IAP2-23-045

The Lake District Legacy: Tracking and tracing past, present and future delivery of contaminated sediment from historic mining headwater catchments

The aim of this project is to better understand the delivery of contaminated mine sediment from disturbed headwater catchments over historical, contemporary and future timescales (under climate change scenarios). The approach focuses on headwater source areas which critically control downstream impacts on the river network by regulating sediment, nutrient and pollution transfer; controlling runoff and flood transmission; providing habitat for endangered aquatic and terrestrial organisms; supporting traditional agroecosystems; and determining connectivity/discontinuity at the catchment-scale. The hydroclimatic regime of headwater catchments, tends to be spatially and temporally very variable promoting extreme flood flows which result in the episodic transfer of sediment and contaminants through the sediment cascade into downstream water bodies and lakes. Such flows are predicted to increase in severity under future climate change scenarios and have direct impacts on the redistribution of mining waste and associated ecosystem services. Recent work by Baynes et al. (2023) has demonstrated that using a multiple catchment approach with combined topographic analysis and detailed mapping of channel and sediment source morphological zones, general predictions of extreme flood impacts can be made. This project will use this approach to investigate sediment delivery of contaminated mining waste in three headwater catchments in the English Lake District with contrasting mining histories.

The key research questions are:
1) How do the fundamental geomorphological characteristics of first and second order streams control sediment transfer during extreme hydrological events in headwater catchments?
2) Does the magnitude and type of mining impact the spatial and temporal release and transfer of sediment from contaminated headwaters?
3) Can historical (documentary and field) records of previous extreme events in headwater catchments and downstream lake basins define past climate trends and be used as a basis for modelling future climate impacts?
4) How effective are contaminants as ‘natural tracers’ for identifying transfer pathways and sediment continuity in the upland source-to-sink sediment cascade?

The project will study three headwater-lake catchments (i) Greenside Mine – Glenridding – Ullswater catchment; (ii) Honister – Gatesgarthdale – Buttermere catchment; and (iii) Coniston Coppermines – Church Beck – Coniston Water system. These catchments satisfy the requirements of the key research questions and make use of a rich data archive held at the host institution. Importantly, the three catchments all consist of coupled headwater-lake systems, were internationally important areas for their respective mining activities (Pb, Cu & Slate), and represent a range of distinct mining settings/operations. The Ullswater area was heavily impacted by extensive lead (Pb) mining; Coniston was similarly impacted by extensive copper (Cu) extraction, while Buttermere had only small-scale metal mining trials (Pb and Cu) but was the site of large-scale slate quarrying.

The project methodology is mirrored at the three sites and consists of four integrated work packages:
1. A detailed geomorphological and topographic analysis to establish the contemporary sediment budget of the headwater catchment and set-up a HEC-RAS modelling framework to examine the local flood hydrology.
2. An archival and geomorphological analysis of each catchment to establish the chronology of mining (sediment production) and record of historical flood events (sediment transfer).
3. Lake coring to determine the downstream sedimentary record of mining, flooding and land-use change in the headwater catchment.
4. Landscape evolution modelling (CAESAR-Lisflood – coupled 2D hydrodynamic flow and geomorphic model) to simulate erosion and deposition over contemporary, historical and future timescales to understand how the current sediment system will respond to predicted future climate and catchment changes.

Data for work packages 1-3 is already available in the existing data archive for Ullswater and Buttermere sites, so new primary data collection will be focussed on the Coniston headwater catchment.

The outputs from the project will greatly increase knowledge of how mining activities impact the upland sediment cascade; provide a critical test of the use of natural tracers to track geomorphic change in active headwaters; and demonstrate how headwater rivers will respond to changing climate and environmental conditions. This will provide direct benefits to stakeholders who seek to manage river pollution, maintain ecosystem services and assess the future viability of river rewilding and flood management schemes.

Year 1

Literature review and project design
Consolidation and compilation of existing data archive in a common framework
Complete detailed geomorphological / topographic analysis and contemporary sediment budget
Start fieldwork in Coniston catchment
Compile archive of chronology of mining and record of historical flood events.
Set up catchment GIS and HEC-RAS modelling framework
Complete lake coring of Coniston Water

Year 2

Complete analysis of Coniston Water lake cores – lab work
Complete fieldwork in Coniston headwater catchment
Set up geomorphological / landscape evolution model (CAESAR-Lisflood) for the study catchments
Drafting of paper outlines and initial paper I

Year 3

Complete geomorphological / landscape evolution modelling (CAESAR-Lisflood)
Submission of first paper for publication
Complete drafts of two other papers (II & III) and begin compilation of final thesis

Year 3.5

Complete final thesis submission of papers for publication

A Training Needs Analysis (TNA) will be conducted to evaluate the student’s skills and design technical training bespoke to the project but also to enhance the general skills portfolio. Key skills will include fieldwork training / risk assessment; GIS & quantitative analysis of DEMs; analysis of large data sets; physical and geochemical laboratory analysis; and hydrologic and geomorphological modelling techniques. Full advantage will be taken of IAPETUS training opportunities e.g. modules in Introduction to modelling in Python and Advanced statistics in R. The thesis will be completed as a series of three publications. The student will attend Department, University and IAPETUS training courses to enhance skills in scientific writing with additional bespoke support from the supervisory team. The student will also be expected to take an active part in the research culture of the Department and IAPETUS Programme attending Department seminars / workshops and The IAPETUS Residential Research Training Week and annual conference. The student will also be encouraged to attend national and international conferences to present their research and network with the wider scientific community.