A dual level design methodology for designing detention basins has been developed in an effort to standardize detention basin design and expedite the design/review process. The methodology utilizes a dual level design approach. The first level involves use of nomographs to determine the dischage and volumetric requirements of a detention facility to meet the drainage specifications set forth by a municipality. The second level of the methodology involves using the values of design discharge and maximum storage obtained from the nomographs along with a computer program to design the outlet works of the associated structure. The developed methodology provides both a uniform and a streamlined process for the design of stormwater detention basins for small urban watersheds where more comprehensive methodologies may not be cost effective or readily available.