If they give it much thought at all, most people dismiss the creeks and streams meandering through their local landscapes as little more than bucolic backdrops to their daily lives.
Jason Hubbart knows it’s more complicated than that. Much more complicated.
The flow of these countless streams is like the Earth’s life support system, says Hubbart, a watershed expert and assistant professor of forestry who specializes in hydrologic processes and water quality. “We could think of it as a peripheral circulatory system of the planet,” he says, “a little bit like our own circulatory system—the way we humans transport nutrients and other essential elements throughout our bodies.”
That’s an important metaphor for streams and rivers, because this powerful global transportation system doesn’t just lug around the good stuff, such as nutrients to feed aquatic flora and fauna. Streams can also carry pollutants that threaten those same plants and animals.
“If you want to check on a person’s general health, what’s the first thing the doctor wants to do? Take a blood sample,” Hubbart says. “There’s a growing consensus around the water management and water quality communities that in order to best manage our watersheds for the future we need long-term studies. By monitoring the long-term health of a watershed, including climate and water quality, a lot can be learned about what’s happening across the landscape.”
Hubbart is working with a team of MU scientists, along with experts from state and federal government, to develop a comprehensive monitoring project for the entire watershed of a beleaguered urban stream. The goal is to understand the full range of physical processes affecting the health of that stream, and how these impact the extended biological communities those streams support. What they learn could significantly boost the prognosis for all of the nation’s waterways.
In this case, the ailing patient is Hinkson Creek, a small stream in central Missouri with a watershed of about 80 square miles. Located entirely in Boone County, its headwaters originate in sparsely populated farm country. From there, the Hinkson flows through suburbs and residential developments that ring Columbia, this college town of some 105,000 people.
If the Mississippi River could be compared to an artery that supplies the human heart with vital blood flow, then the Hinkson might be likened to a tiny, filament-thin capillary that provides nutrients to just a small group of cells. And this capillary is showing some troubling symptoms. Because it flows through the city, the Hinkson is considered an urban stream. In 1998, the Missouri Department of Natural Resources listed the Hinkson as “impaired” under provisions of the federal Clean Water Act. The problem, according to the listing, stemmed from pollution coming from “unknown” sources.
This designation has not been without controversy. If those pollution sources are unknown, local developers and their advocates have asked, how can water quality experts say with certainty that the Hinkson is polluted at all?
One method, researchers say, is to look at similar, nearby streams and compare their biological health: the number of fish species, for example, and the populations of aquatic insects and other invertebrates. By this measure the Hinkson does indeed show some problems. It is not alone.
According to the Environmental Protection Agency, 51 percent, or more than 40,000 of the nation’s waterways that have been assessed for pollution are listed as impaired. That gives water quality managers an onerous job to tackle. “As soon as a creek is listed as polluted, we’re required to address the problem at the risk of being sued by the federal government; it’s a natural resource and public health issue,” Hubbart says.
“The problem with the Hinkson was that after being listed as an impaired waterway, for 10 years there was really no resolution of what those pollutants were. So when you ask, ‘What pollutants is the Hinkson afflicted with?’ Well, that’s why I’m out here doing what I’m doing. Because even after a decade of research and investigations, folks still really don’t know. They don’t have verifiable answers to that question.”
That doesn’t mean scientists haven’t sampled the Hinkson before. They have, plenty of times. But the results from earlier work were less than conclusive, Hubbart says. “One time researchers would sample a site and the Hinkson would be fine; the next time it wasn’t. Once in a while a fish kill would be reported. The problem is that in natural aquatic ecosystems, you sometimes have naturally occurring fish kills.”
It can be difficult to sort out exactly what’s going on. Last year, for example, Hubbart received several phone calls warning of a major pollution event on Hinkson Creek. The water in one area was orange with an oily sheen on top. “I went out and looked at it, and the sighting was absolutely correct. But it wasn’t really pollution,” he recalls. “What had occurred is that the water had slowed down and the aquatic vegetation had senesce [grown old], decayed and oils had been released from the decaying organic matter.” The water was orange, he adds, because Hinkson Creek has a lot of iron in it. That iron settles out, lies in the bottom, and makes the creek look orange. That particular incident might have been a missed call, but the Hinkson is no pristine stream. Like most creeks that flow through an urban landscape, it runs a gauntlet of possible pollution sources.
Engine oil and antifreeze can leak from cars onto parking lot surfaces and flush into the streams during a rain. So can lawn herbicides, pesticides, fertilizers and even animal feces. Road salt and rubber and metal deposits from tire wear can build up on roads and wash into the Hinkson.
Urban areas have higher concentrations of impervious surfaces, such as parking lots and roofs, that channel storm water into creeks like the Hinkson. In a more natural stream system, storm runoff would percolate much more slowly into the groundwater table, says John DeLashmit, chief of the water quality management branch for the EPA’s Region 7 based in Kansas City, Kan.
The issue isn’t that scientists can’t identify pollutants, DeLashmit says, it’s that in urban environments, more storm water flushes into streams much more quickly. “A lot of potential hazards come with that runoff,” he says. “It’s the cumulative effects of all of them.” Data from Hubbart’s Hinkson Creek project could provide water quality managers with information about how impaired streams might instead become a valuable resource, DeLashmit says. “That’s what we’re shooting for.”
There’s a lot of misconception about what’s polluting the Hinkson and how bad it is, the scientists say. “On a regional basis, it’s likely that Hinkson Creek is probably in better shape than many other urban streams,” Hubbart says. But the evidence doesn’t exist, yet, to support even that assumption. “In years past, researchers would go out on the Hinkson and take a sample here and a sample there, and not necessarily go back to the same place or sample at the same time,” he says. “There may have been a lack of replication, or repetition, or robust study design.”
Hubbart set out to design just such a study while a doctoral student at the University of Idaho from 2003 to 2007. His first big project involved monitoring the watershed of a mountain stream on timber company land. The goal was to help identify the impacts of road building, and how timber harvesting, runoff and suspended sediment affected the stream. This involved constructing monitoring stations in the river, each gathering data on water flow, depth, temperature, sediment, and other variables.
At MU, Hubbart figured the same techniques and technology would be well-suited to tackling the Hinkson’s ecological mysteries. Federal and state environmental agencies agreed, eventually providing nearly $2 million to help fund the research.
Thus for the past two and a half years, Hubbart and his graduate students have been riding herd on a set of five futuristic-looking monitoring stations planted on the creek’s banks. These stations look something like lunar-landing modules perched on stilts. Solar panels provide power for instruments that monitor water flow, depth, temperature, climate and nearly 20 other variables. The data are collected every 30 seconds, averaged every five minutes and logged into the system.
Every other day, technicians at each testing site slog up and down the muddy creek bank, collecting water samples to check levels of nutrients, chloride and other substances in the water. Each hour an instrument called a “laser particle diffraction analyzer” measures not only the amount of sediment in the water, but tells researchers how big the particles are.
“The result is an immense pile of data,” Hubbart says, “most of which will supply new information that urban watershed stakeholders haven’t had before. Many of the results will have global urban watershed management implications. I think the Hinkson Creek watershed provides a model watershed for people interested in making science-based water management decisions.”
Hubbart and his team are working in a living environment, not a laboratory. In the field, they wear rubber boots and waders, not starched lab coats. That environment can present some daunting challenges. After a heavy rain, he’s seen the creek level rise two feet in 30 minutes. “When the water gets high and things start moving around, my instruments like to move too,” he says. He’s had pumps, pipes and other equipment wash down the creek, never to be found again. Lightning strikes have fried his instruments, even as floods were drowning them. “You name it and it’s happened,” he says.
But trashed gear is a small price to pay for the information he and his team are collecting, he says. It’s data that are key to understanding how physical processes, like flooding, influence water quality and the health of streams. Take the data on sediment particle size. It could provide clues to general principles about how urban streams operate.
Hubbart isn’t convinced, for instance, that urban areas in general flush more sediment into the Hinkson, but his preliminary results are identifying small-sized sediment particles coming from suburban and urban environments.
“Being able to quantify those relationships is not something that appears in the scientific literature, and the implications are huge,” he says. “Chemical pollutants attach much more readily in higher concentrations to small sediment particles than they do to larger ones. Those finer particles plug up fish gills, are problems for aquatic invertebrates, ruin fish egg-laying habitat, cloud the water, can sequester oxygen and result in a whole lot of other problems. So if we’re able to quantify the finer particle classes and to show that perhaps those are pollutants, that’s a big deal because then we’ve identified the pollutant and can then work on mitigating the problem.”
Early study results are also finding spikes in chloride levels in the winter, perhaps from salt used to de-ice roads, and a higher pulse of nitrogen and phosphorus in the spring when people fertilize their lawns. “We’re aware that these sorts of relationships exist, but to be able to quantify them and to show policy makers what quantifiable levels those concentrations are in the water and their impact on the water supply, is a key element that has been missing,” he says.
John Schulz, a resource scientist with the Missouri Department of Conservation, describes Hubbart’s research as the interface of science and policy.
“Jason’s research will be providing basic hydrological information that drives all of the biological systems” surrounding an urban stream, Schulz says. “All that data has not been available any place else on the globe. That’s exciting stuff. That’s where we truly begin to understand the interface between biology, geology, weather and other variables.”
By providing officials with the information they need to make thoughtful decisions about watershed management, he says, the project will ultimately benefit those who live near streams.
“We would like to help people understand that urban streams don’t have to be open sewers; they don’t have to be places we don’t manage well,” Schulz says. “If we’re not careful we can meet all the legal regulations and we still haven’t done anything to actually improve the health and quality of the stream as it relates to the people who live there.”
And maybe that raises another, more basic question: Why should we care about the health of streams like the Hinkson?
“That’s really an open-ended question, and it’s a tough one,” Hubbart says. “When policy makers approach me with watershed health problems, I’ll often ask, ‘Well, what do you want this watershed to look like in 50 years? What level of water quality do you want? What kind of healthy riparian ecosystem do you want? Do you want trees along the banks, deer, bird populations, parks?’
“You can get a plethora of different viewpoints, and I think therein lies the answer. Why do we care? Because with a highly diverse human population that has a highly diverse set of expectations and needs, we should be striving to maintain a healthy and diverse ecosystem to the greatest degree possible.”