm drainage problem; Ethio china road (Gotera – Wollo sefer), Saris Gotera road (Debrezeit road) and Ring roads are areas selected for this study. Based on primary and secondary data collected, the problems in the areas are categorized as construction, management and design problem. The method used to investigate management problem is direct field data collection and site visit but the construction problem is analyzed using field survey as well as comparison of design with what is implemented in the ground. Design of the study area is evaluated by redesigning of the system using the computation sheet used in American Federal Highway Administration (FHWA) urban drainage design manual and Addis Ababa City Road Authority (AACRA) urban drainage design manual with some modification. Design of storm drainage system evaluated in this research includes inlet spacing, pipe sizing and inlet type selection. The Values of inlet spacing and pipe sizing obtained by redesigning is compared with the original design. The result of this paper shows that the problem in Gotera - Wollo Sefer and Ring road is caused by insufficient drainage operation, over spaced inlet spacing and minimum pipe size is used. The investigation in Saris – Gotera road also shows; the curb inlets are over spaced and constructed with very small opening, the operation system of the drainage is in sufficient and curbs are not constructed according to the design.Finally, based on the result obtained a possible mitigation measures is recommended.
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    Study on Storm Water Drainage Situation in Addis Ababa “Case Study for Jemo-Iii Condominium Site near Glass Factory Area”
    (Addis Ababa University, 2016-03) Tillahun, Tessema; Meron, Mebrahtu (Ms.)
    Flooding has long been recognized as the most damaging and costly natural hazard in many countries considering the frequency and influencing extent. Due to the rapid urbanization and the global climate change in the urban areas, the frequency of devastating floods tends to be higher and the loss of human lives and property show no sign of decreasing. In order to decide on minimizing the impact of floods an effective flood volume estimation model is required. The proper design of any storm drainage system involves the accumulation of certain basic data, familiarity with the project site, and a basic understanding of the hydrologic and hydraulic principles and drainage standards associated with that design. The rational method is the most common method in use for the design of storm-water drains, where the momentary peak flow rate is desired. The method provides peak runoff rates for small urban and rural catchment areas, less than 50 hectares (0.5 km2), but is best suited to urban storm-water drain systems and rural ditches. It shall be used with caution if the time of concentration exceeds 30 minutes. For the study area the storm-water sewer network has been analyzed based on the selected outfall facilities, selected network schematization and agreed designed criteria using interactive mathematical model on Excel. This study shall contribute a lot to control the flooding problems of the study area and enhances the ability of planners, researchers and city development actors to formulate and implement sound policies to minimize undesirable future flooding impacts and management alternatives.