A Method for Comparative Analysis of Recovery Potential in Impaired Waters Restoration Planning Douglas J. Norton Æ James D. Wickham Æ Timothy G. Wade Æ Kelly Kunert Æ John V. Thomas Æ Paul Zeph Received: 8 September 2008 / Accepted: 2 April 2009 / Published online: 19 May 2009 Ó Springer Science+Business Media, LLC 2009 Abstract Common decision support tools and a growing body of knowledge about ecological recovery can help inform and guide large state and federal restoration pro- grams affecting thousands of impaired waters. Under the federal Clean Water Act (CWA), waters not meeting state Water Quality Standards due to impairment by pollutants are placed on the CWA Section 303(d) list, scheduled for Total Maximum Daily Load (TMDL) development, and ultimately restored. Tens of thousands of 303(d)-listed waters, many with completed TMDLs, represent a restora- tion workload of many years. State TMDL scheduling and implementation decisions influence the choice of waters and the sequence of restoration. Strategies that compare these waters’ recovery potential could optimize the gain of ecological resources by restoring promising sites earlier. We explored ways for states to use recovery potential in restoration priority setting with landscape analysis methods, geographic data, and impaired waters monitoring data. From the literature and practice we identified measurable, recovery-relevant ecological, stressor, and social context metrics and developed a restorability screening approach adaptable to widely different environments and program goals. In this paper we describe the indicators, the meth- odology, and three statewide, recovery-based targeting and prioritization projects. We also call for refining the scien- tific basis for estimating recovery potential. Keywords Clean Water Act Á Indicators Á Recovery Á Resilience Á Restorability Á Restoration Á Stressors Á Total Maximum Daily Load Introduction: Impaired Waters Restoration Under the Clean Water Act In 1990, a special issue of Environmental Management (1990) on lotic systems recovery identified the importance of recovery science as a foundation for restoration practice. While acknowledging the uncertainties of prediction (Cairns 1990), the issue’s governmental and academic authors displayed optimism about developing the theoreti- cal basis and technical tools to apply recovery concepts in D. J. Norton (&) Office of Water, U.S. Environmental Protection Agency (4503T), 1200 Pennsylvania Avenue NW, Washington, DC 20460, USA e-mail: norton.douglas@epa.gov J. D. Wickham Á T. G. Wade Office of Research and Development, National Exposure Research Laboratory, U.S. Environmental Protection Agency (E243-05), Research Triangle Park, NC 27711, USA J. D. Wickham e-mail: wickham.james@epa.gov T. G. Wade e-mail: wade.timothy@epa.gov K. Kunert Office of Water, U.S. Environmental Protection Agency (4204M), 1200 Pennsylvania Avenue NW, Washington, DC 20460, USA e-mail: kunert.kelly@epa.gov J. V. Thomas Office of Policy, Economics and Innovation, U.S. Environmental Protection Agency (1807T), 1200 Pennsylvania Avenue NW, Washington, DC 20460, USA e-mail: thomas.john@epa.gov P. Zeph Pennsylvania Department of Environmental Protection, Office of Water Management, P.O. Box 2063, Harrisburg, PA 17105-2063, USA e-mail: pzeph@state.pa.us 123 Environmental Management (2009) 44:356–368 DOI 10.1007/s00267-009-9304-x