Glacial Lake Russell

When the glacial ice receded northward, reaching the Olympia area, a low drainage was reached in the eastern Black Hills. Using the Black River as its primary drainage, Lake Russell came into existence was continued after the edge of the ice had withdrawn from the region. Using two channels, the waters drained south to the Chehalis River valley. A northern channel left the Budd Inlet in near Butler Cove. A southern channel passed through Capitol Lake. A third channel may have existed from the Eld Inlet. They merged where Black Lake now exists, following the Black River southward. Following the south side of a line of hill, the channel is 150 to 155 feet (46 to 47 m) above sea level with a gravel plain 160 feet (49 m) across the outlet. This barrier is thought to be deposits from the outflow.[1] Percival Creek contains the Northern Pacific Railroad route over the pass between Puget Sound and the Chehalis Valley. In the pass is a long, narrow swamp, which drains to both Puget Sound and Grays Harbor. Its altitude is 120 feet (37 m) above sea level. Along the southern margin is a gravel bluff at 150 to 160 feet (46 to 49 m) of considerable size. The northern margin has a gravel terrace at 140 feet (43 m) above sea level, and another narrow terrace is at 160 feet (49 m). The existing valley is the result of post-glacial erosion. The bluffs along both sides are seen as evidence of this theory.[1] Black Lake resides in the pass, beginning as a swamp. Black Lake is 2 to 2.5 miles (3.2 to 4.0 km) long and 0.5 miles (0.80 km) wide. It stands 120 feet (37 m) above tide.[1] Withdrawal of the edge of the ice from Thurston County left both the Deschutes and Nisqually Rivers free to flow directly northward to the growing body of water in the unobliterated interglacial valleys. The Nisqually carried a large volume of water when it first entered Lake Russell, since the Ohop channel still contributed the drainage of the northern and western slopes of Mount Rainier. It appears to have entered the western side of the interglacial Gate Pathway River valley, and to have contributed considerably toward the obliteration of that valley by deposition of the Sherlock Delta.[1]