Tree Blowdown Impacts of Hurricane Harvey on Hydrologic Surface Connectivity in a Coastal River Channel-Floodplain System
Abstract
Given the vulnerability of coastal plains to impacts from winds and flooding produced by tropical cyclones, it is critical to advance our understanding of these impacts on river channel-floodplain interactions. The Mission River, which is located on the Coastal Bend of Texas and a part of the Mission-Aransas National Estuarine Research Reserve (MANERR), lied along the destructive path of Hurricane Harvey. Heavy rainfall from Harvey resulted in only moderate flooding for the river, but the category 3 winds caused a substantial amount of tree blowdowns along the riparian zone. Tree blowdowns can alter flood patterns, which can then influence erosion/deposition processes and result in a reconfiguration of the geomorphic structure within the river system. This study is the first assessment of tree blowdown impacts from Hurricane Harvey, and, one of the first such studies of any hurricane, on a coastal river. We aim to answer the question: What are the tree blowdown impacts from Hurricane Harvey on hydrologic surface connectivity between the Mission River channel and floodplain? Our specific objectives are: 1) quantitatively determine the spatial extent and patterns of tree blowdowns on the floodplain; and 2) evaluate the impact of tree blowdowns on hydrologic surface connectivity between the river channel and the floodplain. These objectives involve integrating field investigations, high resolution geospatial data, and hydrodynamic modeling. Preliminary findings indicate that the distribution of the blowndown trees reflects the influences of channel and floodplain geomorphology and tree, hurricane-wind, and soil characteristics. The effect of topographic irregularities created by blowndown trees (either as individuals or in assemblages) is scale dependent. In areas with irregularities above certain thresholds, blowdown trees cause noticeable changes in hydrologic surface connectivity by varying the topography and surface roughness. The findings can help develop successful landscape and ecosystem management of the riverine habitats within the MANERR, with applicability to similar systems which might include human habitation and infrastructure. Results from this research aim to increase awareness of the impacts of tropical cyclones on river systems and their associated ecosystem services.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMEP41D2713G
- Keywords:
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- 0483 Riparian systems;
- BIOGEOSCIENCESDE: 0483 Riparian systems;
- BIOGEOSCIENCESDE: 1813 Eco-hydrology;
- HYDROLOGYDE: 1813 Eco-hydrology;
- HYDROLOGYDE: 1820 Floodplain dynamics;
- HYDROLOGYDE: 1820 Floodplain dynamics;
- HYDROLOGYDE: 1825 Geomorphology: fluvial;
- HYDROLOGYDE: 1825 Geomorphology: fluvial;
- HYDROLOGYDE: 1862 Sediment transport;
- HYDROLOGYDE: 1862 Sediment transport;
- HYDROLOGYDE: 4217 Coastal processes;
- OCEANOGRAPHY: GENERALDE: 4217 Coastal processes;
- OCEANOGRAPHY: GENERAL