Water Resource Engineering

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Browsing Water Resource Engineering by Subject "Alternative source"

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    Rainwater harvesting for Addis Ababa city; a Case of Jemo Condominium site
    (Addis Ababa University, 2015-05) Kebede, Ashebir; Sahilu, Geremew(PhD)
    The main objective of this thesis is to assess the potential of rain water harvesting practice to solve problems of both increasing water demand and storm water in Addis Ababa city. The research is carried out based on case-study of Jemo condominium site, from November 2014 to May 2015 that is found in the south western part of Addis Ababa city. The site has about 337 residential blocks with an average roof area of 286m2 and 50 communal blocks with an average roof area of 216m2 roof area and serves for about 9,800 households in which they serve for about 42,140 population. A descriptive quantitative study was carried out in order to achieve the objectives of the study. A monthly rainfall data, catchment characteristics, roof material, population data, water consumption and water demand data were collected from primary and secondary sources. People's attitude and practice towards rainwater was also assessed. The collected data was analyzed using different tools including samsamwater RWH model, Google earth, rainwater harvester, AutoCAD, MS Excel spread sheets and etc. Calibration and validation of the finding was carried out using appropriate instruments. Based on the findings the total annual rainfall in an average year is 1219mm. A 6 months of water consumption data of Jemo I collected from AAWSA Mekanisa branch shows that only 30% of the demand is supplied to residents by the municipality at private water pipes. The average annual RWH potential at Jemo I condominium site is not enough to fulfill the total water demand at this site. However, it might still be worthwhile to construct a rainwater harvesting system. With a storage reservoir of 113400 litres (113.4 m3) for a single building a rainwater harvesting system could provide about 36% of non-potable demand and RWH can reduce water demand problems by 36% for only non-potable demands and 10% for all domestic demands based on the current AAWSA standard. The total cumulative runoff generation from this site throughout the year is 723,450m3 and the amount of water that RWH system only from roof tops can harvest could be 90,290.2m3. With this estimation RWH from roof tops at Jemo condominium site can reduce runoff by 12%. This contributes for sustainable storm water management and best management practices. Therefore RWH has many benefits once it is applied for any building for sustainable alternative water supply and sustainable storm water management. The big problem here will be the size of storage tank should be big enough since the rainfall is concentrated for limited months which will not be cost effective but related to other interventions RWH is more cost effective and sustainable than other options. Key words: Rainwater, Harvesting, water demand, Stormwater, Alternative source, Non potable, Jemo, Domestic, Urbanization, Condominium, Addis Ababa, Ethiopia