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Drought assessment using the standardized precipitation index (SPI) in GIS environment in Greece
Abstract
The scope of the present research is to assess drought events using the Standardized Precipitation Index (SPI), which can provide accurate results of drought features on a spatiotemporal scale for Greece. The climate in Greece is a typical northern Mediterranean, with most of the rainfall events noted throughout the period between November and April, with hot and arid summers. However, owing to their unique topography, Hellenic territories have a significant variety of microclimates. Moreover, in western Greece (Region of Epirus), Pindus starts from north to south and has a wet climate with maritime features. SPI is a useful tool, and its importance can be noted in its clarity and power to recognize the severity, duration, and extent of a drought phenomenon. In addition, an alert drought warning system may be combined with contingency planning and water resource planning. In this context, the study area, as it often faces devastating drought damage and impacts, offers a very suitable opportunity for this application. The proposed methodology studies the SPI calculation for all Hellenic territories, and it was evaluated using precipitation time-series data. The selected calibrated SPI application covers the period 1981–2010 using data from 33 precipitation stations and time scales of 6 and 12 months. The SPI is calculated using software developed by the DMCSEE Project. Then, the spatial transformation of the SPI outputs was achieved using geostatistical methods using geographical information systems. Based on the index results, the drought years were 1989–90, 1992–93, 2000, and 2007–08 with the most severe event, both in duration and intensity, were in 1989–90. The SPI results underline its potential in a drought warning system and forecasting attempt as part of a sustainable drought contingency planning effort.
... Η έγκαιρη παρακολούθηση της ξηρασίας και τα συστήματα έγκαιρης προειδοποίησης επιτρέπουν τη λήψη προληπτικών μέτρων, όπως ο περιορισμός του νερού και η κατανομή των πόρων έκτακτης ανάγκης, μετριάζοντας τις κοινωνικοοικονομικές επιπτώσεις της ξηρασίας. Η διαφοροποίηση των πηγών νερού μέσω της συγκομιδής βρόχινου νερού και της επαναχρησιμοποίησης λυμάτων εξασφαλίζει μια πιο ανθεκτική και βιώσιμη παροχή νερού, ιδίως σε περιόδους παρατεταμένης λειψυδρίας , Tsesmelis et al., 2022aTsesmelis et al., 2022b;Tsesmelis et al., 2023). ...
Η ξηρασία είναι ένα επαναλαμβανόμενο φυσικό φαινόμενο με σημαντικές κοινωνικοοικονομικές και περιβαλλοντικές επιπτώσεις. Η ικανότητα ακριβούς χαρτογράφησης και παρακολούθησης των συνθηκών ξηρασίας είναι ζωτικής σημασίας για την αποτελεσματική διαχείριση των υδατικών πόρων και τις στρατηγικές μετριασμού. Η παρούσα μελέτη αποσκοπεί στη χαρτογράφηση των προτύπων ξηρασίας κάνοντας χρήση του Τυποποιημένου Δείκτη Βροχόπτωσης (SPI - Standardized Precipitation Index) στην Ελλάδα σε περιβάλλον Συστημάτων Γεωγραφικών Πληροφοριών (ΣΓΠ). Τα ΣΓΠ παρέχουν ένα ισχυρό εργαλείο για την ενσωμάτωση διαφόρων γεωχωρικών δεδομένων, συμπεριλαμβανομένων κλιματικών, τοπογραφικών και υδρολογικών πληροφοριών, επιτρέποντας μια ολοκληρωμένη αξιολόγηση των συνθηκών ξηρασίας. Αναλύοντας ιστορικά δεδομένα βροχόπτωσης, ο SPI μπορεί να ποσοτικοποιήσει τη ένταση και τη διάρκεια της ξηρασίας σε σχέση με τον μακροπρόθεσμο μέσο όρο βροχόπτωσης. Στην παρούσα μελέτη, περιγράφεται η εκδήλωση του συγκεκριμένου φαινομένου και αναλύονται τα χαρακτηριστικά του (ένταση και διάρκεια – χωρική και χρονική κατανομή) με την εφαρμογή του. Για τον υπολογισμό του δείκτη χρησιμοποιήθηκαν δεδομένα από μετεωρολογικούς σταθμούς κατανεμημένους σε όλη την επικράτεια. Στη συνέχεια, δημιουργήθηκαν χάρτες ξηρασίας με την εφαρμογή γεωστατιστικών μεθόδων. Το χρονικό βήμα που χρησιμοποιήθηκε για τον υπολογισμό και τη χαρτογράφηση του δείκτη επιλέχθηκε στους έξι (6) και τους δώδεκα (12) μήνες. Επιπρόσθετα, οι δευτερογενής επιπτώσεις της ξηρασίας στην φυτοκάλυψη αξιολογήθηκαν από δορυφορικά δεδομένα χρησιμοποιώντας του δείκτες NDVI (Normalized Difference Vegetation Index) και Normalized Difference Water Index (NDWI). Οι προκύπτοντες χάρτες ξηρασίας μπορούν να χρησιμεύσουν ως πολύτιμος πόρος για τους υπεύθυνους χάραξης πολιτικής, τους διαχειριστές υδάτων και τα ενδιαφερόμενα μέρη που εμπλέκονται στον σχεδιασμό των υδατικών πόρων και στις διαδικασίες λήψης αποφάσεων. Οι χωρικά σαφείς πληροφορίες που παρέχουν οι χάρτες επιτρέπουν τη στοχευμένη κατανομή των πόρων, την εφαρμογή μέτρων μετριασμού της ξηρασίας και την ανάπτυξη στρατηγικών προσαρμογής στην ξηρασία σε περιφερειακή και τοπική κλίμακα. Συνολικά, η μελέτη αυτή καταδεικνύει τις δυνατότητες της τεχνολογίας ΣΓΠ και των δεικτών στη χαρτογράφηση και παρακολούθηση των συνθηκών ξηρασίας στην Ελλάδα. Η ενσωμάτωση διαφόρων περιβαλλοντικών συνόλων δεδομένων ενισχύει την κατανόηση των πολύπλοκων αλληλεπιδράσεων και παραγόντων που επηρεάζουν την ξηρασία, διευκολύνοντας πιο τεκμηριωμένες και προληπτικές στρατηγικές διαχείρισης των υδάτων ενόψει της αυξανόμενης κλιματικής μεταβλητότητας και των προκλήσεων των ξηρασιών.
... Local climatic conditions, such as drought, low precipitation, and dry winds, are region-specific [4,7]. Furthermore, droughts are one of the most serious natural hazards, particularly in terms of agriculture, with potentially catastrophic socioeconomic effects [8,9]. Droughts diminish surface and groundwater resources, resulting in lower water availability and quality, crop failure, lower agricultural output, decreased power generation, and various other socioeconomic effects [10,11]. ...
The Pacific region of Colombia is known to be one of the most vulnerable to changes in precipitation patterns. A study was conducted using standardized precipitation index (SPI) analyses to understand the potential changes in precipitation in this region during the 21st century. The analyses were conducted using historical precipitation data from 1950 to 2005 and projected precipitation data from 2022 to 2100 under the Coordinated Regional Climate Downscaling Experiment (CORDEX) climate scenarios (RCP 4.5 and RCP 8.5). The results of the study showed that compared to historical data, SPI3 precipitation in this region is predicted to increase by 2040 under both climatic scenarios. However, in the 2041–2070 period, the region is expected to be wetter under RCP 8.5, although the difference between the two scenarios was not statistically significant. Similarly, SPI 6 precipitation is predicted to increase in the 2022–2040 and 2071–2100 periods under both scenarios. SPI 12 precipitation is also predicted to increase in the 2022–2040 period under RCP 4.5. In the 2041–2070 period, dryness is predicted to be more frequent under RCP 4.5, and wetness is predicted under RCP 8.5. The findings of this study can help in determining the most pertinent reference periods and computation time increments for evaluating the effects of future climate change on agricultural production and food security in the Pacific region of Colombia. It suggests that changes in precipitation patterns are likely to occur in the coming decades, which may significantly impact crop growth, water availability, and other aspects of agricultural production.
Climate change is linked to the increase of natural disasters occurrence over the world. The increasing frequency of wildfire events constitutes a threat toward ecology, economy, and human lives. Hence, accurate information extracted from detailed burnt area cartography plays a primary role in the ecosystems’ preparation. Geoinformation has enabled rapid and low-cost Earth Observation data acquisition and their processing in cloud-based platforms such as Google Earth Engine (GEE). In the present study, a GEE-based approach that exploits machine learning (ML) techniques and ESA’s Sentinel-2 imagery is developed with the purpose of automating the mapping of burnt areas. As a case study is used an area located in the outskirts of Athens in Greece, on which it was occurred one of the largest wildfires in the summer of 2021. A Sentinel-2 image, obtained from GEE immediately after the fire event, was combined with ML classifiers for the purpose of mapping the burnt area at the fire-affected site. Validation of the derived products was based on the error matrix and the Copernicus Rapid Mapping operational product available for this fire event. Our study results clearly demonstrated the importance of rapid and accurate burnt area mapping exploiting sophisticated algorithms such as ML, when applied to Sentinel-2 imagery. Our findings provide valuable information regarding random forests and support vector machines classifiers through comparisons during their implementation as well as the potential of automated mapping in cloud-based platforms such as GEE. All in all, burnt area mapping is very valuable toward preparation activities regarding postfire management in future fire incidents.
In recent decades, a critical factor that policy makers have taken into account when assessing the environment is climate change. This global natural process has already caused many problems in the natural and man-made environment. In the future, these problems are expected to multiply and become more severe. As a result, there will be much more pressure on water resources, resulting in water shortages in many more areas. The management of water, such an important resource, requires the adoption of management techniques adapted to the needs of each region and each season. It is one part of the spectrum of environmental management. It seeks an acceptable balance between the available water resources and the often-competing uses of water using technical and non-technical means. The decline in groundwater resources, their degradation and intensive use mean that surface water exploitation projects need to be promoted. Projects that ensure the exploitation of surface water (dams, reservoirs, dams, refineries) are more environmentally friendly and help to protect the environment, save energy and, in some cases, generate energy from renewable sources. These projects are made even more attractive by the availability of unused water, greater protection for consumers, the possibility of multiple uses of water and the creation of new jobs. This chapter presents a methodology for selecting suitable sites for the construction of small reservoirs to harness surface runoff. The use of primary data, such as meteorological and spatial data in a Geographic Information Systems (GIS) framework, with the integration of an appropriate hydrological model can reveal locations/areas suitable for the construction of small reservoirs. The island of Andros (Cyclades, Greece) is the study area for this proposed methodology. Several locations on the island were examined and finally three locations were selected for the construction of small reservoirs.
Floods are among the most catastrophic natural events worldwide that affect human and animal life, properties, infrastructure, the environment and crops. Greece has recorded a large number of historical floods followed by a significant impact on several types of land use/cover that resulted in a high economic cost for compensation and/or restoration. Globally it is expected that climate change will increase such events in the upcoming decades. This work integrates Sentinel-1 satellite images and high spatial resolution land use/land cover data for the estimation of the catastrophic effects of a prolonged period of intense and continuous rainfall, and thus, extreme flooding that took place in Sperchios’ river valley from the end of January until the beginning of February of 2015. The investigated flood phenomenon caused severe damage to the region’s infrastructure and crops, covering the highest percentage of the Sperchios’ river valley plain. The proposed methodology intends to exhibit the delimitation of the flooded areas through the analysis of Sentinel-1 satellite images, which temporally covered the aforementioned period of the event, and estimate the effects of the flooding extent via high-resolution land use/land cover data of the area of interest. This methodology can be used as an operational tool for mitigating, rapid mapping and restoration after disastrous flooding events, particularly in agricultural areas.
Erosion has become one of the extreme ecological dangers in up to date. Decrease of minerals in the upper layer of soil leads to failure in sustainable crop practices. Many researchers have developed prediction models of Sediment Yield (SY) in gauged basins. But modelling for an ungauged basin is very difficult due to the difficulty in validating the predicted model. The primary goal of the study was to identify the sedimentation in the study area using multiple(SY) methodologies, including Sediment Delivery Ratio (SDR) and Modified Universal Soil Loss Equation (MUSLE), in an ungauged basin with a high-resolution satellite precipitation dataset.. Different attributes such as LULC (land use / land cover), soil texture, precipitation, topography, etc. was incorporated to estimate the SY in Ponnaniyar river basin,. The generated SY map from SDR and MUSLE was evaluated by the receiver operating characteristic curve (ROC). The SDR model was found to be an efficient method for determining the SY for Ponnaniyar river basin, and also satisfied the criteria of AUC value of 0.752. The severely affected sub-watershed of Ponnaniyar river basin was identified with the help of erosion and yield spatial map. The obtained results will help prioritize the sub-watershed for locating water harvesting structures in further studies. This study suggests placing the gauging station in Ponnaniyar river basin to monitor the daily observation of discharge and SY estimation to prevent soil loss during flash flooding.
The objective of this research was to analyse hydrological variability by conducting an intensive analysis of extreme events, under dry and wet conditions. Drought conditions were assessed using the Standard Precipitation Index (SPI) and Rainfall Anomaly Index (RAI), while the Soil Conservation Service (SCS) method was used to simulate flooding at four stations. The SPI results indicated that the amount of rainfall within the catchment area is near to normal, ranging from 64% to 75%, with some extremely wet exceptions which may cause flash floods. The RAI results also indicated that the amount of rainfall within the catchment area is near to normal, but the extremely wet category obtained the largest percentage (ranging from 36% to 50%) and the very wet category had the lowest percentage (ranging from 9% to 36%). The simulated flooding, using SCS, tended to slightly underestimate the observed streamflow, while the performance showed some weaknesses when the observed flooding was less than 1 m3/s. The Nash–Sutcliffe Efficiency showed higher performance at closer rainfall stations to the outlet, with values of 0.92 and 0.94. Distant stations simulated floods that showed a lower level of efficiency, with values of 0.77 and 0.81. Given the fact that hydrological extremes (dry and wet conditions) are connected, the findings of the two indices and the SCS method are consistent and suitable for monitoring drought and flood events under climate change.
Future changes in drought characteristics in Greece were investigated using dynamically downscaled high-resolution simulations of 5 km. The Weather Research and Forecasting model simulations were driven by EC-EARTH output for historical and future periods, under Representative Concentration Pathways 4.5 and 8.5. For the drought analysis, the standardized precipitation index (SPI) and the standardized precipitation-evapotranspiration index (SPEI) were calculated. This work contributed to achieve an improved characterization of the expected high-resolution changes of drought in Greece. Overall, the results indicate that Greece will face severe drought conditions in the upcoming years, particularly under RCP8.5, up to 8/5 y of severity change signal. The results of 6-month timescale indices suggest that more severe and prolonged drought events are expected with an increase of 4 months/5 y, particularly in areas of central and eastern part of the country in near future, and areas of the western parts in far future. The indices obtained in a 12-month timescale for the period 2075–2099 and under RCP8.5 have shown an increase in the mean duration of drought events along the entire country. Drought conditions will be more severe in lowland areas of agricultural interest (e.g., Thessaly and Crete).
The Standardized Precipitation Index (SPI) is a vital component of meteorological drought. Several researchers have been using SPI in their studies to develop new methodologies for drought assessment, monitoring, and forecasting. However, it is challenging for SPI to provide quick and comprehensive information about precipitation deficits and drought probability in a homogenous environment. This study proposes a Regional Intensive Continuous Drought Probability Monitoring System (RICDPMS) for obtaining quick and comprehensive information regarding the drought probability and the temporal evolution of the droughts at the regional level. The RICDPMS is based on Monte Carlo Feature Selection (MCFS), steady-state probabilities, and copulas functions. The MCFS is used for selecting more important stations for the analysis. The main purpose of employing MCFS in certain stations is to minimize the time and resources. The use of MCSF makes RICDPMS efficient for drought monitoring in the selected region. Further, the steady-state probabilities are used to calculate regional precipitation thresholds for selected drought intensities, and bivariate copulas are used for modeling complicated dependence structures as persisting between precipitation at varying time intervals. The RICDPMS is validated on the data collected from six meteorological locations (stations) of the northern area of Pakistan. It is observed that the RICDPMS can monitor the regional drought and provide a better quantitative way to analyze deficits with varying drought intensities in the region. Further, the RICDPMS may be used for drought monitoring and mitigation policies.
Natural resources degradation poses multiple challenges, particularly to environmental
and economic processes. It is usually difficult to identify the degree of degradation and the critical vulnerability values in the affected systems. Thus, among other tools, indices (composite indicators) may also describe these complex systems or phenomena. In this approach, the Water and Land Resources Degradation Index was applied to the fifth largest Mediterranean island, Crete, for the 1999–2014 period. The Water and Land Resources Degradation Index uses 11 water and soil resources related indicators: Aridity Index, Water Demand, Drought Impacts, Drought Resistance Water Resources Infrastructure, Land Use Intensity, Soil Parent Material, Plant Cover, Rainfall, Slope,
and Soil Texture. The aim is to identify the sensitive areas to degradation due to anthropogenic interventions and natural processes, as well as their vulnerability status. The results for Crete Island indicate that prolonged water resources shortages due to low average precipitation values or high water demand (especially in the agricultural sector), may significantly affect Water and Land degradation processes. Hence, Water and Land Resources Degradation Index could serve as an extra tool to assist policymakers to improve their decisions to combat Natural Resources degradation.
Efficient and sustainable exploitation of water resources requires the adoption of innovative and contemporary management techniques, a need that becomes even more demanding due to climate change and increasing pressures coming from anthropogenic activities. An important outcome of this reality is the qualitative and quantitative degradation of groundwater, which clearly indicates the need to exploit surface runoff. This study presents an integrated Geographic Information System (GIS)-based methodological framework for revealing and selecting suitable locations to build small-scale reservoirs and exploit surface runoff. In this framework, the SWAT model was used to quantify surface runoff, followed by the simulation of reservoir scenarios through reservoir simulation software. Andros Island (located in Cyclades Prefecture), Greece was selected as the study area. The obtained results indicated the most suitable location for creating a reservoir for maximizing exploitation of surface runoff, based on the specific water demands of the nearby areas and the existing meteorological, hydrological, and geological background potential. Thus, two selected dam locations are analyzed by using the proposed framework. The findings showed that the first dam site is inappropriate for creating a reservoir, as it cannot meet the demand for large water extraction volumes. In addition, the outcomes confirmed the efficiency of the proposed methodology in optimum selection of locations to construct small-scale water exploitation works. This research presents a contemporary methodological framework that highlights the capability of GIS, SWAT modeling, and reservoir simulation coupling in detecting optimal locations for constructing small reservoirs.
The questions of scale, limit, and areal extent are central points for any drought assessment effort. Drought indices, such as the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), are assisting to demarcate drought characteristics and spatial extent. The current approach utilizes the E-OBS gridded dataset's hydro-climatic parameters (precipitation, minimum and maximum temperature) for applying SPI and SPEI on a Pan-European scale for a detail drought assessment during the 1969-2018 period. The two indices are estimated for the 6 and 12-month scales. In this effort, drought is defined as an event that has index value less than minus 1.5 for at least three consecutive months. Based on this, drought characteristics (frequency, duration, and severity) are derived. The results are displayed in 5-year windows and they are also assessed against independently recorded droughts as occurred. Overall, it may be reported that there has been little change in drought characteristics over the past 50 years in Europe. Furthermore, given the variety of climatic locales on a continental level, the 6 and 12-month time scales for both indices may offer an improvement on drought critical areas identification, threshold definitions, and comparability.
The potential consequence of global climatic change caused the rise in temperature and precipitation decline, the aftermath of which has led to phenomenon like drought. As the agriculture is mainly dependent on the timely availability of water, delayed arrival of rainfall or decrease in the intensity of precipitation highly affects the growth of crops. If such situation persists for a longer period, the soil moisture content will be exploited completely and maturity of the crop will be stunted, finally adversely affecting the annual crop yield. In the present study, the capability of shortwave-infrared (SWIR) channels in detecting the agricultural crop stress in Raichur district of Karnataka state, India, using spectral vegetation indices namely Global Vegetation Moisture Index (GVMI) and Normalized Multi-band Drought Index (NMDI) has been analyzed using multi-temporal MODIS data. The vegetation health analysis by utilizing both indices were carried out from year 2002 to 2012 for the Kharif season, and it was seen that the year 2002 suffered major agricultural drought where the lower GVMI and NMDI values were covering the majority of the crop areas and in the year 2010 agricultural crop production was observed to be good. The average values of GVMI and NMDI for the years 2002 and 2010 were plotted with the average NDVI values of all months of both years and the results revealed that NDVI values were in concurrence with both NMDI and GVMI.
Indices are used for representing complex phenomena; however, concerns usually arise regarding their objectivity and reliability, particularly dealing with their uncertainties during the development process. The current overarching objective is to reveal the significance of employing different weighting techniques in the application of the Standardized Drought Vulnerability Index (SDVI) and demarcate any pertinent implications that may emerge in drought decision making. Greece, as it is very often facing the catastrophic effects of droughts, presents an almost ideal case for the SDVI testing. SDVI outcomes were tested utilizing five weighting techniques deriving from four weighting methods. The analyses indicated that the use of complex weighting models may not be necessary in all cases and that the simple equal weighting method seems more effective to estimate drought vulnerability. It also seems more important to address the search for valid, reliable and relevant individual indicators forming the complex index as well as appropriate index development processes that would measure performance of water bodies, systems and schemes, monitor the process of equitable sharing, and provide mechanisms for monitoring the state and changes in interdependent water systems.
Rainfall is a major natural process, with severe impact on human population. Recent changes in rainfall are directly linked with climate change. This study aims at the spatial and statistical analysis of rainfall in Greece during the last two decades of the 20th century. Its main objective is to investigate current conditions and evaluate emerging trends. Analysis relies on data from 74 meteorological stations all over the country and covers the years 1981-2000. Methodo-logically, the paper is divided into two parts. In the first part, Thiessen polygons have been created to determine their influence zones, and spatial correlation has been estimated using Moran's I index, weighted by appropriate spatial proximity matrices. Analysis has been performed using GeoDa software. At a second level, and having selected a representative sample from those stations , descriptive statistics were applied to determine current status and identify future trends. For each one of the years studied, analysis refers to two sub-periods, the dry and the wet one, as well as to the year as a whole. Differences detected between dry and wet seasons, as well as the similarities between wet and year period imply that the characteristics of annual rainfall are mainly conditioned by those of the wet season. This approach, if applied for multiple and continuous time-periods, could serve as a very useful tool for researching and analyzing future trends and spatial patterns, in different areas worldwide. Thus, important conclusions can come of about rainfall (or climatic in general) differentiations, possibly due to climate change.
The degradation of natural resources at an intense rate creates serious problems in the environmental systems particularly with the compounding effects of climatic vagaries and changes. On the one hand, desertification is a crucial universal, mostly an anthropogenic environmental issue affecting soils all over the world. On the other hand, drought is a natural phenomenon in direct association with reduced rainfall in various spatial and temporal frames. Vulnerabilities to drought and desertification are complex processes caused by environmental, ecological, social, economic and anthropogenic factors. Particularly for the Mediterranean semi-arid conditions, where the physical and structural systems are more vulnerable, the abuse and overuse of the natural resources lead to their degradation and ultimately, if the current trends continue, to their marginalization. The scope of the current effort is trying to find any common drivers for the pressures of both processes. Thus, the vulnerabilities to drought and desertification are comparing by using the Standardized Drought Vulnerability Index (SDVI) and the Environmentally Sensitive Areas Index (ESAI). The indices are calculated from October 1983 to September 1996 in Greece. Greece is prone to desertification and it is often experiencing intense droughts, thus it presents an almost ideal case study area. The results may indicate that the most important factor for such procedures is the deficits in water resources, either due to lower than usually expected rainfall or to higher societal water demand.
California's current extreme drought must be a lesson for managing water in a warmer, more densely populated world, say Amir AghaKouchak and colleagues.
Feeding the world population, 7.3 billion in 2015 and projected to increase to 9.5 billion by 2050, necessitates an increase in agricultural production of ~70% between 2005 and 2050. Soil degradation, characterized by decline in quality and decrease in ecosystem goods and services, is a major constraint to achieving the required increase in agricultural production. Soil is a non-renewable resource on human time scales with its vulnerability to degradation depending on complex interactions between processes, factors and causes occurring at a range of spatial and temporal scales. Among the major soil degradation processes are accelerated erosion, depletion of the soil organic carbon (SOC) pool and loss in biodiversity, loss of soil fertility and elemental imbalance, acidification and salinization. Soil degradation trends can be reversed by conversion to a restorative land use and adoption of recommended management practices. The strategy is to minimize soil erosion, create positive SOC and N budgets, enhance activity and species diversity of soil biota (micro, meso, and macro), and improve structural stability and pore geometry. Improving soil quality (i.e., increasing SOC pool, improving soil structure, enhancing soil fertility) can reduce risks of soil degradation (physical, chemical, biological and ecological) while improving the environment. Increasing the SOC pool to above the critical level (10 to 15 g/kg) is essential to set-in-motion the restorative trends. Site-specific techniques of restoring soil quality include conservation agriculture, integrated nutrient management, continuous vegetative cover such as residue mulch and cover cropping, and controlled grazing at appropriate stocking rates. The strategy is to produce "more from less" by reducing losses and increasing soil, water, and nutrient use efficiency.
Drought is a complex natural phenomenon that lacks a universally accepted definition, thus it is difficult to confront holistically. Several efforts have been made towards managing the widespread and catastrophic drought impacts. In this quest, the concept of vulnerability to drought seems to offer some significant potential. In the present attempt, a standardized drought vulnerability index (SDVI) is presented, applied, and spatially visualized through geostatistical methods on a country scale. Greece, experiencing frequent and intense droughts, was selected as the study site. In an effort to link drought characteristics to impacts, the index incorporates water supply information, demand data, the state of the relevant water infrastructure and climatic parameters represented by the standardized precipitation index. The index showed potential in portraying various vulnerability states and followed satisfactorily the vulnerability fluctuations in Greece in relation to recorded drought hazard dimensions and impacts. The SDVI may be considered as a first step for the emergence of an integrated SDVI with multiscalar applications in environmental research and decision-making. It is believed that improving techniques in index formulation may complement more reasonable and acceptable solutions to water challenges posed by droughts and help avoid a drifting sense of continuous ‘water crises’.
Forecasting is one of the most important elements in fire and flood danger confrontation schemes for wildland and urban interface areas. The difficulty in studying such natural hazards in general, and in the islands of the Aegean Archipelago in particular, includes not only an assessment of their causes, territorial distribution and damage inflicted in time, but also their dependence on human socio-economic activities. In this context, wildfire danger rating systems have been adopted by many developed countries dealing with wildfire prevention, so that civil protection agencies are able to define areas with high probabilities of fire ignition and resort to necessary actions. Focusing also on floods, it is impossible to avoid them; however, an overall understanding of their nature and development may facilitate their quantitative prediction, and therefore may lead towards appropriate management responses as well as in early warning so as to mitigate their catastrophic effects (loss of human lives, resources and property damage). This paper, having a two-prong emphasis, first presents an initial attempt towards a systematically approached Greek fire danger rating system in the study area of Lesvos Island, Greece. The proposed system estimates the spatial fire danger while it has the ability of risk forecasting based on meteorological data. The main output of the system is the Fire Danger Index, which is based on four other indices: the fire weather index, the fire hazard index, the fire risk index and the fire behavior index. These indices are not just a relative probability for fire occurrence but a quantitative rate for fire danger appraisal in a systematic manner. In addition, the incorporated flood analysis and forecasting module may offer considerable services particularly after a devastating flood event. Such an effort points out that there must be a fundamental shift from a prevailing crisis management approach (short-range preoccupation and technological fixes) to a more anticipatory risk management that allows concentrating on contingency planning and reasonably foreseeable futures. The developed short-term dynamic fire and flood danger indices aid in decision support for better and realistic prevention and pre-suppression planning.
A new general drought index is proposed for the assessment of meteorological drought severity. The new index called Reconnaissance Drought Index, RDI, is based on cumulative values of precipitation and potential evapotranspiration. Three expressions of RDI are given: the initial, the normalised and the standardised. The standardised RDI can be directly compared to the Standardised Precipitation Index (SPI) which is widely used. The new index has certain advantages when compared to SPI since it is more representative of the deficient water balance conditions than an index based only on precipitation.
There is increasing concern worldwide about the ineffectiveness of current drought management practices that are largely based on crisis management. These practices are reactive and, therefore, only treat the symptoms (impacts) of drought rather than the underlying causes for the vulnerabilities associated with impacts. Through the adoption of national drought policies that are focused on risk reduction and complemented by drought mitigation or preparedness plans at various levels of government, the coping capacity of nations to manage droughts can be improved. The time for adopting an approach that emphasizes drought risk reduction is now, given the spiraling impacts of droughts in an ever-increasing number of sectors and the current and projected trends for the increased frequency, severity and duration of drought events in association with a changing climate. This paper discusses the underlying concepts of drought, the principles and objectives of national drought policies and a drought planning process that has been effective in the preparation of drought mitigation plans.
The pressure on water resources is expected to be even greater during the next years due to population growth, climate change, regional polarizations of economic activities, etc. Thus, the management of water resources requires, beyond the adoption of policies preventing water wastage and depletion, the implementation of water schemes based on surface runoff development techniques to meet needs at regional/local level. It is, therefore, necessary, in many cases, to conceive, plan and build water projects founded on adequate/adapted technology, by using locally-regionally existing materials and techniques, aiming at the development of local socio-economical dynamics, creation of jobs, protection of the environment, etc. There is no contradiction in modern environments if combining the above mentioned type of technical paradigms with high technology standards. This paper presents the systemic advantages of that type adequate/adapted technology small reservoirs and a GIS-based land planning technique for their positioning.
The use of standardised precipitation index (SPI) may lead to an understanding of a droughts magnitude and duration and thus contributing to integrated drought management options. Greece, a semi-arid country, has very often faced the hazardous impacts of droughts. The worst drought on record lasted from 1989 to 1993, and affected all the country, particularly the urban water supply of Athens metropolitan area. Rainfall time series from 41 rain stations were used to calculate SPI, for time scales of 3, 6, 12 and 24 months. Forty eight (48) interpolation surfaces were produced and assessed using historical data and statistical parameters for the SPI spatial visualisation through GIS kriging of the 1989–1993 drought. The results suggest the use of SPI as a drought monitoring tool, namely in areas with a distinct dry season, supporting drought forecasting and assisting integrated strategies for drought management.
The Environmental Vulnerability Index (EVI) was developed by the Pacific Islands Applied Geoscience Commission as a global composite index that quantifies the vulnerability of an area's environment. Greece has been selected as reference area due to its current physical and anthropogenic conditions that may lead to environmental instabilities in the natural, social, and economic infrastructure environment. Hence, in the present approach, using data on Greece, an effort to define the range of information that the EVI may provide for the pertinent country is presented and a discussion on whether the index may be further developed is conveyed. Advantages as well as shortcomings of the Index are also delineated.
Droughts are ubiquitous phenomena presenting nascent obstacles for any planning and management efforts. Such difficulties may emanate from the fact that the pertinent efforts try to incorporate physical processes as well as highly complex interactions with the surrounding environment. The Athens metropolitan area, in Greece, has recently suffered through some of the worst droughts on record. In this context, the Athenian region provides a unique opportunity for a specific examination of drought, drought management implementation efforts on a large scale and of their evaluation under stressed physical, structural and socio-economic conditions. The overall approach allows also for a broader consideration of water resources in Greece, and of water resources planning and management status. As a result, drought management options may be introduced of both structural and non-structural measures with a greater sensitivity to the particular environment of the Athenian metropolis and by extension to similar localities around the world.
Drought constitutes a rather severe hazard to all human activities, and especially to water supply. After numerous efforts to improve planning and management actions against droughts, many deficiencies still remain. The major new challenge is the development of integrated, comprehensive, and effective drought management schemes, with the aid of decision support systems (DDS), particularly under extreme and adverse condition. These conditions can be found in the physical, structural, socio-economic and institutional environment. The metropolitan Athens area in Greece, a semiarid area where the water supply is accomplished by a series of reservoirs and conveyance structures approximately 190 km to the west of the region, reflects such a case. In this regard, the present paper is trying to identify appropriate solutions for the above problematic areas by incorporating elements of integrated drought management strategies. The resulting options may be used as a means to avoid undesirable effects or major future crises in meeting the continuous challenge of drought and in fortifying a risk management commitment.
The main premise of the current effort is that the use of a drought index, such as Standardized Precipitation Index (SPI), may lead to a more appropriate understanding of drought duration, magnitude and spatial extent in semi-arid areas like Greece. The importance of the Index may be marked in its simplicity and its ability to identify the beginning and end of a drought event. Thus, it may point towards drought contingency planning and through it to drought alert mechanisms. In this context, Greece, as it very often faces the hazardous impacts of droughts, presents an almost ideal case for the SPI application. The present approach examines the SPI drought index application for all of Greece and it is evaluated accordingly by historical precipitation data. Different time series of data from 46 precipitation stations, covering the period 1947–2004, and for time scales of 1, 3, 6, 12 and 24 months, were used. The computation of the index was achieved by the appropriate usage of a pertinent software tool. Then, spatial representation of the SPI values was carried out with geo-statistical methods using the SURFER 9 software package. The results underline the potential that the SPI usage exhibits in a drought alert and forecasting effort as part of a drought contingency planning posture.
Severe drought is a recurring problem for the United States, as illustrated by widespread economic, social, and environmental impacts. Recent drought episodes and the widespread drought conditions in 1996, 1998, and 1999 emphasized this vulnerability and the need for a more proactive, risk management approach to drought management that would place greater emphasis on preparedness planning and mitigation actions. Drought planning has become a principal tool of states and other levels of government to improve their response to droughts. For example, since 1982, the number of states with drought plans has increased from 3 to 29. Many local governments have also adopted drought or water shortage plans. Unfortunately, most state drought plans were established during the 1980s and early 1990s and emphasize emergency response or crisis management rather than risk management. This paper presents a substantive revision of a 10-step drought planning process that has been applied widely in the United States and elsewhere. The revised planning process places more weight on risk assessment and the development and implementation of mitigation actions and programs. The goal of this paper is to encourage states to adopt this planning process in the revision of existing drought plans or, for states without plans, in the development of new plans.
The impacts of different spatial resolutions and different data assimilation schemes of the available re-analysis data sets (NCEP/NCAR and ERA-40) on the assessment of drought variability are analysed. Particular attention has been devoted to the analysis of the possible existence of a linear trend in the climatic signal. The long-term aspects of drought over the globe during the last forty years have been evaluated by computing the Standardized Precipitation Index (SPI) on 24-month time scale. The SPI, in fact, seems to be a useful tool for monitoring dry and wet periods on multiple time scales and comparing climatic conditions of areas governed by different hydrological regimes. To unveil possible discrepancies between the analyses carried out with the two data sets, we studied the leading space-time variability of drought by applying the principal component analysis (PCA) to the SPI time series. Results suggest that on the global scale, the two re-analyses agree in their first principal component score, but not in the associated loading: both re-analyses capture a linear trend, though the areas where this feature should be most likely observed are not uniquely identified by the two data sets. Moreover, while the ERA-40 unveils the presence of a weak net “global” trend towards wet conditions, the NCEP/NCAR re-analysis suggests that the areas in the world characterised by positive/negative trends balance to zero. At large regional scale, a good agreement of the results with those obtained from the observations are found for the United Stated, while for the European sector the two re-analyses show remarkable differences both in the first loading and in representing the timing of the wet and dry periods. Also for these areas a linear trend, superposed on other short-term fluctuations, is detectable in the first principal component of the SPI field.
Unlike other natural disasters, drought events evolve slowly in time and their impacts generally span a long period of time. Such features do make possible a more effective drought mitigation of the most adverse effects, provided a timely monitoring of an incoming drought is available.
Among the several proposed drought monitoring indices, the Standardized Precipitation Index (SPI) has found widespread application for describing and comparing droughts among different time periods and regions with different climatic conditions. However, limited efforts have been made to analyze the role of the SPI for drought forecasting.
The aim of the paper is to provide two methodologies for the seasonal forecasting of SPI, under the hypothesis of uncorrelated and normally distributed monthly precipitation aggregated at various time scales k. In the first methodology, the auto-covariance matrix of SPI values is analytically derived, as a function of the statistics of the underlying monthly precipitation process, in order to compute the transition probabilities from a current drought condition to another in the future. The proposed analytical approach appears particularly valuable from a practical stand point in light of the difficulties of applying a frequency approach due to the limited number of transitions generally observed even on relatively long SPI records. Also, an analysis of the applicability of a Markov chain model has revealed the inadequacy of such an approach, since it leads to significant errors in the transition probability as shown in the paper. In the second methodology, SPI forecasts at a generic time horizon M are analytically determined, in terms of conditional expectation, as a function of past values of monthly precipitation. Forecasting accuracy is estimated through an expression of the Mean Square Error, which allows one to derive confidence intervals of prediction. Validation of the derived expressions is carried out by comparing theoretical forecasts and observed SPI values by means of a moving window technique. Results seem to confirm the reliability of the proposed methodologies, which therefore can find useful application within a drought monitoring system.
An analysis of drought in Sicily from 1926 to 1996 is presented.In identifying drought over the region, both the NCEP/NCARreanalysis precipitation data and those observed in 43 gauges,located quite uniformly over the territory of the Island, areused. Drought occurrence is estimated by means of theStandardized Precipitation Index (SPI). To study long-termdrought variability, a Principal Component Analysis was appliedto the SPI field.Results suggest that the entire Island is characterised by adrought variability with a multi-year fluctuations and atendency towards drier periods from the seventies onward. Apreliminary comparison between results obtained using themeteorological large-scale analysis and that derived from actualobservations on the ground shows a general good agreement,although further efforts are needed to get a better downscalingof the large-scale precipitation fields. Furthermore, byapplying orthogonal rotations to the principal componentpatterns, it has been found that three distinct areas havingcoherent climatic variability may be identified.Finally, the sensitivity of the SPI values on the calibrationperiod is also investigated.
Drought is a global phenomenon that occurs virtually in all landscapes causing significant damage both in natural environment
and in human lives. Due to the random nature of contributing factors, occurrence and severity of droughts can be treated as
stochastic in nature. Early indication of possible drought can help to set out drought mitigation strategies and measures
in advance. Therefore drought forecasting plays an important role in the planning and management of water resource systems.
In this study, linear stochastic models known as ARIMA and multiplicative Seasonal Autoregressive Integrated Moving Average
(SARIMA) models were used to forecast droughts based on the procedure of model development. The models were applied to forecast
droughts using standardized precipitation index (SPI) series in the Kansabati river basin in India, which lies in the Purulia
district of West Bengal state in eastern India. The predicted results using the best models were compared with the observed
data. The predicted results show reasonably good agreement with the actual data, 1–2months ahead. The predicted value decreases
with increase in lead-time. So the models can be used to forecast droughts up to 2months of lead-time with reasonably accuracy.
Drought has become a recurrent phenomenon in Turkey in the last few decades. Significant drought conditions were observed during years of late 1980s and the trend continued in the late 1990s. The countrys agricultural sector and water resources have been under severe constraints from the recurrent droughts. In this study, spatial and temporal dimensions of meteorological droughts in Turkey have been investigated from vulnerability concept. The Standardized Precipitation Index (SPI) method was used to detail geographical variations in the drought vulnerability based on frequency and severity of drought events at multiple time steps. Critical (threshold) rainfall values were derived for each station at multiple-time steps in varying drought categories to determine least amount of rainfall required to avoid from drought initiation. The study found that drought vulnerability portrays a very diverse but consistent picture with varying time steps. At regional scale, south-eastern and eastern Anatolia are characterized with moderate droughts at shorter time steps, while the occurrence of severe droughts at shorter time steps is observed at non-coastal parts of the country. A similar picture was observed with very severe droughts. The critical (threshold) values exhibited rising numbers during the growing season at 3-month step in the South-eastern Anatolia, which might have significant consequences considering presence of large irrigation projects under-development in the region. In general, rainfall amounts required for non-drought conditions decrease from the coastal parts toward the interiors with increasing time steps.
This paper is predominantly an empirical investigation which reports upon a part of a continuing project into the "greening of accounting", (Gray, 1990; 1992; Gray et al., Bebbington et al., 1994) In particular, the paper reports upon the field work undertaken to attempt to assess what, if anything, accountants were doing—and could do—to help organizations respond to the environmental agenda. The paper is motivated by Power's (1992) argument that change in accounting can have a significant influence on conceptions of the organization but that the direction of such influence cannot be predicted. The investigation is grounded in Laughlin's (1991) model of organizational change and Llewellyn's (1993) explanations of organizational boundary management. The bulk of the paper attempts to explicate these models in the context of change in the natural environment agenda. The empirical investigation then attempts to link observations about current organizational behaviour with these models. However, it becomes apparent that conventional accounting practice is having little, if any, (positive) influence on this process. We do find evidence of a increase in "environmental account" which, it seems, are playing an important role in both aiding the development of the organizations' environmental agenda and helping negotiate the meaning of "the natural environment" for organizations. Whilst we are more positive about the potential for such accounts—and a potential role for accountants—we do conclude by recognizing that questioning the benign nature of "environmental accounting" is a far from trivial activity, (see, for example, Cooper, 1992).
The industrial agriculture system consumes fossil fuel, water, and topsoil at unsustainable rates. It contributes to numerous forms of environmental degradation, including air and water pollution, soil depletion, diminishing biodiversity, and fish die-offs. Meat production contributes disproportionately to these problems, in part because feeding grain to livestock to produce meat--instead of feeding it directly to humans--involves a large energy loss, making animal agriculture more resource intensive than other forms of food production. The proliferation of factory-style animal agriculture creates environmental and public health concerns, including pollution from the high concentration of animal wastes and the extensive use of antibiotics, which may compromise their effectiveness in medical use. At the consumption end, animal fat is implicated in many of the chronic degenerative diseases that afflict industrial and newly industrializing societies, particularly cardiovascular disease and some cancers. In terms of human health, both affluent and poor countries could benefit from policies that more equitably distribute high-protein foods. The pesticides used heavily in industrial agriculture are associated with elevated cancer risks for workers and consumers and are coming under greater scrutiny for their links to endocrine disruption and reproductive dysfunction. In this article we outline the environmental and human health problems associated with current food production practices and discuss how these systems could be made more sustainable.
Drought is a complex natural hazard with its adverse multifaceted impacts cascading in every physical and human system. The vulnerability magnitude of various areas to drought mostly depends on their exposure to water deficiency, the existing water management policy framework and its implementation. The Standardized Drought Vulnerability Index (SDVI) is an integrated attempt towards characterizing drought vulnerability based on a comparative classification system, incorporating precipitation patterns, the supply and demand trends, and the socioeconomic background as the most crucial contributors to drought vulnerability. This work attempts to evolve the SDVI by presenting a more rigorous method of index parameters estimation and argues that the combination of in-situ and satellite data improve the index results in an effort to further minimize the paucity of drought related information. At the same time, it helps to surpass previous limitations in temporal and spatial propagation of the vulnerability concept. The new framework is applied in the South Platte Basin, within Colorado, on the 2012 summer drought (July-September). The proposed index modification may convey drought information in a more holistic manner to decision makers. SDVI could aid in advancing the understanding of each component contribution through in situ and remote sensing data integration and in avoiding existing practices of broken linkages and fragmentation of the reported impacts. Thus, it is believed that the SDVI could serve as an additional tool to guide decisions and target mitigation and adaptation actions, allowing for a more integrated management approach.
This paper reviews research traditions of vulnerability to environmental change and the challenges for present vulnerability research in integrating with the domains of resilience and adaptation. Vulnerability is the state of susceptibility to harm from exposure to stresses associated with environmental and social change and from the absence of capacity to adapt. Antecedent traditions include theories of vulnerability as entitlement failure and theories of hazard. Each of these areas has contributed to present formulations of vulnerability to environmental change as a characteristic of social-ecological systems linked to resilience. Research on vulnerability to the impacts of climate change spans all the antecedent and successor traditions. The challenges for vulnerability research are to develop robust and credible measures, to incorporate diverse methods that include perceptions of risk and vulnerability, and to incorporate governance research on the mechanisms that mediate vulnerability and promote adaptive action and resilience. These challenges are common to the domains of vulnerability, adaptation and resilience and form common ground for consilience and integration.
Water represents an essential element for the life of all who inhabit our planet. But the random nature of this resource, which is manifested by the alternation of wet periods and dry periods, makes it even more precious. Whatever the approach (water planning, water management, drought, economy), in order to maximise the profit produced by the allocation of water it is necessary an understanding of the relationships between physical variables as precipitation, temperatures, streamflows, reservoir volumes, piezometric levels, water demands and infrastructures management. This paper attends to provide a review of fundamental water scarcity and drought indexes that enables to assess the status of a water exploitation system. With the aim of a better water management and governance under water scarcity conditions., this paper also presents a classification of indexes to help decision makers and stakeholders to select the most appropriate indexes, taking as the starting point the objectives of the analysis and the river basin features.
Defining and measuring sustainability is a major challenge. This article argues these limitations need not stop us from trying to identify and value the possible impacts of what we are doing, or are thinking about doing, over time periods much longer than the lives of our investments, or even of the lives of those of us living today. Sustainability is a relative concept that must be applied in an environment undergoing multiple changes, changes that are occurring over different temporal and spatial scales. We depend on our water resource systems for our survival and welfare. Yet no one expects them to be restored to, or survive in, their most productive pristine states in the face of increasing development pressures for land in their watersheds and for water in their streams, rivers, lakes, and aquifers. A continuing task of water resource planners and managers is to identify the multiple impacts and tradeoffs resulting from what we who are living today may wish to do for ourselves and our immediate children and what we can only guess our yet-to-be-born descendants may wish us to do, or not do, for them in some distant future. This task must involve professionals from other disciplines in a context much broader than just water management. Once these impacts and tradeoffs are identified, it is then up to the political process to make choices when they are in conflict. All of us need to be a part of this decision-making process.
Environmental management is a wide, expanding, and rapidly evolving field, affecting everyone from individual citizens to businesses; governments to international agencies. Indisputably, it plays a crucial role in the quest for sustainable development. This comprehensively updated second edition explores the nature and role of environmental management, covering key principles, practices, tools, strategies and policies, offers a thorough yet understandable introduction, and points to further in-depth coverage. Among the key themes covered are: sustainable development proactive approaches the precautionary principle the 'polluter pays' principle the need for humans to be less vulnerable and more adaptable. Reflecting the expansion and evolution of the field, this revised edition focuses strongly on sustainable development. There has been extensive restructuring to ensure the book is accessible to those unfamiliar with environmental management and it now includes greater coverage of topics including key resources under stress, environmental management tools, climate change and urban environmental management. With rapid expansion and development of the subject it is easy for those embarking on a course of study to become disorientated, but with its well-structured coverage, effective illustrations, and foundation for further, more-focused interest, this book is easily accessible to all.
One of the major difficulties in water planning is to determine the water availability in a water resource system in order to distribute water sustainably. In this paper, we analyze the key issues for determining the exploitable water resources as an indicator of water availability in a Mediterranean river basin. Historically, these territories are characterized by heavily regulated water resources and the extensive use of unconventional resources (desalination and wastewater reuse); hence, emulating the hydrological cycle is not enough. This analysis considers the Jucar River Basin as a case study. We have analyzed the different possible combinations between the streamflow time series, the length of the simulation period and the reliability criteria. As expected, the results show a wide dispersion, proving the great influence of the reliability criteria used for the quantification and localization of the exploitable water resources in the system. Therefore, it is considered risky to provide a single value to represent the water availability in the Jucar water resource system. In this sense, it is necessary that policymakers and stakeholders make a decision about the methodology used to determine the exploitable water resources in a river basin.
The Palmer Drought Severity Index (PDSI) has been calculated for about 30 years as a means of providing a single measure of meteorological drought severity. It was intended to retrospectively look at wet and dry conditions using water balance techniques. The Standardized Precipitation Index (SPI) is a probability index that was developed to give a better representation of abnormal wetness and dryness than the Palmer indices. Before the user community will accept the SPI as an alternative to the Palmer indices, a standard method must be developed for computing the index. Standardization is necessary so that all users of the index will have a common basis for both spatial and temporal comparison of index values. If different probability distributions and models are used to describe an observed series of precipitation, then different SPI values may be obtained. This article describes the effect on the SPI values computed from different probability models as well as the effects on dry event characteristics. It is concluded that the Pearson Type III distribution is the `best' universal model, and that the reliability of the SPI is sample size dependent. It is also concluded that because of data limitations, SPIs with time scales longer than 24 months may be unreliable. An internet link is provided that will allow users to access Fortran 77 source code for calculating the SPI.
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Drought is recognized as a major issue in the EU, particularly in the Mediterranean region, posing risks to the environment as well as to local and regional economies. The EU policy on water management is continuously evolving, particularly in relation to water scarcity and drought. Starting with the Water Framework Directive (2000/60/EC), which sets the general policy framework for water management across the EU, the EC Communication on Water Scarcity and Drought COM(2007) 414 final set the priorities for managing water scarcity and drought risks. Three follow-up reports (COM(2008) 875 final, COM(2010) 228 final and COM(2011) 133) highlighted achievements and yearly progress within the context of the implementation of the Water Framework Directive, whereas guidance has further been provided through the issue of Technical Reports (e.g. the EC Water Scarcity Drafting Group Technical Report 2008–023 on Drought Management, Including agricultural, drought indicators and climate change aspects). The 2012 EU Water Review (“Blue Print for Safeguarding European Waters” will assess achievements and identify further requirements towards long-term sustainable water use across the EU. However, a harmonized approach on drought risk management at the EU level is still lacking, whereas drought risk in several countries and regions has not been yet fully integrated in water management and relevant sectoral policies.This paper focuses on a proposed paradigm shift from crisis to risk management, which is currently gaining ground as a means of reducing societal vulnerability to droughts. The paper underlines the importance of engaging into risk assessment and management practices and identifies policy gaps and requirements for further improvement of the drought management policy framework at all levels of governance: at the EU, at the national and at the river basin and regional levels.
Worldwide, economic damages attributed to natural disasters tripled from the 1960s (US$40 billion) to the 1980s (US$120 billion) (Domeisen 1995). The 1990s have witnessed a continued escalation of economic damages, reaching US$400 billion through 1996 (Carol-wicz 1996). Between 1992 and 1996, losses associated with natural disasters in the United States averaged US$54.2 billion per week (Carolwicz 1996). The economic, social, and environmental costs and losses associated with drought are also increasing dramatically, although it is difficult to quantify this trend precisely because of the lack of reliable historical estimates of losses. White and Haas estimated in 1975 that the average annual crop losses associated with drought in the Great Plains region of the United States were about US$700 million. In 1995, the US Federal Emergency Management Agency (FEMA) estimated annual losses attributable to drought at US$6-8 billion (FEMA 1995).
The implementation of water use restrictions in a given district is very much related to the severity of an evolving drought; thus, water management agencies such as City Water Departments often face the question of how critical or severe a particular drought event is. While this question has typically been examined using drought indices e.g., the Palmer Drought Severity Index, unfortunately they do not provide any information on the frequency or recurrence time of the drought or on the risk that specific drought events may occur in a given time horizon. In this paper, the severity of alternative drought events are determined following a similar concept as for the severity of floods, i.e., the return period of a flood event, e.g., the 500-year flood. We develop procedures for determining drought severity based on historical data, generated data, and mathematical algorithms. In particular, we focus on the drought that has been occurring in the Western United States and take the Poudre River, Colo., as an example. The analysis was based on 119 years of records of naturalized flows of the Poudre River. A stochastic model was used for generating long-term synthetic flows, from which the return period and risk of drought events were determined. In addition, we used a mathematical algorithm for determining the distribution of drought events and their return periods. Assuming the sample mean as the water demand threshold, drought severity, frequency, and risk statistics were obtained; e.g., the severity of the 3-year 2000-2002 drought i.e., 3-year drought with D404,011 acre-ft is of the order of a 1,000-year return period and the risk that such a 3-year drought will occur in a 25-year period is about 2.4%.
This study addresses the sustainable use of water resources in the Mediterranean basin, particularly in the Southern and Eastern parts of the region, and the many problems generated by water scarcity and misuse. Water economy in the region is beset by two specific problems: high irrigation needs and changes in consumer demands (especially after population shifts from rural to urban areas and because of increasing tourism and industrialisation). The challenges presented by the water crisis are even greater because of growing populations and estimated future climatic changes in the region. The integrated management of limited water resources in the Southern and Eastern parts of the Mediterranean involves several areas of research. Those most directly related with agriculture concern improving water (and nutrient) use in agriculture through the management and breeding of irrigated and rain-fed crops. However, these fields of research address only one face of a multi-factorial equation that affects water sustainability in the region. Thus, other research fields include the design of comprehensive water policies and integrated planning, and technologies for advanced water treatment and re-use. Moreover, local problems and socio-economic aspects must be considered when addressing research issues.
Spatial and time behaviours of rainfall shortage and excess are analysed for Catalonia (NE Spain) using a database obtained from 99 rain gauges with monthly totals collected from 1961 to 1990. The distribution of monthly amounts for each rain gauge is modelled by means of the gamma or Poisson-gamma distributions. Then, using an equiprobable transformation, monthly amounts described with these distributions are substituted by values given by the Standardized Precipitation Index (SPI), which follows a standardized normal distribution and provides a unique pluviometric scale. After that, principal component analysis (PCA) is applied to the set of monthly SPIs. A double regionalization of the 99 rain gauges, distinguishing between episodes of rainfall shortage and excess, is achieved by taking into account the rotated factor loadings (RFL) correlating rain gauges and principal components (PC). A time classification of rainfall shortage and excess episodes is also established, considering in this case the factor scores (FS) obtained after a PCA of variables based on monthly SPIs. The spatial regionalization achieved becomes a rough picture of the different topographic domains (Pyrenees, Pre-Pyrenees, Central Basin, Littoral and Pre-Littoral chains and Mediterranean coast), the climatic diversity of Catalonia being enhanced by these results. The time clustering suggests a quite complex behaviour of the rainfall shortage and excess episodes. Moreover, the spatial distribution of these time clusters is very disperse, in such a way that monthly shortage and excess sometimes affect the whole of Catalonia and sometimes just a small area. Besides results obtained from PCA and clustering algorithms, it is worth noticing that the severity of the episodes increases remarkably only for rainfall shortage. In addition, an analysis of the number of rain gauges affected by monthly shortage and excess shows an interesting fact: whereas the number of rain gauges associated with a shortage has an increasing tendency, a significant decreasing tendency for excess is detected in the period 1961–1990. Copyright © 2001 Royal Meteorological Society
1] Extreme droughts may be characterized by their duration, severity (magnitude or intensity), spatial extent, and frequency or return period. Comparing the time series of water supply and water demand and analyzing droughts based on the theory of runs may determine these characteristics. This study is focused on drought analysis where the underlying water supply process is periodic stochastic, such as for monthly streamflows. The probability mass function (pmf) of drought length and associated low-order moments are derived assuming a periodic simple Markov chain. The derived pmf allows estimating the occurrence probability of droughts of a given length and its return period. The applicability of the drought formulations has been illustrated using a variety of water supply series such as monthly and weekly precipitation, monthly streamflows, the Palmer hydrologic drought index, and the standardized precipitation index. The results obtained confirm the validity of the analytical derivations for drought lengths and associated return periods. The overall conclusion of the study is that simple definitions of droughts enables one characterizing droughts using stochastic approaches and analytical derivations. They are particularly useful for drought analysis because the limited hydrologic records that are generally available do not allow observing many drought events of a particular duration and, in fact, extremely long droughts may not even be observable from the historical sample. This hinders the applicability of an inferential approach for finding the probability distributions of drought lengths and their associated return periods because it is either impractical or not feasible.
Efficient Water Management is an important factor for regional development and requires a set of actions in order to manage
water resources in a sustainable way. This paper describes a methodology of water resources exploitation, with the potential
of creating small mountainous and upland reservoirs. This can be done with the integration of Geographic Information Systems
(GIS), while using the SWAT hydrological modeling and Reservoir Simulation software. Andros Island was chosen as the study
area. This project involves the hydrologic analysis and the assessment of runoff (using SWAT model for a 100 years simulation
in the Afrouses basin). In two different selected sites, the feasibility of constructing a dam with the simultaneous creation
of a reservoir based on annual failure rates of deliverability of certain volume of water is investigated.
In the present study the Standardised Precipitation Index (SPI) is used to detect drought events in spatial and temporal basis.
Using monthly precipitation data from 23 stations well spread over Greece and for a period of 51 years, a classification of
drought is performed, based on its intensity and duration. Results indicate that, mild and moderate droughts reduce from north
to south and from west to east on the 3- and 6-months time scale, while for the class of severe drought, the frequencies in
the southern part of Greece are higher than in the other parts of the country. Furthermore the frequency of occurrence of
severe and extreme drought conditions is very low over the whole Greek territory on the 12-month running time scale. Finally
SPI was compared to the “de Martonne aridity index (I)” and a satisfactory correlation between them was found.
Owing to the rise in water demand and looming climate change, recent years have witnessed much focus on global drought scenarios. As a natural hazard, drought is best characterized by multiple climatological and hydrological parameters. An understanding of the relationships between these two sets of parameters is necessary to develop measures for mitigating the impacts of droughts. Beginning with a discussion of drought definitions, this paper attempts to provide a review of fundamental concepts of drought, classification of droughts, drought indices, historical droughts using paleoclimatic studies, and the relation between droughts and large scale climate indices. Conclusions are drawn where gaps exist and more research needs to be focussed.
Older Australians living in rural areas have long faced significant challenges in maintaining health. Their circumstances are shaped by the occupations, lifestyles, environments and remoteness which characterise the diversity of rural communities. Many rural regions face threats to future sustainability and greater proportions of the aged reside in these areas.
The emerging changes in Australia's climate over the past decade may be considered indicative of future trends, and herald amplification of these familiar challenges for rural communities. Such climate changes are likely to exacerbate existing health risks and compromise community infrastructure in some instances.
This paper discusses climate change-related health risks facing older people in rural areas, with an emphasis on the impact of heat, drought and drying on rural and remote regions. Adaptive health sector responses are identified to promote mitigation of this substantial emerging need as individuals and their communities experience the projected impact of climate change.