Spatial and temporal variability of sediment delivery from alpine lake basins, Cathedral Provincial Park, southern British Columbia

This paper presents reconstructions of Holocene sediment yield from four alpine lakes in southern British Columbia. Sediment yield is reconstructed on the basis of suites of dated and correlated cores from each lake. Facies analysis of the complete set of cores suggests that significant changes in sediment delivery have occurred during the Holocene, specifically a shift to a higher energy sedimentary environment in cooler wetter conditions in the late Holocene. Estimated sediment yields range between 2.3 and 11.2 t km−2 a−1. Maximum Holocene variability is a 115% increase at one site. Highest variability is observed at sites just above treeline suggesting that reduced vegetation cover under cooler conditions is a key control on temporal variability of sediment yield at these sites. The temporal variability observed at Holocene timescales is within the range of natural spatial variability observed between the four closely spaced lakes. Overall, the results suggest that the response of small catchments to climate change is highly contingent upon local catchment conditions, and that at all but the most sensitive sites sediment yield changes associated with moderate climate warming are likely to be of a lesser magnitude than the natural spatial variability.