Scientists are studying the health of the South Platte’s aquatic life

BY BELEN WARD BWARD@COLORADOCOMMUNITYMEDIA.COM

There might be plenty of sh in the sea, but in the section of the South Platte River from the Denver Metro Water facility down to Fort Lupton, they’ve all but disappeared. rough testing, Metro Water Recovery scientists discovered that aquatic life was not present in this part of the South Platte River due to low dissolved oxygen levels. Metro Water Recovery, in an agreement with Colorado Parks and Wildlife, the United States Environmental Protection Agency and the Colorado Health Department will address the issue.

Dissolved oxygen levels mean the river is too low for aquatic life. When they did the study, the scientists found that the South Platte River from the Denver Metro Water facility down to Fort Lupton had no sh habitat.

ey started a six-phase project on the South Platte River from 88th & Colorado Boulevard to Fort Lupton in 2018 to improve aquatic life that was disappearing from low dissolved oxygen.

“Many factors cause dissolved oxygen in a river, such as runo , nutrients and how highly managed the river is and owing slowly in some locations. In addition, algae grow when the river slows down and eats up oxygen at night,” said Senior Quality Manager for Metro Water Jim Dorsch.

“A number of factors were involved and since Metro Water created the river, it made sense for us to take the lead on trying to correct it,” Dorsch said.

Scientists are working daily on the South

Platte River collecting aquatic macroinvertebrates, which are bugs. Many of these types of organisms and microhabitats live in the river, under rocks or in woody debris in the river, Dorsch said, adding that they can also live inside rocks or live in boulders.

“ e objective is to sample the macroinvertebrate that lives at the bottom of the river to assess the invertebrate which is species without a backbone to test their diversity and abundance within the river channel and determine overall aquatic life health,” said Jordan Harman, a senior water quality scientist with Metro Water.

Harman said the macroinvertebrate data is used in Colorado as the primary indicator of aquatic life health in streams and rivers. ey collect samples in the fall, and the macroinvertebrates are picked out with tweezers and placed into collection jars lled with isopropyl alcohol for preservation.

“We then send these preserved specimen samples to a taxonomic expert and they identify and count the macroinvertebrates and send the identi cation enumeration data back to us. is is simply identi cation of preserved specimens, they are not looking at live specimens,” Harman said. e scientists could get a general sense of overall water quality based on the type of invertebrates. Certain macroinvertebrates are sensitive to pollution, such as may ies, caddis ies and more. Bugs that are relatively tolerant of pollution include aquatic worms, midge larvae and more, according to Harman and Dorsch.

“When we observe a diverse group of