COLUMBUS, Ohio (AP) - Ohio transportation officials say filters on roadsides used to reduce pollution from the rainwater runoff don't work and won't be used anymore.
The state has since 2005 used exfiltration trenches as a pollution-control feature in new and expanded highways.
They were supposed to replace the concrete rain channels that separate curbs from asphalt. Instead of flowing straight to a storm drain, rainwater is supposed to soak through layers of porous concrete and gravel to filter pollutants.
But they've been scrapped after researchers at Ohio University determined they are prone to clogs.
The finding undercuts the state's efforts to meet state pollution standards that are supposed to protect streams and aquatic wildlife from storm runoff.
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