Iowa DNR
Iowa DNR Fish Kill Database

Fish Kill Event - Stormwater Containment Structure

Ft Madison

Event ID
Date of Kill
Waterbody Type
Cause Origin
2 (101 - 1000 fish killed)
Estimated Fish Killed
ESD Field Office
FO 6
Fisheries Office
Lake Darling State Park
Created Date
3/28/2019 8:20:53 AM
Last Update
3/28/2019 8:20:53 AM
For more information about this fish kill event, contact the Field Office or Fisheries Office listed above.
Impacted Assessment Segments
No segments listed
Lat/Long uses WGS84 datum
Onsite Comments

On 06/16/2017 at ~1640 I contacted Mr. Bill Mason, Cryotech Deicing Technology, regarding a report of a fish kill. Mr. Mason provided the following:

  1. The kill occurred in their stormwater containment pond.
  2. To his knowledge their was no discharge or release of any contaminate to the pond that may have contributed to the kill.
  3. The water in the pond is normally maintained at ~3 feet.
  4. There is a valve between the pond and outfall to the river. The valve is kept open when the river level is high and closed when the river drops.
  5. The river level at the time of the kill was low so the valve was closed.
  6. The water level in the pond was extremely low. Estimated at ~1 ft.
  7. It was reported that fish had been observed jumping in the pond on Monday
  8. On Wednesday, water was pumped into the pond to raise the water level ~16 inches.
  9. On Thursday people walking the path near the pond noticed dead fish.
  10. They investigated on Friday and noticed it was worse then people had reported.
  11. Estimated ~200 Grass Carp & lots of fingerlings.
  12. Ben Schlader, DNR Conservation Officer, was contacted.

We discussed what may have caused the kill. It was explained, based on the information provided, that due to the low water levels the dissolved oxygen levels may have been low which may have stressed the fish. In addition, water temperature in the pond may have been higher than the river water. So when they added water, the change in water temperature may have been enough to cause the kill.