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State of the Bays report reveals stagnating water quality despite mitigation efforts

The Center for the Inland Bays’ new State of the Bays report finds water quality in the vulnerable Sussex County watersheds hasn’t measurably improved.

The report offered a mostly bleak assessment of the health of Rehoboth Bay, Indian River Bay and Little Assawoman Bay: While pipes that once poured wastewater directly into them are all gone or mitigated, and despite ongoing efforts by Sussex County and the Delaware Department of Natural Resources and Environmental Control to replace less-reliable septic systems with sewer connections, nutrient levels remain far above healthy levels.

Agricultural runoff – namely fertilizers and animal waste – remains a substantial contributor. Both DNREC and Sussex County have worked with the poultry industry to move poultry waste further from the local watershed and to improve the use of litter as fertilizer, but report co-author Marianne Walch says other mitigation methods, including the restoration of natural forest buffers and the use of cover crops on fields, remain underused.

But Sussex County's population boom has fueled even greater challenges for the health of the bays. Residential construction along the bayshores has destroyed many forests and marshes that helped protect the bays from runoff. Since the 1990s, the bayshores area alone has lost more than 18 percent of its forested areas; that data does not yet reflect the 2020 housing construction boom in Sussex County.

Those new neighborhoods are also sources of nutrient runoff and other pollution, whether from cars or lawns, as are faulty and un-remediated septic systems at manufactured home parks along tributaries of the bays. The expanding sprawl has also required the construction or expansion of new roads, fragmenting the remaining wetlands and forests.

Sussex County Council adopted rules requiring wider buffers between new residential subdivisions and waterways in 2022, but the policies don't require forested buffers — by far the most effective at limiting runoff.

The results include more frequent fish die-offs and algae blooms, while eel grass — a crucial element of healthy bay ecosystems — no longer exists in Delaware’s bays. Report co-author Marianne Walch says Delaware’s bay grass ecosystems are in worse condition than in neighboring states.

“The center did a recent survey that found only 10.7 acres of bay grasses in total in the inland bays," she said. "That’s compared to neighboring coastal bays in Maryland and New Jersey that support thousands of acres of bay grasses.” The Center could not point to a definitive reason for the dire state of Delaware's bay grasses relative to neighboring states.

While the report identifies areas within the bays — generally further away from tributaries — where bay grasses could make a comeback, Walch notes that the Center and its partners will need to reintroduce the grasses. "We're at the point where we don't even have seed sources within the bays," she said.

Indian River Bay has especially low water quality, with six times the level of nitrogen considered healthy for a bay ecosystem — a degree of contamination that has remained essentially unchanged for decades.

The report points to some progress, including a fledgling commercial shellfish farming industry that could help improve water quality. The report also notes the discovery of previously unknown patches of bay grass in Little Assawoman Bay and stable or growing populations of some wildlife, including ospreys, blue crabs and summer flounder.

Meanwhile, the EPA plans to double funding for the Center, intending to work with local researchers to continue ongoing preservation and mitigation efforts while searching for new strategies to deal with the combined pressures of rising sea levels and sprawling development.

Center for Inland Bays Director Christophe Tulou says given the impacts of land use on the watershed, his organization will also be increasingly vocal in local and state discussions about land use reform.

“Based on what we’re learning about land use and its impact on the bays," he said, "we can and will formulate policy suggestions and advocate for those with the county, with the state or wherever it’s appropriate.”

Despite the stalled progress of water quality improvement efforts, EPA regional administrator Adam Ortiz contends that Delaware's bays aren't in a uniquely challenging position. "This story isn't uncommon," he said. "Some places are getting better, some are getting worse, but we're essentially holding the line... We've taken care of the low-hanging fruit, and we now have to take on more challenging issues."

Paul Kiefer comes to Delaware from Seattle, where he covered policing, prisons and public safety for the local news site PubliCola.