Authors: |
Mark S. Riedel |
Year: |
2006 |
Type: |
Scientific Journal |
Station: |
Southern Research Station |
Source: |
Second Interagency Conference on Research in the Watersheds, May 16-18, 2006. 9 p. |
Abstract
Abstract--The impacts of forest disturbance and roads on stream sedimentation have been rigorously investigated and documented. While historical research on turbidity and suspended sediments has been thorough, studies of stream bed sedimentation have typically relied on semi-quantitative measures such as embeddedness or marginal pool depth. To directly quantify the impacts of a functioning off-highway vehicle (OHV) trail on stream sedimentation, we employed a marked-recapture sediment tracer approach that allowed us to directly measure the movement of sand eroded from the trail and transported through the stream. We seeded a controlled section of an operating O W trail with manufactured limestone sand (MLS). Fine fine fractions of the MLS were washed from the road and increased stream water calcium concentrations, [Ca2+]. Stream water [Ca2+] began to return to pretreatment levels within 12 weeks. Coarser fractions, greater than 0.5 mm, were eroded from the road with rain events and moved along the study reach in pulses. Much of the coarse sediment appeared to be within the study reach eight weeks following application of the tracer. Tracer results and estimated stream bed sediment transport times indicated the small section of OHV trail had contributed at least 2.45 kg (302 kg/ha) of coarse sediment to the stream bed in 8 weeks (1,960 kg/ha/yr).
Citation
Riedel, Mark S. 2006. Quantifying trail erosion and stream sedimentation with sediment tracers. Second Interagency Conference on Research in the Watersheds, May 16-18, 2006. 9 p.