By Catawba Riverkeeper Brandon Jones

Harmful Algal Blooms (HABs) are dense blooms of toxin producing cyanobacteria capable of harming humans and warm blooded animals (usually dogs or livestock). They are increasing in frequency across the central and southern Catawba Basin. This is due to several factors including longer warmer summers, increased nutrient runoff, and better monitoring/reporting. Not all blooms are capable of producing toxins, and those that are capable don’t always produce them in dangerous concentrations. However, because of the ephemeral nature of blooms and the time required to test samples, we recommend treating all blooms as hazardous.

Please avoid swimming and keep your dogs out of bright green or discolored water.  

Boyd’s Cove Lake Wylie, August 5
Sample collected by Charlotte Mecklenburg Storm Water Services

There are currently two confirmed HABs in the watershed. Last week a bloom of Microcystis was identified in Boyd’s cove on Lake Wylie. The bloom was of sufficient size and density that Mecklenburg County issued a swim advisory for the entire 100 acre area. The cooler weather and rain will cause it is to dissipate, but residents should remain watchful when warm weather returns. In Lake Wateree a bloom of Microseira (formally known as Lyngbya) has been present in many coves for several years. Unlike most other HABs, it is benthic, growing in mats on the shallow lake bottom. In our region, phosphorous is usually the limiting factor algal growth.  

Catawba Riverkeeper, Charlotte-Mecklenburg Storm Water Services, Duke Energy, NC DEQ and SC DHEC all monitor blooms in their jurisdictions. Unfortunately, once active there is little that can be done except public warnings. In addition to public education, we advocate for policies which limit nitrogen and phosphorus runoff.

You can learn more in our recently released HAB Report.  

Learn more about HABs and what to do if you see one.