EPA Region 10 Climate Change and TMDL Pilot. Project Research Plan.

摘要

Global climate change affects the fundamental drivers of the hydrological cycle. Evidence is growing that climate change will have significant ramifications for the nation's freshwater ecosystems, as deviations in atmospheric temperature and precipitation patterns are more frequently recorded across the United States (Bates et al. 2008; Karl et al. 2009). For example, stream temperature is projected to increase in most rivers under climate change scenarios due in part to increases in air temperature, which, in turn, could adversely affect coldwater fish species such as salmon (Brekke et al. 2009). It is critical that watershed management, planning, and regulatory approaches incorporate climate change science and understanding to ensure holistic and accurate analysis. The total maximum daily load (TMDL) program is one of the primary frameworks for the nation to maintain and achieve healthy waterbodies, implemented pursuant to section 303(d) of the Clean Water Act (CWA). More than 40,000 TMDLs have been developed in the United States to determine the maximum pollutant loads allowable that would still permit attainment of water quality standards. However, the majority of these analyses have been conducted using assumptions of a stationary climate under which historical data on flow and temperature can be assumed to be an adequate guide to future conditions (Johnson et al. 2011). Research is needed to illuminate the ways in which climate change considerations could be incorporated into a TMDL, and how climate change might influence restoration plans.