Critical Comparative Assessment of UGR-AQUAFOR Streamflow Forecast Model and Seasonal Forecasts. Application to the Upper Genil River within the Guadalquivir River Basin (Spain)

Despite the advantages of using reliable and accurate streamflow forecasting models, these still remain underused by many Water Authorities and Water decision-makers. Their decisions on how to best allocate the available water resources between the different water users and environmental needs are crucial, especially in water-stressed regions where there is a strong competition for scarce water resources. The impacts of water pollution, population growth and extreme hydro-meteorological phenomena (floods, heatwaves, droughts, etc) are aggravating the already challenging water situation worldwide. In this context, risk-based streamflow forecasts can provide consistent support to Water Authorities to adopt efficient, sustainable and integrated water resources management strategies as well as the opportunity to assess the potential environmental and socio-economic consequences in advance. In Spain, for example, the Guadalquivir River Basin (GRB) Authority is responsible for taking the strategic decisions on controlled released outflows from reservoirs in the Guadalquivir River Basin. However, they still do not rely on streamflow forecasting models to support their strategic decisions but their historical experience in dealing with droughts and managing water resources in this area. This paper presents a comparative critical assessment of the risk-based streamflow forecasts provided by AQUAFOR (a simple and robust monthly and yearly streamflow forecasting model developed by the University of Granada) compared with the results in two different scenarios: i) no streamflow forecast models are used (current situation at the GRB); ii) seasonal forecasts provided by the Spanish Meteorological Agency are used. The methodology has been applied to the particular case of the Upper Genil River within the Guadalquivir River Basin in southern Spain. The results highlight the importance of using streamflow forecasts to support sustainable water management practices whilst minimising potential negative impacts and add transparency to facilitate Stakeholder communication. In consequence, recommendations to improve the efficiency and transparency of water management are given to Water Authorities and Water Managers.