A foam streak develops where the inflowing water from Gilbert Bay enters the red waters of Gunnison Bay. A culvert allows water to flow from the south end of the lake (Gilbert Bay) into the north where it evaporates to saturation. The foam is thought to be due to high levels of dissolved organic carbon (DOC/DOM), and the streak forms where the two water masses meet. Additional foam has piled up on the rocks in the foreground and there are additional foam streaks on the water to the left. The rocks in the foreground are part of the railway causeway dividing the lake.