When a tipster told Miami Waterkeeper that a leaky sewage pipe was spewing human waste right into Biscayne Bay, the environmental organization wasted no time sending a diver to investigate. Sure enough, they discovered the pipe was blasting the bay with thousands of gallons of harmful waste.

But the worst was yet to come: After finding the leak, the group's executive director, Rachel Silverstein, was appalled to learn the county had known about — and ignored — the problem for a whole year.

"Part of our organization's mission is to empower citizens to protect their own water," she says, "so I think it's particularly egregious that a citizen made this report and that they were ignored."

Silverstein was raised on the opposite coast in San Diego, where she grew up going on field trips to the beach and taking scuba-diving lessons with her dad. With a passion for marine life, she left Columbia University with a degree in environmental biology and moved to Miami in 2007 to study how coral reefs were being affected by climate change.

A decade later, Silverstein is now one of the county's only watchdogs protecting the local water supply and the ecosystems within it. In recent years, she's lobbied the Florida Legislature to stop the state from loosening clean-water regulations and successfully sued the U.S. Army Corps of Engineers for killing coral with sloppy dredging at PortMiami. After learning of the sewage leak earlier this year, she also plans to take the county to court to demand a full inspection of the aging three-and-a-half-mile pipe that pumps human waste into the ocean.

"Another issue that we uncovered as we were looking into this leak was that the sewage outfall pipes had not been inspected in over a decade," Silverstein says. "So it's highly likely there are more leaks."

Despite having a pint-size staff (until last year, Silverstein was the only paid employee), Miami Waterkeeper has big plans to tackle sea-level rise, sewage dumping, and even FPL's Turkey Point nuclear power plant, which the group says has contaminated the Biscayne Aquifer. And for Silverstein and her staff, punching above their weight has never been more important.

"There's a huge need for this kind of environmental conservation and advocacy work in this region," she says. "We have such a unique and fragile environment, and it's such an important part of why people live here."