gwtransport#

gwtransport enables timeseries analysis of groundwater transport of solutes and temperature. 1) Estimate aquifer properties either from temperature tracer tests or streamline analysis. 2) Predict residence times and solute transport, and assess pathogen removal efficiency in bank filtration systems.

Testing of source code
Testing of examples
Package

What you can do with a calibrated model#

Calibration refers to the estimation of the aquifer pore volume distribution. Once you have estimated this, you can:

Predict residence time distributions under varying flow conditions
Forecast contaminant arrival times and extracted concentrations
Design treatment systems with quantified pathogen removal efficiency, compatible with tracer dating decay rates
Assess groundwater vulnerability to contamination with a retardation that may depend on its concentration (non-linear sorption)
Enable early warning systems as digital twins for drinking water protection

Two ways to obtain model parameters#

The aquifer pore volume distribution is constant over time and can be obtained using:

1. Streamline Analysis#

You already have computed the groundwater flow with an analytical solution or a numerical groundwater flow model. Compute the area between streamlines from flow field data to directly estimate the pore volume distribution parameters.

from gwtransport.advection import infiltration_to_extraction

# Measurements
cin = [1.0, 2.0, 3.0]  # Concentration infiltrated water [g/l]
flow = [100.0, 150.0, 100.0]  # Flow rates [m3/day]
tedges = pd.date_range(start="2020-01-05", end="2020-01-08", freq="D")  # Time edges for cin and flow bins

# Information from groundwater flow model
areas_between_streamlines = np.array([100.0, 90.0, 110.0])  # [m2]
depth_aquifer = 2.0  # [m] Convert areas between 2D streamlines to 3D aquifer pore volumes
porosity = 0.35  # [-]
aquifer_pore_volumes = areas_between_streamlines * depth_aquifer * porosity  # [m3]

cout = infiltration_to_extraction(
    cin=cin,
    flow=flow,
    tedges=tedges,
    cout_tedges=tedges,
    aquifer_pore_volumes=aquifer_pore_volumes,
    retardation_factor=1.0,
)  # [g/l] same units as cin

# Note: Initial output values are NaN until the first cin value has fully passed the aquifer

This efficiently computes cout with 1D transport for every aquifer pore volume and then averages over all aquifer pore volumes.

2. Temperature Tracer Test#

Approximate the aquifer pore volume distribution with a two-parameter gamma distribution. Estimate these parameters from measured temperatures of infiltrated and extracted water. Temperature acts as a natural tracer, revealing flow paths through heterogeneous aquifers via calibration. No groundwater model is required.

from gwtransport.advection import gamma_infiltration_to_extraction

# Measurements
cin = [11.0, 12.0, 13.0]  # [degC] Measured temperature infiltrated water
flow = [100.0, 150.0, 100.0]  # Flow rates [m3/day]
tedges = pd.date_range(start="2020-01-05", end="2020-01-08", freq="D")  # Time edges for cin and flow bins

cout_measured = [10.5, 11.0, 11.5]  # [degC] Measured temperature extracted water (required for calibration only)

cout_model = gamma_infiltration_to_extraction(
    cin=cin,
    flow=flow,
    tedges=tedges,
    cout_tedges=tedges,
    mean=200.0,  # [m3] Adjust such that cout_model matches the measured cout
    std=16.0,    # [m3] Adjust such that cout_model matches the measured cout
    retardation_factor=2.0,  # [-] Retardation factor for the temperature tracer
)

# Compare model output with measured data to calibrate mean and std parameters (see example notebook 1)

Here, the continues gamma distribution for the aquifer pore volume distribution is discretized into bins. For every bin, 1D transport is computed and then averaged over all bins.

Installation#

pip install gwtransport

Documentation Contents#

For an in-depth discussion of the core modeling approach, see Core Concepts. To determine when gwtransport is appropriate for your application and understand the underlying assumptions, see Assumptions.

Examples

API Reference

License#

GNU Affero General Public License v3.0

gwtransport

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