A massive fish kill that occurred last week on the North St. Vrain Creek following a gasoline spill is being investigated by Colorado Parks and Wildlife (CPW).
The Environmental Protection Agency (EPA) estimated that between 500 and 1,000 gallons of fuel were released from the tanker truck following the rollover crash on US 36 at Apple Valley Road last week.
Several hundred dead fish have since been collected and and are being stored as evidence as part of the investigation to assess the damage to aquatic life.
In large-scale incidents, such as this one, counting or collecting every single dead fish is typically impossible, according to CPW. However, officials say they are able to use "statistically valid methods to accurately estimate the losses."
Mindi May, CPW’s water quality coordinator, and Dr. Pete Cadmus, an aquatic research scientist at CPW’s Aquatic Toxicology Lab, spent Saturday assessing the river. Officials say they collected macroinvertebrate samples, took water quality measurements, measured algae, and continued to survey for fish.
“We visited numerous sites on the river from just upstream of the crash site all the way down to the confluence with the South Saint Vrain,” May said.
Information and observations about dead fish or other wildlife impacts related to the spill can be reported to Colorado Parks and Wildlife at firstname.lastname@example.org.
The investigation to assess the damage to aquatic life is ongoing for Colorado Parks and Wildlife alongside several partners including the Environmental Protection Agency, Colorado Department of Public Health and Environment, and Colorado State Patrol.