DNR investigates fish kill near Burlington

BURLINGTON ? The DNR investigated white material in Flint Creek north of Burlington last week.

A DNR investigator found a white material flowing from Big Hollow Creek into Flint Creek, and several locations with dead and dying fish, but was unable to find the source of the pollutant before nightfall Nov. 4.

Investigators returned Nov. 5 to trace the white material to a pool below the Des Moines County Conservation Board?s Big Hollow Lake. Field tests showed extremely low dissolved oxygen levels in the pool, along with dead fish.

DNR determined a discharge from the lake caused the fish kill after a county conservation board employee opened an overflow gate on the lake about 3 p.m. Nov. 3. Lake water discharged for about 10.5 hours, lowering the 178-acre lake by approximately one foot and releasing low oxygen sediment into Big Hollow Creek.

The white color is likely gypsum clay from the bottom sediments in Big Hollow Lake. White sediment traveled about 19 miles downstream, but the fish kill was limited to the first two miles in Big Hollow Creek directly below the lake.

DNR fisheries staff counted 252 dead fish Nov. 6, mostly minnows and Johnny darters, followed by green sunfish and a few sport fish. The DNR will continue to monitor the situation and consider appropriate enforcement action, including fish restitution and investigation costs totaling $459.94.