twinning water quality modelling in latvia helene ejhed, 20070626 final workshop twinning on...
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Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Final workshop
Twinning on development of modelling capacity to support
water quality monitoring in Latvia
Modelling: rationales and selection
Photo Lake Övre hammardammen, Fredrik Ejhed
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Experience ?•Model tested for similar conditions
•User experience•User interface
Data ?•Requirements
•Availability
Purpose ?
•Load and source apportionment•Scenario of change•Investigative modelling•Substances
Resolution ?– temporal and spatial•Daily drive data but annual results•Dynamic results needed in lakes and coastal processes•Spatial resolution – time and cost proportional•WFD demand both high spatial resolution and overview
•Monitoring data dependence
Models ?
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Freeware vs commercial -aspects
Access
Support
Developments
Modules - Package
Cost
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Model concepts
Level of complexityModel type
Physical
Empirical
High
Low
Daily simulations of flow and solute concentrations
Annual predictions based on export coefficients
Methods differ profoundly in their complexity, level of process
representation and data requirements
Rewritten from EUROHARP documentation
• Combination of models above
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Model concepts Limitations and advantages
Model type
Physical
Empirical
Advantages
•Process descriptions•Scenarios possibilities
•Low data requirements•Simple models
Limitations
•Expert user•High data requirements•Timeconsuming
•Few scenario possibilities•Valid only for model range
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Calibration of models The conceptual and processbased model is calibrated using
monitoring data
Empirical models e.g. regression analysis are only valid within the data range used
Fig. Total nitrogen concentration before and after calibration of soil retention, Skivarpsån Sweden, model for HELCOM PLC4 and WFD
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Results –weakest link rule A good model need good driving data
Ex. problems with faulty point source coordinates in an inlet watercourse to lake Vättern in Sweden, model for HELCOM PLC-4 and WFD. Total nitrogen concentrations vs. time.
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Purpose and resolution Latvia
WFD demands high resolution for programmes of measures as well as overview for characterisation.
Eutrophication– Load and source apportionment– Scenario of change
Priority hazardous substances– Load and chemical fate– Dispersion– Ecological status
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Monitoring vs. Modelling
Monitoring at strategic sites
Regionalised data – WFD typology
Modelling gives overview
Modelling gives physical processes
Models needed to plan measures
No model without monitoring data
Monitoring sites in Sweden used for WFD and HELCOM PLC-4
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
6 Parameter regions for calibration of HBV hydrology
HBV230 stations for calibration140 stations for validationtimesplit validation also
Hydrological modelling HBV
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Models to meet Latvian purpose and resolution – diffuse sources of eutrophication
EUROHARP models for eutrophication– EH evaluated models to harmonize reporting procedures
on diffuse sources.– Only 2 out of the nine EH models evaluated very suitable
for scenario calculations and hydrology, TRK and SWAT
– TRK and SWAT have been applied with good results in Sweden with similar climate as in Latvia.
Alternative eutrophication model– INCA, a good alternative due to a modest need of input
data, single interface and a complete catchment model.
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Selected models - Eutrophication Hydrology models
Because of the importance of process and models selected due to their difference in complexity:– SCS– HBV
Water quality modelsBecause of the varying need of high resolution in hydrology environment– CE-QUAL-W2
Catchment modelsBecause of the importance of diffuse and point sources and the models ability to perform scenario calculations– TRK– SWAT– INCA
Source apportionment and scenario toolsBecause of the importance of presentation and user friendly tests of scenarios of change– WATSHMAN
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Models comparison
Models SCS HBV CE-QUAL-W2
TRK SWAT INCA WATSHMAN
Modest data requirements
Y Y N Y N Y Y
High time resolution N Y Y Y Y Y Y
High spatial resolution
Y Y Y Y Y Y Y
Processbased conceptual model
N Y Y Y Y Y N
Calibration data required
N Y Y Y Y Y N
Scenario possibilities
N Y Y Y Y Y Y
Complete catchment model
N N N Y Y Y Y
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Models comparison - continueModels SCS HBV CE-
QUAL-W2
TRK SWAT INCA WATSHMAN
Distributed Y Y
(semi)
Y
(fully)
Y
(semi)
N
(semi)
Y
(semi +)
Y
(semi)
Time consuming N Y Y Y Y Y N
Single interface N Y Y N Y Y Y
Exchangeable submodels
N Y - Y N* - Y
Applied for national assessments
- Y - Y - - N
Applied in Northern Europe
Y Y Y Y Y Y Y
Non-Expert user Y N N N N N Y
Freeware Y Y Y Y Y Y Y
* some process submodels can be chosen in a scrollist and some can be exchanged- have not been verified
Twinning water quality modelling in LatviaHelene Ejhed, 20070626
Priority hazardous substancesModels and concept
Decision support system – SOCOPSE.se
Recommendation of concept:
Chemical fate modeling – fugacity approach
Screening monitoring
MFA (Material Flow analysis) and LCA (Life Cycle Analysis)
QSAR modeling – for chronic toxicity and physical data for new substances
OMEGA for ecological status
Fully distributed hydrological model for dispersion in water environment