Blue-green algae has become part of everyday life for lakeshore residents … and they”re not happy about it. In fact, a number of people are calling upon the county to do something about it. Several town hall meetings have been held to discuss the algae situation, but there are still no answers.
The worst areas have been in the southshore near Redbud Park and Cache Creek. At times the algae has been so thick at the boat ramp at Redbud Park that many boaters are refusing to launch their boats because the algae tends to stick to the boats and get into the motors. The other problem is the stench the rotting algae gives off. It smells just like a sewer or a septic tank. In fact, in some areas along Cache Creek, homeowners are forced to keep their windows closed because of the smell.
Algae has been part of Clear Lake for thousands of years. Research shows that Clear Lake has been clear for very short periods, mainly during the winter months. Algae tends to form in April and can continue to bloom until well into October. Blue-green algae is actually a bacteria and it reproduces by photosynthesis. Adding to the confusion are the more than 100 species of algae in Clear Lake, however, not all bloom each year. For example, the species of algae that”s presently causing so much concern in the south county is lyngbya. It is relatively rare in Clear Lake.
The question just about everyone is asking is how to get rid of it? It”s much easier to prevent it from growing in the first place than trying to eradicate it after it has spread around the lake. Algae requires nutrients to grow and the best preventative method is to control the amount of nutrients flowing into the lake. Nutrients, especially phosphorus, washes into the lake from nearby farmlands and even from the hills. Low, clear water also plays a major role. This year the lake level is at its lowest in many years. This past spring the water also was very clear. These are all perfect conditions for an algae bloom.
Getting rid of the blue-green algae once it has become established is a challenging task. One of the most effective methods is by aerating the water. Spraying water on the algae mats will cause them to break up and sink to the bottom. In fact, one lakeside resident who lives in Clearlake told me he has rigged several water sprinklers at the end of his dock. He lowered a small pump into the lake which in turns feed the sprinklers. The sprinklers run 24 hours a day and he said the initial results are promising. He has been keeping much of algae away from his dock.
Another method that has proven effective in the past is to equip a pontoon boat with high-pressure water hoses and spray the algae mats. This would be a good project for the county to embrace. The county could purchase the pontoon boats and equip them. Volunteer crews could man the boats and cruise the shoreline while spraying the mats.
The rains that arrive this fall will disperse the algae. Actually, it doesn”t take much rainfall to get rid of the algae but that won”t happen until well into November.
It”s not just the south end of the lake that has algae problems. Green algae is now forming in the Lakeport area. This is considered the good algae because it supports phytoplankton, which the young fish feed on. But the nuisance blue-green algae could be just a week or two away. It all depends on how much hot weather we receive.
Whereas the algae will clog up outboard motors and foul the beaches, it doesn”t hurt the fish in the lake for the most part. An exception is back in the channels where fish get trapped and die from a lack of oxygen.
A number of people are wondering why there is so much blue-green algae in the south end of the lake and little in the north end. The prevailing winds at Clear Lake are normally west to northwesterly and they tend to push the algae to the south end. The other factor is that the north end had a massive growth of aquatic weeds this year. The weeds used up the nutrients the algae need. Now that the weeds have died off in the north end, those same nutrients will be used by the algae and there will be blue-green algae blooms.
Whether or not the algae returns next summer will be determined by the amount of rainfall we receive. If the lake level can rise to at least 8 feet on the Rumsey Gauge, there should be less algae. However, if we have another winter of less-than-normal rainfall, then the problem will surface again.
