4.5 Article

The role of chronic and episodic disturbances on channel-hillslope coupling: the persistence and legacy of extreme floods

Journal

EARTH SURFACE PROCESSES AND LANDFORMS
Volume 41, Issue 10, Pages 1437-1447

Publisher

WILEY
DOI: 10.1002/esp.3958

Keywords

-

Funding

  1. Geological Society of America student grant
  2. Dartmouth Neukom Institute CompX Faculty Grant
  3. National Science Foundation [BCS-1222531]
  4. Division Of Behavioral and Cognitive Sci
  5. Direct For Social, Behav & Economic Scie [1222531] Funding Source: National Science Foundation

Ask authors/readers for more resources

Landscape form represents the cumulative effects of de-stabilizing events relative to recovery processes. Most geomorphic research has focused on the role of episodic rare events on landscape form with less attention paid to the role and persistence of chronic inputs. To better establish the interplay between chronic and episodic extreme events at regional scales, we used aerial photography and post-flood sediment sampling to assess stream and hillslope response and recovery to a 100-300yr. flood caused by Tropical Storm Irene in New England. Within a 14 000km(2) study area, analysis of aerial photographs indicated that the storm initiated (n=534) and reactivated (n=460) a large number of landslides. These landslides dramatically increased overall estimates of regional erosion rates (from 0.0023mm/yr. without Irene to 0.0072mm/yr. with Irene). Similarly, Irene-generated LWD inputs of 0.25-0.5 trees/km exceeded annual background rates in a single event, and these concentrated inputs (10(1)-10(2) of trees/landslide) are likely to result in large jams and snags that are particularly persistent and geomorphically effective. Finally, we found that landslide scars continue to provide elevated sediment inputs years after the event, as evidenced by sustained higher suspended sediment concentrations in streams with Irene-generated landslides. Overall, our results indicate that infrequent, high-magnitude events have a more important geomorphic role in tectonically stable, more moderate-relief systems than has been previously recognized. Understanding the role of these events has particular relevance in regions such as New England, where the frequency and magnitude of extreme storms is expected to increase. Further, these effects may force reconsideration of conservation and restoration targets (for example in channel form and large wood loading and distribution) in fluvial systems. Copyright (c) 2016 John Wiley & Sons, Ltd.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.5
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available