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School of Agriculture and Environment
College of Sciences
Channel change and sediment transfers in the Ruamahanga catchment: a multi-scalar approach
I am evaluating sediment transfers and channel changes at multiple spatial and temporal scales in the tectonically-forced Ruamahanga catchment. Morphotectonic mapping is underway to establish process domains for sediment transfers and has identified forced channel, floodplain, terrace, and valley forms whose proximity to tectonic landforms implicates ongoing influence of the southern North Island Fault System. Several valley segments with higher potential for break-out flooding and/or avulsion that would impact Wairarapa communities have been selected for more detailed (segment/reach scale) investigation. Envelope analysis of the cross-sectional data record (initiated ca 1989) indicates general bed deflation. However, interval evaluation (3-5 years) indicates considerable spatial variability including transient, localized aggradation of a magnitude significant to flood control efforts. Field observations have identified multiple instances of bar-scale sediment accretion not captured by monumented cross-sections. Event-based sediment translocation and channel changes associated with discharges less than half of the annual recurrence flood have been observed and a proposal to intensify event-based investigation is pending. Structure-from-Motion (SfM) outputs will inform morphological sediment budgeting and characterize coarse sediment flux. The spatially-continuous nature of the collection is expected to capture flux in a more robust manner that, coupled with increased sampling frequency, will facilitate more responsive river management.
My research will inform flood planning and management human safety and property protection. Geomorphologists, geologists, civil engineers, and floodplain managers will have the greatest interest in this research.
The communities of Masterton, Carterton, and Greytown and their surrounding residents will directly benefit from a broader and deeper knowledge pool for flood management as well co-seismic contingency planning.
After 25 field seasons in Washington state and Wyoming it was time to answer the call of New Zealand's active landscapes. My career has been highly applied and interdisciplinary and generally fluvially-oriented. After eighteen years of applying geomorphology, hydraulics, and construction engineering to river restoration projects, the Physical Geography group and Innovative Research Solutions program at Massey are providing the opportunity to deepen my knowledge of river dynamics, engage emerging technologies, and incorporate fluvial, tectonic, and hazard themes into PhD research. I anticipate my post-PhD career will follow similar themes in the government or consultancy sectors.
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Last updated on Tuesday 04 April 2017