The hot summer months are just around the corner and that means heavy weed growth on Clear Lake. The clearer than normal water this year could lead to an explosion of aquatic weeds. In fact, weeds are already starting to appear on the surface in many areas and are just below the surface throughout much of the lake.
Just about everyone is aware of the aquatic weed problem in Clear Lake. The lake is home to an estimated 44 different species of weeds of which six are non-native. The past five years has seen an outcry from lakeside residents concerning the weed problem. Many of the channels such as the Clearlake Oaks Keys and the Lakeport Lagoons get completely choked off with aquatic weeds, which makes running a boat through them nearly impossible. In fact, the area around the Ferndale Resort in Soda Bay is already getting choked off by weeds.
The question lakeside homeowners are asking is what can they do about the weeds that will be denying them access to the lake from their own docks? County officials have been wrestling with the weed problem for a number of years but have yet to come up with a solution.
Lakeside homeowners realized years ago that when algae is abundant weed growth is down, but when the water is clear, such as this year, the weeds come back with a vengeance.
When the lake was covered with algae years ago there was very little weed growth because the sunshine couldn”t penetrate to the bottom to stimulate their growth. That all changed about 10 years ago when the water clarity started to improve because of less nutrient loading.
The primary weeds in Clear Lake are sago pondweed, potomogeton, coontail and water primrose. All are native to the lake. Eurasian waterfoil is a foreign plant but becoming common in the lake. The other weed of concern is hydrilla, a non-native plant that first appeared about 20 years ago. To date, the state and county have been very successful in curtailing the growth of this plant.
The aquatic weeds provide both good news and bad news to people who use the lake. The good news is that the weed growth supplies rich oxygen to the lake, which in turn helps the fisheries. In addition to providing cover for the juvenile fish, the weeds attract plankton and other microscopic creatures that are on the bottom of the food chain. For example, a small aquatic species called daphnia is now in the lake by the billions. Daphnia provide a valuable food source for young bass, crappie and bluegill. Daphnia also feed on blue-green algae, which has plagued the lake in the past.
The other good news is as long as there is an overabundance of weeds, there will be less of the foul smelling blue-green algae. The weeds use up the nutrients the algae requires.
The bad news is heavy weed growth chokes off entrances to the docks and harbors, making boating nearly impossible. Many of the lakeside residents weren”t able to use their boats for a good part of the summer in past years because of the weeds.
Lakeside residents are allowed to spray the water around their docks with an approved herbicide to control the weeds. However, there are certain conditions they must follow. They must first obtain a permit from the Lake County Department of Water Resources. They must also hire a state-licensed herbicide applicator. Spraying weeds isn”t cheap. Typically it will cost in the neighborhood of $1,000 or more to apply a single application of herbicide around the average dock. Often it takes several applications of a herbicide to control the weeds for the summer. Last summer there was only limited spraying. However, that could all change this year depending on the weed growth.
Many of the fishermen complain about the spaying because they claim it can kill the fish. While that”s true in some cases, in many cases there is no alternative because the heavy weed growth can close off vast areas. It”s a fine line the county has to tread.
The other method of getting rid of the weeds around the docks is by mechanical harvesting. However, the problem is that many of the weed areas also contain hydrilla, a noxious weed that the state has spent millions of dollars trying to control. If a stalk of hydrilla is cut and then drifts off, the chances are good it will re-root itself in another section of the lake. The cost of mechanical harvesting is also much higher and more work intensive than using a herbicide. The county must also give permission to do any mechanical harvesting and a permit is only given if no hydrilla has been found within a quarter mile from the desired weed eradication site.
Clear Lake is a dynamic body of water. It offers some of the best fishing in the nation and is also popular for other water sports. Coping with unwanted weeds and mussels is just another problem that we have to deal with if we want to live in Lake County.
