ABSTRACT
As watershed districts, municipalities, stormwater engineers, and other stormwater professionals strive to manage stormwater in an optimum and cost-effective manner, they face myriad choices and design decisions. One of the ‚rst and perhaps most fundamental questions that must be answered is what kind of stormwater management practice (SMP) or technique will be optimum for a speci‚c project and location over the life of the project? In this case, optimum means the best use of current and future resources. For example, will a bioretention pond, constructed wetland, or in‚ltration trench best use current and future resources? Alternatively, perhaps the installation of a standard dry detention pond will optimize resources. Many SMPs are available and often times a single geographic region will have a variety of different kinds of SMPs. To select the optimum SMP, associated construction and operating and
CONTENTS
Introduction ........................................................................................................ 9 Cost Estimation ................................................................................................ 11
Water Quality Volume ................................................................................ 12 Total Construction Costs ............................................................................ 13 Land-Area Requirements ........................................................................... 18 Operating and Maintenance Costs ........................................................... 21 Total Present Cost ........................................................................................ 22
Effectiveness of Contaminant Removal ........................................................ 30 Runoff Fraction Treated .............................................................................. 31 Pollutant Loading ........................................................................................ 35 Fraction of Contaminants Removed ......................................................... 37 Example ........................................................................................................ 39
References .......................................................................................................... 42
maintenance (O&M) costs need to be estimated and re‚ned as the project progresses. An accurate ‚rst estimate will reduce the magnitude of later changes to the project, and thereby improve the process of choosing the optimum SMP.
