Grand Coulee at the higher side of the flexure. Encountering the steep slope of the monocline, the new river would have cascaded off the rim, down onto a broad plain where Coulee City and Dry Falls State Park now stand. Upper Grand Coulee began as an cascade just north of Coulee City. As the rush of water eroded the surface, it steepened into a waterfall. The falls continued to erode backward (northward) creating the canyon. When the falls reached the divide into Lake Columbia, i.e., preglacial Columbia Valley, it disappeared, leaving the elongated notch. Today, the waters of the Lake Roosevelt are
Plum Coulee Plum Coulee Plum Coulee is an unincorporated urban community in the Municipality of Rhineland within the Canadian province of Manitoba that held town status prior to January 1, 2015. It is west of Altona, one hour southwest of Winnipeg and half an hour from the United States border. It is also the former home to the Plum Coulee Xpress hockey club. It has a man-made beach located in town. Philanthropist Saidye Bronfman was born in Plum Coulee. Plum Coulee's population of 800 is growing through land development. Working with local land owners, the former Town of Plum Coulee developed a