By Clay Wallace

Intern Ian Kratzer separates bugs from other organic material and silt gathered by the kicknet. Photo by Clay Wallace

When the car pulls into the grass beside the small road in Mercer County, just south of Harrodsburg, three scientists from the Division of Water are quick to don boots and waders. It’s late spring, already hot despite the early start, and environmental scientist Mary Rockey begins to prep for the long day, opening the hatchback to reveal a cooler, a jug of pure water, and tubs stacked full of gloves and empty bottles.

Today, the scientists – Rockey, Jacob Becraft, and intern Ian Kratzer are collecting samples from Dry Branch, a creek just upstream of the Salt River.

Their work has a long legacy. For over forty years, the Division of Water has measured surface water quality in accordance with the Clean Water Act – a mammoth undertaking considering the Commonwealth boasts more miles of shoreline than Florida, and is second only to Alaska in its abundance of navigable waterways.

Becraft, Kratzer, and Rockey performing a stream assessment. Photo by Clay Wallace

Kentucky’s water monitoring program is designed to meet both federal and state objectives. In measuring the water quality of rivers, streams, and reservoirs, the Division of Water can determine when standards are not met, identify particular hazards and sources of impairment, and support the development of programs and practices which promote the health of Kentucky’s water resources.

As part of this monitoring, Rockey, Becraft, and Kratzer gather stream water samples , which will be tested at the lab for  chemical composition and nutrients.

However, these water samples only tell a partial story; though they faithfully recount the creek’s present state, they can’t provide information about how its conditions may have changed over time.

Rockey and Becraft entering Dry Branch. Photo by Clay Wallace

For instance, a sample gathered shortly after farmland in the watershed has been fertilized might show higher-than-usual amounts of nitrogen, while a sample gathered after long periods of rain may show an increased amount of dissolved oxygen.

“We use the richness and abundance of macroinvertebrates as an indicator,” said Rockey, pointing at the small isopods called “roly-polies” dotting the algae in the creek below. “ They’re pretty tolerant. They’re everywhere, and there shouldn’t be that many of them.”

To get a better sense of the stream’s average conditions, the trio pulls out a net, some buckets, and a pair of forceps; they’re going to ask the bugs.

 Kratzer and Becraft performing multi-habitat sampling. Photo by Clay Wallace

Diversity of species is one of the things the team is looking for. An assortment of different bugs can indicate that the stream offers a balanced habitat, while large populations of a single type of bug can signal there’s some factor overwhelming the stream’s environment.

In the case of Dry Branch, the overabundance of isopods is related to their ability to survive in environments that would be too harsh for other water-bound bugs.

“Fish and amphibians are what we call ‘obligate’,”  Rockey said. “In their larval life stages, they’re fully immersed in the water. It’s in full contact with them all the time, so they’re really impacted by changes in the water just like we would be if the air around us was toxic all the time.”

As the team wades into the water, they stumble upon a significant clue regarding the isopods’ dominance; their boots tangle among the dense cover of Cladophora, carpeting the bottom of the stream.

Dry Branch in Mercer County; mats of Cladophora visible as the dark green spots in the stream bed. Photo by Clay Wallace

“It’s a filamentous algae,” explains Becraft, an environmental biologist. “If I were to pick it up, you would see hair-like strands. It’s very common throughout the bluegrass region of Kentucky because it really likes to grow in nutrient-rich streams, and the nutrients come from farms as agricultural runoff. When there’s a lot of nutrients and enough mixing of the water, it gets everywhere and chokes out the environment.”

The Division of Water employs two different methods to collect macroinvertabrates – kicknet sampling and multi-habitat sampling.

The team is equipped to perform both collections today because, like the chemical samples, each method accounts for the data the other method may overlook.

Rockey, Kratzer, and Becraft beginning to sort a kicknet sample. Photo by Clay Wallace

They begin with the kicknet sample, in which sediment is disturbed (the kick) and collected (the net). The scientists then sort through the silt to pick out all the bugs.

“The kicknet is a semi-quantitative sample,” Becraft said, as he takes the first of what will be four samples with the net. Each sample is gathered from a riffle environment – a portion of a stream characterized by shallow, quick-moving water – and the samples are pooled together after the team returns to the lab.

“No matter what stream we’re looking at, as long as it has a riffle, we can get the same cutout of that biodiversity and compare it between streams.”

As Becraft and Kratzer work on sifting through the kicknet sample, Rockey scouts the area further downstream for areas suitable to start gathering multi-habitat samples.

“The multi-hab is a little more intricate in some ways,” said Becraft. “We have certain habitat types that we want to sample from – bedrock, slab rock areas, undercut banks with roots – and we expect to find different species of bugs living in those different environments.”

“Organisms are either able to live here or they’re not,” added Rockey. “Based on everything we know about what you would find in the bluegrass region in a stream like this, if we should be able to find them here and we don’t, there’s a chronic problem.”

The data gathered today is part of a year-long project with the city of Harrodsburg. Under an amendment to the Clean Water Act, funds are  allocated toward improving community streams’ water quality.
Harrodsburg applied for these resources and works with the Division of Water on a watershed plan.

Becraft and Kratzer walk downstream with their supplies to begin the multi-habitat sampling. Photo by Clay Wallace.

“What that means is you’re coming up with a plan to determine what kind of changes you need to make in the land use in your watershed to improve the water quality,” Rockey said. “The first step of that is collecting data on the condition of the stream.”

The team has been regularly sampling 14 different locations along the upper segments of the Salt River in Mercer and Boyle counties.

“It’s a community effort to keep water clean because we all want to use it,” Rockey said. “We want our lakes to be things we can swim in and go fishing in. That’s what we’re trying to do, make sure that all those important functions of a stream are able to be maintained.”