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Duncan Dam Reservoir Archaeological Overview Assessment Final Report Figure 2-1. DDMMON12 Study Area, Duncan Lake Reservoir, British Columbia Eagle Vision Geomatics & Archaeology Ltd. 6 November 28, 2010
2.2 Palaeoenvironment Duncan Dam Reservoir Archaeological Overview Assessment Final Report Duncan Reservoir occupies part of the floor of the Purcell Trench, a north-south trough that separates the Purcell and Selkirk Mountains. This mountainous area was extensively glaciated during the Pleistocene Epoch of the last few million years. Glaciers covered various parts of the region several times, blocking the existing drainage systems and redistributing fragments of bedrock and its constituent minerals, both directly into the till and indirectly via outwash. Terminal Pleistocene deglaciation is suggested to have commenced about 15,000 years ago (Ryder 1981). Higher elevations apparently became ice-free first (Clague 1989) while melting ice blocks lingered at some places in the valley bottoms. Sediments eroded from the ice-free valley walls were deposited at lower elevations in large proglacial lakes dammed by moraines and melting ice blocks. As these lakes drained, a series of deltas, alluvial fans, terraces and other relict watercourse features were left behind at various elevations, graded to the changing hydrological baselines. While much of the landscape is very steep, expanses of nearly level terrain lie in the upper portions of, and adjacent to, Duncan Reservoir. These include the large delta upon which present-day Howser is situated and smaller deltas at the mouths of the major tributary streams. Some of these are graded to an elevation of ca. 598 m / 1960 ft above mean sea level (a.m.s.l.). This correlates with the level of an extensive proglacial lake that can be traced south-westward to where the Columbia River was dammed at the Grand Coulee by the Okanagan Ice Lobe (Richmond et al. 1965). Radiocarbon dates on a much smaller lake in the Selkirk Trench to the west indicate that the prominent 598 m terrace system surrounding Kootenay and Duncan lakes was an emergent land surface prior to 10,000 years ago (Choquette 1996). Below this elevation are additional terrace remnants, some of them apparently graded to higher post-glacial stands of Kootenay Lake prior to the outlet being carved by the ancestral Kootenay River down to bedrock. One such lake level at 546 m / 1790 ft (ca. 14 m above Kootenay Lake) was recognized by Fulton (1967: 59) during geological reconnaissance of the future Duncan Reservoir. It is apparent that Duncan and Kootenay lakes were a single body of water as the outlet of the West Arm of Kootenay Lake was being downcut. The time of separation of the two lakes is not known. A number of variables could have produced several different lake levels: erosion of the Eagle Vision Geomatics & Archaeology Ltd. 7 November 28, 2010
Page 1 and 2: Duncan Dam Water Use Plan Cultural
Page 3 and 4: Acknowledgements / Disclaimer Dunca
Page 5 and 6: Duncan Dam Reservoir Archaeological
Page 9 and 10: List of Plates Duncan Dam Reservoir
Page 11 and 12: 1.0 INTRODUCTION 1.1 Background Dun
Page 13 and 14: 1.3.1 Approach Duncan Dam Reservoir
Page 15: 2.0 DOCUMENTARY RESEARCH 2.1 Study
Page 21 and 22: 2.3 Archaeological Record 2.3.1 Pre
Page 23 and 24: Table 2-1. Existing Archaeological
Page 25 and 26: Borden Number DR3 WC4 WC5 Setting C
Page 41 and 42: 11 12 13 Duncan Dam Reservoir Archa
Page 43 and 44: Figure 4-2. Pre-Dam and TRIM Mappin
Page 49 and 50: 5.0 RESULTS Duncan Dam Reservoir Ar
Page 51 and 52: 5.1 Transect 2 Duncan Dam Reservoir
Page 53 and 54: Figure 5-1. Map of Survey Transect
Page 55 and 56: Plate TR2-1: View S from the N end
Page 57 and 58: Plate TR2-9: Worked grey quartzite
Page 59 and 60: 5.2.3 Archaeological Potential Summ
Page 61 and 62: Figure 5-4. Location Map for Archae
Page 63 and 64: Plate TR3-5: Pink quartzite biface
Page 65 and 66: 5.3 Transect 5 Duncan Dam Reservoir
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Figure 5-5. Map of Survey Transect
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Plate TR5-1: Overview NW of Duncan
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Plate TR5-9: Marginally retouched K
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Duncan Dam Reservoir Archaeological
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Figure 5-8. Location Map for Archae
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Plate TR10-1: View S across Clancy
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Plate TR10-9: Utilized pink quartzi
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Table 5-2. Summary of Archaeologica
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6.0 DISCUSSION Duncan Dam Reservoir
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7.0 MANAGEMENT RECOMMENDATIONS Dunc
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8.0 REFERENCES CITED Duncan Dam Res
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