Lake Tahoe Environmental improvements
Lake Tahoe, a rare national treasure, lies on the border between California and Nevada. It is situated in the Sierra Nevada Mountains at about 6,229 feet above sea level. The main appeal of the Lake Tahoe area is its natural beauty and peaceful environment. More than 3.5 million people visit Lake Tahoe each year.
Lake Tahoe is known as one of the three clearest alpine lakes in the world. NDOT is proud to work with partnering agencies to assist in the protection of that clarity; however, while trying to maintain it, we must also maintain our roads. Cars emit pollutants and, during the process of maintaining our roads in the winter, NDOT uses sand and salt to melt the snow in an effort to keep the roads safe for the traveling public. These sediments and other pollutants are then washed off the road, down the adjacent embankments by rain or snowmelt and ultimately into the lake. Our goal is to minimize the amount of all sediments and pollutants that actually reach the lake.
NDOT owns and maintains approximately 39 miles of roadway within the Lake Tahoe Basin, including such thoroughfares as U.S. 50, SR 431/Mt. Rose and SR 207/Kingsbury Grade. The Department helps reduce sediment and pollutants that reach Lake Tahoe through environmentally-sensitive transportation construction and maintenance activities on these roads. Please see our Tahoe construction and Tahoe maintenance webpages for details.
Roadside Drainage Improvements
Infiltration Basin: An infiltration basin is basically a large man-made depression in the ground that helps trap sediment. Unlike the two water treatment facilities shown below, an infiltration basin "fills up" with a sediment/water mix and then over time, the water portion of the mixture seeps into the ground from the basin, leaving behind the sediment and other trapped material. However, like other water treatment facilities, maintenance crews clean out these basins on an as needed basis.
Sediment Traps: A sediment trap allows sediment to fall out of the incoming water and be stored at the bottom of the trap, until NDOT maintenance crews can clean it out. Crews clean out the traps once or twice a year. The traps are basically a series of below ground storage structures with a drop inlet or grate on the surface.
Treatment Vaults: Once the storm water flows into a treatment vault, the structure allows both fine and coarse sediments to settle to the bottom of the vault, while floatable and petroleum products rise and become trapped underneath a barrier until cleaned out by NDOT maintenance crews.
Bin Walls: A bin wall consists of a series of small bin or box like structures constructed of concrete or corrugated steel, that when placed side by side create a wall. The bins are filled with sand or a similar material, which ultimately forms a gravity retaining structure. Some of the walls are faced with a rock-like finish. Upon completing the wall, roads or other structures can be constructed on top of or adjacent to the structure. Galvanized corrugated steel is typically used for wall construction however due to its reflective nature, it is not allowed under most circumstances in the Tahoe Basin. Instead, "weathering steel", which lacks reflective properties is used but deteriorates more rapidly as it is not protected from environmental factors.
Since 1995, NDOT has been planning, designing, and constructing an Environmental Improvement Master Planning (EIMP) program for the Tahoe Basin. Since the inception of the program, NDOT has been prominent in implementing innovative approaches in science, technology, and environmental stewardship. The EIMP and its elements have received local and national recognition; raising the bar among transportation agencies in environmental collaboration and context sensitive design. The success of this program has been reflected in the several local and national awards and has also been accepted as a role model by other agencies.
NDOT has succesfully implemented millions in projects in the Tahoe Basin over recent years to build and maintain a safe, effective transportation system that supports a vibrant economy and improves the environment, while maintaining Tahoe’s social and cultural heritage for future generations – money well spent to help preserve one of the nation’s most magnificent scenic resources! NDOT’s effort in Lake Tahoe is a profound example of its commitment toward protecting, improving, and enhancing the state’s environment. NDOT will continue to use its organizational might and staff’s strong sense of dedication to environmental stewardship toward this commitment.
The Basin is home to a host of individual, private and public entities, all focused on enhancing the Lake Tahoe environment. However, as an individual entity, often the project focus was in the past limited to improvements made within boundaries defined by jurisdictions. NDOT initiated its award-winning partnering process in 1996 to enhance commitment to help solve Lake Tahoe’s environmental problems. This approach was a fundamental change in the relationship between environmental regulators and highway agencies, and was a benchmark for context sensitive design approach.
This process of enhanced partnership has greatly improved NDOT's interagency coordination. Regulatory agencies, NDOT's internal divisions, and the public are working together as partners in an atmosphere of mutual trust and respect, committed to solving Lake Tahoe's environmental problems. Currently, NDOT is able to join more than 20 agencies for regular meetings and continual coordination. Design and approvals are being expedited and environmental remediation is increased. All agencies are working together to communicate and address issues regarding funding, planning, design, construction, and maintenance. The partnering process allows agencies to develop solutions that are agreeable to all involved and meet all environmental improvement expectations.
NDOT will continue the partnering process to assure the success of future projects within the Tahoe Basin.
Tahoe Fun Facts/Links
Some of the fun facts about Lake Tahoe are that if all the water from Lake Tahoe were to spill over, there would be enough water to cover a flat area the size of California with 14 inches of water. Also, the amount of water that evaporates from the surface of the lake every year could supply a city the size of Los Angeles for 5 years.
Credits: USGS at http://tahoe.usgs.gov/facts.html
NDOT Hydraulics Section
1263 S. Stewart Street, Room 113
Carson City, Nevada 89712