Overall Comparison between Portugal and Spain

Portugal and Spain have a long and common history of severe drought events, which pose several challenges. Those events highlight the importance of adapting water resources planning and management to face the corresponding impacts and water use limitations. The two countries follow a common frame and approaches on drought planning and management, but their implementation differs. One difference relates to the approach and time for the development of DMPs. While Spain developed DMPs in 2007 for the Spanish RBDs, Portugal is expected to implement a national DMP, following a proposal prepared in 2015 but not yet formally approved. In fact, in some Spanish RBDs (e.g., Douro and Guadiana), a review and/or adjustment of some aspects of the corresponding DMPs (namely, the indicators' assessment and/or evaluation) was already conducted in the scope of the first and second RBMPs approval. A complete revision of Spanish DMPs is being undertaken and is expected to be completed by the end of 2017.

In terms of institutional frameworks, namely concerning RBDs governance, the countries exhibit some differences in the broad range of water resources management. In Portugal, the water resources administration concentrates on a national institution (APA), which is the national water authority; in Spain, this structure is shared by central government, autonomous communities, and the RBDAs. This difference in governance structure is also reflected in terms of drought management. The different spatial scale approach may also be observed at the operational stage. That can be illustrated by the role of regional, local, and water users' organizations on drought management. In Portugal, where the recently (2012) established drought management bodies have a nationwide monitoring area, the role of local/regional entities when a drought situation is declared remains unclear, denoting a lack of a drought operational framework. In Spain, the RBDAs play an important role in drought management provision, and drought management actions are taken at all water user levels. Indeed, Spanish DMPs define the role of each drought organization/stakeholder as far as the drought event develops.

Spain has fully implemented a drought monitoring system that provides information on the level of drought in different regions (zonas de explo- tacion) of all Spanish river basins. In Portugal, the PT DMP's proposed drought monitoring system remains to be fully implemented. As in the case of Spain, the system is expected to provide information on a similar number of levels of drought, taking into consideration the evolution of hydrological variables.

Regarding drought early warning systems, neither Spain nor Portugal has a fully operational DEWS at regional and/or national scales, as recommended in the 2007 European guidelines (EC 2007a). Hence, there is a clear need to develop those systems in both countries. In Portugal, a pilot version for a DEWS was developed by the former Portuguese Water Authority (INAG), but it is not yet operational (Maia 2011). Nevertheless, the Portuguese National Water Plan has established a goal to implement a DEWS by 2021 (DR 2016). In Spain, efforts are evolving to develop a DEWSs for the Spanish river basin, in order to enable the medium-term prediction of droughts in addition to the current capability to confirm the presence of drought. Furthermore, within the DMPs revision, Spanish drought indicators will be defined in order to include seasonal meteorological forecasts, provided by AEMET.

Table 23.1 provides a brief comparison of the main topics associated with drought planning and management in Portugal and Spain.

The evaluation of drought planning and management in both countries makes it clear that a common or coordinated drought monitoring and management is still far away. To achieve this, there is a need to first adjust the indicators, thresholds, and alert levels between both countries, as agreed on and planned under CADC work. In fact, those adjustments must be suited to transboundary agreements, notably the Albufeira Convention, as described in Maia (2009).

Under the terms of the Albufeira Convention, Spain is to guarantee MFRs at the upstream border of the shared rivers, except in exceptional years—this corresponds to the accumulated precipitation (in referenced monitoring stations), in a defined period, being lower than a preestablished minimum. That means that the MFRs (except for Guadiana, where the storage volume on predefined reservoirs is also taken into account) are only dependent on precipitation values from predefined precipitation stations. The drought monitoring system used in Spain, defined in the DMPs, includes several hydrological indicators as noted before, but not the pluviometric indicators defined within the Albufeira Convention in some river basin systems (e.g., Douro and Tejo); if those indicators are included, as in the case of the Guadiana RBD, they are mixed with other pluviometric indicators (Maia 2009).

Figure 23.5 enables a comparison of the drought alert levels obtained for the same period when considering the pluviometric indicators of the Albufeira Convention (Figure 23.5a) or the indicators used in the system defined in the DMPs (Figure 23.5), in this case from the Douro river basin (CHD 2016).

As Figure 23.5 shows, different results and correspondent classifications are obtained for both situations. For example, alert and emergency situations are more frequent using the indicators established by the Albufeira Convention (CHD 2016; Maia 2009). This highlights the necessity to reach a concrete homogenization of indicators between the two countries and their previous agreements. Thereafter, within the second RBMP of Spanish Douro, a revision of the indicators to be used was performed, and it considered the inclusion of the Albufeira Convention precipitation indicators in the Spanish indicator system for that RBD (CHD 2016).

Drought Monitoring and Management Comparison between Portugal and Spain as of March 2017

TABLE 23.1

(Continued)

TABLE 23.1 (Continued)

Drought Monitoring and Management Comparison between Portugal and Spain as of March 2017