Subtask Description:
Deliberate with Deliberation Support Tools or Systems.

Action points of the implementation:

  1. Deliberate with the KerDST Software.

Pertuis Charentais, France

Policy Issue:
Freshwater allocation in the Charente river catchment

Human Activities:
Agriculture, oyster farming, recreational fishing, drinking water consumption.

General Information:
The river is a strategic resource for the whole region. Due to agriculture diffuse pollution and water shortage recurrent events during summer. 52% of the water bodies of the Charente basin show a risk of failing the WFD objectives in 2015. The management of the river and its coastal zone implies to take into account the management of agricultural activities and of water supply in the river basin. The main stakeholder concerns (most of them policy makers) are connected to the sustainable management of the water resources and the achievement of the good ecological status. The policy options are considering the modification of the “authorised volumes of water” for each consumptive uses (drinking water for households, irrigation for agriculture) and the improvement of the limitation rules which apply to the consumptive uses during the periods of water shortage.

Example of Implementation:

For the building of scenarios in Pertuis Charentais, the team decided to try to make an extensive use of the potential of a “complex system” integrated model: for that purpose, the stakeholders had been invited to formulate any assumptions regarding the possible future of the system. This had lead to the identification of 57 hypotheses regarding possible changes of each component of the system: external drivers, user behaviours and management options. Then a transparent procedure of votes was implemented so as to sort the hypotheses while merging those which capture each other or produce the same evolution of the system. This second step of the participative approach for scenario building lead to the selection of 17 hypotheses which could then be combined in order to form complex scenarios. At this step of the process, participants were asked to vote first for the most interesting management options when considering one particular change in the external drivers or in the user behaviours, and second for the most interesting combinations of management options (Figure 1). At this step, the Ker-Coast deliberation matrix was used to illustrate stakeholder preferences.

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Figure 1: Stakeholder deliberation on the combination of policy options.

The changes which are envisaged concerned the climatic evolution, the implementation of management tools which could be economic or regulation tools and the evolution of users toward more or less competing demand. All along the process, the preferences of stakeholder remain coherent as the changes which were considered as of less importance were still afforded with a low priority level (expressed by higher notes) during the building of complex scenarios. This is for instance the case of the hypotheses regarding the shellfish farming practices or the need for nature preservation as regards the user behaviour changes, and the hypotheses regarding the transferable use-rights for water and the new settlements for drinkable water production as regards the management options.
The exploratory scenarios that were elaborated through the votes of stakeholder were presented during the final meeting according to a classification into four main categories which reflect the principles of the system dynamic theories:
-external exploratory scenarios: the system evolution is simulated under the influence of the three big external drivers which are the increase of drought summer frequency, the climatic change over the long run and the increase of drinking water needs; these hypotheses can also serve as the basis for the test of the main management options (strategic scenarios);
-conflict cumulating scenarios: these scenarios include cumulative effects of internal changes through the increase competing demands within the system (increase of the irrigated cultivated area, increase of the drinking water needs) and estimate the effectiveness of the four management options which are the most likely to mitigate the impacts of such an increasing pressure on the resource (decrease of the authorised volumes, collaborative irrigation strategies, adjustment of the subsidies for irrigated crops and taxes on irrigation);
-conflicting mitigating scenarios: these scenarios include compensative effects of internal changes through the decrease competing demands within the system (substitution of cultivated crops, more efficient irrigation practices) and estimate the effectiveness of the three management options which are the most likely to mitigate the residual impacts of this decreasing pressure on the resource (adjustment of the subsidies for irrigated crops collaborative irrigation strategies and decrease of the authorised volumes);
-policy mix scenarios : when residual impacts of changes remain important, in terms of physical damages as well as in terms of costs for some user groups, complex policies may be implemented ; the most interesting combination of policy option are on the one hand the tax on irrigation with the collaborative irrigation strategies, the adjustment of the subsidies for irrigated crops and the reinforced control of restrictions, and on the other hand the decrease of the authorised volumes with the collaborative irrigation strategies, the adjustment of the subsidies for irrigated crops and the reinforced control of restrictions.

Contact: Remi Mongruel,