FFing Duo
12-06-99, 11:03 AM
Chattahoochee's trout may fall victim to runoff
Hot storm water from roofs, asphalt makes river too warm for its own good, state says.
Julie Bryant - Staff
Monday • December 6
Hot water running off scorched roofs and asphalt during the summer is raising the temperature of the Chattahoochee River and endangering the river's fish population.
Preliminary results of a state Department of Natural Resources study have connected storm water runoff to sudden increases in the river's water temperature, a phenomenon that could threaten the Chattahoochee's reputation as a year-round playground for anglers.
The overall health of the river also is at stake.
"We're looking at quite a warm river," said Lisa Klein, a DNR biologist.
In May, researchers dropped thermal sensors in seven spots along the river, from Buford Dam in Forsyth County to Peachtree Creek in south Fulton County.
Since retrieving the gauges in October, biologists piecing together data have concluded that unless something is done to control storm water runoff near the banks of the Chattahoochee, parts of the river may soon become seasonal habitats, if they are left with any fish at all.
"There's too many people and too little water," said Roy Burke, environmental engineer for the state Environmental Protection Division. "There's too much unrestricted growth and too much activity on the watersheds, and that affects river temperatures."
Rapid development near and along the river's banks has produced greater quantities of runoff as impervious surfaces --- such as roads, parking lots and shingles on houses --- increase.
During the summer storms, rain hits those surfaces, which have been heated in the summer sun. The runoff makes its way downhill, eventually introducing a flash flood of warm water into the Chattahoochee.
Trout living in the river cannot survive the tumultuous changes in temperature, Klein said. "Once the water reaches a certain temperature they will die," she said. Steady summertime temperatures can range from 50 to 70 degrees Fahrenheit, depending on location. One spike cited by Klein showed a nine-hour increase from 63 degrees to nearly 81 degrees.
DNR researchers programmed cigar-length thermographs to record water temperatures in the river every hour for a four-month period.
Klein said she expected to find temperature spikes below Morgan Falls Dam, where water coming all the way from Lake Lanier has time to heat up on its own. What she didn't expect to see were significant jumps in temperature above Morgan Falls Dam, as high up as the Jones Bridge Road area.
"That section of the river is served by Lake Lanier water releases," she said. The water typically comes from the bottom, which is the coolest portion of the lake, as it passes through Buford Dam.
"Spikes in that area indicate a source like a stream that's allowing storm flow to come in, which means there are probably a lot of impervious surfaces in the area," Klein said.
The DNR stocks the river with thousands of dollars' worth of fish each year. Losing the fish would mean losing money and losing a valuable tourist draw, not to mention some of the natural beauty of the Chattahoochee. Trout also act as natural indicators of the waters' health.
"It's kind of like canaries in a mine," Burke said. "Trout are sensitive fish. If they can live in the water, you know it's clean."
Since Buford Dam was built more than 40 years ago, the section of the Chattahoochee now being scrutinized has been kept clean and cool enough to allow fish to reproduce naturally, something seldom seen in stocked waterways.
But unrestricted growth will end that, Klein said. Year-round fishing on the river will rapidly become a thing of the past, replaced by seasonal fishing only.
Burke said developers argue that sustaining fish in the Chattahoochee is an unreasonable expectation, given current growth trends. But storm water runoff brings more than heat into the river, Klein said --- it also carries sediment and other pollutants. In recent years local governments have spent more money on filtering the increasingly cluttered waters.
"People should be concerned about whether the river can hold trout," Klein said.
-------------------------------------------
AJC Newspaper Online brought to you in partnership with AccessAtlanta
© 1999 Cox Interactive Media
Hot storm water from roofs, asphalt makes river too warm for its own good, state says.
Julie Bryant - Staff
Monday • December 6
Hot water running off scorched roofs and asphalt during the summer is raising the temperature of the Chattahoochee River and endangering the river's fish population.
Preliminary results of a state Department of Natural Resources study have connected storm water runoff to sudden increases in the river's water temperature, a phenomenon that could threaten the Chattahoochee's reputation as a year-round playground for anglers.
The overall health of the river also is at stake.
"We're looking at quite a warm river," said Lisa Klein, a DNR biologist.
In May, researchers dropped thermal sensors in seven spots along the river, from Buford Dam in Forsyth County to Peachtree Creek in south Fulton County.
Since retrieving the gauges in October, biologists piecing together data have concluded that unless something is done to control storm water runoff near the banks of the Chattahoochee, parts of the river may soon become seasonal habitats, if they are left with any fish at all.
"There's too many people and too little water," said Roy Burke, environmental engineer for the state Environmental Protection Division. "There's too much unrestricted growth and too much activity on the watersheds, and that affects river temperatures."
Rapid development near and along the river's banks has produced greater quantities of runoff as impervious surfaces --- such as roads, parking lots and shingles on houses --- increase.
During the summer storms, rain hits those surfaces, which have been heated in the summer sun. The runoff makes its way downhill, eventually introducing a flash flood of warm water into the Chattahoochee.
Trout living in the river cannot survive the tumultuous changes in temperature, Klein said. "Once the water reaches a certain temperature they will die," she said. Steady summertime temperatures can range from 50 to 70 degrees Fahrenheit, depending on location. One spike cited by Klein showed a nine-hour increase from 63 degrees to nearly 81 degrees.
DNR researchers programmed cigar-length thermographs to record water temperatures in the river every hour for a four-month period.
Klein said she expected to find temperature spikes below Morgan Falls Dam, where water coming all the way from Lake Lanier has time to heat up on its own. What she didn't expect to see were significant jumps in temperature above Morgan Falls Dam, as high up as the Jones Bridge Road area.
"That section of the river is served by Lake Lanier water releases," she said. The water typically comes from the bottom, which is the coolest portion of the lake, as it passes through Buford Dam.
"Spikes in that area indicate a source like a stream that's allowing storm flow to come in, which means there are probably a lot of impervious surfaces in the area," Klein said.
The DNR stocks the river with thousands of dollars' worth of fish each year. Losing the fish would mean losing money and losing a valuable tourist draw, not to mention some of the natural beauty of the Chattahoochee. Trout also act as natural indicators of the waters' health.
"It's kind of like canaries in a mine," Burke said. "Trout are sensitive fish. If they can live in the water, you know it's clean."
Since Buford Dam was built more than 40 years ago, the section of the Chattahoochee now being scrutinized has been kept clean and cool enough to allow fish to reproduce naturally, something seldom seen in stocked waterways.
But unrestricted growth will end that, Klein said. Year-round fishing on the river will rapidly become a thing of the past, replaced by seasonal fishing only.
Burke said developers argue that sustaining fish in the Chattahoochee is an unreasonable expectation, given current growth trends. But storm water runoff brings more than heat into the river, Klein said --- it also carries sediment and other pollutants. In recent years local governments have spent more money on filtering the increasingly cluttered waters.
"People should be concerned about whether the river can hold trout," Klein said.
-------------------------------------------
AJC Newspaper Online brought to you in partnership with AccessAtlanta
© 1999 Cox Interactive Media