Computations for stormwater management should consider the duration, frequency and intensity of rainfall, wet season water table, antecedent moisture conditions, soil type and surface storage, time of concentration, tailwater conditions, changes in land use or land cover and any changes in topography and hydraulic characteristics. Large systems should be divided into sub-basins according to artificial or natural drainage divides to allow for more accurate hydraulic simulations. Examples of acceptable methodologies for computation of runoff hydrograph are: Santa Barbara Urban hydrograph Method; Soil Conservation Service Curve Number and Unit hydrograph (TR-20 and TR-55); and U.S. Army Corps of Engineers HEC-1 Computer Program. The methodology to be used for computation of runoff for water quality requirements is the rational method.