Snow Effects on Water Availability

The Guadalfeo River Basin is a 1345 km2 mountainous, coastal watershed in southern Spain, ranging from the Mediterranean Sea coastline to the Sierra Nevada mountains (up to 3450 m a.s.l.). Urban supply, tourism and agriculture, together with hydropower generation at the headwaters, compete for a water resource allocation highly dependent on snow. Water users and managers often face a highly variable precipitation and snow regime, which determines water availability on seasonal and annual scales, and water allocation warranties.

The SWICCA indicators provide an open framework to obtain assessment of the seasonality expected shifts associated to changes in the snow regime, and to estimate their impact on the decision making process and prepare operational strategies both in the medium and long term.

The future climatic context poses a risk for the current supply system and water resource availability on a long term basis. But the shift of the snow regime in Mediterranean areas is likely to enhance mostly flow and water availability variability. Water resource management benefits from SWICCA CIIs capability to assess different impact scenarios and adaptation plans in these mountainous regions.

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Almond trees in the Guadelfeo River Basin, Spain

Case Study Description
Data Description
Reference information

Water-management issue to be addressed

The Guadalfeo River Basin hydrology shifts from a snow-dominated regime in the North to a warm coastal regime in the South, in a 40-km distance. The climate variability adds complexity to this heterogeneous area. The uncertainty of snow occurrence and persistence for the next decades poses a challenge for the current and future water resource uses in the area. Adaption plans would benefit from the predictability of water resource availability and regime. The development of easy-to-use climate indicators and derived decision-making variables is key to assess and face the economic impact of the potential changes.

Decision support to client

Results will assess the prevision of water allocation success on an annual and decadal basis, and get a deeper insight on the seasonal future potential regime. Regarding the hydropower generation, besides the evaluation of the potential future efficiency and provisions under the expected shift of the snow regime, further assessment on the minimum environmental flows and their impact on the activity can be assessed. Additional concern about the need of an adequate inflow measurement has been achieved and some actions to improve the gauging system are under project at present.

This is still an early stage to value this. However, the three clients have expectations about the potential results and their impact on their decision making process. This is especially significant for water allocation directly dependent on snow occurrence and persistence, whose future regime is likely to shift to more torrential conditions, and thus higher uncertainty.

Temporal and spatial Scale

The time scale required for the results is both the seasonal and long term scales to assess decision making in an adaptation framework, which means a 5-yr  and 20-yr horizon. The decision-making affects the local and basin scales.

Knowledge Brokering

UCO has had a fluid contact and interaction with the appointed clients in this study case, especially with the water authorities in the river basin both on the regional government and local managers. This propitiated the inclusion of this study case in SWICCA. Initial meetings took place during the preparation of the proposal. Once the project began, e-mail and phone call have been the usual means of interaction during the first stage of the project.

A second stage began after the summer, once the fundamental set of CIIs were already available at different spatial and time scales in the SWICCA Demonstrator. A row of meetings with the three clients in the study case, the Water Office in the Granada headquarters, the Mancomunidad of Municipios de la Costa Tropical in Motril (Granada coast), and the Central South Office of Endesa Generación in Córdoba took place to show them the current version of the SWICCA Demonstrator and check with them what kind of specific information, and the significant scales, could be relevant for their operation on a medium and long term.

During this stage, contact is programmed to be more frequent and meetings will take place every two months on average, depending on the particular advance reached and the need of feedback from them.

Climate Impact Indicators

Pan-European Indicators

  • Precipitation (seasonality, 0.5 degree grid and catchment scale)
  • River flow (seasonality, 0.5 degree grid and catchment scale)
  • Snow water equivalent (seasonality, 0.5 degree grid and catchment scale)
  • Wetness 1 (catchment)
  • Wetness 2 (catchment)

Essential Climate Variables (ECVs) time series used:

  • Precipitation (catchments), daily values
  • River flow (catchments), daily values
Local indicators

The final result of this second stage will be a definite final set of local indicators; some of them have been already proposed from the results reached so far. Further analysis about their usefulness and performance is still needed.

Pan-European data to local scale

Lessons learnt

The most relevant lessons learnt at this point are related to the scale effects arising when carrying out this kind of analyses; this applies to steps 1 to 3. The inclusion of indicators on a catchment scale has been important in the process. Particularly, in mountainous regions this poses a big constraint for a successful implementation of Pan-European data. The existence and accessibility to hydrological tools already validated on a local basis has been crucial to downscale and achieve the current results and prove their usefulness.

At present, analysis and discussion is being carried out to identify the best way to obtain the final local indicators: from comparison of absolute values or from correction by means of relative anomalies. This issue still needs further effort in our study case because of the relevance of the spatial scale issues associated to its topography and the snow presence.

Importance and Relevance of Adaptation

This regions development and economy is highly dependent on the snow regulation of river flows. The impact of the future climate on this water reservoir is expected to produce at least significant changes in the seasonal availability of river flow, and then impacts on the water supply and energy production systems.

Knowledge about the changes in this seasonal regime will allow the provision of adaptation strategies further than adapting water planning rules. The inclusion of three clients as reference users will provide a sound basis to design an integrated river basin management tool, which will facilitate the development of adaptation strategies.

Pros and Cons or Cost-Benefit analysis of climate adaptation

Water management in Spain, and particularly in Andalusia, is dependent on the operation of reservoir networks and other hydraulic structures, which makes these regions less vulnerable to droughts and floods. However, most of them were designed and built during the second half of the past century; the design values for flow and weather extremes have significantly changed both up- and downstream in the reservoirs. Climate adaptation is essential to revise the current scheme, the operational rules, and the water allocation priorities and time distribution. The economic gain from implementing climate adaptation actions arises from the prevention of structure damage, operational failure in demands’ guarantee, and the consciousness itself of these effects, which makes end-users more apron to protect their economical activity (insurance) and shift slowly to sustainable working conditions, minimizing risks.

The most valued aspects by the clients so far are the possibility to have access to local indicators shaped for their specific conditions and much more feasible to use than global climate indicators. The SWICCA goals bridge this gap between the huge amount of global information generated nowadays and the potentially interested users’ capability of exploiting it.

An additional benefit is the possibility of consulting any location in the European space. Even at this scale, the advantages of downloading and viewing data from one-click with sound explanation associated are clearly identified by purveyors and clients. Moreover, the catalogue of SWICCA CIIs is wide enough to attract many clients, and even raise interest on additional issues. For instance, one of the clients showed recent interest on knowing whether water quality indicators in SWICCA could estimate potential shift in their supply conditions, despite this was not their main interest when the proposal was developed.

On the other hand, this easy access might lead to misuse of the data if the downscaling process is not appropriately performed. There are certain conditions and regions in which this is key to guarantee reliable final data. Final instructions or briefing of lessons learnt specifically for this topic could be included in the final version of the Demonstrator (something like “Common mistakes in …”).

For some potential clients, a language different from their mother tongue is certainly a strong constraint for their access and use to the Demonstrator.

Policy aspects 

Besides the pilot Decision Support System for the Basin Authority that may arise from the integrated river basin management tool, the knowledge about the available amount of water resources for allocation among existing users is the basis for the River Basin Management Plans, which have been just revised in 2015.

At the present stage, no final results have been provided yet to the clients. The reliability of the local indicators derived from the SWICCA-CIIs is key to obtain successful results and supported by their acceptance by the users’ community, and further work is being done on this.


University of Cordoba

Medina Azahara Avenue, 5
14071 Cordoba
Telephone: (+34) 957 21 80 00 /  (+34) 957 21 82 00

Prof. Dr. María J. Polo



Relevant EU policy 

University of cordoba

Purveyor: Prof. Dr. María J. Polo
email: mjpolo‹at›

Value added by Copernicus Climate Change Service: 


Tropical Coast of Granada

Tropical Coast of Granada, Municipalities Community, Spain

Endesa Hydropower Generation

Endesa Hydropower Generation, Andalusian Office

Andalusian Department of Enviroment

Andalusian Department of Enviroment, Mediterranean Area Office



Figure 2. Snow in the head areas of the watershed
Snow in the head areas of the watershed


Figure 1. The Guadalfeo River Basin in Spain (altitudes expressed as m.a.s.l.)

The Guadalfeo River Basin in Spain (altitudes expressed as m.a.s.l.)


Figure 6. Tropical crops in the basin

Tropical crops in the Guadelfeo River  basin


Figure 4. The Béznar reservoir systems

The Béznar reservoir systems


Figure 3. The Rules reservoir systems

The Rules reservoir systems