A risk assessment framework for quantifying drought impacts on thermal and water extremes

Folegot, Silvia (2018). A risk assessment framework for quantifying drought impacts on thermal and water extremes. University of Birmingham. Ph.D.

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Abstract

By deploying Fibre-Optic Distributed Temperature Sensing, this thesis aims to improve understanding of the influences of drought-induced low flows, surface water warmings, shifts between up- and downwelling flows, and hydroclimatological controls on surface water and streambed temperature dynamics. First, the potential drought impacts on surface water and streambed temperature patterns of lowland streams are quantified. Second, high-resolution streambed sediments temperature distributions following altered groundwater-surface water exchange under distinct increased surface water temperatures are analysed. Third, the hyporheic refuge hypothesis is tested at high spatio-temporal resolution under different groundwater-surface water exchange and warming scenarios. Fourth, high-resolution seasonal variability in streambed sediments temperature distributions of a forested stream reach is quantified. The main outcomes are: 1) surface water and streambed temperature patterns in co-evolved vegetated artificial lowland streams varied with water level; 2) the direction of groundwater-surface water exchange impacted on the transfer of thermal stress into gravel streambeds under different warming scenarios; 3) alterations of the direction of groundwater-surface water exchange influenced the potential of the hyporheic zone of gravel streambeds to provide a refuge under warming; 4) seasonal variations of streambed temperatures in a forested stream reach are primarily driven by hydroclimatological conditions.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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