Content
Economic modeling is a cornerstone of evidence-based water governance. It provides a scientific basis for policy choices and helps stakeholders anticipate the impacts of different management strategies. In InnWater, models were developed and applied to support tariff design, subsidy targeting, and scenario analysis, helping balance financial sustainability, equity, and resource conservation.
What models are for
In practical governance processes, models serve four key functions:
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Quantifying impacts: simulating how tariff reforms, subsidies, or investments affect households, utilities, and the broader economy.
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Exploring trade-offs: making the consequences of different options visible, to balance cost recovery, affordability, and conservation.
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Enhancing transparency: making assumptions and results explicit, supporting informed dialogue and consensus-building.
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Guiding adaptive management: testing responses to shocks (e.g., droughts, economic crises) and adjusting strategies over time through scenario analysis.
Two complementary model families
InnWater mobilises both macro and micro perspectives, which are best understood as complementary rather than competing.
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Macroeconomic models (CGE) assess economy-wide impacts of water policies by simulating how changes in pricing, allocation, or investment ripple across sectors (agriculture, industry, households). They capture indirect effects and feedback loops and typically rely on Social Accounting Matrices (SAM). Their main strength is a holistic view useful for long-term planning; their main limitations are heavy data requirements and sensitivity to assumptions and calibration.
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Micro-simulation models (MSM) focus on household- or firm-level responses to policy changes (tariff reforms, subsidies). They help assess who pays more, who benefits, evaluate social tariffs and targeted subsidies, and simulate impacts on consumption and affordability. Their main strength is detailed, equity-focused analysis; their limits include being data-intensive and potentially missing wider macroeconomic feedbacks.
What modeling produces (and why it matters)
To be usable in governance, modeling outputs must be more than technical results. InnWater emphasises scenario comparisons, clear explanations of assumptions, and accessible outputs (visual dashboards, graphs and simple indicators) so that non-specialists can interpret results and use them in discussions. This is also why the project links modeling to digital environments and dashboards that improve transparency and make complex analyses easier to understand.
Application in InnWater pilot sites
Pilot applications illustrate how models support real policy questions: in La Réunion, micro-simulation was used to test progressive block tariffs and assess affordability, revenues, and conservation under changing demand and climate scenarios; in Brenta, modeling supported ERC integration and compensation mechanisms; and the approach was shared with Figueres, Westcountry and Middle Tisza for scenario analysis, subsidy design and alternative pricing options, often in participatory workshop settings.