Few other large lakes in California undergo as many changes as Clear Lake. Whereas a few weeks ago the lake was covered with weeds and algae, the waters are now pretty much weed free and the algae has all but disappeared. What”s going on?
At a Lake Task Force meeting on Saturday that was organized by Lorene McGuire, a group of concerned citizens learned about the dynamics of Clear Lake. Greg Giusti, a scientist with the University Of California, and Scott De Leon, the Lake County Director of Water Resources, presented a number of facts about Clear Lake ranging from the history of aquatic weeds and algae to what can be done to control both the weeds and algae in the coming years.
Giusti said that contrary to what many believe, data shows Clear Lake is actually getting clearer each year and that is one reason why the aquatic weeds have grown at such a rapid rate. He also said algae isn”t being caused by agriculture runoff or by septic systems leeching into the lake. He said the type of algae that was in the lake this summer is generated by sunlight, nutrients and nitrogen.
According to Giusti, the reason the algae is much thicker in the south end of the lake is because natural currents and wind action moves the algae from the north to the south. He said studies have shown that it takes a molecule of water 100 days to travel from the northern end of the lake to the southern end. Not all the algae are bad, according to Giusti. In fact, the green algae creates phytoplankton, which is vital to the fish and other aquatic creatures in the lake.
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 and at night they consume oxygen. Clear Lake has had heavy growths of algae during the summers for thousands of years.
As for the aquatic weeds, which this year extended all the way out to the middle of the lake, they are relatively new and, according to Giusti, are directly related to the clearer-than-normal water.
De Leon outlined what the county is doing to control the algae and aquatic weeds. He told the Task Force that there is still no solution to the algae problem but the county is studying various methods to control the nuisance algae. The county did provide pumps to various resorts to aerate the water around their docks, which in turn dispersed the algae. As for the weeds, he said the county hired a firm to mechanically harvest the weeds in selected areas and it has proven to be successful. This past summer the firm harvested approximately five acres of weeds around docks and at the public boat ramps. Boating lanes, which allow access to the main body of the lake, were also created. There was also limited spraying of herbicides to control the weeds. The cost to harvest the weeds came to $500,000.
According to De Leon, the county plans on taking an aggressive approach to managing the algae and aquatic weeds next summer but it takes money. Hopefully grant funds or other sources of funding can be found.
Actually, the weed and algae problems only occur about four months out of the year and that is during the hot summer months. During the fall, winter and spring months the lake is in beautiful condition, just like now. The problem is that the summer months are when the tourists come to Lake County. One thing the county could do is start publicizing what the county has to offer during the rest of the year. For example, the Mendocino National Forest has unlimited recreational opportunities. The recent acquisition of Mount Konocti by the county is a tourist”s dream.
Clear Lake is beautiful for nine months out of the year and the fishing is outstanding all year. In fact, most of the fishermen prefer the weeds and algae and often complain when the lake is too clear. What other lake in the country is 3 million years old and was here long before humans walked on the earth? That in itself makes Clear Lake very special and well worth living or visiting here.
