Delineating Drinking Water Protection Areas Using Analytic Element Models (AEMs) With Focus on Enabling Uncertainty Analysis Using Monte Carlo Simulations
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Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Infrastructure and environmental engineering (MPIEE), MSc
Publicerad
2023
Författare
ZAMZAMI, MARYAM
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The delineation of a wellhead protection area (WHPA) is a crucial task aimed at safeguarding
underground water resources. There are various methods available to achieve this, ranging
from simple approaches like fixed radius estimation with inherent limitations to more
sophisticated numerical models, which are considered the most detailed and reliable but
timeconsuming and data-intensive option. An analytical element model (AEM) provides a middle
ground between these two extremes, offering users the flexibility to implement different
boundary scenarios without being constrained by grid limitations. Moreover, AEM can
perform better in cases where data is scarce. However, it is important to recognize that the
output of groundwater modeling can never be claimed to fully reflect reality due to inherent
uncertainties. These uncertainties arise from various sources, including conceptual
understanding, model simplifications, and lack of data. To address these uncertainties, TimML,
a multi-layer, analytic element model, is employed and further enhanced to enable Monte Carlo
Simulations (MCS). To evaluate the effectiveness of the approach, a case study was selected
in which eight different scenarios were considered and caclualtions performed using MCS to
consider uncertainties. The calculated ranges of protection zones from these scenarios are
illustrated for the study area and benchmarked against the outcomes of the wellhead analytical
element model (WhAEM), an existing software for delineation of WHPAs tht does not enable
MCS. The results from the TimML model illustrates the added value of considering parameter
ucnertainties and how it affects the WHPA. Furthermore, the comparison reveals that the
largest differences are between the different scenarios rather than the two applied models. This
emphasizes the significant role of uncertainties arising from different assumptions in the case
study, highlighting that stochastic modeling alone is not sufficient to capture all relevant
uncertainties.
Beskrivning
Ämne/nyckelord
groundwater modeling, analytic element model, uncertainties, water protection, Monte Carlo analysis, stochastic modeling