COLORADO SPRINGS — The City of Colorado Springs has reopened Prospect Lake in Memorial park after a 12-week closure because of elevated levels of microcystin toxin, which is produced by cyanobacteria, also known as blue-green algae.
Since closing on August 9, the parks, recreation and cultural services department has worked closely with the Colorado Department of Public Health and Environment to conduct weekly water tests.
"We are thankful to community members for their patience during the lake closure and particularly pleased that the public adhered to our warnings of avoiding water contact over the last three months," said Erik Rodriguez. " Safety is our priority, and we are continuing to actively research ways to address the long-term health of Prospect Lake."
Tests returned on October 21 and 29 were both well below the acceptable recreational level for the toxin, which is 4 micrograms per liter.
Blue-green algae are a type of bacteria common in lakes throughout Colorado. When conditions are right, blue-green algae multiplies quickly. Those conditions include sustained hot weather, stagnant water, and polluted stormwater runoff.
These conditions result in too much nitrogen, potassium, and phosphorus in the water. This causes the harmful bacteria to grow faster than the ecosystem can handle. The increased bacteria harm water quality, decrease the amount of oxygen available to animals living in the water, and can produce a toxin that is harmful to humans and pets.
Blue-green algae are self-limiting, naturally-occurring bacteria, which means it eventually phases itself out of bodies of water.