Stormwater Ponds Protect While Contributing to Climate Change
New research from the University of Florida shows that stormwater ponds -- man-made stormwater systems to help manage flooding and filter runoff before reaching waterbodies -- are a major source of greenhouse gas emissions. While these ponds can serve as ecosystems for local wildlife, this new study suggests their effects on climate change may outweigh their benefits.
Wes Taylor Engineering: Stormwater Management Ponds, September 21, 2021.
Poseidon Ponds & Landscaping: What is a Detention, Retention and or a Stormwater Pond?, April 21, 2021.
Why This Matters
Stormwater ponds are the most commonly used stormwater systems in the US. In Florida, there are over 76,000 across 260 square miles. These systems certainly help mitigate the effects of climate change by lessening storm surges and absorbing rainwater from increasingly extreme hurricanes. At the same time, these ponds serve as a reminder that local governments should opt for climate change mitigation measures that don’t make the problem worse.
Organic matter like leaves, algae, and manure build up on the bottom of these ponds, and as they decompose, they release methane and carbon. Moreover, stormwater ponds with higher acidity allow more carbon to escape from the water.
"This research highlights the need for effective balancing of competing environmental needs and for constant incorporation of new findings into urban planning processes,” said Fara Ilami, the Regional Resiliency Manager for the Northeast Florida Regional Council, to News4Jax.
Practical Engineering: Where Does Stormwater Go?, November 3, 2020.
Maintaining The Dilemma
While there are recommendations for how to best maintain stormwater ponds, many of these actually may make the problem worse. For example, dredging and the use of pesticides and algaecides kill photosynthesizers in the water that can convert CO2 into oxygen. Worse, dead algae will reduce the pond’s oxygen, which will increase the amount of methane emitted, an even more potent greenhouse gas.
"I think what we’re advocating for really in this research is for the climate science and the carbon science community to recognize that these ponds can definitely be huge sources of greenhouse gases,” Mary Lusk, assistant professor in the Soil and Water Sciences Department at UF, tells Jacksonville Today. [We] ought to include those in our models of statewide and regional, and even global carbon cycling so that we can better constrain how carbon is cycling in our urban environments.”