COLUMBIA — Members of the Missouri Department of Conservation will finish an assessment of Flat Branch on Tuesday after at least 1,000 fish were found dead in its waters.
The Department of Conservation has linked the fish kill to contaminated water that drained into the creek during firefighters' efforts to put out the April 1 blaze on Business Loop 70, but as of Monday, results weren't yet available to conclusively confirm the cause.
The fish kill — a localized die-off of fish populations frequently linked to pollution, oxygen depletion or diseases and parasites — was reported April 1 and is being investigated by the Conservation Department and the state Department of Natural Resources.
Rebecca O'Hearn of the Conservation Department said Monday she had little doubt the fire contributed to the fish deaths in the urban stream. Species found there include sunfish, orange throat darters and minnows.
O'Hearn described the kill as "total" from Flat Branch Park, where the MKT Nature and Fitness Trail begins and the creek appears, to near the trail's 2.0 mile marker.
Battalion Chief Steven Sapp of the Columbia Fire Department said more than 1 million gallons of water were used on the fire that engulfed O'Reilly Auto Parts and several other businesses. That water then drained into the creek, which is fed by numerous storm drains in downtown Columbia.
The auto supply store housed products that included motor oil, brake and starting fluids, battery acids and other petrochemicals, Sapp said.
"There's just a whole group of products there that can be dangerous if they are introduced to the water supply," Sapp said. "If we're applying water into the building, the logical sequence is that the materials in the building will be mixed into the water and into the runoff."
Sapp said the Department of Natural Resources knew fire crews were sending large amounts of water into the creek from the scene, and that the department had agreed with crews' decision to flush water through the system, which diluted contaminants in the runoff.
The fire department tested the creek's water at 1 p.m. April 1 — as the fire still burned — at Flat Branch Park and Cherry Street, and found no measurable quantities of petrochemicals, chlorines or benzines, Sapp said. When the fire was finally extinguished at about 3 p.m., firefighters installed three rows of straw bale "filters," about 20 feet apart and stacked two to three bales high, across from the creek where it emerges from underground near Flat Branch Park.
City crews also installed straw bales around stormwater inlets near the fire, Public Works Department spokeswoman Jill Stedem said.
The fish kill was reported by MU limnology professor Jack Jones and his wife, retired scientist Susan Jones, who were walking along the MKT when they started smelling what he described as petrochemicals.
Jones said he noticed a brown discoloration in the stream, dead fish and "traumatized fish gulping for air." He emailed O'Hearn, a former graduate student of his, later that day to inform her department. O'Hearn received the email Monday and then alerted the Department of Natural Resources and sent one of her department's employees to the creek.
After that employee confirmed dead fish, a strong odor and an iridescent sheen on the surface of the water and in sediments, O'Hearn said she went to Flat Branch to see for herself. These observations were reported to the Department of Natural Resources, and resulted in oil absorbent pads being placed on the creek Monday afternoon.
On April 2 and April 6, Conservation Department workers counted dead fish and sampled the water quality to determine water clarity at three sites along the creek: at Providence and Stewart roads, at Bridge No. 9 on the MKT and at the confluence of Flat Branch and Hinkson creeks. The Department of Natural Resources is analyzing those samples for specific contaminants.
"It is so unfortunate that all these fish have died," O'Hearn said, who added that it's possible all aquatic life in the majority of the creek was killed.
She said her team plans to continue its assessment Tuesday morning, this time looking for macro-invertebrates such as crawfish and dragonflies, which live in the stream in the larval stage. The team also plans to check the sites four times a year, once every season, to look for more fish.