A new study, published by University of Hawai’i (UH) at Mānoa earth scientists, is the first to provide direct evidence that tidally-driven groundwater inundation of wastewater infrastructure is occurring today in urban Honolulu, Hawai’i. The study shows that higher ocean water levels are leading to wastewater entering storm drains and the coastal ocean—creating negative impacts to coastal water quality and ecological health.
To understand the connection between wastewater infrastructure, groundwater, and the coastal ocean, the researchers used chemical tracers to detect groundwater discharge and wastewater present at each site. Radon is a naturally occurring gas that reliably indicates the presence of groundwater, while wastewater can be detected by measuring specific organic contaminants from human sources, such as caffeine and certain antibiotics.
”Our results confirm that indeed, both groundwater inundation and wastewater discharge to the coast and storm drains are occurring today and that it is tidally-influenced,” said McKenzie. ”While the results were predicted, I was surprised how prevalent the evidence for these processes and the scale of it.” This project demonstrates that actions to mitigate the impact from sea-level rise to coastal wastewater infrastructure in Honolulu are no longer proactive but are instead critical to addressing current issues. Through its multi-partner effort, the Hawai’i State Climate Commission also raises awareness around the variety of impacts of sea level rise, including those highlighted by this study.
Source: Lab Manager
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