Presentation by Adam Kovacs (ICPDR, Austria), Jos van Gils (Deltares, Netherlands) at the Delft3D User Days, during the Delft Software Days - Edition 2023 (DSD-INT 2023). Thursday, 16 November 2023, Delft.

1. Adam Kovacs, Technical Expert - Pollution Control
International Commission for the Protection of the Danube River, Vienna, Austria
Jos van Gils, Senior Researcher/Advisor
Deltares, Delft, The Netherlands
How emission modelling can contribute to
management of a large international river basin
The Danube Hazardous
Substances Model

2. Table of contents
2
• Why ICPDR pursued the development of DHSM
• Building blocks for DHSM
• Implementation of DHSM
• Sample results
• Was DHSM successful? What worked? What didn’t ?
Title page photograph: © Hannes Sallmutter/ebswien
© Mikhail Mikheev/Getty Images
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Hazardous
Substances
Model

3. Danube River Basin & ICPDR
800.000 km2
6.500 m3/s
85 Million PE
19 countries
Heterogeneity
Implementation of
the DRPC
EU WFD & FD
coordination
Policy making and
technical work
Chemical status
Protection of water &
ecological resources
Sustainable & equitable
use of water
Reduce nutrients &
hazardous substances
Manage floods
& ice hazards

4. Challenge of hazardous substances pollution
4
• Knowledge gap on enhanced monitoring and modelling tools
• Deficiencies of monitoring data in non-EU MS
• Lack of institutional capacity and intersectoral dialogue
• Climate change impacts (heavy rainfall, drought and low flow)
• Changing EU water legislation with ambitious requirements
• Shift focus from substances to pathways (domestic wastewater,
industrial wastewater, runoff in relation to land use, etc.):
▪ “Marker substances” for specific pathways
▪ “Priority pathways” instead of priority pollutants
© The Strive
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Hazardous
Substances
Model

5. Danube Hazard m3c: science-policy interface
5
Preliminary basin-wide
assessment
Improved basin-wide
emission model
Improved assessment &
scenario analysis
Inputs to DRBMPs
Analysis of existing
policies and strategies
Policy
recommendations
Transboundary
management
Modelling
Policy
support
Pilot sub-catchment
modelling
Inventory & Monitoring Capacity building
Pilot sub-catchment
modelling
Inventory & Monitoring Capacity building
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The
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Hazardous
Substances
Model

6. Building blocks
Methodology
• Common Implementation Strategy for the Water Framework Directive, Guidance Document No. 28
on the Preparation of an Inventory of Emissions, Discharges and Losses of Priority and Priority
Hazardous Substances + Calculating emissions to water – ETC/ICM Report 3/2022
Software
• D-Emissions programme (component of Delft3D FM Suite; under development)
Basin schematization and hydrology (2003-2013)
• E-Hype model by SMHI, Sweden
General information on the Danube River Basin
• ICPDR inventories
Specific information on Hazardous Substances in the Danube River Basin
• DanubeHazard m3c project (Interreg; Danube Transnational Programme)
6
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Hazardous
Substances
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7. Implementation
7
“Source oriented” approach
1. Quantify Sources, and allocate to initial receptor
(e.g. paved surfaces, top soils, sewers)
2. Trace substances pathways
− Wastewater management
− Stormwater management
− Soil system
3. In-stream fate and transport (water quality
model)
Steps 1-2: emission inventory
Step 3: resulting water concentrations
• Model validation
• Evaluate emission reduction measures
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Hazardous
Substances
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8. Implementation (cont’d)
8
• Calculations for about 3,500 schematization
elements
• Every element has a river section that flows into
the downstream element
• HS fluxes along pathways are time-dependent,
controlled by hydrology
• Events are resolved, e.g.
− combined sewer overflows,
− first flush of paved surfaces after dry periods
• Inter-annual variability is resolved
− wet years, dry years
− differences in emissions
− differences in dilution
0
5000
10000
15000
20000
25000
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
Discharge(m3/s)
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Hazardous
Substances
Model

9. Implementation (cont’d)
9
• Spatial data or country data from various
sources
• Specific data on hazardous substances
(DanubeHazard m3c project)
• 17 target substances, selected to represent
different relevant sources and pathways
− 7 metals
− benzo[a]pyrene (BaP), representing PAHs
− 2 pharmaceuticals
− 3 industrial chemicals
− 2 PFAS substances
− 2 pesticides
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Hazardous
Substances
Model

10. Results
10
• Calculated emissions of 17
chemicals
• Distributed over pathways (as
in the WFD CIS Guidance)
Not shown here
• Mass balance of all
compartments (insight)
• Quantified uncertainty of
emissions
• Quantified variability of
emissions between years
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Cd Pb Cu As Ni Hg Zn BaP PFOS PFOA BpA Met Tcz Cbz Dcf NP OP
Emissions to surface water
Atm Ind Agr HHo Nav WWTP Unc CSO StSew ROimp SRO DGW Ero
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Hazardous
Substances
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11. Results (cont’d)
• Spatial variability
• Country totals, subdivided over pathways
• Maps of area-specific total emissions
11
0.0
5000.0
10000.0
15000.0
20000.0
25000.0
DE AT CZ SK HU SI HR BA ME RS BG RO MD UA
Emissions to surface water per country for Zn (g/km2/y)
Atm Ind Agr HHo Nav Min WWTP Unc CSO StSew ROimp SRO DGW Ero
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Hazardous
Substances
Model

12. Results (cont’d)
12
• In-stream concentrations
− along the main Danube River
− annual means
• Variability between years
− Dashed lines
• Effect of uncertainty of
emissions
− Solid lines
• All substances
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0
500
1000
1500
2000
2500
3000
µg/L
Distance from Black Sea (km)
Metolachlor
Min. of 10Y Max. of 10Y P50 emissions P25 emissions P75 emissions

13. Results (cont’d)
• Scenarios
− connection to sewer systems
− wastewater treatment
− advanced treatment
− stormwater management
− erosion control
• Effects on emissions, basin-
wide
− S04: advanced treatment
>10,000 PE
• Effects on in-stream
concentrations,
− grey area is interannual
variability 0
0.005
0.01
0.015
0.02
0.025
2600 2100 1600 1100 600 100
µg/L
Distance from Black Sea (km)
Carbamezepine
Range of 10 years Mean of 10Y S01 S02 S03 S04
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Present S01 S02 S03 S04 S05 S06 S07
Emissions to surface water of Cbz (kg/y)
Atm Ind Agr HHo Nav Min WWTP Unc CSO StSew ROimp SRO DGW Ero

14. Model validation
14
• Measured vs simulated
concentrations
• Often reasonable results
• Pesticides and industrial chemicals
are problematic
Not shown
• Calibration/validation also possible
along pathways
(e.g. collected stormwater)
0.001
0.01
0.1
1
0
500
1000
1500
2000
2500
3000
µg/L
Distance from Black Sea (km)
Carbamezepine
Model-Min Model-Max DHm3c (>80% cens.) TNMN (>80% cens.) JDS4 (>80% cens.)
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Substances
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15. What worked well?
• Chemical emission model for the DRB first time ever
• Cooperation of scientific institutions and Danube countries
• Understanding of regional hot-spots, river loads to Black Sea
• Realistic pathway and source apportionment for the target chemicals
• Tool for future risk assessment regarding WFD compliance
• Tool for management and climate change scenario analysis
• Direct inputs to the DRBMP Update 2021 and its future versions
• Capacity building events on modelling for DRB experts

16. What needs to be improved?
16
• Lack of a basin-wide hydrological model (water balance on the way…)
• Model uncertainties for certain chemicals (pesticides and some industrial chemicals) due to:
▪ Lack of a basin-wide harmonized monitoring in water bodies suitable for modelling
▪ Lack of substance specific data on sources (production and use, industrial emissions)
▪ Lack of substance specific data on emission pathways (runoff, CSOs, groundwater)
▪ Lack of data and information on contaminated sites and legacy pollution stocks
▪ Insufficient understanding of the behavior of certain non-conservative substances
• Further model improvements anticipated in future projects
© netanimations.net
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Hazardous
Substances
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17. The authors acknowledge …
• Partners of the Danube Hazard m3c consortium
• The co-authors:
− Ottavia Zoboli, Matthias Zessner, Steffen Kittlaus,
Nikolaus Weber (TU Wien)
− Martine Broer, Oliver Gabriel (UBA)
− Adrienne Clement, Zsolt Jolankai, Mate Kardos (Budapest
University of Technology and Economics)
− Mugurel Sidău, Melinda Hărăguș, Corina Boscornea
(National Administration „Romanian Waters”)
− Michal Kirchner (Water Research Institute)
• Support of the Danube countries
• Funding received from
Danube Transnational Programme
17
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User
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The
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Hazardous
Substances
Model