High temperatures and wet weather have combined to create large algae blooms on Lake LBJ.

The naturally occurring blue-green algae Lyngbya has become a problem for some lakeside owners in the last few weeks. The algae produce large mats and are fed by nitrogen and phosphorous that was washed into the lake by the heavy spring rains, according to LCRA water quality experts.

Lyngbya (pronounced ling-bee-ya’)produces a sulfur-like odor as it decomposes. Late summer and spring are peak growing seasons for algae, and it is expected to remain until the weather cools.

Residents can manually remove the algae with rakes and add it to compost piles. However, prolonged contact with Lyngbya can cause a rash, so take the proper precautions to minimize exposure to skin. 

Residents also can treat the algae with copper-based algaecides, which can be purchased at gardening or feed stores. Some common brands are Nautique, Cutrine Plus, Komeen and Clearigate.

These products must be used as specified on their labels and should not be overused. It takes a week to 10 days for results to become evident. The best time to apply the algaecide is during the spring and summer active growing season. For more information on algae see http://aquaplant.tamu.edu/database/algae/filamentous_algae.htm.

Nitrogen and phosphorous are nutrients that are typically used in lawn fertilizer. They feed algae blooms after being washed into waterways. To help decrease the severity of such blooms in the future, residents and landowners in the watershed should avoid over-fertilizing lawns and avoid dumping lawn clippings in the lake.

"Lake LBJ is a relatively small lake with a large watershed," said LCRA Senior water Quality Coordinator Jerry Guajardo.  "This means there’s a lot of potential for the rain to pick up nutrients and wash them into the lake.

Lyngbya, a naturally occurring blue-green algae, feeds off nutrients found in common lawn fertilizer. These nutrients can be washed into water bodies by rain.