Presentation by Ms. Ira Wardani (Deltares Indonesia) at the Seminar Hydro Software to support policy development and real-time decision making, during the Deltares Software Days South-East Asia 2019. Wednesday, 27 November 2019, Bangkok.

1. 1
CONFIDENTIAL AND PROPRIETARY
Any use of this material without specific permission by SYSTEMIQ, World Bank, or LIPI
is strictly prohibited
Joint Research
Plastic modelling in Indonesia
“ An estimate baseline of plastic
leakage into the marine environment”
Bangkok, 27/11/2019

2. 2
Government has outlined a Plan of Action with three ambitious targets
1 70% reduction1
of marine plastic debris
2 30% reduction2
of waste at source
3 70% handling rate2
for all waste
Source: (1) Indonesia’s plan of action on marine plastic debris, (2) Indonesia Presidential decree No. 97 year 2017
Need for one national baseline for
all stakeholders to track and report
performance and achievements

3. 3
Existing research on Indonesia lacks local context, while there is minimal empirical and
baseline data in the national level
Jambeck et al 2015
• 0.48 – 1.29 million tons per
year plastic leakage in
Indonesia
• Places Indonesia as #2
highest plastic leakage in
the world
Limitations of global research
• Research applies global averages and does not
use national (Indonesian) data
• Insights provided are not granular enough and
therefore not actionable
• Largely scientific focus on marine litter and don’t
address the source(s) of the problem
Lebreton et al 2019
• 1.63 million tons per
year mismanaged plastic
waste in Indonesia
Lebreton et al 2017
• 0.2 million tons per year
mid point annual emission
into marine environment
Existing research mentioning Indonesia
There is a need for a comprehensive research
focusing on Indonesia with the right granularity
and Indonesia-specific data

4. 4
Building a National Baseline
STATE of
pollution
Baseline for Plastics leakage into the
marine environment
SOURCES
PATHWAYS
NPAP
WB
LIPI
Land-based plastic leakage to water bodies.
Using secondary data, at city level
Flow of unmanaged plastic waste to water bodies
based on NPAP best estimate on (mis)
village/subdistrict level (population only) and
building in hydrology.
Stranded plastic waste on beaches, with
ocean current flow model
Terrestrial
Riverine
Marine
Riverine

5. 5
PreliminaryNational
Baseline
New Baseline Estimates for Plastics Leakage into the Marine Environment
Source:
Cutting Edge Research using Indonesia-specific data (with further validation)
Year Study
Terrestrial Riverine Marine
Solid Waste Management Hydrology Hydrodynamics
2015 Jambeck Global estimates not included not included
2017 Lebreton Global estimates
Stochastic approach
catchment-discharge
not included
2019 NPAP - SystemIQ
National estimates
(Archetypes)
not included not included
ongoing
WB - Deltares/
Haskoning
Higher resolution
estimates building on
NPAP*
Actual rainfall and
hydrological system
not included
2019 LIPI not included not included
Estimates based on
hotspot observations
*Initially for population only, followed by further refinement of solid waste management practices and behavior

6. 6
Incorporating Hydrology and Plastic Fate & Transport

7. 7
Using Hydrology for Waste Flows from Land-based sources and into marine environment
SIMPLIFIED VERSION
Source: NPAP 2019
Source: Deltares/Haskoning 2019
• How is plastic waste transported to the marine
environment?
• Does all plastic waste run-off to rivers/lakes?
• What role does hydrology play in the distribution of
plastic?
Hydrology as a driver for plastic waste

8. 8
Perceptual schematizationUsing modelling …
Source:
Mismanaged plastic waste may leak
into the terrestrial environment (SWM)
Solid Waste Handling Solid Waste Handling
Hydrology
Ocean Dynamics
Rainfall initiates run-off of plastic waste
in the terrestrial environment to the
riverine environment (Catchment)
River discharge transports plastic debris
down the river …
… to the marine environment

9. 9
From a Perceptual Model to a Conceptual Model
Source:
Simulating run-off, fate and transport from the terrestrial environment to the marine environment
wflow for Hydrological processes:
• Rainfall leads to run-off
• Run-off leads to river discharge
D-Emissions for Fate of Plastic Pollutants
• Plastic run-off from terrain (paved/unpaved; buried)
• Plastic degradation processes (disintegration; sinking)
D-Water Quality for Transport of Plastic Pollutants
• Transportation of plastic (sinking, trapping)
Conceptual model based on primary processes
DELWAQ - engine
Historic
Rainfall
(2013-2019)
wflow
model
(calibrated for
high discharges)
Plastic
leakages into
environment
(high resolution)
D-Emissions
module
Discharge
time series
(per catchment)
Preliminary
plastic input
into the
marine
environment
INPUT MODELLING OUTPUT
D-Water Quality
module

10. 10
Using modelling .. wflow – D-Emissions and D-Water Quality (DELWAQ)
Source:
Rainfall-runoff model: run-off and discharge as driver for plastic discharge from terrestrial to marine environment
• For Indonesia co-developed by PusAir and Deltares
• Only model available that covers whole Indonesia
consisting of 7 models with a horizontal resolution of
500m2
• Distributed rainfall-runoff model, open source and
freely available
• Used for river basin modelling
• Input: rainfall 2013-2019, land-use, digital elevation
model
wflow model
rainfall-run-off model, hydrology only
Estimating
infiltration,
run-off, flows

11. 11
Using modelling .. wflow – D-Emissions and D-Water Quality (DELWAQ)
Source:
Behaviour of plastic as a water borne pollutant under various forces
D-Emissions and D-Water Quality (DELWAQ) models
Fate and transport of pollutants
TRANSPORT: Terrestrial to river to marine environment:
From (im)permeable surfaces mediated by runoff events
(precipitation)
Within the river system by river flow
FATE: By removal and retention processes:
(1) degradation in terrestrial environment
(2) burial in terrestrial soils
(3) retention in river systems
1 2 2
1
2
33 3
2
1
1
2
11
22
Cutting edge methodology
Never applied before on this scale
INPUTS
Leakage of Mismanaged Plastics Waste:
(1) direct to surface water and
(2) to terrestrial environment
1
2

12. 12
D-emissions: plastic
Initial receptors Final receptorsSource

13. 13
Linking wflow to D-Emissions: plastic
1 Cell Compartments
Sewage
Paved
Unpaved
River/Lake
Ocean
Boundaries Trash racks Export
Linking wflow to D-Emissions

14. 14
D-Emissions, plastic debris flow modelling
Source:
The various sources and the quantification of the plastic leaks (in kg/timestep) is stored in separate input layers
(shape files or grid files) with the same resolution as the wflow model.

15. 15
Thanks…
Source: