Reducing fine sediment helping Lake Tahoe
By Kathryn Reed
Abrasives put on roadways in the Lake Tahoe Basin are a huge contributor to the loss of lake clarity.
That was one of the messages delivered to the Lahontan board on Thursday when staff gave an update about the total maximum daily load program. The TMDL is designed to keep fine sediment from reaching the lake. Those tiny particles are degrading the lake’s clarity, along with phosphorus and nitrates.
“Caltrans is leading the way with El Dorado County with traction abrasives. They were shooting themselves in the foot by putting fine sediment on the ground,” Bob Larsen, senior environmental scientist with Lahontan Regional Water Quality Control Board, said March 12.
Brine is now being used more often than salt or decomposed granite to handle slick roadways. Sweeping after a storm to collect the leftover matter is also helping to keep material from the lake. Changing abrasives and vigilant street sweeping has proved to be a cost-effective route.
Larsen said it has also been proven that sweeping streets with cracks is not effective.
“That is why it is important to maintain the infrastructure,” he said.
Lake Tahoe clarity is an ongoing issue. Photo/Kathryn Reed
One of the early complaints from the jurisdictions having to comply with the unfunded TMDL mandate was the cost. Larsen told the board it’s important for Lahontan to be an advocate for the stakeholders when it comes to securing funding for projects.
Another tactic is to crack down on lax maintenance of erosion control measures – or best management practices.
Larsen said he is cautiously optimistic that the decline of Lake Tahoe’s clarity is stabilizing.
The Lake Tahoe TMDL is a 65-year program, with this being year four. The goal after all that time is to be able to see what amounts to a white dinner plate being visible 100 feet below the surface of Lake Tahoe. Larsen said the 2016 goal of 71 feet of clarity is on target to be met.
Because the urban runoff is responsible for 70 percent of the fine particles reaching the lake, that is where the emphasis is.
Non-urban areas are also a concern, with unpaved roads in the forest being the biggest problem. Since 2004, the U.S. Forest Service has decommissioned more than 200 miles of roads.
All of the initiatives are likely to help improve the near shore as well, Larsen said. This is the beach area that has turned murkier as the water temperature increases. This area is also being studied by other agencies to determine other reasons why the water is more brown than clear.
While Lahontan only has jurisdiction in California, the TMDL is a joint policy with Nevada. A universal website has been established to encompass what is going on lakewide.
TMDL is not unique to Lake Tahoe. Lahontan also has jurisdiction over the TMDL program for Heavenly Valley Creek, Indian Creek Reservoir, Squaw Creek, Blackwood Creek, and Truckee River.
Rich Booth with Lahontan gave a summary to the board about those water bodies. He said the four main pollutants are metals, nutrients, total dissolved solids, and other things, with bacteria being part of the other.
All but Squaw Creek are on target to meet the 20-year compliance goal, Booth said. He called the increase in fine sediment “disturbing”.
The agency is also going to take a harder look at the Truckee River because by the current standards it is in compliance. However, last year the Truckee River Watershed Council presented information to the board saying it is still an impaired waterway. It’s likely the goals will be reconfigured.
Kae, Good piece about reducing sediment going into the lake. It’s been a problem for a long time so I’m glad it’s being looked into and maybe something will be done to correct this. OLS
Cracking down on BMPs- great idea! That said, the TRPA Advisory Planning Commission just approved language changes that took out the word enforcement and changed to implement in over a dozen places in the code.
Ban the sand.
How many times have I said this, and it has fallen on deaf ears?
Caltrans doesn’t use “sand”, and whatever they use as “grit” becomes airborne, it gets into our water supply, and I wonder if it’s toxic. It’s everywhere, and yet, they don’t use true sand as is used in other parts of the country. Why?
Next up – stop the lakefront homeowners from pumping chemicals and other harmful toxins into their yards and gardens!
After that – have TRPA check for oil leaks in boats they certify!!!!!!
Hard to believe street sweeping can be beneficial, as the street sweepers appear to simply stir up and further dissipate sand, fine sediment, abrasives, dust, dirt, particles, and other detriment into the air. Anyone who has followed one can attest.
A.B.
The list of material used for traction enhancement is very long. I have no idea what you define as “true Sand”. There are as many kinds of sand as there are rocks. Any of them will be ground finer by driving on them, producing dust. Sweeping puts a lot of it into the air as you can see by looking at any street sweeper in action. Some are worse than others. Toxicity is not a major worry with any of the common grits.
Personally, I think the use of lawn blowers should be banned in Tahoe while we are on that warpath. Aside from making clouds of dust, they are a source of considerable noise pollution. Basically they just redistribute the dirt and leaves from one area to another. Usually from private property onto public property. Why not use vacuums? They pose a lesser dust problem.
At the end of the day, what is locally produced and cheap is usually what any given area uses.
Brine is not a bad substitute for salt, but at 50 gallons per lane mile, there is still over a hundred pounds of salt applied per lane mile, according to recent articles about Tahoe.
The salt, which is not native to rocks in Tahoe, must have some affect on the lake, but it is likely negligible, and much flows out to Reno via the Truckee River.
The use of tire chains is a major, major source of fine particles and causes much road damage on any paved surface where they are used. There are states in the US that ban use of studded tires for the same reason public safety be damned apparently.
No matter what, there is a cost to everything. Given he relatively few residents of the Tahoe Basin, I think it would be worth considering an entrance fee for non residents, as several major national parks like Yosemite and Yellowstone do. Distribute the fee toward the extra , wear and tear that all the traffic causes the infrastructure. My guess is, it would not significantly, if at all, diminish the number of non-resident visitors.
Lahontan over-dramatizes the impact of roadway abrasives because their TMDL program feeds their salaries and necessity.
The fact is that yes maybe the abrasives are a minor contributor to pollution but likely only on roadways immediately adjacent to the lake itself and streams.
The over use of abrasives and especially brine solution needs to be restricted and application program revised and followed.
We don’t need to continue to lay down overly excessive brine solution and abrasives along entire roadways simply for the tourists on weekends !
I forgot to mention….
I don’t see any information of a factual nature in the article that speaks to the headline: Reducing fine sediment helping Lake Tahoe.
Lahontan’s tactic must be, if they say it enough, people will begin to believe it.
There will never be enough money to support govt agency programs, since they have no oversite or anyone auditing the efficacy of their work.
There are no performance standards applied to any agency that I know of.
Good to see they are finally looking into salting of the roads with regard to lake clarity. I think this is a major contributor to the problem. There’s just no way you can dump tons of salt and sand on the roads and not have it impact the lake clarity in a big way. And not only does it impact the lake clarity, it impacts all the plants and wildlife around here. Go over to the snow dump and take a look at the trees!
Closing the forest service roads is just a bad idea though. There was a study on an extensive and heavily used network of trails in Kentucky, and they found that the erosion caused by vehicles on the roads amounted to about one 16 oz soda can per day over hundreds of mile of roads. And the forest service roads around here are not very heavily used. Closing these roads just causes them to get overgrown and lost, and when there is a natural disaster like a wildfire, it is impossible to move equipment quickly enough to stop it.
Also, I think the Tahoe City Dam has a major effect on lake clarity. It isn’t natural to be constantly changing the level of the lake.
The streams and creeks around here will always produce sediment, because that what happens when water flow through the dirt. Trying to stop it is just interfering with nature, as well as a waste of time and money.