An Integrated Approach to Flood Risk Management: A Case Study of Navaluenga (Central Spain)

Flood risk management decisions require the rational assessment of mitigation strategies. This is a complex decision-making process involving many uncertainties. This paper presents a case study where a cost-benefit based methodology is used to define the best intervention measures for flood-risk mitigation in central Spain. Based on different flood hazard scenarios, several structural measures considered by the local Basin Water Authority and others defined by engineering criteria were checked for operability. Non-systematic data derived from dendrogeomorphological analysis of riparian trees were included in the flood frequency analysis. Flood damage was assessed by means of depth-damage functions, and flooded urban areas were obtained by applying a hydraulic model. The best defense strategies were obtained by a cost-benefit procedure, where uncertainties derived from each analytical process were incorporated based on a stochastic approach to estimate expected economic losses. The results showed that large structural solutions are not economically viable when compared with other smaller structural measures, presumably because of the pre-established location of dams in the upper part of the basin which do not laminate the flow generated by the surrounding catchment to Navalueng

Evaluating tree-to-tree competition during stand development in a relict Scots pine forest: how much does climate matter?

Key message: Competitive interactions change over time and their influence on tree growth is intensified during drought events in marginal Scots pine populations. Abstract: Competition is a key factor driving forest dynamics and stand structure during the course of stand development. Although the role neighbourhood competition on stand dynamics has received increasing attention, the response of competition to environmental fluctuations and stand development remains poorly explored. We evaluated changes in competition during stand development in a dry-edge Scots pine relict population located in Central Spain. Typically, tree-to-tree interactions have been investigated through static competition measurements, which usually lack the temporal variation associated to natural forest development and environmental conditions. Here, we assessed how individual and neighbourhood components of competition evolved along a 35-year period, and we related competition dynamics to population structure and drought levels. On six plots, 508 trees were mapped and diameters at breast height (DBH) were measured. Two increment cores were taken from target trees to derive basal area increment (BAI), and neighbourhood was reconstructed back to 1980. Results provide insights into inter-annual variability in competition effects and their role on tree radial growth depending on climatic conditions. From the year 2005 onwards, both individual and neighbourhood components of competition showed a decoupled pattern over time. This effect was particularly pronounced during the extreme drought in 2012, in which the individual component decreased, whereas the neighbourhood component increased. In addition, climatic variability modulated the competition effects during stand development. This approach of evaluating competition dynamics proves to be promising for studying forest stand development and the influence of climate impacts on tree populations subjected to xeric conditions

Recent advances on dendrogeomorphological research applied to flood hazard analysis in Spain.

Estudios dendroecológicos para el análisis de regímentes torrenciales y avenida

Geosciences for a Sustainable Planet: a new collaborative network to address societal and environmental challenges in the Anthropocene

The Geosciences for a Sustainable Planet network is an initiative reinforced by the recent integration of the Spanish Geological Survey (IGME) and the Oceanographic Spanish Institute (IEO) within the Spanish Scientific Research Council (CSIC). The network is aimed to provide Geosciences in Spain with a collaborative framework, to maximize synergies and address sustainability and future challenges with a planetary perspective. The network shares the strategic vision for the study and care of planet Earth as the only home available for our future, as embraced by many international organizations (e. g. the European Geosciences Union (EGU), United Nations Environment Programme (UNEP), International Union of Geological Sciences (IUGS), and the European Marine Board (EMB)). In Spain, Geosciences have played a fundamental role in properly assessing, managing, and seeking solutions for several natural and anthropogenic crises, e.g. the oil spill after the sinking of the Prestige petroleum vessel, the dumping of toxic mine sludge in Aznalcóllar, the eruption of the Cumbre Vieja volcano in La Palma island, the 2011 earthquake of Lorca, the environmental collapse of the Mar Menor oastal lagoon, or the decline in the groundwaters of Doñana National Park. Geoscientists have engaged as first responders with government agencies in emergency situations. Besides, geosciences is providing essential knowledge for public administration, as well as energy and mineral resources companies, water supply, contamination and waste elimination and reuse, and adaptation to geological and natural hazards. The network will enhance the capacity of the CSIC to respond to both, societal and public administration demands. Geosciences also provide the temporal and spatial scale to place current climate and environmental crises in the appropriate context. The network will implement outreach activities to illustrate the interactions of surface processes and biosphere with climatic fluctuations, atmospheric CO2 variations, sea-level changes, biodiversity collapses, etc, during the evolution of life on Earth over millions of years. We believe an essential aspect of science's contribution to sustainability is improving the communication of trans-disciplinary knowledge to citizens, future generations, administrations, and companies so they can take informed decisions. The Geoscience network will focus on outreach actions, training new generations of Geoscientists and technology and knowledge transfer. The Geosciences network seeks to facilitate the integration of research groups in the disciplines of Earth Sciences to improve our knowledge of the planet's geological processes across temporal scales ranging from millions of years to instrumental observation. This integration of basic and applied knowledge will enable Geosciences to provide tools to address the social challenges of the UN Sustainable Development Goals. Among them, we have selected four main areas: (1) energy and ecological transition, (2) access to water and geological resources, (3) mitigation and adaptation to geological hazards and risks, and (4) tools for solving environmental and climate crises. We believe that Geosciences network will offer the spatial dimension (from local to planetary) and temporal insight (natural variability beyond the human scale) to provide a common framework with a global, integrative, transversal, and multidisciplinary vision to tackle these challenges

Oxidative Stress in Wild Boars Naturally and Experimentally Infected with Mycobacterium bovis

Reactive oxygen and nitrogen species (ROS-RNS) are important defence substances involved in the immune response against pathogens. An excessive increase in ROS-RNS, however, can damage the organism causing oxidative stress (OS). The organism is able to neutralise OS by the production of antioxidant enzymes (AE); hence, tissue damage is the result of an imbalance between oxidant and antioxidant status. Though some work has been carried out in humans, there is a lack of information about the oxidant/antioxidant status in the presence of tuberculosis (TB) in wild reservoirs. In the Mediterranean Basin, wild boar (Sus scrofa) is the main reservoir of TB. Wild boar showing severe TB have an increased risk to Mycobacterium spp. shedding, leading to pathogen spreading and persistence. If OS is greater in these individuals, oxidant/antioxidant balance in TB-affected boars could be used as a biomarker of disease severity. The present work had a two-fold objective: i) to study the effects of bovine TB on different OS biomarkers (namely superoxide dismutase (SOD), catalasa (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and thiobarbituric acid reactive substances (TBARS)) in wild boar experimentally challenged with Mycobacterium bovis, and ii) to explore the role of body weight, sex, population and season in explaining the observed variability of OS indicators in two populations of free-ranging wild boar where TB is common. For the first objective, a partial least squares regression (PLSR) approach was used whereas, recursive partitioning with regression tree models (RTM) were applied for the second. A negative relationship between antioxidant enzymes and bovine TB (the more severe lesions, the lower the concentration of antioxidant biomarkers) was observed in experimentally infected animals. The final PLSR model retained the GPX, SOD and GR biomarkers and showed that 17.6% of the observed variability of antioxidant capacity was significantly correlated with the PLSR X's component represented by both disease status and the age of boars. In the samples from free-ranging wild boar, however, the environmental factors were more relevant to the observed variability of the OS biomarkers than the TB itself. For each OS biomarker, each RTM was defined as a maximum by one node due to the population effect. Along the same lines, the ad hoc tree regression on boars from the population with a higher prevalence of severe TB confirmed that disease status was not the main factor explaining the observed variability in OS biomarkers. It was concluded that oxidative damage caused by TB is significant, but can only be detected in the absence of environmental variation in wild boar

Combining terrestrial laser scanning androot exposure to estimate erosion rates

Aims: This paper aims to analyze the reliability of exposed roots oriented perpendicular to the slope to quantify sheet erosion rates based on accurate reconstruction of topography using terrestrial laser scanner (TLS). Methods: The study was performed in an experimental sandy badland located in Central Spain. Sampling procedures were conducted in three different homogenous hydrological response units (HRU). We derived eroded soil thickness from by obtaining accurate microtopographic data using TLS. In addition, dendrogeomorphic procedures, based on anatomical changes in root rings, were used to determine the first year of exposure of 46 Pinus pinaster roots. Results: Results indicate that medium-term (±30year) erosion rates obtained from roots growing perpendicular to the slope were significantly different from those obtained from exposed roots growing parallel to the slope (p-value <0.05). However, at short term (up to 5years), result agree with those obtained from erosion pin monitoring at the study site, which confirms the potential of reconstructions based on perpendicular roots. Conclusion: The utility of exposed perpendicular roots coupled with accurate eroded soil estimation has been proved. It allows theextension of the applicability of dendrogeomorphic approaches, particularly for ungauged badlands where instrumental data is scarce or completely missing

Gully evolution and geomorphic adjustments of badlands to reforestation

International audienceBadlands and gullied areas are among those geomorphic environments with the highest erosion rates worldwide. Nevertheless, records of their evolution and their relations with anthropogenic land transformation are scarcer. Here we combine historical data with aerial photographs and tree-ring records to reconstruct the evolution of a badland in a Mediterranean environment of Central Spain. Historical sources suggest an anthropogenic origin of this badland landscape, caused by intense quarrying activities during the 18th century. Aerial photographs allowed detection of dramatic geomorphic changes and the evolution of an emerging vegetation cover since the 1960s, due to widespread reforestation. Finally, tree-ring analyses of exposed roots allowed quantification of recent channel incision of the main gully, and sheet erosion processes. Our results suggest that reforestation practices have influenced the initiation of an episode of incision in the main channel in the 1980s, through the hypothesized creation of disequilibrium in water-sediment balance following decoupling of hillslopes from channel processes. These findings imply an asymmetry in the geomorphic response of badlands to erosion such that in the early evolution stages, vegetation removal results in gullying, but that reforestation alone does not necessarily stabilize the landforms and may even promote renewed incision

Challenges in paleoflood hydrology applied to risk analysis in mountainous watersheds - A review

© 2014 Elsevier B.V. In many regions of the world flood events in mountain basins are one of the greatest risks to the local population, due to the pressure placed on land use by social and economic development. Conventional hydrologic-hydraulic methodological approaches are not usually feasible in mountainous basins because they are not gauged at all or, in the best-case scenario, are poorly gauged. In this context, palaeohydrological research offers a valuable alternative to the above approaches. However, many palaeohydrological data sources and associated methods have been proposed and initially used in large basins with extensive floodplains. As a result, when they are used in mountainous areas they must be adapted to include different techniques, since the problems to be addressed are different and less data is usually available. In this paper, we review classic data sources and different analytical methods and discuss their advantages and shortcomings with particular attention to mountain basins. For this purpose, examples are provided where improvements in the palaeohydrologic methods are proposed by incorporating uncertainties, describing sources of error or putting forward hypotheses for hydraulic calculation to make palaeoflood hydrology more objective and useful in risk assessment.This work was funded by the MAS Dendro-Avenidas (CGL2010-19274) and MIDHATO (Geolological Survey of Spain, IGME)Peer Reviewe

Late Pleistocene–Holocene multi-decadal patterns of extreme floods in NW Iberia: The Duero River palaeoflood record

Extreme floods are anticipated to become more frequent in a future warmer climate. However, the long-term alterations in flood patterns across different regions of Europe remain unclear. In this study, we present a 15,000-year record of extreme floods in the Duero River, located in the southwestern Atlantic region. We analysed slackwater flood sediments, quantified the discharge and timing of individual flood beds over millennial time scales, and identified their potential climate influences. The composite record includes at least 62 floods grouped into ten flood-rich periods (with an average duration of 230 years). A high-frequency phase of moderate-magnitude floods (>10 events) occurred at ∼11.6–11.5 ka, following a period of reduced flood activity during the Younger Dryas. Similar clusters of Early Holocene floods (10.8–10.3 ka, 9.5 ka) coincided with or preceded meltwater pulses from the North Atlantic. The absence of palaeoflood records with discharges exceeding 6100 m3/s during the Mid-Holocene suggests a decline in winter hydro-meteorological extremes. High flood magnitudes were recorded during transition periods toward cooler and wetter conditions at 4.4, 2.3, 0.5, and 0.11 ka with discharges ranging from 7600 to 10,000 m3/s. These periods were interpreted as indicative of a southward shift in cyclone tracks in Europe driven by negative phases of the North Atlantic Oscillation (NAO). Conversely, flood magnitudes decreased during past warmer climate conditions (1.7 ka, 0.9 ka, and the present), although flood frequency remained high. The current decline in flood frequency reflects an increase in flood regulation due to dams, but it is also consistent with the prevailing positive trend in the NAO observed over the last 40 years.Ministerio de Ciencia e InnovaciónDirección General del AguaFundación BiodiversidadUnion EuropeaDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu