Below is the response we received after discussing the increasing algae issue with our lake management company. We have taken their advice and the fountains will now turn on at 4am until lake levels return to normal. Protecting aquatic life and fishing resources for our residents is the primary concern. If a drought continues, we will stay in contact with the vendor for any further recommendations.
“The lack of rain, high air and higher than normal water temperatures for this time of year, and lower than usual lake levels we are currently seeing produce ideal conditions for algae to grow and grow rapidly. With the lack of rain to fill the lakes back up and the falling lake levels, more and more shoreline that has not been exposed is now receiving more sunlight than it has in a while. With more and more shoreline becoming exposed this is the perfect place for algae to grow. These new parts of the shoreline that are being exposed are loaded with nutrients from decaying plant material that has been previously sprayed. Once the sunlight is consistently hitting it, it promotes algae growth in a big way. Along with that and the high temperatures, algae thrives in shallow waters and will grow rapidly. To add on to the low lake levels, there is only so far the lake can drop before the entire lake bed is able to receive sunlight in which case again more algae will grow. So you can see how with falling lake levels it becomes a compounding factor for potential algae growth. So the short answer is yes, we are experiencing high algae growth from factors that are out of our control. The only thing we can control is how much we treat and how often.
Currently we are spraying/broadcasting algaecides every visit we are on site, and the treatment usually takes effect within 3-4 days and about a full week for the algae to begin to dissipate. There is a thin red line in the treatment process though that we are very aware of and that is we can only treat each lake so much. EPA/TDA regulations only allow us to use a certain amount of product per lake depending on size. So in some cases we cannot use enough product to effectively treat all vegetation/algae that is present and this is for a good reason. If we were to treat each lake with the amount of product that was needed to effectively treat all vegetation/algae, it could cause a dissolved oxygen crash which is detrimental to aquatic life. How this happens is, it is not the amount of product you use, it is the amount of vegetation/algae you treat. What causes the dissolved oxygen to crash is from after the vegetation/algae is treated, it begins the decay process. Through this decay process, the microorganisms and bacteria in the water responsible for the decay uptake dissolved oxygen in the process. So in turn the more decaying matter you produce, the more dissolved oxygen that is taken from the water and this process happens pretty quickly. This rapid uptake of dissolved oxygen for the decay process with all other aquatic life up taking dissolved oxygen causes the levels to plummet. This virtually suffocates fish which in turn causes fish kills. The fountains in the water certainly do help as they are constantly adding dissolved oxygen into the system, but currently the fountains turn off at night. The issue there is that dissolved oxygen levels are constantly falling throughout the night. Without sunlight, all of the aquatic species and plants that produce D.O. throughout the day are no longer supplying it into the water. This coupled with the fountains being off there is no D.O. supplied. Add in the elevated usage of D.O. from the decaying material along with the aquatic species, and there is the perfect storm for a D.O. crash and ultimately a fish kill. The D.O. levels are at their lowest points just before the sunrise. This issue can be alleviated by turning the fountains on earlier in the morning (around 4-5am). By turning them on earlier in the morning this will jump start the D.O. levels rising back up to prevent the dangerous low levels of D.O.
Another factor here is we are only out for maintenance every two weeks. So after we treat and the algae that was treated falls out within a week there is already new algae beginning to grow with these ideal conditions still present. So by the time we come back out for our next visit, there is already new algae growth present. Algae issues are not uncommon because this is Texas and it is always hot in the summers. Typically during the summers, algae can grow within 3-4 days so you can see how quickly this problem can take over. The big problem is that we haven’t had any significant rain since April. In the previous years we have had significant rainfall up to this point which keeps the lakes full to prevent a lot of shoreline exposure where algae likes to grow, helps lower water temperatures, and also if the rain event is significant enough can just purely wash algae out of the system from storm water flow.”