Native people in the area of the Sandy River Delta used the marshes, as well as the rivers, for subsistence and transportation. Women gathered wapato, the edible bulb of a plant that grew in shallow water. They went out in small canoes, ten to fourteen feet long, to load up with wapato. These light-weight canoes were easy for one woman to carry.

Native people living in villages on the Columbia and its nearby tributaries would travel to the Lower Sandy River for fishing and gathering. They could canoe between the Sandy River Delta and the Willamette River along a slough, as an alternative to the Columbia River. When the rivers rose, the slough would become a large lake.