摘要
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 m<sup>2</sup> 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.
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 m<sup>2</sup> 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.
作者
Emma E. Ezenwaji
Chukwudi P. Nzoiwu
Bede M. Eduputa
Emma E. Ezenwaji;Chukwudi P. Nzoiwu;Bede M. Eduputa(Department of Geography and Meteorology, Nnamdi Azikiwe University, Awka, Nigeria;Department of Geography, University of Ibadan, Ibadan, Nigeria;Department of Environmental Management, Nnamdi Azikiwe University, Awka, Nigeria)
