How to Include Economic Analysis in TMDL Allocation

The total maximum daily load approach currently used by the USEPA to restore an impaired stream by allocating allowable loads to the polluters does not mandate any economic consideration. The need for a cost-effective allocation process has long been identified but no single best way to accomplish this has yet been developed. This paper describes how the most economical load allocation scenario may be determined through an optimal placement of control measures within an agricultural watershed. The proposed optimization approach is applied to the bacterially impaired Roses Creek watershed located in the Commonwealth of Virginia. The cost-effectiveness relationships were established for vegetative buffer strips, streamside fencing, pet waste management, and septic system repair and installation to illustrate the methodology. Similar relationships may be established for other control measures provided their load reduction efficiencies are known.