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)

Content

14 november 2016

SFR Overview – Concepts LAYOUT

14 november 2016

𝑄in = 𝑄out

𝑄 = 𝑛𝑤𝑦53𝑆12

𝑦 =𝑄𝑛

𝑤𝑆12

35

• 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

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

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00:00

01

12:00

02

00:00

02

12:00

03

00:00

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12:00

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00:00

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12:00

05

00:00

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12:00

06

00:00

time

wa

ter

lev

el

[m]

unsteady steady

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 =𝑘𝑠𝑤(ℎ𝑟)𝐿

𝑑Δℎ

𝑐 =𝑘𝑠𝑑

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

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

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

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

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

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

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

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

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