There were two important legal rulings in 2011 issued by the 9th Circuit Court of Appeals, which, after the United States Supreme Court, is seen as the most influential tribunal for environmental decisions given the sprawling geography and population within its jurisdiction. Both cases involve the Clean Water Act and offer guidance for future interpretation and application of the Act.
In Northwestern Environmental Defense Center v. Brown, 640 F.3d 1063, the Court struck down an EPA rule that purported to exempt runoff from logging operations from the Clean Water Act's National Pollutant Discharge Elimination System ("NPDES") permit requirements. The Court ruled that stormwater that flows down logging roads and is then collected by and discharged from a system of channels is, indeed, "point source" discharge, thereby requiring a NPDES permit. This ruling is viewed as either closing a major loophole within the Act, or dramatically expanding its scope, depending on one's perspective.
Another case involving the Clean Water Act is NRDC v. County of Los Angeles, 636 F.3d 1235. There, the Court found the County of Los Angeles liable for discharging polluted urban stormwater into navigable waters. What makes this case important is that the polluted water at issue did not originate on county property. Rather, the county's flood stations and storm water system collection systems were sufficient to establish county control over a "point source" for purposes of triggering the requirements of the Act. The County has appealed this ruling to the U.S. Supreme Court.
Next year will likely see more important environmental decisions from the Ninth Circuit.