Martin Seck

Prospect Park Alliance Tackles Toxic Algae Blooms

November 18, 2019

Prospect Park Alliance has begun construction of natural filtration system, known as an ecoWEIR, to reduce toxic blue-green algae blooms and improve the water quality of the park’s waterways. This innovative pilot program, the first in an urban park, is funded by the New York State Office of Parks, Recreation and Historic Preservation through a $390,000 grant.

While the Park is a natural wonderland, many people are not aware that Prospect Park’s lake, pools, waterfalls and streams are fed by the New York City water supply. Phosphates in the water, which make it safe for us to drink, lead to excessive algae growth. This algae growth limits resources for other plant life and wildlife, which is detrimental to the health of the Park’s waterways.

Phosphates in the water also produce blooms of blue-green algae, or cyanobacteria. Certain types of cyanobacteria produce toxins that can pose a health risk for humans and animals. Skin contact can cause rashes or eye irritation, while ingestion can cause more serious effects. These blooms have led to closing areas of the Prospect Park Lake that were previously available for dogs to swim due to concerns over exposure.

The Alliance is installing ecoWEIRs at two locations in the park, near Dog Beach (where city water enters the watercourse). The aim of this system is to reduce phosphates, thereby reducing excessive algae growth. The filtration system and its results will be monitored over the course of multiple seasons to determine if the pilot study is a success. In addition to enhancing the health and resilience of the Prospect Park Lake, this project provides an opportunity to educate the public about water health. If successful, the Prospect Park ecoWEIR project will be replicable in parks nationwide. 

Construction is slated to be completed in 2020.

Learn more about the project in this in-depth article on Gothamist.