This National Natural Landmark is an extensively eroded landscape, located in south central Washington state characterized by hundreds of isolated, steep-sided hills (buttes) surrounded by a braided network of numerous channels, all but one of which are currently dry.

The geologist who initially recognized and documented the evidence for the Ice-Age floods, J Harlen Bretz, wrote: Drumheller is the most spectacular tract of butte-and basin scabland on the plateau.

The Drumheller Channels can also be seen from the paved State Route 262 which runs to the north of the area along the top of the Potholes Reservoir dam (which has inundated part of the scablands) and from the west side from the heights of the Frenchman Hills.

[4] The Drumheller Channels are named for the humble, impoverished, farming family that, in 1922, gave basic over-night hospitality to J Harlen Bretz and his three students who were mapping the area on foot.

Flowing across the current Grand Coulee & Dry Falls regions, the ice age Columbia then entered the Quincy Basin & joined Crab Creek, following Crab Creek’s course southward past the Frenchman Hills and turning west to run along the north face of the Saddle Mountains & rejoin the previous and modern course of the Columbia River just above the main water gap in the Saddle Mountains, Sentinel Gap.

Many of the low areas, including Upper Goose Lake, are filled by water seeping in through cracks in the basalt bedrock, which are connected with Potholes Reservoir to the north.

Grand Coulee was only one part of the Columbia Basin Project, which included four major storage reservoirs, hundreds of pumping plants, 2,300 miles (3,700 km) of canals and laterals to irrigate the region.