Stormwater runoff is a significant contributor to water quality impairments across the country, particularly runoff from developing and urbanized areas. Currently there are thousands of Clean Water Act (CWA) section 303(d) listed waters impaired for stormwater-source pollutants such as pathogens, nutrients, sediments and metals. To effectively address these impairments it is important to strengthen connections between two key federal programs under the CWA-the Total Maximum Daily Load (TMDL) program and the National Pollutant Discharge Elimination System (NPDES) stormwater permitting program. The U.S. Environmental Protection Agency (EPA) has recently developed a draft resource entitled TMDLs to Stormwater Permits Handbook (U.S. Environmental Protection Agency, 2008) to address challenges that are unique to TMDL development and implementation involving permitted stormwater discharges. The Handbook provides a reference for TMDL practitioners and stormwater permit writers on current approaches for developing more detailed stormwater-source wasteloadallocations, coordinating numeric wasteload allocations and NPDES stormwater permit requirements, and supporting TMDL implementation with a better understanding of the process to analyze and select stormwater best management practices (BMPs).The Handbook contains information to give TMDL practitioners and stormwater permit writers a better understanding of (1) cross-program regulatory requirements and programmatic processes;(2) current efforts to establish better cross-program connections; and (3) opportunities to further improve how the TMDL and NPDES stormwater programs interact to address stormwaterrelated water quality impairments. Real-world examples illustrate concepts and approaches for promoting improved implementation of TMDLs through stormwater permits. This paper will discuss key information, case studies and approaches contained in theHandbook. In addition, this paper will identify evolving issues and challenges as EPA and state TMDL practitioners and stormwater permit writers consider and test new approaches and strategies in the future.

Ocean acidification (OA) refers to the decrease in the pH and carbonate saturation states of the Earth's oceans caused by the absorption of anthropogenic carbon dioxide (CO 2 ) from the atmosphere. Like climate change, OA is primarily caused by the increasing CO 2 concentrations in the atmosphere from anthropogenic fossil fuel emissions. To date, surface ocean waters have exhibited an average pH decrease of 0.1 units with an estimated additional decrease of 0.3-0.4 units predicted to occur by the turn of the 21 st century. The absorption of anthropogenic carbon dioxide has resulted in the most drastic shift in ocean chemistry in roughly 800,000 years. These changes in ocean chemistry could negatively impact marine ecosystems, especially those with coral reefs and shellfish (e.g., clams, oysters, crabs) because these species rely on carbonate availability to produce and maintain their calcareous skeletons and shells.Ocean acidification awareness is in its infancy, but attention to this issue is increasing in both the public and private sectors. On November 15, 2010, the US Environmental Protection Agency (US EPA) issued a Memorandum to provide information to assist the Regions and States in preparing and reviewing Integrated Reports related to OA impacts under Sections 303(d), 305(b), and 314 of the CWA as part of a settlement agreement with the Center for Biological Diversity. One of the conditions of the agreement was that EPA would sign a Federal Register (FR) notice requesting comment on how to address OA under the CWA 303(d) program. In addition, EPA agreed to issue a Memorandum by November 15, 2010, describing how EPA will proceed with regard to the interplay between OA and the 303(d) program in light of the responses to the FR notice. This paper summarizes these actions, and presents additional information on assessment methods related to OA that could be useful to States as they move forward to address this important issue. Orr, J.C.; Fabry, V.J.; Aumont, O.; Bopp, L.; Doney, S.C.; Feely, R.A.; Gnanadesikan, A.; Gruber, N.; Ishida, A.; Joos, F.; Key, R.M.; Lindsay, K.; Maier-Reimer, E.; Matear, R.; Monfray, P.; Mouchet, A.; Najjar, R.G.; Plattner, G-K.; Rodgers, K.B.; Sabine, C.L.; Sarmiento, J.L.; Schlitzer, R.; Slater, R.D.; Totterdell, I.Feely, R.A.; Gruber, N.; Key, R.M.; Lee, K.; Bullister, J.L.; Wanninkhof, R.; Wong, C.S.; Wallace, D.W.R.; Tilbrook, B.; Millero, F.J.; Peng, T.H.; Kozyr, A.; Ono, T.; Rios, A.T. (2004) The oceanic sink for anthropogenic CO2. Science, 305, 367-371.