BMP knowledge is spreading
Rainstorms this summer have let people know that Best Management Practices — erosion controls around a home — do make a difference.
“During the last few storms I’ve gotten calls,” said Matthew Graham, leader of the Tahoe Regional Planning Agency’s Erosion Control Team. “People are saying ‘I’ve done my BMPs and my neighbor hasn’t.'”
They can see streams of soil and sediment flow into their yard from neighbors. When the nutrient-laden water does not get absorbed by the land, it can run down a driveway and eventually make its way into Lake Tahoe. That causes algae to grow and degrades the clarity of the lake.
Retired dentist Ted Finkler, 62, attended a Best Management Practice workshop last week sponsored by South Lake Tahoe and El Dorado County. He was one of about 50 contractors and homeowners who listened to erosion experts explain the latest BMP technology using a house under construction on Jicarilla Trail as a model.
“My neighbor is replacing her lawn,” Finkler said. “With all the rains, her topsoil washed into my yard.”
Finkler, a resident of Tahoe for 34 years, said he has used Best Management Practices even before the concept of BMPs was created. His front yard is sloped and erosion-prone, so he terraced the land and planted lupines to hold soil in place.
Sometimes that’s all one needs to do help protect the lake, said Eric Larson, program coordinator for the Backyard Conservation Program. How many dry wells and infiltration trenches a property needs depends on two things: how fast the soil in question is able to absorb water; and how much unnatural surface — a paved driveway, a roof — exists on a property. Cost to install them or have someone else do it ranges from about $300 to as much as $15,000 for a large home, Larson said.
Calculations that indicate what BMPs a property needs are offered free on both sides of the Lake Tahoe Basin. After that, the next step is to decide whether to use gravel or prefabricated plastic rain storage devices, about twice as expensive, to help a yard absorb runoff.
But the work is not finished once a BMP is in place. The soil and sediment that builds up in a well or trench needs to cleaned out and properly disposed of or else it will go right to the lake. Gravel trenches need to be cleaned out every six to eight years. Prefabricated devices need maintenance every eight to 12 years.
Richard Lynn, a 69-year-old retired forensic psychologist, says in his experience gravel-filled wells and trenches are more than difficult to maintain.
“Sit there and lift all that rock out and get rid of the silt,” said Lynn, who plans to install prefabricated storage devices on his property this fall. “Nobody can maintain a rock dry well.”
Graham, the basin’s BMP expert, disagrees. A layer of filter fabric about 3 inches below a top layer of gravel does the trick. Fabric at that level is easy to get to and clean. But Graham is undoubtedly an optimist, a requirement for someone trying to get thousands of homeowners to do a major amount of yard work by 2008.
“I really see the tide turning with what’s happening in Tahoe,” Graham said. “People are seeing the connection. It’s not an environmental issue. Clean drinking water and a clean lake is community issue.”
To schedule a BMP evaluation for a residence on the California side of the basin, call (530) 543-1501 ext. 6. Homeowners who live on the Nevada side of the basin should call (775) 586-7223 ext. 1. BMP evaluation requests for commercial can be made by calling the TRPA Erosion Control Team at (775) 588-4547, ext. 217.
— Gregory Crofton can be reached at (530) 542-8045 or by e-mail at firstname.lastname@example.org