In late August, 2013, a bright green scum became visible on the water surfaces at Lake Needwood and Lake Frank. This is the result of a very dense ‘bloom’ of single-celled plants called algae. This particular algae thrives in hot, dry weather and in waters which have high amounts of nutrients (i.e. fertilizers).
According to the Maryland Department of Natural Resources, “Some strains of Microcystis may produce toxins that have been reported to result in health problems to animals that drink the water, and minor skin irritation and gastrointestinal discomfort in humans that come in contact with toxic blooms.”
Montgomery County Parks has posted bright yellow warning signs for visitors to these recreational areas. Residents should not drink or touch the water, nor swim or wade in areas where this bright blue-green bloom is evident, and should keep children and pets out of these areas. If contact is made, wash off with plenty of fresh water. The signs are temporary until the algal problem is resolved.
To find out the status of the current bloom and the Parks recreational facilities, contact Parks at 301-495-2595.
The algae that is the cause of concern in Lake Needwood and Lake Frank is a commonly found species in Montgomery County. The size of the algae population is typically held in check by natural factors such as temperature, nutrient level (food for algae) and rain levels. In the summer and early autumn months, especially after minimal rainfall, algae can grow beyond safe levels and can cause the issues we’re finding in the two lakes.
A fact sheet on this type of algae can be found here.
Human activity contributes to the frequency of algal blooms. We can all do our part so as to minimize the occurrence of algal blooms in our local lakes as well as the Chesapeake Bay tributaries.
Stormwater management practices, especially ponds, can occasionally see algae growing on the water, or in rare instances, algal blooms. This is most common in the summer months. If you are concerned about the algal level in your stormwater practice, first consider the following questions before taking further steps.
Contact the Montgomery County Department of Environmental Protection with further questions about your stormwater management practices at firstname.lastname@example.org