Accounting System for SEgura River and Transfers ASSET
The policies for the sustainable management of water resources are a priority on the European and national governmental agendas. Current challenges at the European level are to enhance the knowledge base on the reference situation in terms of water availability and demand, as well as to define a Guidance Document on the Application of Water Balances for supporting the implementation of the Water Framework Directive (WFD). In addition, valuation of costs and benefits and target setting is required, integrated in the River Basin Management Plans (RBMPs), taking into account the vulnerability of the measures due to future changes, for example climate change.
In this framework, the main aim of the ASSET (Accounting System for the SEgura river and Transfers) project, funded by the European Commission under the topic Halting Desertification in Europe, was to obtain, assess and standardize detailed information on the Segura River basin (SRB, Southeast of Spain), including the significant external transfers of water into the basin.
The consortium and team involved in the redaction of this technical report is as follows,
- Universidad Politécnica de Cartagena (UPCT);
- Confederación Hidrográfica del Segura (CHS);
- Futurewater (FW-ES) and
The Segura River Basin (SRB, Spain), located in the Southeastern part of the Iberian Peninsula with an area of 18,870 km2, has the lowest percentage of renewable water resources of all Spanish basins and is highly regulated. The main water demand comes from agriculture, covering more than 43 % of the basin surface, of which one-third is brought under irrigation. In 2007 the agricultural water demand from irrigated areas of the SRB accounted for 85% of the total water demand in the entire basin. The available water resources per inhabitant in the SRB correspond to 442 m³/inhabitant/year. The difference between water supply and demand is high. Consequently, two incoming water transfers together with desalinization are considered the most attractive options to increase water availability in the basin. The problems of water scarcity and droughts are persistent in the basin, affecting the economy of the region and generating water conflicts between the final users (such as irrigation communities).
Throughout the project, the utilization of resource management, technological and economic measures to decrease water scarcity in this drought-prone region was analysed and demonstrated to be of value. The principal tool employed for this purpose was SEEAW (System of Economic and Environmental Accounts for Water), complementing the EU water resource balances with local data for SRB.
The specific planned objectives were successfully reached:
- Collect and assess data water on availability and demands, both in time, space and on the sector-level, principally from existing studies and documents, and adapt the data for the implementation of the UN System of Environmental-Economic Accounting for Water (SEEA-W) implementation.
In summary, considering a time period of 10 years (2000-2010) and a spatial discretization of the basin based both on European Catchment and Rivers Network System (ECRIN) aggregation and the exploitation systems, seven Representative Elementary Watershed Management Units (REWMU) were defined in the basin and the corresponding tables were generated:
- Physical Supply and Use Tables (PSUTs) at annual scale for each REWMU
- Hybrid Supply and Use tables at annual scale for the whole basin
- ASSET tables at monthly scale for each REWMU
In addition, a deep analysis of some economic indicators was completed. At the basin scale, indicators of Water Productivity (WPe), and others related to the cost of supplying water were evaluated, including Implicit water price (IWP) and Implicit wastewater treatment price (IWTP) as well as the Average water supply cost (AWSC) and the Average wastewater treatment cost (AWTC). Also, by industry, other indicators have been estimated in order to show the differences among water users sectors.
(ii)Test several innovative methodologies which allow closing the water balances and increasing the accuracy of the water accounts.
Among the outcomes of the project, highlight the development of GIS-embedded spatio temporal toolbox for processing ASSET tables; implementation of an innovative methodology for generating input to water balances from remote sensing (such as actual evapotranspiration retrieval from satellite images); the deep analysis of rainfall and drought trends (through annual maximum dry spells lengths) obtained from Regional Climate Models (RCMs) by novel RCMs ensemble methods.
The actual evapotranspiration (ETa) is a key input to water balances, and sometimes a source of uncertainty. Assessing ETa from satellite images (MODIS data) provides spatial-temporal distributions. The ground truth validation with eddy covariance, demonstrated the reduction of uncertainties involved.
(iii)Integrate the water accounts with the RBMP, demonstrate their use for the local planning, disseminate and interact with other local stakeholders and provide recommendations for upscaling of findings.
Promising steps were taken in the integration of these types of methodologies in the RBMPs. The active participation in activities hosted by the Ministry of Food, Agriculture and Environment (MAGRAMA) of Spain promoted the SEEAW dissemination and interaction with other stakeholders for its application.
- Identify a set of measures, both management, technological and economic, which should reduce the water scarcity in the basin and its vulnerability to drought;
ASSET project promoted the engagement of stakeholders, and advice from external experts, by hosting several meetings (such as the International Meeting on Water Accounting) and the participation in workshops. The strong involvement of the Segura river basin authority (CHS), which started the public consultation process for the RBMP, encouraged the identification and assessment of selected measures included in the Programme of Measures (PoM) of the RBMP.
(v)Assess the basin vulnerability for future changes (climate change, economic, demographic)
In this context, specific studies were made both from observed data and RCMs. Three critical issues were addressed: (a) calculation of a set of use-to-availability indicators at the sub-basin scale from the SEEAW tables; (b) analysis of the effects of a 4-year drought period on the use-to-availability patterns observed at the basin; and (c) impact evaluation of various water management measures on water shortage, taking into account climate change and population growth. Finally, an analysis of the potential impacts resulting from a reduction of the exploitable resources in the basin as consequence of climate and population changes and the effects that a set of resource management measurements could have in softening a future scenario featuring higher water shortages was addressed.
In conclusion, the ASSET project, by the innovative methodologies developed for implementing SEEAW framework and the indicators derived, provides relevant outcomes to RBMP for efficient allocation of water resources, and complements the EU water resources balance at the local scale. The project provides recommendations to improve the SEEAW methodology and overcome the barriers in its implementation.