TY - JOUR
T1 - Statistical characterisation and stochastic parameterisation of sedimentary geological formations on their reaction capacity for sustainable groundwater quality management
AU - Griffioen, J.
AU - Vermooten, S.
AU - Keijzer, T.
AU - Bakr, M.
AU - Valstar, J.
N1 - EGU General Assembly 2012, held 22-27 April, 2012 in Vienna, Austria.
PY - 2012
Y1 - 2012
N2 - The fate of contaminants in groundwater aquifers is determined by the
buffering capacity of those aquifers together with the composition of
inflowing groundwater. A nationwide characterisation of the
environmental geochemistry of the shallow subsurface (down to 30 m below
surface) has been started in the Netherlands. This covers: 1. the
reaction capacity of sediments as buffer for contamination, and 2.
typical elemental composition of geological formations and the
association between trace elements and major minerals. For this purpose,
the Netherlands is subdivided into 27 so-called geotop regions each
having a unique geological build-up of the shallow subsurface. Here,
four types are recognised based on vertical hydrogeological build-up.
The regions are statistically characterised on their geochemical
composition using combinations of lithological class and geological
formation as strata. The statistical data are subsequently coupled with
a geological voxel model of the subsurface to stochastically
parameterise the geological units on reaction capacity. This combined
approach will be illustrated for the Dutch province Zeeland. Reaction
capacity is considered as a series of geochemical characteristics that
control acid/base condition, redox condition and sorption capacity. Five
primary reaction capacity variables are characterised: 1. pyrite, 2.
non-pyrite, reactive iron (oxides, siderite and glauconite), 3. clay
fraction, 4. organic matter and 5. Ca-carbonate. Important reaction
capacity variables that are determined by more than one solid compound
are also deduced: 1. potential reduction capacity (PRC) by pyrite and
organic matter, 2. cation-exchange capacity (CEC) by organic matter and
clay content, 3. carbonate buffering upon pyrite oxidation (CPBO) by
carbonate and pyrite. A statistical investigation of several hunderds of
sediment analyses is performed that provides the geochemical properties
of the sediments. Here, classification based on sedimentary facies may
provide additional insight on spatial heterogeneity within lithological
classes. A two-step stochastic algoritm is established for
parameterisation of a geological voxel model. First, the cumulative
frequency distribution (cfd) functions are calculated for the
geochemical strata. Next, all voxels are classified into the geochemical
strata and the cfd functions are used to put random reaction capacity
variables into the geological voxel model. The result is a heterogeneous
geochemical reaction capacity model of the subsurface having grid cells
of 100x100x0.5 m. This model can be used in e.g. groundwater transport
models or other instruments for groundwater quality management.
AB - The fate of contaminants in groundwater aquifers is determined by the
buffering capacity of those aquifers together with the composition of
inflowing groundwater. A nationwide characterisation of the
environmental geochemistry of the shallow subsurface (down to 30 m below
surface) has been started in the Netherlands. This covers: 1. the
reaction capacity of sediments as buffer for contamination, and 2.
typical elemental composition of geological formations and the
association between trace elements and major minerals. For this purpose,
the Netherlands is subdivided into 27 so-called geotop regions each
having a unique geological build-up of the shallow subsurface. Here,
four types are recognised based on vertical hydrogeological build-up.
The regions are statistically characterised on their geochemical
composition using combinations of lithological class and geological
formation as strata. The statistical data are subsequently coupled with
a geological voxel model of the subsurface to stochastically
parameterise the geological units on reaction capacity. This combined
approach will be illustrated for the Dutch province Zeeland. Reaction
capacity is considered as a series of geochemical characteristics that
control acid/base condition, redox condition and sorption capacity. Five
primary reaction capacity variables are characterised: 1. pyrite, 2.
non-pyrite, reactive iron (oxides, siderite and glauconite), 3. clay
fraction, 4. organic matter and 5. Ca-carbonate. Important reaction
capacity variables that are determined by more than one solid compound
are also deduced: 1. potential reduction capacity (PRC) by pyrite and
organic matter, 2. cation-exchange capacity (CEC) by organic matter and
clay content, 3. carbonate buffering upon pyrite oxidation (CPBO) by
carbonate and pyrite. A statistical investigation of several hunderds of
sediment analyses is performed that provides the geochemical properties
of the sediments. Here, classification based on sedimentary facies may
provide additional insight on spatial heterogeneity within lithological
classes. A two-step stochastic algoritm is established for
parameterisation of a geological voxel model. First, the cumulative
frequency distribution (cfd) functions are calculated for the
geochemical strata. Next, all voxels are classified into the geochemical
strata and the cfd functions are used to put random reaction capacity
variables into the geological voxel model. The result is a heterogeneous
geochemical reaction capacity model of the subsurface having grid cells
of 100x100x0.5 m. This model can be used in e.g. groundwater transport
models or other instruments for groundwater quality management.
M3 - Meeting Abstract
SN - 1029-7006
VL - 14
SP - 3550
JO - Geophysical Research Abstracts
JF - Geophysical Research Abstracts
ER -