twinning water quality modelling in latvia helene ejhed, 20070626 final workshop twinning on...

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


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 ?


Freeware vs commercial -aspects

Access

Support

Developments

Modules - Package

Cost


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


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


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


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.


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


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


6 Parameter regions for calibration of HBV hydrology

HBV230 stations for calibration140 stations for validationtimesplit validation also

Hydrological modelling HBV


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.


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


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


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


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

twinning water quality modelling in latvia helene ejhed, 20070626 final workshop twinning on...

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