Grand Coulee the Ice Age Floods. Archeological records date human presence back to nearly the end of the Ice Age, but the raging torrents erased the land of clear evidence, leaving us to question who, if anyone, may have survived. With the end of the last glacial advance, the Columbia settled into its present course. The river bed is about below the Grand Coulee. Walls of the coulee reach in height. Grand Coulee is the longest and deepest of eastern Washington canyons. Its unique characteristics include a lower floor at the head of the channel than at its outlet and the widest
Birch Coulee Battlefield edge is a steep wooded ravine, a landform known locally by the French term "coulee," also spelled "coulie" or "cooley." Birch Coulee, known to the Dakota as "Tanpa Yukan" (Place of the White Birch), is deep and runs for a total of down to the Minnesota River. A few hundred yards to the west of the coulee, the prairie rises slightly onto a gentle knoll. On September 1, 1862, a burial detail of about 170 Union Army volunteers and civilians under Major Joseph R. Brown camped on the prairie west of Birch Coulee. The site was selected by Captain Hiram