Water exits the lake through the Abashiri River again and flows 7 kilometres (4.3 mi) to the Sea of Okhotsk.

Artifacts from the Jōmon period have been found in the area around the Memanbetsu River.

In modern times, the course of the Abashiri River has been straightened to provide for irrigation resulting in a serious siltation problem for the lake.

The reduced inflow of water during the winter season causes saltwater to flow upstream from the Sea of Okhotsk and into the lake.

This influx of saltwater has created a layer of saline water with 10,000 ppm of chlorine, 10 metres (33 ft) below the surface of the lake[3] with a freshwater upper layer that makes up 46% of the volume of the lake.