Policy Modelling with ABSS:
The Case of Water Demand Management


CPM Report No.: CPM-02-92
By: Olivier Barthelemy, Scott Moss, Thomas Downing and Juliette Rouchier
Date: 2001


A promising area of application for agent based social simulation is social
policy analysis. This promise stems from the ability of ABSS models to describe key
processes and relationships in actual societies. However, existing descriptive studies
with ABSS have been too abstract convincingly to inform policy analysis. This paper
describes the transition from one such study towards a usefully detailed and realistic
model currently being developed to inform water demand management in the south of
England during a period of climate change.

The FIRMA project, in which this work is being undertaken, was proposed
specifically to use agent based modelling techniques to enable stakeholders to become
involved in the model specification and validation process. The value of the agents
approach in this context is that the stakeholders can assess whether agent behaviour,
interaction among the agents and resulting system level properties are descriptively

Capturing water demand management issues with agent-based models is itself a
highly non-trivial task. In the first place, stakeholders including both regulatory
agencies and water supply companies have identified weather, drought or its absence,
demographic factors and technology as essential elements in any description of the
determinants of water demand. The models to be used in policy analysis will have to
capture all of these phenomena. In practice, this requires an single model relating
consumption to rainfall, temperature and humidity (weather), hydrology relating the
weather to the level of groundwater (drought) and the effects of those on both water
demand and public authorities’ measures for managing that demand. So in a single
model, we have to capture the weather system, the hydrological system, the behaviour
of households and the behaviour of policy agencies and, moreover, to do so in a way
that engages stakeholders in the model development and validation.

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