Treating Nonpoint Source Runoff

Nonpoint source pollution invades our every essence.  We have become adept at removing pollutants from waste streams yet like climate pollution, nonpoint source pollution of our water, air, food, homes, schools, work places, night skies and audio landscape is inescapable.

Bruce Melton, our President, was the principal investigator for a million dollars of stormwater treatment research through the EPA Clean Water Act and Texas Water Development Board. He was responsible for research on three wet ponds, two extended detention ponds, a peat sand filter, an underground peat sand filter and an oil grit separator with oil absorbing pads. Because of this research, he was able to install the first underground sand filter in Austin.

The project was constructed like his research projects, using plastic geometric structural domes to store the stormwater and included a parking lot on top of the underground sand filter. His research is far more valuable than stormwater treatment ponds though. Melton has used his expertise to evaluate DOT projects across the region.

Typically, these projects only meet the most rudimentary of stormwater runoff quality treatment standards, like the Texas Commission on Environmental Quality Edwards Aquifer Criteria. Even Austin’s world renowned stormwater quality treatment criteria are insufficient for treatment of stormwater in sensitive environmental areas.

Austin Edwards Aquifer Standards are labelled as non-degradation meaning, that they do not discharge stormwater pollutants off of the project site. They make this claim because they require all stormwater to stay on the site and be irrigated so that it soaks into the ground—into the aquifer, where it emerges (in Austin) at Barton Springs or one of the sister springs in the vicinity.

They assume that any stormwater pollution is treated by soil en-route to the aquifer. But their conceptualization is flawed and it has been since 1992 when conceived. Over the last five or six years, new science has finally surfaced that shows that stormwater irrigated over the recharge zone ends up at Barton or one of the sister springs within a few days which is months faster than previously understood.

Possibly more fundamental, when researchers captured cave drips after rainfall events and analyzed for stormwater contaminants, virtually no stormwater contaminants were treated in surface soils. Melton works with the region’s leading stormwater hydrogeologists to help popularize this work and his position on the Austin region’s Sierra Club Executive Committee and their Conservation Committee as well.

Melton works to educate our leaders, land developers and private citizens about the latest in stormwater quality science. The latest bit of science that is making a big splash in stormwater circles today is TxDOT’s new asphalt surface friction course. Originally a product to increase traction and reduce surface spray during rainfall events, it not only does these two things but, it reduces noise and actually treats stormwater too. The level of treatment is not large, about as much as an Austin Sand Filter, but wow! Pavement that removes stormwater contaminants at all is phenomenal!