Photos courtesy of the Washington Department of Ecology.
The body of water in the photos is Banks Lake, held back by Dry Falls Dam. The two grades sort of parallel each other, with the Central Washington grade being the further away from the photographer grade. This grade was largely complete from Coulee City to the top of the hill west of town. The Seattle, Lake Shore & Eastern is the incomplete grade between the dam and the CW. There are further sections of completed grade going up the hill, not seen in these images.