Abstract:
Rainwater harvesting and utilization systems have been in place for centuries.
Rainwater harvesting refers to the practice of collecting rainwater from rooftops, land
surfaces, or rock catchments and storing it for human use. Hosanna Water and
Sewerage Enterprise is the only organization responsible for the distribution of water
for the town. Gurgade condominium site residents are facing a big challenge due to
the water shortage problem. Therefore, the objective of this study is to assess rainwater
harvesting as an alternative source for non-domestic purposes in Hosanna Town
Gurgade condominium site. The data used for this study was secondary. Data required,
such as previous water consumption, area of the roofs, rainfall data, population and
runoff coefficient was collected from Hosanna Water and Sewerage Enterprise,
National Metrological Service Agency, Hosanna Land Information Center, Hosanna
Town Municipality and Central Statistics Agency. Precipitation data for Gurgade
condominium was used to determine the amount of water that can be collected.
Calculations of the harvesting areas (areas of the rooftop of the blocks) were made by
using AutoCAD software from the cadastral map of Hosanna Town. And also the data
was collected by personal observations. The built up area of the study was 1536 m2
that can be convenient for rainwater collection. The buildings was composed of 4
blocks (the total area of 1 block was 280 m2
) and 2 communal blocks with each a total
area of 208 𝑚2
. From the area of rainwater harvesting 1069.95 𝑚3 of water will be
collected in a year but this will satisfy only 45.6 % of the total non-domestic water
demand. Accordingly, from the result providing a collecting ground storage reservoir
of 67.74 𝑚3 near the buildings was needed. It was also tried to design the rainwater
harvesting components based on design criteria. Based on the design and analyses
performed, it becomes clear that rainwater harvesting is not the only solution that
will solve all water scarcity issues in Gurgade. Rainwater harvesting can be an
alternative solution to support the increasing water demand and reduce the surface
runoff as a best management practice which helps to satisfy environmental
sustainability which is one of the millennium development goals.
