New pervious concrete could improve Lake Tahoe water quality

A type of concrete that allows water to seep through it has been used in Europe for almost 80 years, according to cement industry experts, but it's just starting to catch on in Lake Tahoe and the West.

The Tahoe Regional Planning Agency, a bistate agency that regulates Lake Tahoe, and Sierra Nevada College in Incline Village are conducting tests on pervious concrete - hoping it could be the answer to pollutant runoff from roads, parking lots and walkways.

"We're encouraged by the technology," said Julie Regan, communications director for TRPA. "We're taking a look at that to see how it works - does the water indeed percolate through?"

The agency installed an 855-square-foot parking pad at the TRPA office in September.

Pervious concrete may sound like an oxymoron, but experts say it could have a huge impact on water quality at Lake Tahoe.

Andy Youngs, a consultant for the California Nevada Cement Promotion Council, said pervious concrete may look like "a big rice crispy treat," but it's just as strong as regular concrete and allows rain water to soak through the cement.

"It acts almost like nothing's there as long as the soil allows percolation as well," Youngs said.

Near the Prim Library, Sierra Nevada College officials have also installed a pervious concrete test site. SNC President Ben Solomon is excited about the new technology and hopes to see it used more around Lake Tahoe.

"It's working beautifully," Solomon said. "The water runs right through the concrete."

But the cement does more than just allow water to run through it. It also acts as a filtration system, catching pollutants before they run into groundwater, creeks or streams.

"As the storm water goes through the pervious concrete, the pollutants end up sticking to the sides, the pores, of the pervious concrete," Youngs said. "It's kind of like turning your parking lot into a septic system."

According to the Green Resource Center, an organization that encourages environmentally-sensitive building practices, pervious concrete can reduce runoff, reduce or eliminate the need for curb gutters and storm sewers and recharge aquifers if the pavement its incorporated into proper design.

Pervious concrete, which has been used in Florida and southeastern states for about 30 years, is often used in flood control projects, as well as being used as an environmentally-sensitive development measure.

Youngs said pervious concrete is a lot easier to install than regular concrete, but the cost is a bit higher. Pervious concrete costs about 10 percent more than regular concrete and 50 percent more than asphalt. But, he said, the cost of pervious concrete is competitive when the cost of a drainage system is added to regular cement.

Despite its permeable qualities, Regan said pervious concrete will still count as land coverage because it does not support vegetation.

"It does satisfy one of those tests, which is water filtration," she said. "But using it still has huge benefits for Lake Tahoe."