Reducing Road Grit In Lake Tahoe With An Eye Toward Water Quality

by admin / Jan 27, 2016 / 0 comments
Caption: : 
Volunteer Krystal Heaney collects a sample from a pipe in South Lake Tahoe. CREDIT JULIA RITCHEY

2016-01-27, 00:35:05 PLACERVILLE CA

  Road crews have stayed busy this winter sanding and clearing Lake Tahoe's streets and highways for skiers and snowboarders making their annual pilgrimage to the Sierras. While road pollutants have posed one of the biggest threats to the lake's clarity — recent efforts to reduce street debris appear to be helping. Last year, clarity improved by 7 feet. 

Reno Public Radio's Julia Ritchey went down to the lake to see how environmentalists and local officials are tackling this challenge and improving the lake’s purity.  

Just off Freemont Avenue in the city of South Lake Tahoe, Krystle Heaney is trudging through some slippery terrain to get to a huge corrugated pipe that spews straight into the lake.

"As you could see just walking down here, we had some hand warmers, and some doggy bags, doggy poop not in a bag."

Heaney is not here to collect trash, though she does find quite a bit of it around the water. Heaney is a volunteer with the Pipe Keepers program run by The League to Save Lake Tahoe, better known as Keep Tahoe Blue.

After every storm, Heaney rushes to her assigned pipe to collect samples of water gushing out to check the level of cloudiness, called turbidity.

"When it first starts storming, you get the wash off the roadways that has been building up for awhile," she explains, "so it tends to be a lot dirtier. Toward the middle of the storm, it's not going to be quite as dirty, and at the end, it would be even less dirty." 

She's one of more than 50 year-round residents who participate in the three-year-old program, which empowers locals to become the eyes and ears of the lake. 

“The league is very adamant about citizen science,” she says. “So taking the regular population that doesn’t have Ph.D.s and using them to collect useful data that we can put to good use in the basin.”

Heaney holds up her bottle to check the color of the water and look for things like oil or grease that may have been improperly washed down a drain. If the water is blackish, that's typically a sign of grit and fine sediment being washed from the roadways — by far one of the largest polluters of the lake.

"There have been some areas around the lake where we've been taking these water quality samples and we've been able to go to the regulatory agencies and say, 'Hey, we're getting a lot of good data out of this pipe--it's really dirty. What can we do about it?' And, so, they've put in some control measures to filter it before it goes into the lake,” says Heaney.

Putting Out Less Cheese


Russell Wigart, left, and Jason Burke, right, are in charge of storm water operations for El Dorado County and the City of South Lake Tahoe, respectively. Both jurisdictions have made strides in reducing the amount of road pollution that ends up in the lake.
CREDIT JULIA RITCHEY

"I've been kind of a watchdog for storm water for quite a while, so I've been looking at pipes and what's coming out of pipes for quite a long time, trying to understand process, and function and treatment,” says Russell Wigart, storm water coordinator for El Dorado County.

These days, his focus is reducing the amount of ultra-fine abrasives from the county's roadways, so they don't end up in Heaney's sample bottle.

"Right now we're at the El Dorado County maintenance yard,” he says. “This is where we store our sand and heavy equipment for winter operations; our rotary blowers, which are gigantic snow blowers, our snow plows, front-end loader, our graters for snow removal.”

Since 2009, the county has implemented a pollutant-reduction plan looking at ways to clean up the water going into the lake.

One of the first things they did was switch from using imported volcanic cinder, a black ultra-fine abrasive, to a material called Washoe granite.

"We have this new sand that we're using, which we believe to be, I'll just say, the saving grace of Tahoe at this point," Wigart says.

Not only is the granite less prone to breaking down and mucking up the water, but it also comes from nearby Sparks, more closely matching the natural granite that the Tahoe Basin sits on. Wigart calls this a form of source control.

"Well, we can build a better mousetrap or we could put out less cheese,” he says. “And I thought the analogy was really neat in that, well, we could put together a filter system, which is high capital, high maintenance, or we could just put out less material to begin with."

To reduce the amount of sand — or cheese — they put out, they also began using a saltwater brine system, which allows the sand to more efficiently stick to the road and prevent ice from forming.

Doing so has allowed them to cut back on the amount of salt they're using by almost 80 percent. 


A pile of Washoe granite sand in the El Dorado County maintenance yard. The county switched to this sand four years ago from volcanic cinder, which has resulted in less fine sediment being washed into Lake Tahoe.
CREDIT JULIA RITCHEY

Jason Burke is storm water coordinator for the City of South Lake Tahoe. He oversees similar projects, but on a much smaller scale and budget than Wigart.

Burke says they, too, have switched to granite sand and hope to add a brine system by next winter.

"The other thing the city has worked on is instead of sanding complete segments of roads, we focus on our intersections and our steep streets, so we're not just sanding entire segments,” he says.

Focusing on what's on the roads and how to clean them has given these jurisdictions the most bang for their buck. And there’s evidence it may be working. Just last year Tahoe’s clarity improved by about 7 feet, according to scientists, the biggest improvement in more than a decade.

But with some 150-200 pipes dumping material directly into the lake, even the best snow removal system won't stop all debris.

In fact, reducing the amount of traffic would probably do more to reduce lake pollutants than any of these efforts combined. But in a car-dependent region like Tahoe, that may be more like pushing a snowball uphill.

Listen to the storyhttp://kunr.org/post/lake-tahoe-reducing-road-grit-eye-toward-water-qual...

 

--> Geo Locate: