Presentation by Huite Bootsma (Deltares, Netherlands) at the Hydrology Suite User Days (Day 1) - Hydrology Suite introduction and River Basin Management software (RIBASIM), during the Delft Software Days - Edition 2023 (DSD-INT 2023). Tuesday, 28 November 2023, Delft.

1. Huite Bootsma
28 November 2023
Coupling RIBASIM to a
MODFLOW groundwater
model

2. Why?
2
https://www.destentor.nl/harderwijk/dode-karpers-in-drooggevallen-vijvers-rond-kasteel-
in-hierden~a53c99d8/
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3. Why?
• Groundwater is the largest terrestrial water
store
• Groundwater models are extensively used
in water management studies
• Most effects are found at the surface
− Water availability
− Ecological baseflows
• Large impact of water management –
especially in highly engineered systems
such as the Netherlands
• We require instruments to simulate both
groundwater and managed surface water
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4. Long history of water management simulation
4
Goeller, B. F. (1983). Policy analysis of water management
for the Netherlands. Vol I: Summary report. R-2500/1
NETH for Rijkswaterstaat.
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5. Surface water in MODFLOW
• Surface water is a boundary condition in
MODFLOW
• Surface water bodies are generally represented
by the River package in MODFLOW
• Each cell of the groundwater model is assigned
a River boundary
• Discharge to the River is linear function of:
aquifer head – river stage
• Infiltration is limited when the aquifer head falls
below the river bed elevation
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6. RIBASIM-MODFLOW coupling
RIBASIM simulates surface
water: result in a water level
Set water level in MODFLOW
MODFLOW computes
groundwater-surface water
exchange
Return net flows to RIBASIM
6
RIBASIM (surface water)
MODFLOW 6 (groundwater)
stage
Dis-
charge
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7. Hooge Raam: Basin delineation
Illustrate the principals of the
MODFLOW coupling with the Hooge
Raam area:
Divided into 53 basins: lumped
hydrological representations
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8. Hooge Raam: Basin delineation
Illustrate the principals of the
MODFLOW coupling with the Hooge
Raam area:
Divided into 53 basins: lumped
hydrological representations
Let’s focus on this area
8
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9. Hooge Raam: MODFLOW River boundary
Shown here is the main
watercourse
25 m grid resolution
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10. Hooge Raam: surface water slope within basin
River bed elevation
can show relevant
slope within a
single basin
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11. Hooge Raam: D-Flow FM nodes
We have derived the hydraulic properties
of the RIBASIM Basins from a hydraulic
model (Delft3D FM Suite 1D2D):
D-Flow FM nodes → RIBASIM basin
We can also go in reverse direction:
RIBASIM basin → D-Flow FM nodes
water levels
These nodes provide sufficient detail for
MODFLOW
11
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12. Hooge Raam: Distributed water levels
The Basin / subgrid table
contains a piecewise
linear interpolation from
the basin level (by
node_id) to the detailed
element (subgrid_id)

13. Hooge Raam: Couple detailed water levels to MODFLOW
MODFLOW River boundary 42
linked to subgrid element 108,
which is located in basin 11
Coupling link can be spatially
verified

14. Hooge Raam: Results
Single basin, water
levels at three
locations marked by a
red cross
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15. Conclusion
RIBASIM contains simplified relations for spatially “lumped”
hydrologic units: basins
The parameters are derived from spatially distributed data
Translate basin level back to spatially distributed water levels
Set spatially distributed water levels in MODFLOW coupling
MODFLOW computes groundwater-surface water exchange,
lumped by RIBASIM
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DSD-INT
2023
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Hydrology
User
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16. info@deltares.nl
@deltares linkedin.com/company/deltares
www.deltares.nl
@deltares facebook.com/deltaresNL
Thank you!