Moses Coulee the southern portion of the plateau. These streams had combined into a canyon that drained to the Columbia near the current mouth of Moses Coulee. These side drainages are still visible today along the coulee walls as truncated streambeds, interspersed with gable-like highlands. The Okanogan lobe of the Cordilleran Glacier moved down the Okanogan River valley, covering 500 mi² of the Waterville Plateau and blocked the ancient route of the Columbia River, backing up water to create Glacial Lake Columbia and Lake Spokane. Initially water discharged from Lake Columbia by running up through the head of Grand Coulee and down
Coulee City, Washington males. The median income for a household in the town was $25,938, and the median income for a family was $42,500. Males had a median income of $31,375 versus $17,250 for females. The per capita income for the town was $14,411. About 14.9% of families and 22.1% of the population were below the poverty line, including 29.2% of those under age 18 and 11.7% of those age 65 or over. Coulee City, Washington Coulee City is a town in Grant County, Washington. The population was 562 at the 2010 census. The town was named after nearby Grand Coulee. Coulee City