In the News

Tahoe’s Construction Season Runs May 1 – Oct. 15
date posted: May 18 2004

By John Cobourn, Water Resource Specialist;
and Heather Segale, Environmental Education Coordinator; University of Nevada Cooperative Extension

Grading and construction activities generally remove native vegetation, topsoil and the duff layer. These activities result in bare soil, which is vulnerable to water and wind erosion. Since Tahoe has what is called a Mediterranean climate, with wet winters and dry summers, resource managers have adopted the strategy of limiting grading and excavation during wet winter months to try to minimize the harmful effects of erosion on Lake Tahoe’s water quality. This is why Tahoe’s building season runs May 1 – Oct. 15. It is illegal to permit or perform any activities disturbing more than 3 cubic yards of soil Oct. 15 – April 30.

Another strategy to limit construction-induced sedimentation is use of temporary best management practices (BMPs) during construction of new structures or landscapes. BMPS are techniques designed to reduce water pollution from land management activities.

Just as all home and business owners are required to install permanent BMPs, all excavators, pavers, builders, and other contractors must install temporary BMPs prior to starting new projects. These BMPs can be as simple as fencing off natural areas on a property that can be left totally undisturbed during construction. These natural areas should be as large as possible, and are to remain off limits to driving, parking, and materials storage. The bonus at the end of construction is that the property owners will have a slice of undisturbed natural habitat adjacent to their home. This will provide beauty and opportunities for wildlife viewing. It also won’t require maintenance, other than annual pruning and cleanup of debris for defensible space purposes.

BMPs at Lake Tahoe, whether temporary or permanent, must be designed to protect soil from erosion and infiltrate the runoff from a “20-year, one-hour storm” into the soil on the property. This equates to receiving approximately 1 inch of rainfall during an hour. Because we generally have such clear, rain-free summers, builders are sometimes surprised by an intense thunderstorm that drops an inch of rain in an hour on a summer afternoon. Such storms can cause severe sedimentation in the lake. For this reason, contractors and their workers must frequently inspect all BMPs to make sure they will work effectively throughout the year.

Like most lake restoration efforts comprising the Lake Tahoe Environmental Improvement Program (EIP), temporary and permanent BMPs are being improved each year. For example, a few years back, contractors routinely placed straw bales around grading projects during construction. Because these bales have been found to be a source of noxious weed seeds, a new line of weed-free, erosion-control logs, fences, and fabrics has now mostly replaced them.

Another improved practice is use of a leaf rake and a gentle touch when raking up dead pine needles lying on unvegetated soil. It is recommended that property owners leave both a duff layer and 1 inch to 2 inches of decomposing pine needles in place to guard against soil erosion. Property owners should prune back dense stands of flammable shrubs, but not dig out the roots, which hold soil in place. Pine cones, dead branches and dead vegetation should be removed within 30 feet of structures. Inorganic mulch is now recommended within 5 feet of structures. Such improvements are part of an ongoing effort to integrate the practice of defensible space with implementation of BMPs for water quality. Homeowners can call (775) 586-7223, ext. 1 or (530) 543-1501, ext. 6 for a free BMP Site Evaluation of their properties.

Watch for “The Lake Tahoe Report” in the North Lake Bonanza each Friday, and tune in to KOLO-TV News Channel 8 Tuesdays at 5 p.m. to learn more. Next week, learn about the upcoming Tahoe Research Symposium. “The Lake Tahoe Report” is a collaborative effort of the Lake Tahoe Environmental Education Coalition, University of Nevada Cooperative Extension, UC Davis and the USDA Forest Service. For more information, contact Heather Segale, University of Nevada Cooperative Extension, (775) 832-4138, or logon to www.lteec.org or www.unce.unr.edu.