Technical Reports

DROUGHT-R&SPI Technical Report No.37 - Drought Classification, Propagation Analysis, and Prediction of Anomalies This study investigates relations between drought and crop yields. Systematic investigation on these relations for widely cultivated crops was still missing on a pan-European scale. We used 35-years of observed annual crop yield data of five selected crops (i.e. barley, wheat, sugar beet, potato and maize), which were de-trended by i) moving average and ii) linear regression to eliminate multiannual trends due to technological development. The crop yield data were related to the meteorological drought indices Standardized Precipitation Index (SPI) and Standardized Precipitation and Evaporation Index (SPEI) given for 1979-2009, both including accumulation periods of 1, 2, 3 and 6 months. For both the drought indices and the crop yield data, information was gathered at NUTS2 level. Statistical models were made on European level and the three biggest climate regions, i.e. Atlantic, Continental and Mediterranean. SPI and SPEI were highly correlated and considered in separated linear statistical models. The models showed that for the SPI as well as for the SPEI the highest correlations were found for barley and wheat in the moving average de-trended data set. SPEI did not give higher correlations than SPI. Impacts of dry spells on crop yield at European scale is visible, but regional differences within biogeographical climate regions exist.
Biazenlegn S. Beyene, Henny A.J. van Lanen and Paul J.J.F. Torfs, Wednesday 15 July 2015
DROUGHT-R&SPI Technical Report No.36 - Links between Meteorological Drought Indices and Yields (1979 – 2009) of the main European Crops Threshold level approaches are widely used to identify drought. The threshold is determined below which the flow or other hydrometeorological variable is characterized as drought. However, depending on the hydrometeorological behaviour of the catchment, these approaches may introduce artefact drought events or provide characteristics that do not represent the actual drought event as it is felt by one or more water-related sectors. In this study the variable threshold level approach was investigated. Four annual variable curves of daily threshold levels were obtained using (i) moving average of monthly quantile (MAM), (ii) moving average of daily quantile (MAD), (iii) thirty-days moving window quantile (TMW) and (4) Fast Fourier Transform of daily quantile (FFT). These four different threshold series were applied to the time series of hydrometeorological variables that were simulated using a semi-distributed conceptual rainfall-runoff model (HBV) for five European catchments with contrasting climate conditions and catchment properties. Drought duration and deficit volume were used to investigate the propagation pattern (through the summary statistics of hydrometeorological variables), classification of the drought typologies and prediction of anomalies. We found that all four different approaches can be used alternatively to investigate drought propagation patterns and to identify drought typologies. However, the TMW threshold approach seems to be a more reliable approach in snow-dominated catchments, like the Narsjø catchment in Norway where the flow sharply rises during the snow melt.
Larissa Gunst, Francisco M.C.C. Rego, Susana M.A. Dias, Carlo Bifulco, James H. Stagge, Marta S. Rocha and Henny A.J. Van Lanen, Friday 10 July 2015
DROUGHT-R&SPI Technical Report No.35 - Historic droughts beyond the modern instrumental records: an analysis of cases in United Kingdom, France, Rhine and Syros In this report a historical approach has been deployed to improve understanding of the frequency and severity of the droughts during the last 500 years. This approach mainly covers the period beyond instrumental records. It demonstrates how combining textual and instrumental data recorded in the archives since the 16th century improved knowledge on European droughts between 1500 and 1950. Several drought-related events in the United Kingdom, France, Jucar Basin (Spain), Upper Rhine valley and Syros (Greece) were investigated to better understand the variation of these climatic extreme events during the last 500 years across European regions and their social and economic impacts. Key drought events in Europe since 1500 were identified (e.g. the 1566, 1666, 1719, 1818, 1893, 1921 drought). An intercomparison of the long drought series showed that the UK droughts were identical to those in the Ile-de-France in 32% of cases for the period 1500-2009 against 26% in the Upper Rhine Valley. The historical drought time series from England, France and Rhine do not prove any increase in frequency of dry periods since the 16th century. However, the historical approach requires careful consideration, because it is based on impacts, and hence, it is associated with a region’s changing vulnerability to drought. For this reason the droughts in Syros Island were investigated in more depth to explore the link between drought and vulnerability. It appeared that vulnerability was affected by factors such as the rapid population growth, change in agricultural practices (greenhouse cultivations) and the success of new water supply measures (desalinization plants). Re-introduction of historical land and water management measures is expected to decrease drought vulnerability. Reconstructions of historical droughts can improve reliability of climatological and hydrological models by exploring if these models can capture past drought events beyond the instrumental record.
Emmanuel Garnier, Dionysis Assimacopoulos, Henny A.J. van Lanen, Sunday 5 July 2015
DROUGHT-R&SPI Technical Report No.34 - Evaluation of the potential and limitations of Pan-European analyses of drought as a natural hazard on local and national scales This report evaluates the potential and limitations of pan-European analyses (performed within the DROUGHTR&SPI project), with respect to drought indicators, early-warning, forecasting, and future projections, for application in water management and policy at the local, river basin and national scale. The background information is based on papers and reports published within the work package that dealt with the large-scale natural hazard, from which 17 keypoints were distilled. These keypoints were presented in a questionnaire to stakeholders or intermediaries in the Case Study regions of the DROUGHT-R&SPI project. The intermediaries have an overview of the stakeholder’ views. For each keypoint stakeholders could indicate whether the information was `directly applicable', `interesting, but not directly applicable', `applicability unknown', or `not applicable' in their case study region. Responses were obtained from 12 stakeholders or intermediaries in the six Case Study regions. In general, the large-scale drought hazard studies were regarded as very interesting, but not always directly applicable to the local water management. The main determinants for the applicability of large-scale drought hazard studies in small-scale water management or policy were: 1) whether or not the specific conditions of the large-scale study were relevant in the Case Study region, and 2) whether or not there was expertise in the case study to work with the results of the large-scale study. Lack of applicability occurred when the specific conditions did not occur in the case study (e.g. no intermittent rivers or no snow and ice), when the specific conditions did occur in the case study region, but there was not enough local knowledge, and when there was a lack of expertise or resources to apply the recommended methodology or to translate the results to the local situation. The stakeholders in the Jucar basin and in Portugal were most positive about application of the results of large-scale drought hazard studies. The stakeholders in Switzerland were least positive. The four themes of this investigation, i.e. drought indicators, early-warning, forecasting, and future projections, showed comparable patterns. The keypoints on indicators and triggers for early-warning were regarded as useful when they referred to relevant conditions in the Case Study region and when they could give clear recommendations that complemented existing drought monitoring plans. The keypoints on forecasting were, in general, not very applicable because the stakeholders lack opportunities for doing forecasting themselves and most forecasting is done on larger scales than the Case Study regions. The keypoints on future projections were indicated as useful, because stakeholders feel the urgency of this topic. The stakeholders were mostly satisfied with the results of the large-scale drought hazard studies. They do point out that for applicability on local scale more differentiation in results is needed (e.g. north vs. south Europe or biogeographical regions). Furthermore, it is recognised that the translation from large-scale scientific results to local-scale application is most successful when done in steps. This means first from large-scale drought hazard studies to local drought hazard studies, and subsequently from local drought hazard studies to local water management and policy. At both steps intermediaries or facilitators are needed and time should be allocated to dialogue between scientists, water managers and policy makers.
Van Loon, A.F., Van Lanen, H.A.J., Kampragou, E., Assimacopoulos, D., Haro Monteagudo, D., Andreu, J., Dias, S., Rego, F., Gudmundsson, L., Wolters, W., Thursday 23 April 2015
DROUGHT-R&SPI Technical Report No.33 - Drought Indicators: Monitoring, forecasting and early warning at the case study scale This report first summarizes monitoring requirements in the six Case Study areas, including a review of the monitoring systems and indicators already in place, which were reported in the first phase of the DROUGHT-R&SPI project. Next this was complemented by information on indicators and monitoring recommendations that was obtained from pan-European studies on the natural hazard and impacts scale. The report describes how European drought monitoring data can be used for drought monitoring indicators at the Case Study level. These sources of information were synthesized in ten recommendations for drought monitoring, early warning and management at the Case Study scale. Two case studies, i.e. the Jucar River basin and the Netherlands, precede these recommendations and illustrate in detail drought monitoring and early warning at the river basin and national scale. These cases show that in addition to the use of comprehensive information technology, the involvement of stakeholders in using the entire drought preparedness and management system is essential. This is not only to support decision making during drought events, but even more important during the planning phase to select meaningful drought indicators.
Andreu, J., Haro, D., Solera, A., Paredes, J., Assimacopoulos, D., Wolters, W., Van Lanen, H.A.J., Kampragou, E., Bifulco, C., De Carli, A., Dias, S., González Tánago, I., Massarutto, A., Musolino, D., Rego, F., Seidl, I. and Urquijo Reguera, J. (2015): Drought indicators: monitoring, forecasting and early warning at the case study scale. DROUGHT-R-SPI Technical Report no. 33, Valencia, Spain, 46 pg., Monday 13 April 2015
DROUGHT-R&SPI Technical Report No.32 - "From spi to spi-i”: discussing what is beyond science-policy interfacing, at the 4TH PAN-European Drought Dialogue Forum This report describes the outcome from the 4th pan-European Drought Dialogue Forum (pan-EU DDF). The dialogue was about: (i) European experience with Science-Policy Interfacing to cope with drought, (ii) How to implement the EU Guidance on Ecological Flows, (iii) Implementation of Science-Policy Interfacing in the Júcar and in other Mediterranean River Basins, (iv) UK Drought 2010-12: Experience and Policy Implementation Experiences, and (v) Efficient Use of Water in Irrigated Agriculture, science-policy-implementation in Portugal. The Dialogue was among the DROUGHT-R&SPI consortium and drought experts from the European Commission - DG Environment, Júcar River Basin Authority (CHJ), MENBO (Mediterranean Network of Basin Organisations), UK Environment Agency and Directorate General of Agriculture and Rural Development, Ministry of Agriculture and the Sea, Portugal.
Wolters, W., Witmer, F.P., Van Lanen, H.A.J. and Davy, T., Tuesday 31 March 2015

Project objectives

  • Drought as a natural hazard, incl. climate drivers, drought generating processes and occurrences
  • Environmental and socio-economic impacts
  • Vulnerabilities, risks and policy responses, incl. the further development of drought management plans in support of EU and other international policies