twinning water quality modelling in latvia helene ejhed, 2006-09-05 kickoff meeting twinning on...

Twinning water quality modelling in LatviaHelene Ejhed, 2006-09-05

Kickoff meeting

Twinning on development of modelling capacity to support

water quality monitoring in Latvia

Overview of available water quality models

Photo Lake Övre hammardammen, Fredrik Ejhed


Overview water quality models - selection

Eutrophication and acidification are well known problems

Water flow and pathways models are numerous

Nutrients N and P have been extensively investigated and models tested

EUROHARP project provides model test results

Water quality models are often chains of submodels

Priority substances WFD annex X often unknown transport pathways and fate


Euroharp project Towards european harmonised procedures for quantification of nutrient losses from diffuse sourceswww.euroharp.org

All 9 models applied in 3 country catchments

By lottery applied in 3 additional country catchments

Susve in Lithuania modelled with MONERIS, REALTA, SA and NOPOLU

Nationally used models for international report obligations


Processes of water qualityTransport and retention and source apportionment

leakage of nutrients from landuse

hydrology and flow pathways

denitrification processes

biota cycling, sedimentation

source apportionment

point sourcecontributions


Simple balance model within EUROHARP

”SA” Source apportionment – follows the procedure by HARP-NUT guidelines– Agricultural load is determined only by subtraction of

other sources (including retention and background load) from monitored and unmonitored river load on the sea.

– The empirical retention models for lakes require only the hydraulic loading, water temperature, N and P loading and an estimate of the P pool in lakes.


Hydrology and flow pathways

Hydrological descriptions are very important for pollution load calculations

Only 4 EH models include hydrological module ANIMO, SWAT, HBV (TRK), EveNFlow– Topography, landuse and soil type divide each basin into

hydrological response units HRU (ANIMO, SWAT) or subbasins (HBV) or response groups (EveNFlow)

– Daily climate data are drive data– Major differences in snow routines, surface runoff descriptions and

how water balance is calculated

SCS (Soil Concervation Service) model – calculates using flow transport factors dependent on landuse and

soil type. Snow routine and monitored baseflow can be added. Daily data.


Hydrology example results

Top graph shows model flow results vs monitored data. Low graph shows model transport total N results vs monitored data. TRK (HBV hydrology) model


Diffuse sources models- agricultural contributions

Empirical models– For example regression analysis of most important

factors for N and P transport– Ex. EH models REALTA and NOPOLU.– Limited possibilities to scenario calculations

Process based models with a high resolution are mainly developed to evaluate the effects of agricultural management practices or detailed (sub-)catchment management.– Ex. EH models SWAT, NL-CAT (ANIMO), TRK(SOILNDB)– Input data heavy– Expert user


Ex. Animo –fertilization level, soil management to nutrient leakage


Ex SOILNDB –calculates standard N leaching rates from combinations of soils,crops, normal yield, normal climate per region


Retention models

Retention – recycling within the freshwater ecosystem

Biota exchange, sediment exchange, atmospheric exchange and lake compartments exchange etc.

EUROHARP-RETNUT– Retention capacity

derived empirically


Application for scenario analysis

Only few of EUROHARP models were considered suitable for scenario analysis (predicting effects of measures)– MONERIS, NL-CAT(ANIMO), SWAT, TRK (SOILNDB)– But MONERIS cannot be used for water measures


Watshman PC tool

Data management, pollution flow, source distribution and action/investment scenarios


- Data management and presentation options as selecting, editing, simple calculations and usual GIS functions. ArcHydro connections under development.- Nutrient transport options with chains of models as diffuse leakage, lake retention model etc.- Scenario management options as changes in crop, landuse, sewage treatment etc.


Results for Lithuania Susve river catchment

MONERIS performed well– difficulties in DIN peak year– Susve 34 % N retention and

66 % P retention

REALTA only calculates risc

NOPOLU no results yet

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DIN load (t/a)

DIN load calc. DIN load obs.

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TN load (t/a)

TN load calc. TN load obs.


Proposal to approach in Latvian application WFD demands

– Typology– Reference conditions– Characterisation– Pressures– Measures

Get a quick overview using simple balance calculations if data are available

Identify problem issues, ex. eutrophication acidification, other pollutants, hydrological issues resolution etc.

Identify important processes, ex. snow routines, flooding, sediment transport, wetland and lake processes etc. to apply the right models.

Use combinations of well known models tested from similar areas.

twinning water quality modelling in latvia helene ejhed, 2006-09-05 kickoff meeting twinning on...

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