Presentation by Peter Vermeulen (Deltares) at the iMOD International User Day, during Delft Software Days 2016. Tuesday 1 November 2016, Delft.

1. The SFR-package in iMOD to support large-
scale groundwater flow model Rhein-valley
14 november 2016
Entwicklung und Bereitstellung von
speziellen Tools für die
Modellsoftware iMOD für das
Hessische Landesamt für
Naturschutz, Umwelt und Geologie
Peter Vermeulen, Bernhard Becker
(Deltares)

2. Content
14 november 2016

3. SFR Overview – Concepts
LAYOUT
14 november 2016
𝑄in = 𝑄out
𝑄 = 𝑛𝑤𝑦
5
3 𝑆
1
2
𝑦 =
𝑄𝑛
𝑤𝑆
1
2
3
5
• Exchange Groundwater
• Surface overland flow
• Precipitation
• Evaporation
• External sources
Manning’s Equation
w: width of the stream
y: depth of water in the stream
n: Manning’s roughness coefficient
s: slope of stream

4. SFR Overview – Concepts
LIMITATIONS
14 november 2016
 No storageterm;
 No damping of waves;
 Steady state for each timestep (quasi-transient approach);
 Uniform flow, driven by gravity and predefined flow directions (per timestep
adjustable though;
 Distribution at branching must be specified:
 Up to a specified flow rate is diverted to the stream;
 Only above a specified flow rate in the stream the flow is diverted;
 The diversion rate is assigned by a predefined fraction;
 All flow is diverted in excess of a specified flow (flood control).
• Fixed amount taken from a stream (extraction)
10.0
11.0
12.0
13.0
14.0
15.0
01
00:00
01
12:00
02
00:00
02
12:00
03
00:00
03
12:00
04
00:00
04
12:00
05
00:00
05
12:00
06
00:00
time
waterlevel[m]
unsteady steady

5. SFR Overview – Concepts
EXCHANGE WITH GROUNDWATER
14 november 2016
Q, q: leakage flux, exchanged amount of water
c: leakage coefficient as ks / d;
w: interface width as function of river stage
L: length of stream
h: head difference between river stage hr and groundwater
level hg
d: sediment layer thickness of river bed
kS: hydraulic conductivity of riverbed
q
q1
q2
Δh
Δh1
Δh2
infiltration
drainage
𝑄 =
𝑘 𝑠 𝑤(ℎ 𝑟)𝐿
𝑑
Δℎ
𝑐 =
𝑘 𝑠
𝑑

6. SFR Overview – Concepts
COMPUTING WATERLEVELS
1. Interpolation between given levels;
2. Manning‘s Equation with a rectangular cross-section;
3. Manning‘s Equation with a 8-point cross-section;
4. Function assuming stream depth and width can be related to
streamflow by an equation;
5. Table with values of depth and width for given streamflows.
14 november 2016

7. SFR Implementaton in iMOD
DATA STORAGE
14 november 2016
ISG-RIV ISG-SFR
RIV-package SFR-package
BDGRIV BDGSTR
ISG-RIV
Four attributes per calculation
points, many calculation points per
segment allowed – interpolation
over the segments by iMOD
Eleven attributes per calculation
points, only two calculation points
per segment – interpolation over the
segment by the SFR package
Exchange flux between surface-
and groundwater
Exchange flux between surface-
and groundwater
Stream Stages, -Depth, -Width and
-Discharges

8. SFR Implementaton in iMOD
DATA STORAGE
14 november 2016
S1
S2
S3
S4
S5
S6
S8
S7
Transient connections, riverbed width, -conductivity
and -thickness, calculation options, runoff flow
Connection and flow
direction
Cross-sections Discharge-
width/depth relations

9. SFR Implementaton in iMOD
CONNECTIONS
14 november 2016
Functionality
to
interactively
select the
down- or
upstream
connected
stream
diversion
Flow direction
Connection
S1
S2
S3
S4
S5
S6
S8
S7

10. SFR Implementaton in iMOD
GRIDDING FOR SFR PACKAGE
14 november 2016
Intersection with
modelling raster
S1
S2
S3
S4
S5
S6
S8
S7
S1
S2
S3
S4
S5
S6
S8
S7
Segment is splitted into 6 reaches
for the model

11. SFR Implementaton in iMOD
RESULTS
14 november 2016
Stream Depths (m)
Stream Discharge (m3/sec)
Transient results:
 Stream Depth;
 Stream Width;
 Stream Stage;
 Stream Discharges
per segment written in ISG-file

12. SFR Implementaton in iMOD
RESULTS
14 november 2016
Select more segments, S1,
S2, S6 and S8
S1
S2
S3
S4
S5
S6
S8
S7
Visualize Stream Levels, Stream
Depth, Stream Width or Stream
Discharges over the selected
segment in a profile
S1
S2 S6
S8

13. SFR Implementaton in iMOD
RESULTS
Visualize Stream Levels,
Stream Depth, Stream
Width or Stream Discharges
for a) the selected segments
or b) all segments in the 2D
plot
Select any available date to
display the corresponding
results
.. or rasterize
the results to
conventional
IDF files

14. SFR Implementaton in iMOD
CONCLUSIONS
Part of the current Project:
 Include of the FHB package that allows for a mix of constant FLUX and
constant HEAD boundary conditions;
 Include of the LAK-package that allows the lake levels to be depending on
the inflow from the SFR package;
 Scheduled release of the above: February 2017 with iMOD v3.5