Improving our Waterways

Prospect Park Alliance

Innovate

As part of a pilot program, Prospect Park Alliance constructed natural filtration systems called ecoWEIRs beneath the Long Meadow and also next to Fallkill Falls, where the park's watercourse begins. This is to test out how the weir performs beneath turf versus native grasses found in the park's woodlands. Both weirs collect water from Fallkill Falls then filter the water prior to sending it through Dog Beach to the rest of the watercourse.

Through a grant from the New York State Office of Parks, Recreation and Historic Preservation, Prospect Park Alliance is undertaking an innovative pilot program aimed at reducing toxic blue-green algae blooms and improving the quality of Prospect Park's watercourse.

While Prospect Park is a natural wonderland, many people are not aware that its lake, pools, streams and waterfalls were all constructed as part of the creation of the park, and fed by the 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. 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.

This pilot project will enable the Alliance to create a filtration system-known as an ecoWEIR-at this location, where city water enters the watercourse. The aim of this system is to reduce phosphates, thereby reducing excessive algae growth. Working in partnership with Brooklyn College, the ecoWEIR will be monitored over the course of multiple seasons to determine its success. If successful, the Prospect Park ecoWEIR project will be replicable in parks nationwide.

The ecoWEIR filters water underground and uses plants grown on top to absorb excess nutrients. The system contains and holds the water on a timed, 24-hour cycle, and then it is released via a smart sensor. The weir contains gravel and sandy soil at the bottom, creating a reservoir to collect water, followed by a top layer of well-drained sandy soil. Native grasses are then planted in the top sandy soil layer, with their roots tapping into the bottom layer of stored water, minimizing the need for watering or irrigation. The water saturated soil in the bottom layer naturally undergoes an anaerobic process that removes the excess nutrients that can be absorbed by the plants.

Prospect Park Alliance is the non-profit organization that sustains, restores and advances Prospect Park for the benefit of the diverse communities we serve. We provide critical staff and resources that keep the park green and vibrant.

Learn more at prospectpark.org/ecoweir.

Submitted by @lampbane