Rainy season could erase drought’s benefits
For months, drought eased what’s been killing the Indian River.
The region’s lack of rain reduced storm water gushing into the coastal estuary, carrying with it pollution from fertilizers, pet waste, decomposing vegetation and other sources.
“It has been a really great spring for us,” said Virginia Barker, director of Brevard County’s environmental agency, but she added, “Summer could be horrible.”
After six months of extraordinarily dry weather, the region’s annual “rain machine,” as forecasters call it, appears to be cranking up for the summer. Downtown Orlando got nearly as much rain during the past three days — 3 inches through Thursday — as during the rest of this year.
But as Barker and many other environmental officials with local governments fear, the first downpours leading to the start
of the rainy season potentially will flush a stockpile of pollution into rivers and lakes.
That nutrient-rich pollution can trigger explosive growth of harmful algae, which in turn brings on fish kills, devastation of aquatic habitats and warnings for people and their pets to stay out of waters rendered opaque or scummy.
“Algae can change sometimes from hour to hour and day to day, and we can’t tell just by looking at algae if it’s toxic,” said Julie Bortles, an Orange County environmental coordinator. “And by the time we take a sample and test it, it could be toxic and then not toxic.”
On Wednesday, the U.S. Geological Survey issued a report on the outbreak of algae in Lake Okeechobee after an extremely rainy beginning of last year.
The huge lake is nearly 100 miles south of Orlando but still receives storm water from the Central Florida region. Okeechobee ultimately drains to the Atlantic and Gulf coasts near Stuart and Fort Myers.
The agency documented that within the lake’s highly visible blooms of algae were several forms of bacteria capable of producing toxic compounds.
The likelihood of an algae bloom triggered by the arrival of a rainy season could hinge in part on the level pollution already present in a lake or river, experts say.
“Rain which occurs after a drought probably contains a large loading of nutrients, solids, and leaves, and certainly has a potential to stimulate an algal bloom,” said Harvey Harper, founder of Environmental Research and Design, a water-quality engineering company in Orlando.
However, he is not aware of studies that have examined the effects of storm water during the onset of a rainy season compared with storm water later in the season.
Lisa Henry, manager of Orlando’s storm water division, also isn’t certain what a laboratory analysis would say about pollution levels at the start of a rainy season.
To perhaps pin that down, the city expects to gather several years of data at Lake Silver in College Park to establish links between pollution types and levels, rainfall, temperature and algae blooms.
“If we can figure out what’s happening with Lake Silver, we may be able to extrapolate from there what’s going on with other lakes,” Henry said.
Just as it has done for the Indian River, drought did a favor for Orlando lakes, she said.
“As the waters have receded, trash that has been stuck on the bottom of lakes has presented itself,” Henry said. “Drought has been an opportunity to clean up shorelines.”
As for the Indian River, Barker said the estuary, which spans all of Brevard’s coast and runs for more than 150 miles in all, got so little rain that ocean tides were able to flush out some of the pollutants in the waterway.
She hopes widespread bans in Brevard on summer-time fertilizing of lawns, along with growing public awareness that lawn clippings also contribute to water pollution, will help spare the Indian River from another collapse like the one in recent years linked to manatee deaths, fish kills and die-offs of seagrass that serves as food and shelter for marine life.
If all goes well, she said, the Indian River could even enjoy a significant resurgence in coming months.
“The best seagrass years we have ever recorded were during extended drought years,” Barker said.