Viewing Total Maximum Daily Loads as a Process, Not a Singular Value: Adaptive Watershed Management

Abstract

This paper describes adaptive watershed management, which combines concepts for adaptive management and watershed management to address the various uncertain elements in a total maximum daily load (TMDL). The paper discusses how adaptive watershed management allows initial progress to be made while additional information is collected and incorporated in the TMDL. Adaptive watershed management differs from the conventional TMDL approach as a result of feedback loops, which allow managers to proceed with implementation of controls in a progressive manner, avoiding unproductive and irresolvable debate over uncertainty in the numeric value of the TMDL or the efficacy of the controls. Over time, improvements in monitoring, modeling, TMDL analysis, water quality targets, and control actions contribute to the improved effectiveness of the TMDL. The adaptive watershed management approach can be applied in situations dominated by nonpoint sources or having significant uncertainty in any number of issues. The paper includes examples of previous uses of adaptive approaches, a discussion of additional elements that need to be considered, and identification of regulatory and other obstacles.