Rock Island Dam Island Pool. Rock Island Dam is constructed on Columbia River basalt similar to that which is exposed on the cliffs near the dam. These columnar basalts were formed from lava flows during the mid- to late-Miocene Epoch, some 14 to 16 million years ago. The rock is strong and durable and provides a very stable foundation for the structure. Columbia River stream flows at the Project averaged 73,700 cubic feet per second (2090 m³/s), a decrease of 37% from 2000 and 63% of the 20 year average of 116,700 cubic feet per second (3305 m³/s). The Rock Island Hydro Project
Nisga'a Memorial Lava Bed Provincial Park legend that accounts for the lava as well as geological causes. The park has waterfalls, pools, cinder cones, tree moulds, lava tubes, spatter cones, a lava-dammed lake, caves and other features created by lava flows. The park aims to protect moose, goats, marmots, bears and many other species of wildlife. The park covers 178.93 square kilometres in area. It is believed to be the site of Canada's most recent volcanic eruption and lava flow, a geological disaster that killed an estimated 2,000 people. The source of the eruption was the Tseax Cone. Large lava flows dammed the Nass River and