Cost functions for small town water systems in Ghana - a minor field study

Abstract: Using data gathered by researchers from WASHCost project in Ghana, this thesis examines how cost drivers can be used to predict capital expenditure for construction of piped water systems for small towns in Ghana. The data is collected from 45 small towns and communities in peri-urban areas in the Volta, Ashanti and Northern region. I have used correlation analysis and multiple regression analysis to derive cost functions for small town water systems and for the components in a water system. The aim is to derive functions for the total capital expenditure of a small town water system and for the fixed assets: mechanized borehole, water reservoir, pipe work and stand post. The resulting functions are created both for initial use before planning a new system and after having done the first design of a water system. The results are presented as eight functions, representing the total capital expenditure for a water system and capital expenditure for the assets water reservoirs, pipework and stand posts. The data was insufficient in deriving a function for mechanized boreholes. Key parameters for validating the functions are presented in relation to the functions. Explaining variables that were frequently used are design population, length of pipeline, volume of reservoir and dummy variables for region (location). The functions vary in accuracy with an explanation coefficient R2 varying from 0.42 to 0.88. The functions that have explaining variables, requiring a first investigation at place of the intended water system, are particularly interesting to use in forecasting capital expenditure.