POLO LAKE PHOSPHORUS
TREATMENT PROJECT

In 2022, Polo Lake in Roger Williams Park underwent a phosphorus inactivation treatment using Phoslock, a natural product that binds with free nutrients, helping reduce phosphorus levels in water to limit algal blooms. Eutrophic ponds like Polo Lake, rich in nutrients, often experience harmful algal blooms (HABs), which can impact water quality and aquatic life. Phoslock aims to trap phosphorus in the lake's sediment, curbing excess algae growth.

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To monitor the treatment’s impact, water samples were taken from four locations in Polo Lake. Parameters measured included total and dissolved phosphorus, total nitrogen, water clarity, temperature, and chlorophyll, an indicator of algae. Although initial post-treatment results showed slight reductions, nutrient levels did not stay low, possibly due to factors like stormwater inflow, carp disrupting sediment, and the lake’s aeration fountain, which can reintroduce nutrients into the water.

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Despite these challenges, the project provided essential insights into managing nutrient levels in urban ponds. Continued efforts and complementary strategies may be necessary to fully address the factors contributing to nutrient enrichment and HABs in Polo Lake.