The IJsseloog (Dutch pronunciation: [ˈɛisəlˌoːx], "IJssel eye") is an artificial island in the Ketelmeer (province of Flevoland, the Netherlands) used as a depository to store polluted silt.

During construction of the IJsseloog, a major concern was to preserve the water table and the environment of Ketelmeer.

To avoid nuisance to agriculture, to local residents, and to prevent groundwater contamination, the silt depository was built in the centre of the lake and not on the coast.

[1] To prevent leakage, the floor of the depot is sealed with clay and the dike is lined with foil.

When storage is full, the layers of clay and sand will be sealed, and the island itself will be used for recreational purposes.