Investigating the impact of geological heterogeneity on groundwater flow in the permo-triassic sandstone aquifer system of the eden valley, cumbria (uk)
File(s)
Author(s)
Colyer, Alex
Type
Thesis
Abstract
This thesis investigates the impact of geological heterogeneity on regional groundwater flow in the Permo-Triassic Sandstone aquifer system of the Eden Valley, Cumbria. Four distinct studies were conducted to address this aim, each focusing on a different aspect of hydrogeology. Study one analysed groundwater time series data to correlate hydrological signatures with geological heterogeneity. Three hydrogeological regimes were identified using seasonal trend decomposition by LOESS (STL), revealing that while meteorological factors influence groundwater seasonality, they do not dominate other groundwater flow behaviours. Study two developed and installed low-cost ultrasonic river level monitoring sensors to collect hydrological data, which led to two key insights: (1) Scandal Beck loses water to the southern Penrith Sandstone Brockram facies as it transitions from Carboniferous to Permo-Triassic geology, and (2) Knock Gill has a net-zero water exchange with the underlying St Bees Sandstone. These findings offer a novel contribution to understanding the region's hydrogeology. In study three, a geological and hydrogeological model of the Permo-Triassic Sandstone aquifer was developed, incorporating new pumping test data and borehole log information. Finally, study four built a numerical groundwater model, demonstrating that the Penrith Sandstone is well-characterized by a three-layer system, while the St Bees Sandstone remains poorly defined. This highlights the need for further regional characterization of the St Bees Sandstone. The impact of geological heterogeneity on groundwater flow was evaluated by simulating groundwater level time series using models of varying complexity. The analysis revealed that geological heterogeneity is a dominant factor influencing the observed groundwater level fluctuations. The findings underscore the importance of incorporating geological heterogeneity into regional groundwater flow models to improve the accuracy of groundwater forecasting and management in the region.
Version
Open Access
Date Issued
2023-08-05
Date Awarded
01/01/2025
License URL
Advisor
Butler, Adrian
Peach, Denis
Hughes, Andrew
Sponsor
Natural Environment Research Council (Great Britain)
British Geological Survey (Firm)
Grant Number
NE/L002515/1
Publisher Department
Civil and Environmental Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)