Towards Benchmarking Time Series Analysis with Process-Based Groundwater Models. The Case of Hydrogeological Impacts of Tunnel Construction
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Infrastructure and environmental engineering (MPIEE), MSc
Publicerad
2024
Författare
Lilja, Erik
Zander, Zackarias
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This thesis evaluates time series modelling for investigating groundwater impacts due to
tunnelling in an urban environment based on a process-based, benchmark groundwater model.
The Haga site in Gothenburg, Sweden, as part of the Västlänken infrastructure project was used
as case study area.
Utilizing datasets from various sources, including climate data from SMHI, head observations
from the Haga site, and MODFLOW simulations. The study employs MODFLOW simulations
and time series analysis to simulate and evaluate GW dynamics. Through Python-based transfer
function noise modelling (TFN) using the Pastas package, the study constructs time series
models to assess potential tunnel leakage and its impact on GW levels. The thesis emphasizes
the importance of accurate data collection and precise modelling techniques to correctly
calibrate the model to show the effects on GW systems.
The calibration of the MODFLOW model showed good correlation with observed groundwater
data, but urban complexities and model limitations caused discrepancies. Refinements, such as
improved calibration techniques and improving the representation of groundwater recharge,
could enhance model accuracy. The TFN models demonstrated strong performance, especially
with added stress data of tunnel leakage. This indicates that the ability of TFN models to
investigate groundwater impacts can be benchmarked with a groundwater flow model.
However, this study also highlighted challenges due to data scarcity, leading to mismatches
between groundwater observations and simulations with the benchmark model, which in future
studies could be addressed with more advanced calibration and integration techniques. Future
research should focus on refining these models and investigating the skill of TFN models when
more groundwater impacts are present.
Beskrivning
Ämne/nyckelord
Transfer function-noise modelling, , Time series analysis , Pastas , MODFLOW model , Groundwater