In an effort to restore the Ventura Marsh in Ventura, Iowa, thousands of carp have died and washed up on land.

For the $5 million restoration a new emergency spillway and a new pump station were constructed. The pump was used to lower the marsh’s water level, causing the fish kill.

Eliminating some of the carp population was part of the goal during the restoration. Rough fish, like carp, stir up sediment and prevent the marsh from acting like a filter for water going into the lake.

Read more about the restoration project here.

Read an article about a decision to let the dead carp decompose naturally here.