Our Executive Director, Rachel Silverstein was interviewed by CNN about sea level rise and pollution threats. Sea-level rise is already impacting Miami by way of flooding, ecosystem and habitat loss, and saltwater intrusion. Sea-level rise is also impacting our wastewater infrastructure -- including our sewage system and many backyard septic tanks.
Miami-Dade County recently released a report regarding sea level rise. As sea levels rise, groundwater levels also rise. Many areas will experience groundwater levels within half a foot of the surface more than 25% of the year by 2040. Septic tanks require a layer of dirt underneath them in order to allow for proper filtration of septic effluent. Older regulations required only a foot of soil, but newer regulations require about 2 feet of soil. Rising groundwater makes the dirt layer beneath the septic tank soggy, and wastewater doesn't filter the way it's supposed to with wet soil beneath the septic tank. In some cases, the wastewater can flood a homeowner's yard with fecal matter. High tides or heavy rains can push feces-filled water elsewhere, such as down storm drains which lead to nearby waterways or Biscayne Bay. Nutrients from this wastewater can contribute to algae blooms which can have detrimental effects for seagrasses, fish, and coral reefs.
The Miami-Dade County report shows that by 2040, under some sea level rise projections, 64% of county septic tanks (more than 67,000) could have issues with inadequate filtration or surface level flooding every year. This will not only cause problems for the people who rely on septic tanks for sewage treatment, but could also create issues for the region's drinking water supply and the health of anyone who might wade through flood waters.
Sea level rise affects water quality in other ways as well. It increases stormwater runoff, which can transport pollutants and harmful contaminants into nearby bodies of water. Sea level rise also impacts our groundwater, increasing the likelihood of saltwater intrusion into our drinking water aquifer and making less potable water available to us for drinking over time. Preparing for sea level rise requires a holistic approach; we will have to work to make our wastewater infrastructure, energy infrastructure, and other systems more resilient while protecting our waterways, our ecosystems, and our communities.
A big thank you to CNN for featuring our work on the ground in Miami. We look forward to sharing the final piece with our supporters soon. For more information about our work in the resiliency space, please visit https://www.miamiwaterkeeper.org/sea_level_rise_ready