November 2010 - BC Hydro

Duncan Dam Reservoir Archaeological Overview Assessment Final Report
of 50° north latitude is apparent from reports of Schaeffer's Ktunaxa informants (Schaeffer
1940).
The environmental effects of the Little Ice Age were severe enough that they resulted in the
disappearance of bison, antelope and prairie chicken from the East Kootenay and north-western
Montana areas (Johnson 1969). Given the evident extent of recent glaciation in the mountains
surrounding the Duncan Reservoir, the animal residents would undoubtedly have been similarly
affected by this severe climatic episode.
The lakes and rivers in the study area supported large populations of fish species including
rainbow, cutthroat, bull trout, lingcod and sturgeon. While anadromous (ocean-going) salmon
could not ascend beyond the falls on the Kootenay River below Kootenay Lake in historic times,
the presence of landlocked kokanee salmon in Kootenay Lake indicates that pacific salmon
were present in the study area vicinity at some time in the past. The 10,000 BP dates on the
488 m lake in the Selkirk Trench provide an upper limiting age for the present 532 m a.m.s.l. of
Kootenay Lake that is controlled by these falls. As the mouth of the Columbia River and many of
its major tributaries are well to the south of all of the Pleistocene ice fronts, salmon runs were
undoubtedly established in the Columbia drainage long before most of British Columbia's other
rivers could support them. Therefore, salmon could have been ascending into the Purcell
Trench during early postglacial times before their access to Kootenay Lake was cut off by the
exhumation of the falls on the lower Kootenay River.
Eagle Vision Geomatics & Archaeology Ltd. 10 November 28, 2010