coupling swat with in-stream models for an integrated ... · 2011 international swat conference...
TRANSCRIPT
2011 International SWAT Conference Toledo, Spain, June 15-17 2011
Kiesel J.1, Fohrer N.1, Schmalz B.1, Brown G.L.2
Coupling SWAT with In-stream Models for an
Integrated Assessment of Sediment Transport
1 Institute for the Conservation of Natural Resources, Dep. of Hydrology, Kiel University
2 USACE Coastal and Hydraulics Laboratory, ERDC, Vicksburg, MS
Dep. of Hydrology and Water Resources Management – Fohrer et al. -2-
Outline
1. Background and scope of the project
2. Model coupling
3. Modeling water fluxes on three scales
4. Modeling sediment fluxes on three scales
5. Discussion
Dep. of Hydrology and Water Resources Management – Fohrer et al. -3-
Integrated ecohydrological river basin assessment
Kirchweddelbek (SH), Foto: U. Holm
Catchment
processes
In-stream
processes
(1D, 2D)
Habitat
Reality Abstraction
HEC-RAS
Modelling
Dep. of Hydrology and Water Resources Management – Fohrer et al. -4-
The in-stream models
Widely used hydraulic model for simulating open
channel flow and sediment processes in river networks
ArcGIS interface available
Adaptive Hydraulics model for simulating 2D-shallow
water problems with sediment transport on a triangular
finite element mesh
Dynamic adaption of mesh resolution during simulation
ArcGIS interface had to be programmed
HEC-RAS
1D
(USACE 2010)
2D
(Berger et al. 2010)
Dep. of Hydrology and Water Resources Management – Fohrer et al. -5-
Why additional in-stream models?
HEC-RAS
1D
(USACE 2010)
2D
(Berger et al. 2010)
supplies spatially distributed results from the catchment
no differentiation of stream properties beyond subbasin (Arnold et al. 1998)
supplies spatially distributed results at cross sections
too coarse to model in-stream morphodynamics for
habitat assessments
supplies spatially distributed results on points
very high resolution in the stream possible
Dep. of Hydrology and Water Resources Management – Fohrer et al. -6-
Outline
1. Background and scope of the project
2. Model coupling
3. Modeling water fluxes on three scales
4. Modeling sediment fluxes on three scales
5. Discussion
Dep. of Hydrology and Water Resources Management – Fohrer et al. -7-
Lowland characteristics
(JOSE 2006)
Kielstau catchment, UNESCO demosite for Ecohydrology
• 50km²
• 8.2°C
• 870mm/a
• Low hydraulic
gradients,
near-surface
groundwater
• Agricultural
land use
• Urban
influence
Dep. of Hydrology and Water Resources Management – Fohrer et al. -8-
Process depiction on three scales
3 km
Flow,
Sediment Velocity,
Depth,
Sediment
HEC-RAS
Velocity,
Depth,
Sediment
Dep. of Hydrology and Water Resources Management – Fohrer et al. -9-
Model coupling
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
LTOTday
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
06/02 12/02 06/03 12/03 06/04 12/04 06/05 12/05 06/06 12/06 06/07
Dis
ch
arg
e m
³/s
Discharge measured
Discharge modeled(drains+potholes)
Q
ArcGIS 9.2 PYTHON script:
• SWAT tributary flows (output.rch) are transferred to the according
HEC-RAS cross sections. Subbasin flows are distributed
among all subbasin cross sections
• SWAT tributary sediment loads (output.sub) are transferred to
the according HEC-RAS cross sections. Subbasin loads are
distributed among the tributary cross sections
• SWAT water temperature is transferred to HEC-RAS time series
• The interface supplies quasi unsteady and steady flow data
HEC-RAS
Dep. of Hydrology and Water Resources Management – Fohrer et al. -10-
HEC-RAS Model coupling
HEC-RAS
channel
HEC-RAS
cross section
(xs)
ADH
mesh
10m
Dep. of Hydrology and Water Resources Management – Fohrer et al. -11-
HEC-RAS flow values
and loads of each grain
fraction are transferred
from the cross section
to the ADH inflow
mesh nodes for each
daily time step
HEC-RAS
channel
HEC-RAS
cross section
(xs)
ADH
mesh
ADH
inflow
nodes
HEC-RAS Model coupling
Dep. of Hydrology and Water Resources Management – Fohrer et al. -12-
Outline
1. Background and scope of the project
2. Model coupling
3. Modeling water fluxes on three scales
4. Modeling sediment fluxes on three scales
5. Discussion
Dep. of Hydrology and Water Resources Management – Fohrer et al. -13-
Catchment hydrology
0
1
2
3
4
5
1999 2000 2001 2002 2003 2004
0
40
80
120
160
200
240
280
PCP
Observed
Modelled (calibration)
0
1
2
3
4
5
2004 2005 2006 2007 2008 2009
0
40
80
120
160
200
240
280
PCP
Observed
Modelled (verification)
mm
Flo
w [m
³/s]
Flo
w [m
³/s]
r² = 0.82
NS = 0.78
r² = 0.82
NS = 0.78 mm
Sinks Drains
Dep. of Hydrology and Water Resources Management – Fohrer et al. -14-
1D stream hydraulics HEC-RAS
C
A B
Dep. of Hydrology and Water Resources Management – Fohrer et al. -15-
1D stream hydraulics HEC-RAS
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Measured
Mo
de
lle
d
C B A
HEC-RAS depth [m]
0.0
0.2
0.4
0.6
0.8
0.0 0.2 0.4 0.6 0.8
Measured
Mo
de
lle
d
C B A
HEC-RAS velocity [m/s]
Water depth Flow velocity
r²=0.90 r²=0.88
24 flow scenarios: Qmin = 0.06m³/s Qmax = 1.26m³/s
Dep. of Hydrology and Water Resources Management – Fohrer et al. -16-
2D stream hydraulics
20m
depth cross sections
depth and velocity cross sections
Dep. of Hydrology and Water Resources Management – Fohrer et al. -17-
0.0
0.2
0.4
0.6
-0.2 0.0 0.2 0.4 0.6
Measured
Mo
de
lled
2D stream hydraulics
Water depth Flow velocity
r²=0.70 0.0
0.2
0.4
0.6
0.8
1.0
1.2
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Measured
Mo
de
lled
r²=0.93
1 flow scenario: Q = 0.73m³/s
Dep. of Hydrology and Water Resources Management – Fohrer et al. -18-
2D stream hydraulics
20m
depth cross sections
depth and velocity cross sections
1
2
3
Dep. of Hydrology and Water Resources Management – Fohrer et al. -19-
0.0
0.2
0.4
0.6
0.8
1.0
0.5 1.0 1.5 2.0 2.5 3.0 3.5
0.0
0.2
0.4
0.6
0.5 1.0 1.5 2.0 2.5 3.0 3.5
2D hydraulics – cross sections
0.0
0.2
0.4
0.6
0.8
1.0
0.5 1.0 1.5 2.0 2.5 3.0
0.0
0.2
0.4
0.6
0.5 1.0 1.5 2.0 2.5 3.0
modelled measured
Water depth [m] Flow velocity [m/s]
1
2
3
0.0
0.2
0.4
0.6
0.8
1.0
0.5 1.0 1.5 2.0 2.5 3.0 3.5
0.0
0.2
0.4
0.6
0.5 1.0 1.5 2.0 2.5 3.0 3.5
Distance from left bank [m] Distance from left bank [m]
Dep. of Hydrology and Water Resources Management – Fohrer et al. -20-
Outline
1. Background and scope of the project
2. Model coupling
3. Modeling water fluxes on three scales
4. Modeling sediment fluxes on three scales
5. Discussion
Dep. of Hydrology and Water Resources Management – Fohrer et al. -21- 21
Daily sediment loads in lowland catchments
Field River Drains
0
1
2
3
4
5
6
7
8
9
10
11
12
Oct-
06
Nov-0
6
Dec-0
6
Jan-0
7
Feb-0
7
Mar-
07
Apr-
07
May-0
7
Jun-0
7
Jul-07
Aug-0
7
Sep-0
7
Oct-
07
Nov-0
7
Dec-0
7
Jan-0
8
Feb-0
8
Mar-
08
Apr-
08
May-0
8
Jun-0
8
Jul-08
Aug-0
8
Sep-0
8
Oct-
08
Nov-0
8
Dec-0
8
Sedim
ent lo
ad [kg /d] )
Simulated MeasuredSeries3
Calibration Validation
Loading from HRUs/Subbasins
Loading from Subbasins + channel degradation/deposition
15% 15% 70%
R²=0.63
NSE=0.57
R²=0.65
NSE=0.58
Dep. of Hydrology and Water Resources Management – Fohrer et al. -23-
1D stream sediment - temporal HEC-RAS
-5
5
15
25
35
01/2
00
7
04/2
00
7
07/2
00
7
10/2
00
7
01/2
00
8
04/2
00
8
07/2
00
8
10/2
00
8
01/2
00
9
04/2
00
9
07/2
00
9
10/2
00
9
[t/day]
Sed. load MUSLE&DRAIN&BED
Sed. load DRAIN
Sed. load MUSLE
Measured load
Missing measured values
r² = 0.31, monthly r² = 0.68
Dep. of Hydrology and Water Resources Management – Fohrer et al. -24-
1D stream sediment - spatial HEC-RAS
Channel change in 4 years (2006 to 2009)
- 6.6 cm
0 cm
+ 3.0 cm
Dep. of Hydrology and Water Resources Management – Fohrer et al. -25-
2D stream sediment
Bed displacement [m]
-0.13 - -0.08
-0.08 - -0.05
-0.05 - -0.04
-0.04 - -0.02
-0.02 - -0.01
-0.01 - 0.00
0.00 - 0.01
0.01 - 0.02
0.02 - 0.04
0.04 - 0.060 31.5
m
20m
Bed displacement 01.-30. April 2008
Dep. of Hydrology and Water Resources Management – Fohrer et al. -26-
Outline
1. Background and scope of the project
2. Model coupling
3. Modeling water fluxes on three scales
4. Modeling sediment fluxes on three scales
5. Discussion
Dep. of Hydrology and Water Resources Management – Fohrer et al. -27-
Discussion
•The combined SWAT – HEC-RAS model is a feasible way to model different
sediment pathways over yearly periods in a reasonable resolution
•The shown temporal and spatial 1D sediment results are plausible and can be
used to identify erosion and deposition sections
•The combined HEC-RAS – ADH model can simulate detailed substrate
conditions, but with a high computational demand
•The shown spatial 2D sediment results need further calibration, as current
displacement rates are too high
•The capability of the model system to depict hydraulic- and substrate conditions
on different scales based on catchment and in-stream properties is valuable for
habitat assessments