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
Lava bear Alfred Bayne. As late as 1981, scientist were being asked to identify small bear tracks in the Fort Rock area to determine if they were made by lava bears. Today, it is accepted that lava bears are actually common American black bears. It is also generally acknowledged that all of the animals that were killed or captured between 1917 and 1934 were either black bear cubs or small adults stunted from malnutrition. In 1924, Bend Senior High School selected the lava bear as the school’s sports mascot. The mascot was chosen shortly after a living bear was exhibited in Bend.