ABSTRACT
The aim of the study was to assess the contributions
of rainwater to water supply of Enugu metropolitan area. To achieve this aim 42
years rainfall data (1971-2012) were collected from Enugu airport as well as
the catchment area of house roofs in the town from the Ministries of Urban
Development and Housing. Meteorological data (Rainfall) obtained were tested
for normality, while ANOVA technique tested rainfall variance among four
decades (70’s, 80’s, 90’s and 20’s) of the study. Trend and Regression analyses
were utilized for the long range data. Finally, augmented Dickey-Fuller test
(stationarity test) revealed whether the independent variable explained the dependent.
Result shows that rainfall data were normally distributed and not significantly
different in the four decades studied. The trend shows a general increase in
rainfall amount over 42 years while the regression model indicated that for every
one year, rainfall amount increases by 1.19 mm with a base constant of 113.2 mm.
The amount of water realized from rainfall in the city for 2015, 2016 and 2017
based on catchment area of 102,500,000 m2 is 37,578,000, 37,742,000
and 37,967,000,315 litres per annum, representing about 3% of total water
supply in the town equivalent to commercial water demand. Recommendations
include revision of the existing water policy to include mandating residents
and shop owners to install catchment gutters to collect rain water from their
roofs, promotion of a programme of rainwater harvesting against certain
barriers with respect to socio-cultural beliefs and attitudes etc.