The ruling is a defeat for an alliance of agriculture and forestry groups which was trying to prevent the EPA from putting California’s Garcia River on a list of impaired waterways.

Environmentalists have welcomed the ruling. Kathy Nemsick, National Co-ordinator of the Clean Water Network, told edie that “the decision is extremely significant and timely” and a significant development in the Congressional debate about whether EPA has the authority to require clean-up plans for rivers polluted by non-point sources of pollution.

In March 1998, the EPA developed ‘total maximum daily loads’ (TMDL) to definine the amount of sediment that could be introduced into the Garcia River without exceeding the river’s water quality standard. The agency also defined the reductions in sediment necessary for the river to reach the water quality standard set by the State of California.

The American Farm Bureau Federation and other agriculture and timber groups claimed that the EPA and the states should calculate TMDLs only for pollutants that are discharged from point sources such as pipes.

The court rejected this argument, holding that the Clean Water Act is designed to provide a comprehensive solution to US water quality problems, “without regard to the sources of pollution.”

According to the EPA, only one percent of polluted waterways in California fail to meet water quality standards solely because of pollution that comes from pipes, municipal waste treatment works or other point sources. Meanwhile, 54% of California’s impaired waterways are polluted by non-point sources exclusively, while another 45% are polluted by a combination of point and non-point sources.

The ruling, which is the first to address the issue of the scope of the Clean Water Act’s water quality standards programme, reaffirms that Congress intended TMDLs to apply to all sources of pollution when it wrote the Clean Water Act 27 years ago.

Nemsick expects the forestry and agriculture alliance to appeal and continue to try to change the law instead of comply with it. “It’s time for the Farm Bureau Farm Bureau and other agricultural industry groups to stop trying to shirk their responsibilities and put more money into cleaning up the water than into lobbying and lawsuits to weaken and delay implementation of the Clean Water Act,” Nemsick told edie.

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie