HRWA Builds Scientific Muscle

By Peter Jordan

"Rather than love, than money, than fame, give me truth." 
Henry David Thoreau, Walden.

"Be it life or death, we crave only reality," says Thoreau in Walden, proposing to erect a "Realometer" to find a "solid bottom" and separate fact from the "mud and slush of opinion."

Creating "realometers" is perhaps the most important mission of the Harpeth River Watershed Association. Since its founding in late 1999, the conservation organization has brought a solid foundation of scientific research to the policy table in Middle Tennessee. Until then, no one had more than opinion and personal observation to back up their sense that the river was under strain and getting worse in places, nor enough information on which to build plans for making things better.

River-lovers had observed subjectively that the Harpeth and its tributaries seem to be muddier and smellier, drier in summer and more likely to flood in winter and spring, but it took the HRWA team of scientists, technical advisors, and volunteers to put existing data together with new research in order to begin drawing an accurate and objective picture of the river's health.

The HRWA began analyzing United States Geological Survey (USGS) water flow data from the Harpeth going back to the 1920s, water quality sampling done by the Tennessee Department of Environment and Conservation (TDEC) to generate its list of impaired streams, recent field work by the United States Environmental Protection Agency, and HRWA's own research projects, to determine what is needed to improve degraded areas of the Harpeth. Some of the data has only been collected in the last year or two, some as a result of law suits against the Lynwood sewage treatment plant and other state issues.

Believing, as Thoreau did, that "Any truth is better than make-believe," HRWA has built a solid portfolio of scientific facts about the condition of the Harpeth and its tributaries. Whether measuring how much dirt floats down the river (the sediment study), observing the impact of development (the visual stream assessment), measuring whether the river has enough dissolved oxygen for fish to survive, assessing the level of threat from lead in the river, or studying how fast our streambanks are disappearing, HRWA is finding out first hand about the status of the watershed ó and forming plans and suggesting ways to improve its health.

Liquid Mud?

As reported in last year's newsletter, the sediment study conducted in partnership with the Cumberland River Compact (CRC) yielded a 'dirty picture' of many subwatersheds, with high levels of turbidity (dirt in the water) caused by stormwater runoff, faulty erosion control on construction sites, and agriculture and lawncare practices. Designed by Dave Wilson (see the Volunteer Profile on page 9) and a team of experts with the USGS, TDEC, and the state's Nonpoint Source Program, the study combines their expertise with hundreds of man-hours of river-loving volunteers, who went out to 46 different locations, hanging off bridges over rain swollen rivers as well as went out in storms to take 1,050 water samples at all hours of the day and night.

A Raft of River-Rats

The sediment study underscores the importance of taking careful precautions as Middle Tennessee continues its rapid development. But beyond the data actually collected, the sediment study is important because of its methodology. The combination of volunteer samplers willing to get cold, wet, and muddy plus the scientific and number-crunching expertise of the project's leaders can be duplicated in future research projects here and in other watersheds.

"The sediment study shows how to take the scientific and technical expertise of people like Dave Wilson and John McFadden and exponentially multiply the brainpower, using trained volunteers to do the testing and collect the samples," says Dorie Bolze, HRWA executive director.

Where is the Habitat?

The visual stream assessment study leveraged brainpower as well. HRWA staff trained volunteers to look for sixteen significant environmental benchmarks at 217 different sites. Eight of the benchmarks were quantified, so the volunteer observers could give each site a numeric score in addition to photographing the conditions (and over 800 photographs were taken!). They identified 48 sites with serious water quality related problems.

ìIf natural resource agencies had done this assessment with tax dollars and professionals, they would have spent countless dollars surveying the Harpeth watershed streams to identify polluted sites,"  says Bolze. "Our volunteers not only helped identify the worst problem areas in the watershed, they also showed how natural resources managers can work with HRWA to use their limited staff time more efficiently. Our volunteers spent more than 550 hours on this project alone. If it weren't for volunteers, our research projects would be prohibitively expensive."

Death by Suffocation?

Like people, fish and other aquatic life need oxygen to survive. Dissolved oxygen (DO) levels are highest in shallow, turbulent, cool waters, while the oxygen levels decrease in deep water and in areas where bacteria and algae consume the oxygen.

"High numbers of bacteria and algae can use up all the oxygen in the water, causing fish and other aquatic life to suffocate," explains Dave Wilson, one of the designers (with Rick Lockwood and John McFadden) of "The Harpeth River Mainstem Dissolved Oxygen Study" completed in the fall of 2002. "A DO study is like taking the pulse of the river's health. It gives us an idea of the river's resiliency and its ability to overcome certain types of stress."

As a result of this work and the EPA's, TDEC added the section of the main Harpeth from Franklin to Cheatham County where the clean south Harpeth comes in to the 2002 list of impaired streams.

Unfortunately, this river stress test sets off some environmental alarm bells. At five of the six sites tested, DO levels were "low on oxygen and potentially harmful to river life," says Wilson. "The Harpeth River is under the influence of many factors that can lead to low DO conditions harmful to aquatic health," says Wilson. "The river receives excessive nutrients from waste water treatment plant effluents, suburban runoff, and agricultural runoff. It also has long unshaded stretches lacking riparian vegetation and many deep sections with poor aeration."

But the river isn't terminal, according to our environmental cardiologists. Anyone with a creek (even a dry one) in or along their property can get those aquatic arteries flowing more effectively by restoring a vegetation buffer. Planting trees or shrubs, not mowing, limiting livestock access, and other options will restore a buffer along the stream that will provide critical shade and a filter. The most significant finding of the visual steam assessment was that over 100 sites had severely degraded "riparian" (streambank) zones or none at all.

Losing Ground?

Meanwhile, HRWA initiated yet another study, this one on streambank erosion. More than 30 volunteers have signed up for a year-long study of the rate of erosion in the watershed, committing to visit sites near their homes six to eight times during the year to measure how fast the streambanks are disappearing into the flow of the rain-swollen Harpeth or one of its tributaries. Designed by McFadden and Wilson, the study complements the sedimentation study, examining the streambank erosion responsible for much of the sedimentation.

"Because of erosion, landowners are losing property, and the river is losing important habitat,"  says Wilson. "With this study, we hope to get an objective measurement of this process and to suggest where to focus efforts to minimize erosion."

A key focus for HRWA is suggesting how to design developments to reduce runoff, by encouraging rainwater to soak into the ground rather than running off into the nearest drain and flooding the watershed. New federal stormwater regulations affecting much of the Harpeth River watershed require cities and counties to reduce pollution and flooding from stormwater runoff. HRWA is also bringing in collaborators and providing expertise on how to devise land use plans that have water quality goals as a purpose.

But we can't do anything effective about problems like stormwater until we know the facts. HRWA's field work has been critical to obtaining and analyzing this 'on-the-ground' information. Now HRWA can form strategies to restore degraded areas and protect healthy sections. HRWA's research projects are helping the people of Middle Tennessee discover how their river system works and what they can do to protect and restore it.

-From Voices for the Harpeth, Fall 2003