Ecosystem accounting for water resources at the catchment scale, a case study for the Peloponnisos, Greece

The System of Environmental-Economic Accounts - Ecosystem Accounting (SEEA EA) has become the world’s leading natural capital accounting system. It provides a valuable decision-making tool for spatial planning and integrated development. SEEA implementation is a current key challenge for European Union (EU) Member States (MS), mainly due to high requirements on budget, technical capacity, and data, varying between countries. Within this frame, the objective of this paper is to demonstrate how the SEEA framework can be applied to analyse water ecosystems at river basin scale, building exclusively upon the officially registered, standardized national and EU datasets. We test how water resources can be accounted for using SEEA EA, with an additional component assessing water use based on SEEA Water. Within the EU Water Framework Directive (WFD), two reporting cycles of river basin management plans have been completed for water ecosystems, providing spatial and temporal datasets. This material together with numerous data available at EU and national levels, water-relevant databases and repositories, resulting from MS reporting obligations, are tested and utilised for water accounting. The Alfeios river basin in Western Peloponnisos Greece serves as the case study area for compiling extent accounts, condition accounts, and supply and use accounts for provisioning water ecosystem services (drinking and irrigation water) for the periods 2009–2015 and 2015–2021 (the two WFD reporting cycles). It is demonstrated that readily available EU datasets can support the initial mapping and compiling of water ecosystem accounts at local scale, as applied in Greece, and therefore potentially also in other EU countries with fragmented data scattered in various administrative services and authorities with overlapping responsibilities on water resources. It is also concluded that future WFD reporting cycles and revisions of the river basin management plans could be better structured to enable a more direct connection of the collected data to ecosystem accounts.