Dallow, G (2020) QUANTIFYING TRANSIENT STORAGE IN REALIGNED AND NON-REALIGNED RIVER REACHES. Other thesis, Liverpool John Moores University.

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Abstract

Transient storage has been used to quantify catchment-channel interactions, and more recently, as a proxy of ecosystem health in river restoration schemes. However, the impact that river restoration has on transient storage is not well studied. A key area that has not been extensively studied is the effect river restoration has on surface-subsurface interactions, and the evolution of these processes once restoration is completed. This study aims to quantify the effect that river restoration has on transient storage in order to understand how a river responds to restoration efforts and to make recommendations for future restoration schemes. The study site located on the Swindale Beck in Cumbria, UK comprised of three realigned reaches and one non-realigned reach. A conservative salt tracer injection (NaCl) and modelling approach was used to quantify transient storage. Breakthrough curves of the tracer were used in conjunction with the One-Dimensional Transport with Inflow and Storage model, OTIS, to estimate reach hydrodynamic parameters. These parameters were input into the modified OTIS model, OTIS-P, to calculate the transient storage metrics. These metrics were used to quantify transient storage after one month and after one year after restoration. In conjunction with transient storage data, UAV derived photogrammetry of the channel allowed for changes in geomorphological features, channel length, bankfull depth, and width to be quantified. The transient storage metrics describe that residence of channel water time in storage and the length of the storage zone was lower in realigned reaches compared to non-realigned reaches. Storage zone exchange flux and hydrological retention factor show a higher value in the realigned reaches compared to the non-realigned reach. This suggests that the realigned reaches are dominated by rapidly exchanging surface storage, whereas the non-realigned reach was dominated by much slower subsurface storage. A conceptual model is proposed in order to better understand how river restoration affects surface-subsurface exchange within realigned and non-realigned river reaches. It is suggested that the removal of the reinforced banks however, would allow the channel to return to a state of dynamic equilibrium as floodplain access is realigned and natural channel progression can being to occur.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Transient Storage; Realigned Rivers; Quantifying Transient Storage; Swindale Beck; OTIS; OTIS-P; Conservative Salt Tracer Injection; Damköhler Number; Spatial and Temporal Patterns in Transient Storage; FMed@200; Conceptual Model of Transient Storage
Subjects:	Q Science > QR Microbiology
Divisions:	Biological & Environmental Sciences (from Sep 19)
Date Deposited:	23 Jun 2020 09:52
Last Modified:	21 Dec 2022 11:47
DOI or ID number:	10.24377/LJMU.t.00013105
Supervisors:	Byrne, P
URI:	https://researchonline.ljmu.ac.uk/id/eprint/13105

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