Disentangling landuse and climatic roles in sediment delivery to upland British lakes


  • Supervisors: Dr Heather Sangster, University of Liverpool
    Prof. Richard Chiverrell, University of Liverpool


  • External Supervisors:

  • Contact:

    Dr Heather Sangster, University of Liverpool, Heather.Sangster@liverpool.ac.uk

  • CASE Partner:

Application deadline: 10 January 2020

Introduction:

Lakes and reservoirs act as sinks for both anthropogenic and natural processes occurring in catchments, therefore their sediments can provide valuable information on temporal changes in catchment processes. The role of landuse change and climate on British upland systems over the last 150 years has resulted in notable and in places significant changes in sediment delivery to the hydrological system (Smith et al., 2018), with phases of erosion being recorded within lake systems (Schillereff et al., 2014). Recent methodological developments permit a now much higher resolution analysis of sedimentary depositional rates within British upland lake systems (Chiverrell et al., 2019).  These developments alongside advances in archival analysis and mapping of archive based materials in GIS (Sangster et al., 2018);  provide new opportunities for exploring the competing roles of climate and landuse on sedimentary processes using landscape evolution models (LEM: e.g. CAESAR Lisflood).

Project Summary:

The studentship seeks to exploit existing datasets compiled at Liverpool for a series of catchments from around the UK and develop new sites to disentangle the competing roles of landuse and climate on sediment delivery to lakes. This will be achieved through several objectives:

  1. Reconstruct landuse patterns through time, using existing archival sources the project will examine how landuse and farming practices have modified the landscape.
  2. Reanalyse and reconstruct precipitation series for areas where no/partial existing records extending back to 1860, the start of British Rainfall - systematic rainfall recording across the UK
  3. Evaluate how changes in regional, national and international policies have shaped agricultural practices
  4. Develop new lake profiles, characterising sedimentary characteristics and depositional processes and rates of sediment accumulation.
  5. Use these new landuse and precipitation data in catchment scale LEM’s to simulate change in sediment fluxes to lake basins, and validate these using the lake sediment record. 

The PhD will include bespoke training in field data collection and processing, reconstruction of past landscapes using archival sources, GIS mapping, with training in lacustrine sediment characterization for geochemistry (XRF), mineral /organic content (NIRS), and particle size (laser granulometry) using the Environmental Change Laboratories at Liverpool. LEM simulations would draw on experience using CAESAR Lisflood to test the comparative importance of human and climate drivers of catchment erosion and sediment flux.

References:

Chiverrell, R.C., Sear, D.A., Warburton, J., Macdonald, N., Schillereff, D.N., Dearing, J.A., Croudace, I.W., Brown, J., Bradley, J., 2019. Using lake sediment archives to improve understanding of flood magnitude and frequency: recent extreme flooding in northwest UK. Earth Surf. Process. Landforms esp.4650. https://doi.org/10.1002/esp.4650

Sangster, H., Jones, C., Macdonald, N., 2018. The co-evolution of historical source materials in the geophysical, hydrological and meteorological sciences: Learning from the past and moving forward. Prog. Phys. Geogr. 42, 61–82. https://doi.org/10.1177/0309133317744738

Schillereff, D.N., Chiverrell, R.C., Macdonald, N., Hooke, J.M., 2014. Flood stratigraphies in lake sediments: A review. Earth-Science Rev. 135, 17–37. https://doi.org/10.1016/j.earscirev.2014.03.011

Smith, H.G., Peñuela, A., Sangster, H., Sellami, H., Boyle, J., Chiverrell, R., Schillereff, D., Riley, M., 2018. Simulating a century of soil erosion for agricultural catchment management. Earth Surf. Process. Landforms 43, 2089–2105. https://doi.org/10.1002/esp.4375

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