This view to the west shows a basin in a basalt landscape near Potholes Coulee (west of Quincy, Washington). In the distance the Columbia River is barely visible. This is an area noted for extensive irrigation.

The basin contains basalt boulders partially coated with a white substance, possibly chemicals contained in irrigation water. The ubiquitous basalt rock underlying the farming land is porous, allowing irrigation water (and the fertilizing chemicals it contains) to seep out of the ground at exposed places such as the cliff seen here. Then it flows downhill. At times it must fill the basin.

My vantage point was at the center of this Wikimapia aerial view.

This photograph could not have been produced without the level-headed support of Joe Tripod, my photographic assistant in the field.