Leveraging On-Site Rainwater Harvesting For Water Supply Challenges of High-Occupancy Mixed-Use Buildings In Addis Ababa; The Case of Crown Hotel 40/60 Condominium
No Thumbnail Available
Date
2024-05-01
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Addis Ababa City Administrations has built different types of condominium housing since 2005 through its Housing Development Program. 40/60 condominium is one of the program schemes intends for higher middle income residents. However, most of these housing sites supplied water twice a week. This research aims to investigate the water supply demand gap as well as potential rooftop and surface runoff RWH for supplementary water supply and flood reduction in Crown Hotel 40/60 condominium site. Monthly water demand is projected from household survey data collected from 193 residential and commercial units; the current water consumption determined from six-month monthly water bill. Rooftop RWH potential of site is calculated by interpolating the mean monthly rainfall data of 15 rain gauge stations collected from National Meteorological Agency. As well as, the catchment hydrology is analyzed using rational methods; infiltration trench and basin is proposed for surface runoff harvesting in accordance to the catchment suitability criteria. The result indicates, the study site has a monthly water supply gap of 0.41m3 per housing units. Each buildings have rooftop RWH potential of 1190.2m3 annually, this amount can contribute 11 percent of the buildings annual water demand. The required size of infiltration trench and basin are 14.72m2 for trench and is 22.7m2 basin. These components have a potential of 22,511.28m3 surface runoff harvesting annually by infiltrating to ground soil. Both rooftop and surface RWH system can reduce 63 percentages of floods generated from the study site. Thus, practicing both surface and rooftop RWH systems are comprehensive to encounter the city water supply challenges and flood related problems caused by the combination of population growth, climate and land use change.
Keywords: Water sensitive urban design, water; rooftop rainwater harvesting; surface runoff, stormwater, 40/60 condominium