The potential impacts to coral reefs and live bottom are better understood, and project applicants now must provide “reasonable assurance” that coral reefs and live bottom won’t be harmed and that nearshore hardbottom won’t get buried without mitigation. But depending on who you ask, “reasonable assurance” is a gray area, and mitigation reefs rarely remain uncovered to achieve the specific ecological functions of nearshore hardbottom.

Bulldozer spreads sediment on Dade County surf zone. Top marine scientists and anglers decry the consequential smothering of gamefish habitat and forage.

After decades of reef degradation by dredging, DEP and other regulators now require buffer areas between the dredge sites and reefs, which are federally designated as Essential Fish Habitat and/or Habitat Areas of Particular Concern. But, there are no consistent standards, and as sand supplies shrink, regulators will likely face pressure to decrease buffer distances.

Indeed, it’s already happening. A permit issued for four Broward County borrow sites requires the dredge operator to stay only 400 feet from 1,000-year-old coral reefs that contain almost half the coral species found in Caribbean waters. Marty Seeling, DEP Environmental Administrator of the Bureau of Beaches & Coastal Systems says, “The Corps balked at 400 feet, and insisted upon only a 200-foot buffer. But we wouldn’t give in.” Still, activists who discovered a staghorn coral colony overlooked by the Corps studies say the buffer isn’t sufficient, and that the sediments will also migrate offshore and bury shallow coral reefs.

“The proposed massive dredge-and-fill project will add chronic silt, sediment and turbidity impacts to coral reefs and hardbottom already stressed by algae and pollution,” testified Dan Clark, Director of Cry of the Water, a Broward County coral reef monitoring group, before the Coral Reef Task Force.

Meanwhile, the value of nearshore reefs is becoming better understood. Nearshore hardbottom (a.k.a. worm reef or coquina reef) provides habitat to more than 530 marine organisms, including 320-plus animals. It’s home for a variety of post-larval and juvenile snappers, grunts, groupers and wrasses (e.g. hogfish), plus a variety of reef cleaners. An early paper (1989) written by Walter Nelson entitled “Beach Renourishment and Hardbottom Habitats: A Case for Caution,” wryly stated that, “Direct burial will be a terminal problem for many of the organisms that live on hard bottoms.”

Moreover, wind, waves and tides carry these sediments well beyond the seaward and longshore boundaries of the fill site, burying or scouring additional reefs, snuffing photosynthesis in algae and corals and making it harder for juvenile drums, pompano and other gamefish to see prey in the surf zone. These re-suspension events can last from hours to decades. Dr. Hal Wanless, Chairman of Geological Sciences at the University of Miami’s Rosenstiel School explains that it has do with the nature of the sediments.

“Except for shallow shoals where sediments have recently been exposed to wave energy, there really aren’t any offshore sediments suitable to place on the beach,” Wanless said. “The sediments mined offshore either ‘grew’ there or migrated there because they’re too fine to stay on the beach. Even when the grains are roughly the same size as the polished quartz beach sediments, they won’t behave the same in the surf zone. They’re hollow, angular shell fragments that have been bored into by algae and microorganisms. Once they’re placed in a high-energy environment they break apart, release fine sediments into the surf zone, and migrate rapidly along with the silt component back offshore.”

This explains why “re-nourished” beaches erode much more quickly than undisturbed beaches. It also explains the reef impacts, and, in terms of water quality, it explains why the surf zones of disturbed beaches in places such as Juno Beach, Jupiter Island, Fort Lauderdale and Longboat Key turn milky when the tradewinds blow. Most insidiously, it also points to why experienced surf anglers avoid “re-nourished” beaches, and reinforces the findings of a peer-reviewed study in North Carolina that showed an 86 to 99 percent decrease in sandfleas ( Emerita talpoidea) ten weeks post-nourishment. Subsequent monitoring showed hardly any long-term re-recruitment of this vital forage species on several repeatedly filled beaches in North Carolina, apparently “as a consequence of the poor match in sediment grade.” In a survey of 45 South Florida anglers with more than 1,100 years combined fishing experience, the majority of anglers, including three bait & tackle shop owners who sell sandfleas, said that beach-fill projects had reduced or eliminated sandfleas along Southeast Florida beaches. There aren’t any monitoring studies of beach-invertebrate impacts under way in Florida; meanwhile, emerging bonefish and permit research gives even more cause for concern for beach invertebrates.

“We now know that permit spawn year round, and that juveniles less than six inches long need windward beaches for habitat,” explains Dr. Aaron Adams, a Mote Science Foundation researcher and author of The Fisherman’s Coast. “New data also suggest that juvenile bonefish also prefer windward beaches.”

These juveniles are too small to devour sandfleas, and scientists think they’re feeding on micro-invertebrates such as amphipods. (A family of tiny, lobster-like crustaceans.)

“Flats guides in Biscayne Bay, for example, may have a real reason to be concerned about beach nourishment projects,” Adams says.

In the May issue, learn why politicians are under so much pressure to fund projects that carry a documented number of negative impacts.

[Read part II]

FS