Assessing the geomorphological effectiveness of river restoration using multi-stage channels (with CASE partner SEPA)

Assessing the geomorphological effectiveness of river restoration using multi-stage channels (with CASE partner SEPA)

Supervisor: Dr Richard Williams, School of Geographical and Earth Sciences, University of Glasgow, richard.williams@glasgow.ac.uk; Prof Trevor Hoey, School of Geographical and Earth Sciences, University of Glasgow, trevor.hoey@glasgow.ac.uk

Description: Channelisation has led to a legacy of rivers characterised by uniform channel geometry and river-bed sediment (1,2), and a lack of flow variability required to provide varied ecological habitat (3). In rural settings, with no constraints, restoration of such rivers to enable river migration and sediment connectivity, often involves channel diversion and re-meandering (4). Such schemes are expensive due to excavation works and land use change compensation. Further, for deeply incised rivers and in many urban areas, realignment is not physically feasible. Alternative strategies to improve the morphological condition of incised, straightened rivers include the creation of “multi-stage” channels, where embankments are set back and banks reprofiled to create floodplain benches, and in-channel structures, such as flow deflectors (5), are used to vary flow and induce sediment transport. The effectiveness of such restoration approaches has yet to be investigated. Evaluation of morphological responses to multi-stage channel restoration is therefore vital for river managers to design, implement, and adaptively manage this type of restoration scheme.

This studentship addresses the need for quantitative evidence to assess interactions between sediment, morphology and hydrology in channels that are restored using multi-stage design. The primary hypothesis is that multi-stage channel design produces significant increases in the diversity of morphology, river-bed sediment and flow patterns.

The project uses multi-stage channel restoration schemes on the River Nith (Ayrshire), Glazert Water (Dumbarton) and Pow Burn (Angus), a total of 10 km of river. Integrated monitoring and numerical modelling will answer the following questions:

HOW DO THE MORPHOLOGY AND SEDIMENTOLOGY OF MULTI-STAGE CHANNELS EVOLVE AFTER FLOW EVENTS?

Repeat topographic surveys will be undertaken using the most appropriate technique for each site (UAV imagery & SfM photogrammetry, TLS, RTK-GNSS, total station. Automated, field-calibrated, photo sieving and roughness analyses will be used to map river bed and bar sedimentology. Fixed point photos and meso-habitat (flow/substrate) surveys will also be undertaken. Geomorphic change (6) will be calculated and analysed. Analysis of these data will be used to begin to evaluate the timescales over which dynamic equilibrium may re-establish after restoration.

WHAT CONTROLS FLUVIAL LANDFORM ASSEMBLEGES AND THEIR EVOLUTION?

Delft3D hydraulic models of flow pattern will be built using topographic survey data. Metrics for 3D landform shape and depth/velocity relationships will be used to map landforms and habitats. Geospatial patterns, and associated controls, between landforms will be investigated (cf 7).

WHAT IS THE EFFECTIVENESS OF DIFFERENT FLOW DEFLECTION STRUCTURES IN INITIATING GEOMORPHIC PROCESS?

SEPA will trial a range of different woody dams, deflectors and diverters to initiate bank erosion and/or change flow patterns. Repeat, high-resolution acoustic Doppler current profiler (8) mapping of hydraulics will be used to map geomorphic change, and calibrate Delft3D morphodynamic change models to inform adaptive management of deflectors.

References: (1) Gilvear et al 2002 Sci Total Env 294 131-159. (2) Gurnell et al 2010 Geomorphology 116 135-144. (3) Miller et al 2010 Restoration Ecology 18 8-19. (4) Addy et al 2016 CREW Report CRW2014/10. (5) Hoey 1998 SNH Report 47. (6) Wheaton et al 2010 Earth Surf Proc Landf 35 136-156. (8) Williams et al 2015 J Geophys Res: Earth Surf 120 604-6. (7) Wyrick et al 2014 Geomorphology 210 14-22.

Funding notes: The studentship will be tenable for up to 4 years and provides the following package of financial support:

  • A tax-free maintenance grant set at the UK Research Council’s national rate (£14,553 for 2017/18).
  • Tuition fees at the Home/EU rate;
  • Access to an extensive Research Training and Support Grant (£11,000 over four years with an additional £1,000 per year from SEPA);
  • Travel costs for internships at SEPA.

Eligibility: This project would suit a candidate with a background in physical geography, geology, environmental science, engineering, mathematics and statistics, or computing science.

The University is only able to consider applications from Home/European Union candidates. International candidates are not eligible to be considered and where an candidate from another EU country has not been resident in the UK for 3 years or more prior to the commencement of their studies, they will only be eligible for a fees-only studentship.

Candidates should have the following qualities and backgrounds:

  • A first or 2:1 undergraduate degree, or have relevant comparable experience;
  • In addition, candidates may also hold or be completing a Masters degree in their area of proposed study or a related discipline; &

An outstanding academic pedigree and research potential, such as evidenced through the publication of articles, participation in academic conferences and other similar activities.

How to Apply: To apply for this project you need to email the following documentation to Dr Richard Williams, richard.williams@glasgow.ac.uk

  • Current CV;
  • A cover letter, which should consist of a 500 word statement on (i) how you would seek to develop the project beyond the initial project outline and (ii) your motivation for applying for this PhD studentship.
  • Two academic references (these can be sent directly by the referees to Dr Richard Williams but it is the applicant’s responsibility to arrange);

Deadline: 26 January 2018. Shortlisted candidates will be interviewed in February 2018.

Start Date: 1 October 2018