Better Than “Optimal” Method for Designing Drainage Systems

Abstract

The Lotus 1‐2‐3 spreadsheet package has been used to develop a stormwater drainage design method which is based on the Florida Department of Transportation's (FDOT) hand tabulation form (FDOT 1987). By using the FDOT procedure, the spreadsheet method allows engineers already familiar with the manual calculation procedure to more easily adapt to the new microcomputer environment. The spreadsheet performs the necessary calculations quickly and easily while not hindering the user with tedious input procedures and confusing algorithms typical of many computer codes. The spreadsheet method also employs a heuristic cost estimation approach which allows the user to find a least cost design. This method has been used to solve a problem previously solved with two dynamic programming algorithms. Since the spreadsheet method does not use a sophisticated optimization algorithm, many simplifying assumptions made in the dynamic programming algorithms are not necessary. The results show that the spreadsheet method was able to significantly improve on the dynamic programming designs while more consistently meeting the design criteria.