Monitoring burned and unburned hillslopes from North Carolina to southern California: insights into hydrologic and geomorphic controls on disturbance-recovery cycles
Abstract
On steep hillslopes, vegetation often provides an important ecosystem function by preventing landsliding, debris flows, and floods, thereby protecting human lives and infrastructure. Disturbances that disrupt vegetation - from wildfire and forest clearing to landslides themselves - can abruptly alter hillslope hydrologic and geomorphic processes thereby increasing the threat of these natural hazards. Two major challenges from a hazard assessment perspective are: (1) quantifying disturbance impacts on near-surface hydrologic responses, and (2) understanding the relevant processes and timescales associated with disturbance-recovery cycles. These challenges are complicated by the limited availability of long-term monitoring in pre- and post-disturbance environments. Therefore, many tools designed to provide rapid situational awareness and improve disaster preparedness and response rely on temporally invariant parameterization or locally derived empirical relations that are not necessarily transferrable across different geologic or climatic settings. Here we examine hillslope hydrologic response in landslide-prone terrain across the continental US, from the West Coast to Appalachia, to explore these issues related to disturbance-recovery cycles. Wildfire is a recurring disturbance along the actively uplifting mountains in semi-arid southern California, and heavy winter storms arriving from the Pacific are frequently able to produce debris flows in recently burned areas. Although wildfire is less common in the much wetter Cascades and Coast Ranges of Oregon and Washington, frequent landslides and forest clearing disturbances also influence hillslope hydrology and slope stability. In contrast, the recent wildfires in Tennessee, Georgia, and North Carolina have highlighted critical knowledge gaps related to post-fire hydrology and natural hazards in the geologically stable and humid sub-tropical southeastern US, where severe wildfires are less common than other disturbances. Our continuous monitoring from several burned and unburned hillslopes across these diverse geologic and climatic settings reveals variations in the disturbance impacts and recovery timescales, as well as the need for further monitoring, modeling, and synthesis across regions and scales.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.H23N..04M
- Keywords:
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- 1815 Erosion;
- HYDROLOGY;
- 1834 Human impacts;
- HYDROLOGY;
- 1836 Hydrological cycles and budgets;
- HYDROLOGY;
- 1850 Overland flow;
- HYDROLOGY