During this pilot action, an overall approach and tools were developed using the SEEA-Water – System of Environmental-Economic Accounting for Water- for
i) improving the knowledge on water resources available in the Arno River basin and their use within or outside the basin; 
ii) assessing the potential impact of management, technological and economical measures to reduce the vulnerability of the territory against water scarcity and drought.

Water accounts have been prepared on a monthly basis for the period 1993–2013, and considering development and climate change-based scenarios, simulations have been processed to define and evaluate the optimal water saving measures for the Arno River Basin Management Plan.

A participatory approach was applied to each activity through the organisation of Stakeholder Workshops and regular concertation meetings with local stakeholders and data providers, in particular concerning data collection, estimations, validations, and measures assessment. 

A Visual Basic Application for MS-Excel was produced by the PAWA Consortium to automatically compile the SEEA-Water “Physical Use & Supply” tables (PSUAT) and the “Asset Account” tables. This tool was useful, and it will be useful for the future application, to perform the compilation of tables and the production of thematic graphs, in a quick and reliable way, directly using the data stored in the PAWA geo-referenced database (which can be easily updated) that was developed and populated for the project activities. The PAWA tool can be also used to support water decision-makers to find the best combination of measures to be implemented in the different territories, in order to reach specific water saving targets. In the future, economical assessment of measures implementation should be added as it is an important criterion for planning.

The water account approach together with prospective scenarios based on the application of a set of measures and various climate change hypotheses allowed the assessment of their potential impact compared to a reference situation (i.e., without applying any measure). Thus, the SEEA-Water tables appear to be a good decision support tool to define the most suitable water efficiency measures for a selected area. As the SEEA-Water tables do not take into account e-flows, such requirement can be considered during the optimisation of measures process by defining a specific target for the Water Exploitation Index Plus (WEI+) (which was set below 40% in the case of the simulation done for PAWA).

This pilot action was carried out during 15 months by ISPRA – Institute for Environmental Protection and Research , ARBA – Arno River Basin Authority and EMWIS TU – Technical Unit of Euro-Mediterranean Information System on know how in the Water Sector. 