Quality infrastructure has been and still is the top priority of any economy especially in
the developing. This has been a daunting task to many governments though it has been
declared a millennium development goal to be achieved in this century. The Kenyan
government has also outlined this to achieve its vision for the year 2030 which is the
country’s new development blue print covering the years 2008 to 2030.This goal cannot
be achieved if expensive construction methods and approaches are still used as is the case

The physical changes in the landscape created by urbanisation considerably alter the
hydrological response of an area to rainfall through higher river flow magnitudes, faster runoff
response to rainfall periods, lower levels of groundwater recharge, and reduced base flow. A
drainage system within an urban area has to deal with these difficulties so as to mitigate the
arising effects, particularly when the design flood occurs or is exceeded. Flood and
precipitation runoff prediction for design of stormwater controls is a highly statistical process,