Wildfire Effects on the Quantity and Composition of Suspended and Gravel-Stored Sediments |
| |
Authors: | Ellen L Petticrew Philip N Owens Timothy R Giles |
| |
Institution: | (1) School of Geography, University of Plymouth, Plymouth, UK;(2) National Soil Resources Institute, Cranfield University, North Wyke, UK;(3) British Columbia Ministry of Forests and Range, Kamloops, British Columbia, Canada;(4) Geography Program, University of Northern British, Columbia, Canada |
| |
Abstract: | In August of 2003 a severe wildfire burnt the majority of Fishtrap Creek, a 170 km2 catchment in central British Columbia, Canada. The objective of this study was to determine the short-term (15-month) influence
of the wildfire on the amount and composition of fine sediment delivery and retention in the system and to compare it to a
similar unburnt catchment. In the spring of 2004 automatic water samplers were installed at a gauging site on Fishtrap Creek
to collect suspended sediments from the snowmelt runoff and gravel traps were deployed on the channel bed surface to collect
composite samples of suspended fine sediment. Jamieson, the reference creek, exhibits similar geology and pre-burn vegetation
and was sampled in the same manner for comparison. Composite suspended sediment collected in the traps was removed from the
streams in mid-summer and early September. Quantitative estimates of the amount and particle size structure of the naturally
stored fine sediment in, and on, the gravel creekbed were obtained in pre-melt, mid and late-summer conditions. Estimates
of suspended sediment yields indicated that while the burnt system delivered 66% more material per unit area, the total seasonal
suspended sediment yield was low (855 kg km−2) compared to other fire-disturbed systems. While the burnt catchment was primed to deliver sediment, the hydrologic drivers
were not of sufficient magnitude to generate a substantial response, suggesting that in this first post-fire year the system
was transport-limited, not supply-limited. Differences were noted in the spatial and seasonal composition of the <500 more
OM% composite suspended sedimentswith the burnt catchment having significantly (P≤0.05) more OM%. Seasonally a significant
increase of OM% in late summer samples was associated with instream biofilms and possible delivery of black carbon. The system’s
post-fire response was not geomorphically substantial but significant biological differences were noted in the short-term. |
| |
Keywords: | organic matter sediment yield sediment response suspended sediment wildfire |
本文献已被 SpringerLink 等数据库收录! |
|