TAMPA — If you looked up and down the Hillsborough River in the 1980s, you would have seen much of the shoreline reinforced with vertical walls built in an attempt to stave off erosion or, in some cases, as a convenient place to park a boat.
Back then, little thought was given to how pollutants such as motor oil, pesticides and fertilizers were impacting the river's health. Those pollutants can harm fish and wildlife and foul water quality.
But as the Hillsborough River plays an ever greater role in the growth of downtown Tampa, the challenge of keeping it healthy is more important than ever.
And that can be difficult, said Shawn College, team leader for the Hillsborough City-County Planning Commission, who spoke Tuesday at a Tampa Downtown Partnership panel that discussed the river's role in the region.
"Vast areas of the river are surrounded by developed areas, like neighborhoods, where water washed from the roads finds its way into storm drains without treatment," said College, who also is executive director of the Hillsborough River Board. "Little by little, the City of Tampa has been trying to address that issue, but it's a big issue to tackle."
Since much of the land around the river was built before modern stormwater rules were implemented, it's difficult to make those improvements, College said. That's why areas that are seeing recent development, such as the new Julian B. Lane Riverfront Park, are seeing stormwater upgrades.
Instead of vertical seawalls, the park uses enhanced seawall techniques such as planting aquatic vegetation, which helps to filter out pollutants. Planners also installed layered rocks, known as rip raps. These are broken, recycled concrete or limestone that helps cover exposed soil, which protects shoreline erosion while providing a semi-natural habitat for fish and wildlife.
When it can, the city also installs what is known as baffle boxes along the river, which are concrete or fiberglass structures that remove sediment and suspended particles. These boxes also contain trash screens that collect garbage and other larger material.
"Any additional vegetation or change to help mitigate pollutants entering the river is a good thing," said Sam Elrabi, the director of water management at the Hillsborough County Environmental Protection Commission. "Some are better than others, but on a small scale, any interceding technique can help the quality that winds up in the river itself."
The EPC monitors point-source discharges directly into the water and does not regulate stormwater permits. However, Elrabi said water quality has improved in the last 20 years, and is much better than nearly 40 years ago, when less water reached the lower Hillsborough River near the downtown area, causing the water to be stagnant.
In 2007, the city and the Southwest Florida Water Management District, which regulates water use in the region, reached an agreement on a plan to restore the lower river's ecosystem by pumping water to the river from various springs, including Sulphur Springs and the Blue Sink area, as well as the Tampa Bypass Canal.
The project also modified an existing dam and pumping station to manage the minimum daily water flow from the springs off Nebraska Avenue, to the base of the dam at Rowlett Park.
That project, College said, drastically improved the health of the river.
"The river is healthy right now, but there are always opportunities for improvement," College said. "We are seeing manatees, dolphins all the way to the upper part of the river, near the dam. So the major issues have been addressed. Now it's time to get the low-hanging fruit."
Contact Tim Fanning at email@example.com. Follow @timothyjfanning.