Published August 31, 2022 | Version 1
Other Open

H2020 773782-COASTAL MAL03 Model - Norrström-Baltic region

  • 1. Stockholm University


To address stakeholder system understanding and representation requirements, the system dynamics (SD) model developed for MAL3 focuses on water availability and quality, and their interactions with and implications for key inland and coastal sectors as a land-sea and sector interaction and impact tracer. Two SD sub-models were structured separately to address all relevant land-sea interactions for these model themes (water quantity model and water quality model). The two SD sub-models were further connected to develop an integrated MAL3 land-sea system model that describes key policy indicators (KPIs) for water quantity (water availability for socio-economic sectors, water availability for natural sub-systems and proxy of seawater intrusion risk) and water quality (net waterborne total Nitrogen (TN) and total Phosphorous (TP) inputs to and loads from socio-economic sectors, net waterborne TN and TP inputs to and loads from natural water systems, policy and management indicators for water quality). This integrated model has been used to simulate water quantity and quality changes under scenarios of shared socioeconomic pathways (SSPs), representing various land cover changes that involve urbanization, forest expansion, and agricultural development, as well as climate change impacts related to representative concentration pathways (RCPs). Effects of management alternatives targeting agriculture, wastewater treatment plants and legacy sources on water quality have also been simulated under the different SSP scenarios.

The input variables include:

  • Scenario number – A dimensionless value between 0-5;
  • Precipitation change rate – A dimensionless value in the range of [-1, 1] where negative and positive values indicate decrease and increase in precipitation, respectively;
  • Urban growth rate – A dimensionless value in the range of [0, 1], indicating inland/coastal urbanization;
  • Forest land change rate – A dimensionless value in the range of [0, 1];
  • Agricultural land change rate – A dimensionless value in the range of [0, 1] indicating inland/coastal agricultural development; Average nitrogen and phosphorus concentration levels in surface and subsurface waters – Value (kg/m3) in the range of [0, 1];
  • Average nitrogen and phosphorus concentration levels in discharges from WWTPs – Value (kg/m3) in the range of [0, 1];
  • Nitrogen and phosphorus concentration in flow from agricultural lands to surface and subsurface water – Value (kg/m3) in the range of [0, 1].

These input variables are further described in D19 and D20 and can be found in H2020 773782-COASTAL MAL03 Scenarios for the Norrström-Baltic region ( and H2020 773782-COASTAL MAL03 Management set for the Norrström-Baltic region (

The folder contains the following files:

MAL3-SU model_Dashboard_RCPs&SSPs.mdl

MAL3-SU model_Dashboard_RCPs&SSPs._2Py  - The model has also been converted to Python using the PySD library.

The different variables modified for the SSP scenarios and management measure sets are provided in a separate Excel file for each management measure set (which can be loaded into the Python SD model):






Files (164.0 kB)

Name Size Download all
164.0 kB Preview Download

Additional details

Related works

Is supplement to
Other: 10.5281/zenodo.6854491 (DOI)
Other: 10.5281/zenodo.6855357 (DOI)


COASTAL – Collaborative lAnd Sea inTegration pLatform 773782
European Commission