Clear Lake is Unique
The lake has changed shape over time, with a continuous lake for at least the last 450,000 years in the Upper Arm (between Lakeport and Lucerne), while the Oaks Arm and Lower Arm are only about 12,000 years old.
Clear Lake is very productive and scenic, a lush paradise for fish and wildlife. The high productivity of the Clear Lake Basin attracted Native Americans early in their settlement of North America. Archeological evidence indicates human habitation around Clear lake for the last 12,000 years.
Known as the Bass Capital of the West, Clear Lake supports large populations of bass, crappie, bluegill, carp and catfish. Two-thirds of the fish caught in Clear Lake are largemouth bass, with a record of 17.52 pounds.
In addition to fish, there is abundant wildlife within the Basin. There are year-round populations of ducks, pelicans, grebes, blue herons, egrets, and osprey, and winter populations of bald eagles and white pelicans. The Basin also supports abundant populations of deer, bear, mountain lion, raccoon and other animals.
The expansive warm, water of Clear Lake makes it popular for high activity watersports, such as swimming, water skiing, sailing, boat races, and jetskiing. With its scenic beauty, clean air and abundant wildlife, the Clear Lake is an excellent place to slow down, enjoy nature study,photography or just plain loafing.
Along with Clear Lake's high productivity, algae in the lake can create a situation which can be perceived as a problem to humans. Algae are tiny water plants that cycle normally between the bottom and the surface, floating up and sinking down. During the day, algae generate oxygen within the lake; at night they consume oxygen.
The algae in Clear Lake are part of the natural food chain and keep the lake fertile and healthy. Because of the lake's relative shallowness and warm summer temperatures, the algae serve another important purpose. They keep the sun's rays from reaching the bottom, thus reducing the growth of water weeds which would otherwise choke off the lake.
Nuisance blue-green algae, however, can be a problem. From more than 130 species of algae identified in Clear Lake, three species of blue-green algae can create problems under certain conditions. These problem blue-greens typically "bloom" twice a year, in spring and late summer. The intensity of the blooms vary from year to year, and are unpredictable. The problem occurs when algae blooms are trapped at the surface and die. When this occurs, unsightly slicks and odors can be produced.
The most effective method of keeping the algae from becoming a nuisance is to keep them alive and in a normal cycle. This may be done by agitating the water surface to break up the trapped algae, letting the algae sink. Boat traffic and spraying the trapped algae with water have proven effective in breaking up the trapped surface algae.
FIVE COMMON QUESTIONS
Is the lake eutrophying or dying?
The lake is definitely not dying. It is healthy and very much alive. A lake is eutrophic when it is productive in the same way a grassy field is more productive than a desert. Studies indicate that Clear Lake is eutrophic now and has been eutrophic for more than 10,000 years. It is believed blue-green algae populations have increased this century.
Are dead fish around the lake due to a lack of oxygen in the water?
Although oxygen levels in land-locked lagoons can get dangerously low for aquatic life, oxygen in the open surface waters of Clear Lake is always high enough to sustain fish. Near the lake bottom, oxygen levels may be lowered, but this area is avoided by fish. Natural conditions of old age, disease and rapid temperature changes are more likely causes of dead fish in Clear Lake.
Is it safe to swim in the lake?
Yes, the lake is safe for swimming. Monitoring has shown that the lake consistently meets or exceeds water quality standards for swimming. If the water surface is covered with scum or floating algae mats, then do NOT swim in it nor allow dogs to drink or swim in the water.
Is the lake water safe to drink?
Disease-causing organisms are present in nearly all surface waters, even crystal clear mountain streams. As with all natural surface waters, drinking water directly from the lake should be avoided. When lake water is properly treated, as it is all around the lake, it is safe to drink.
Is it safe to eat fish caught in the lake?
Algae do not affect the edibility of fish. However, due to elevated mercury levels in some of Clear Lake's fish, the advisory from the California Department of Health Services limiting the number of fish consumed should be heeded. Mercury occurs naturally in Clear Lake, although levels have been elevated due to historic mercury mining at Sulphur Bank. The U.S. Environmental Protection Agency has begun remedial steps including the reinforcement and stabilization of the shoreline to reduce the input of mercury to the lake. Other steps are being investigated.
REDUCING BLUE-GREEN ALGAE
The County of Lake has supported research and several projects to reduce the growth of blue-green algae in Clear Lake. Working in cooperation with the State Department of Water Resources and the University of California, Lake County officials completed studies that have shown there is an over-abundance of nutrients (food for the algae) within the lake. Because the lake is so large, spraying algae to reduce nuisance conditions is not a practical long term solution. Reduction of lake nutrient levels is anticipated to reduce the quantities of nuisance, blue-green algae.
Nutrients come from erosion and other sources within the watershed, the land which drains into Clear Lake. A key to improving the water quality in the lake is to manage the entire watershed. Management tools of erosion control, creek and wetland protection, and vegetation management, are being implemented to improve the water quality of Clear Lake and the quality of life in Lake County by reducing the amount of nutrients in Clear Lake.
For technical information on Clear Lake, please contact the Lake County Water Resources Department, at (707) 263-2344 or write 255 North Forbes Street, Lakeport, CA 95453.
For recreation information around Clear Lake, please contact the Lake County Marketing Program at (800) 525-3743, (707) 274-5652, or write 255 North Forbes Street, Lakeport, CA 95453.