Temporal change in land use system due to city expansion in urbanized watersheds poses a potential of increasing storm runoff rates, and therefore increasing the risk of flooding. Detention basins or ponds are generally considered as effective structures for storm water quality and quantity control in these areas. The present study was taken up to assess the impact of changed land use system over a period of time on hydrology and preliminary design of a detention basin for three different storms events for a site at Little Kitten Creek watershed near Manhattan, Kansas, USA. Seven different methods for estimating detention basin volumes were investigated in this study. SMADA model was used to develop final designs of the detention basin using the computed mean detention basin storage volumes of seven methods estimated. Three different storm events for 24 hours were used to develop hydrograph. The study found that, larger storms such as 100 year storm event overtops the detention basin by a considerable depth, and also quite expensive to design and construct. Therefore it is recommended to design and construct series of smaller detention basins well spaced within the watershed that are capable of handling storm runoff and also improves the aesthetic value in the urban settlement.
