Hydraulic Infrastructure Research Articles

Evolution of capture technologies of water in the oases: Moghrar, Tiout and Boussemghoun (Algeria)

Abstract This article discusses the various water harvesting techniques used in the oases of Boussemghoun, Moghrar and Tiout for more than nine centuries. Several hydrological assessments have been conducted in the three oases since 2002 including surveys and investigations with the local communities. The results obtained showed that after the decrease in discharge of the sources, the population had resources to various ancestral hydraulic infrastructures such as: well, foggara, and small dams (Essad). The water harvesting technique is specific to the region and depends on the hydrogeology and the topography. Traditional low-flow water-saving technologies preserve the environment, modern hydraulic techniques give more water but have a negative impact on the environment. The drying up of springs and lowering of water tables are the result of the population growing and the socio-economic development. They require more and more water. A compromise between traditional and modern techniques (or types of management) can solve this problem.

Estimating Lag to Peak between Rainfall and Peak Streamflow with a Mixed‐Effects Model

AbstractWe test the use of a mixed‐effects model for estimating lag to peak for small basins in Maine (drainage areas from 0.8 to 78 km2). Lag to peak is defined as the time between the center of volume of the excess rainfall during a storm event and the resulting peak streamflow. A mixed‐effects model allows for multiple observations at sites without violating model assumptions inherent in traditional ordinary least squares models, which assume each observation is independent. The mixed model includes basin drainage area and maximum 15‐min rainfall depth for individual storms as explanatory features. Based on a remove‐one‐site cross‐validation analysis, the prediction errors of this model ranged from −42% to +73%. The mixed model substantially outperformed three published models for lag to peak and one published model for centroid lag for estimating lag to peak for small basins in Maine. Lag to peak estimates are a key input to rainfall–runoff models used to design hydraulic infrastructure. The improved accuracy and consistency with model assumptions indicates that mixed models may provide increased data utilization that could enhance models and estimates of lag to peak in other regions.

Influence of climate change on flood magnitude and seasonality in the Arga River catchment in Spain

Climate change projections suggest that extremes, such as floods, will modify their behaviour in the future. Detailed catchment-scale studies are needed to implement the European Union Floods Directive and give recommendations for flood management and design of hydraulic infrastructure. In this study, a methodology to quantify changes in future flood magnitude and seasonality due to climate change at a catchment scale is proposed. Projections of 24 global climate models are used, with 10 being downscaled by the Spanish Meteorological Agency (Agencia Estatal de Meteorologia, AEMET) and 14 from the EURO-CORDEX project, under two representative concentration pathways (RCPs) 4.5 and 8.5, from the Fifth Assessment Report provided by the Intergovernmental Panel on Climate Change. Downscaled climate models provided by the AEMET were corrected in terms of bias. The HBV rainfall-runoff model was selected to simulate the catchment hydrological behaviour. Simulations were analysed through both annual maximum and peaks-over-threshold (POT) series. The results show a decrease in the magnitude of extreme floods for the climate model projections downscaled by the AEMET. However, results for the climate model projections downscaled by EURO-CORDEX show differing trends, depending on the RCP. A small decrease in the flood magnitude was noticed for the RCP 4.5, while an increase was found for the RCP 8.5. Regarding the monthly seasonality analysis performed by using the POT series, a delay in the flood timing from late-autumn to late-winter is identified supporting the findings of recent studies performed with observed data in recent decades.

Return period assessment of urban pluvial floods through modelling of rainfall–flood response

AbstractIntense rainfall in urban areas can often generate severe flood impacts. Consequently, it is crucial to design systems to minimize potential flood damages. Traditional, simple design of urban drainage systems assumes agreement between rainfall return period and its consequent flood return period; however, this does not always apply. Hydraulic infrastructures found in urban drainage systems can increase system heterogeneity and perturb the impact of severe rainfall response. In this study, a surface flood return period assessment was carried out at Lystrup (Denmark), which has received the impact of flooding in recent years. A 35 years' rainfall dataset together with a coupled 1D/2D surface and network model was used to analyse and assess flood return period response. Results show an ambiguous relation between rainfall and flood return periods indicating that linear rainfall–runoff relationships will, for the analysed case study, be insufficient for flood estimation. Simulation-based mapping of return periods for flood area and volume has been suggested, and moreover, a novel approach has been developed to map local flood response time and relate this to rainfall characteristics. This approach allows to carefully analyse rainfall impacts and flooding response for a correct flood return period assessment in urban areas.

Climate change and water resources in Algeria: vulnerability, impact and adaptation strategy

The climate changes going on for a long time now have ceased to be a scientific curiosity. They constitute the major environmental question which dominates our time and pose the major challenge to environmental organizations of control. Water is one of the most important raw materials in Algeria. Because of its importance, it is essential to know its vulnerability with the climate changes. In Algeria, the vulnerability due to the climate changes is expressed through several aspects: demographic explosion, probable reduction in the water run-offs, scarcity of the resources, the degradation of the hydraulic infrastructures, threats to wetlands, etc. In the face of this situation, Algeria has taken quantitative and qualitative adaptive measures within the framework of durable management of this invaluable resource for the future.

Developments in the management of flood defences and hydraulic infrastructure in the Netherlands

This article highlights recent developments in flood risk management in the Netherlands and presents approaches for reliability analysis and asset management for flood defences and hydraulic infrastructure. The functioning of this infrastructure is of great importance for the country as large parts of it are prone to flooding. Based on a nationwide flood risk assessment, new safety standards for flood defences have been derived in the form of maximal acceptable failure probabilities. A framework for the reliability-based analysis of the performance of hydraulic infrastructure is introduced. Within this context, various challenges are discussed, such as the dynamic nature of loads, resistance and reliability requirements over time. Various case studies are presented to highlight advances and challenges in various application fields. The first case illustrates how structural health monitoring contributes to a better characterisation of the reliability of the defences and how innovative measures can enhance the reliability. The second case discusses how the river system can be managed in the context of the new safety standards. The third case shows how upgrades and reinforcements of hydraulic structures can be evaluated taking into account (uncertain) future developments, such as sea level rise.

Resilience of socio-ecological systems in volcano risk-prone areas, but how much longer? Assessment of adaptive water governance in Merapi volcano, Central Java, Indonesia

In 2012, about 1.3 million people lived on the slopes of Merapi, one of the most active volcanoes in the eastern part of Java Island in Indonesia. A majority of Merapi inhabitants, grouped together in small villages, live off agricultural income, relying on hydraulic infrastructures for their daily activities. Not only do these farming activities require a substantial amount of water, but an entire community in one village also depends on water resources to maintain its organization and functioning. The proximity of water availability and its access with community dependence on it is well illustrated by the first water management position in the community initiatives: the term socio-hydraulic system highlights the dependency of the community organization profile on water resources. However, the eruption of Merapi in 2010 and the following pyroclastic flow or lahar-related crises have recently made water availability and access to water the main challenges to be addressed by the hydraulic community. Many research projects have highlighted actions taken by the Merapi communities to face successive disasters using the resilience concept, which is closely linked to sustainability. However, the interviews we carried out in 2013, 3 years after the eruption and a few months after lahar recurrences, revealed persistent fragilities and readjustments to water management in hazard-prone areas. This present work first aims to discuss multiple social vulnerabilities and in some cases, the capacity to adapt, by investigating the hydraulic community’s responses in the face of lahar issues after the 2010 Merapi eruption. In order to reassess the resilience concept and to draw the limits of its operative aspects, studies of multi-dimensional responses to the interviews and of explicative factors have been developed within the Merapi community. Focusing on resources, people’s roles and socio-environmental risks, we discuss the main influence of the ‘cultures of risks’ observed through a 1-month period of fieldwork, a notion that add another focus to the notion of local resilience(s): in doing so, we defend the idea that risk assessments must be undertaken through a systemic approach, focusing on the coupled-notion vulnerability/resilience, and we question the limits of the operative aspect and the durability of the resilience concept on longer temporality and geographical scales.

Orographic Effects on Extreme Rainfall at Different Durations: A Case Study in Campania Region (Southern Italy)

Long-term probabilistic prediction of extreme rainfall at the regional scale is a significant tool in the mitigation of hydro-geological disasters: it actually provides the starting point in the design of strategic hydraulic infrastructures and emergency plans. A crucial task of regional estimation of extreme rainfall is how to include the complex effects of orographic barriers in a mathematical model for Intensity-Duration-Frequency (IDF) curves. Here, an analysis of how orography can affect extreme rainfall at different durations is presented for three orographic systems that are very relevant for hydrological risk assessment in the Campania Region in Southern Italy. Then, we introduce a power law model to link the amplification factor to the duration, thus allowing a simple and effective enhancement of the IDF model in mountainous areas.

Modelos de abastecimiento urbano de aguas en la Bética romana: las cisternas = Urban Water Supply Models in Roman Baetica: The Cisterns

Las cisternas son el principal medio de aprovisionamiento de agua en las ciudades romanas en muchos casos. La historiografía ha identificado la existencia de un verdadero modelo de gestión del agua que emplea únicamente estas construcciones, o bien que las utiliza en conjunción con otros medios, como el aprovechamiento de aguas subterráneas mediante pozos. Partiendo desde una conceptualización teórica del término latino cisterna, realizamos un recorrido en la identificación de este modelo en casos específicos de Hispania como marco general del estudio, y en la provincia Ulterior Baetica como marco particular.Water storage cisterns are the main source of water supply in roman cities in many cases. Their existence has been identificated as a water management model which employs these hydraulic infrastructures exclusively, or together with others forms as groundwater extraction by wells. Starting to a theoretical conceptualization of the latin term cisterna, we carry out a review to identify this model in specific cases in Hispania as general spatial framework, and in Hispania Ulterior Baetica province as particular framework.

Challenges and Proposals for Socio-Ecological Sustainability of the Tagus–Segura Aqueduct (Spain) under Climate Change

Since its inauguration in 1979, the Tagus–Segura Aqueduct has become one of the hydraulic infrastructures that has had the most significant socio-economic repercussions in Spain during the past few decades. The aqueduct is significant for its strategic importance and developmental potential for south-east Spain, where it provides water for agriculture as well as for tourism and urban consumption. The aim of this study is to analyze the uncertainties regarding the future functioning of this infrastructure in view of the reduction of water resources and a higher frequency of drought episodes due to climate change. To this end, an analysis was performed on previous studies of hydrological plans, regulations and studies on climate change in order to enable an assessment to be made of the possible effects of these changes on the normal functions of the Tagus–Segura Aqueduct. Consideration is also given to the new management rules that have regulated this infrastructure since 2014, the use of alternative water resources, and proposals such as measures to increase resilience in light of future climate change scenarios and their effects on the Mediterranean.

Effect of temporal aggregation on the estimate of annual maximum rainfall depths for the design of hydraulic infrastructure systems

For a few decades the local rainfall measurements are generally obtained by tipping bucket sensors, that allow to record each tipping time corresponding to a well-known rain depth. However, a considerable part of rainfall data to be used in the hydrological practice is available in aggregated form within constant time intervals. This can produce undesirable effects, like the underestimation of the annual maximum rainfall depth, Hd, associated with a given duration, d, that is the basic quantity in the development of rainfall depth-duration-frequency relationships. The errors in the evaluation of Hd from data characterized by a coarse temporal aggregation, ta, and a procedure to reduce the non-homogeneity of the Hd series are here investigated. Our results show that for ta = 1 min the underestimation is practically negligible, whereas for larger temporal aggregations with d = ta the error in a single Hd can reach values up to 50% and in a series of Hd in the average up to 17%. Relationships between the non-dimensional ratio ta/d and the average underestimation of Hd, derived through continuous rainfall data observed in many stations of Central Italy, are presented to overcome this issue. These equations allow to improve the Hd estimates and the associated depth-duration-frequency curves at least in areas with similar climatic conditions. The effect of the correction of the Hd series on the rainfall depth-duration-frequency curves is quantified. Our results indicate that the improvements obtained by the proposed procedure are of the order of 10%.

Hábitos alimenticios de Cathorops aguadulce (Siluriformes: Ariidae) en un ecosistema estuarino al sur del golfo de México

Background. The distribution and diet of fish, as well as the specific composition of their prey, have been affected by the magnification of the spatial variations in salinity due to hydraulic infrastructure and climate change. Cathorops aguadulce was selected based on previous records of its diet and its current dominance in the estuarine systems in the southern Gulf of Mexico. Goals . The feeding habits were evaluated in relation to the variation of size composition, day-night, and seasonality in a coastal lagoon in the southern Gulf of Mexico. Methods. Two hundred ten digestive tracts were analyzed in juveniles and adults captured in a sampling that included the day-night and seasonal variation in three sampling sites located in a salinity gradient. The size composition was correlated (Spearman coefficient) with the spatial and temporal variation of salinity and temperature. The temporal and spatial variations of the Repletion (IR) and Relative Importance (IIR) indexes were analyzed using Kruskal-Wallis test and hierarchical clustering. Results. The size composition was independent of salinity variation and IR values (Kruskal-Wallis; p =0.649). Yet diet intensity in the dry season was significantly greater than in the transition and rainy seasons (Kruskal-Wallis; p =0.00001). Among the 11 food items defined, animal detritus and malacostracans, mainly tanaids, were the dominant feeding categories in the frequency of occurrence and according to the IIR. However, detritus predominated in juveniles, while tanaids were the preponderant item in the adults. Conclusions. Even though laguna Mecoacan recorded an ample salinity variation, C. aguadulce recorded a significant temporal variation in intensity of diet; the ontogenic shift of its diet was more relevant than the effects of the environmental variation of its feeding habits. This conclusion opens the possibility of testing whether the ontogenetic variation of their functional morphological traits is associated with the acquisition of food or movement.

Review on urban design rainstorm

Design rainstorm is the basis of calculating design floods for the design of urban hydraulic infrastructures and many other fundamental facilities. It has significant influence on the planning scale and investment of urban drainage engineering. Without a wise selection of the design rainstorm pattern, it is impossible to guarantee the safety and economic effectiveness of designed urban drainage infrastructures regardless of simulation accuracy or any remarkable techniques. In recent years, cities in China have suffered from severe urban floods, so urban drainage system construction and comprehensive underground corridor building are two enormous and vital task in the near future. In addition, urban construction in China (especially water-related projects aiming at urban areas, such as sponge city project that China is currently implementing nationwide, drainage pipe systems construction and underground reservoir installation) has put forward new challenges to and raised higher requirements for urban hydrological theory and mechanism research, including urban design rainstorm research. In this context, it is highly necessary to systematically summarize the theory and research methods of domestic and foreign urban design rainstorms, to summarize the existing key problems, to clarify the main aspects of the nodus, to discuss and propose the development direction of urban design rainstorm researches. Researches on urban design rainstorms have been conducted both in China and abroad. In the past 30 years, urban design rainstorm research in China has made great progress and important changes, and the theory and research methods of urban design rainstorms in the world become more consummate. Through methods of literature research and analysis, researches all around the world on urban design rainstorm have been sorted and classified, and the theories of urban design rainstorm are systematically reviewed after screening and comparison. The main content of this paper contains summary on sampling methods, frequency analysis, storm formulas and spatial-temporal disaggregation methods of urban design rainstorm. The mainstream methods are summarized and compared; their advantages and disadvantages are analyzed, and the main problems existing are discussed. Finally, combined with the results of literature review, the future research direction of urban design rainstorm researches is proposed. The study of urban design rainstorm in the future may pay more attention to the following aspects: (1) illustrating principles and control methods of error generation in each step of forming an urban design rainstorm, and searching for the link between various aspects during urban design rainstorm forming, to find the optimal matching method between those aspects; (2) conducting urban design rainstorm studies that cover the whole ″rainstorm sampling-frequency analysis-intensity formula-spatio/temporal disaggregation″ process, searching for regional analysis methods based on linear moment (L-moment), and developing tentative national IDF curves as well as popularizing their usage; (3) enhancing the study on evolution laws and characteristics of short-duration urban storms under changing environments, evaluating the impacts of urbanization and climate change on urban rainfall characteristics, and analyzing how urban design rainstorms should reform in response. This paper provides a wide range of perspectives on the study of rainstorms in China and even in the world, and provides important guidance for future research on urban design rainstorm.

The near-term prediction of drought and flooding conditions in the northeastern United States based on extreme phases of AMO and NAO

A series of hydroclimatic teleconnection patterns were identified between variations in either Atlantic or Pacific oceanic indices with precipitation and discharge anomalies in the northeastern United States. We hypothesized that temporal annual or seasonal changes in discharge could be explained by variations in extreme phases of the Atlantic Multi-decadal Oscillation (AMO index, SST: Sea Surface Temperature anomalies) and the North Atlantic Oscillation (NAO index, SLP: Sea-Level Pressure anomalies) up to three seasons in advance.The Merrimack River watershed, the fourth largest basin in New England, with a drainage area of 13,000km2, is a compelling study site because it not only provides an opportunity to investigate the teleconnection between hydrologic variables and large-scale climate circulation patterns, but also how those patterns may become obscured by anthropogenic disturbances such as river regulation or urban development. We considered precipitation and discharge data of 21 gauging stations within the Merrimack River watershed, including the Hubbard Brook Experimental Forest (HBEF), NH, with a median record length of 55years beginning as early as 1904.The discharge anomalies were statistically significant (p-value≤0.2) between extreme positive and negative phases of AMO (1857–2011) and NAO (1900–2011) and revealed the potential teleconnectivity of climate circulation patterns with discharge. Annual and seasonal correlations of discharge were examined with the extreme phases of AMO and NAO at zero-, one-, or two- year/season lags (total of 30 scenarios). When AMO was greater than 0.2, the strongest correlations of AMO and NAO with discharge were observed at headwater catchments. This correlation weakened downstream towards larger regulated and/or developed sub-basins.We introduced a simple approach for near-term prediction of drought and flooding events. An exponential decay function was regressed through the historic occurrence of the relative frequency of wet, average, and dry discharge conditions with regards to the extreme phases of AMO and NAO. While the function was decaying, the tail asymptotically merged into and stabilized at the theoretical probability of the event. As the basin scale increased, the probability of wet, average, and dry discharge conditions decreased. The Merrimack River watershed will most likely experience greater than average discharge as its extreme condition, therefore development should be avoided on flood plains. Furthermore, the current reservoir storage capacity in the Merrimack should be improved in order to accommodate excess water input and minimize flood damage. Future research should target changes in the magnitude and timing of high discharge events in order to develop adaptation strategies for aging hydraulic infrastructure in the region.

Causal Reasoning for the Analysis of Rivers Runoff Temporal Behavior

The accurate knowledge about the influence of time in the behavior of rivers systems is crucial for a proper river basin water management. Traditional techniques such as correlograms or ARMA models have been widespread used over the last decades providing the analyzer with an average behaviour of temporal influence of hydrological series. In the last decade, the development of techniques, under the discipline of artificial intelligent, have increased the range of available analytical tools. On the other hand, hydrological processes have a very strong random nature and they are driven by its high uncertainty and variability. Consequently, it is necessary to build tools, able to incorporate these peculiarities in their analytical functioning. Causal Reasoning through Bayesian Networks (BNs) allows processing and analysing hydrological series, incorporating and assessing all their variability. Causality driven by Bayes´ theorem is used here to dynamically identify, characterize and quantify the influence of time (dependence) for each time step in annual run-off series in five Spanish River basins. Therefore, BNs arise as a powerful tool for getting a deeper understanding on the knowledge of temporal behaviour of hydrological series because this analysis is dynamic and implemented specifically for temporal iterations (decision variables). Implications and applications of this research are largely aimed to improve and optimize the design and dimensioning of hydraulic infrastructures, as well as reducing the risk of negative impacts produced by extreme events such as several droughts or floods, among others.

Technical note: Design flood under hydrological uncertainty

Abstract. Planning and verification of hydraulic infrastructures require a design estimate of hydrologic variables, usually provided by frequency analysis, and neglecting hydrologic uncertainty. However, when hydrologic uncertainty is accounted for, the design flood value for a specific return period is no longer a unique value, but is represented by a distribution of values. As a consequence, the design flood is no longer univocally defined, making the design process undetermined. The Uncertainty Compliant Design Flood Estimation (UNCODE) procedure is a novel approach that, starting from a range of possible design flood estimates obtained in uncertain conditions, converges to a single design value. This is obtained through a cost–benefit criterion with additional constraints that is numerically solved in a simulation framework. This paper contributes to promoting a practical use of the UNCODE procedure without resorting to numerical computation. A modified procedure is proposed by using a correction coefficient that modifies the standard (i.e., uncertainty-free) design value on the basis of sample length and return period only. The procedure is robust and parsimonious, as it does not require additional parameters with respect to the traditional uncertainty-free analysis. Simple equations to compute the correction term are provided for a number of probability distributions commonly used to represent the flood frequency curve. The UNCODE procedure, when coupled with this simple correction factor, provides a robust way to manage the hydrologic uncertainty and to go beyond the use of traditional safety factors. With all the other parameters being equal, an increase in the sample length reduces the correction factor, and thus the construction costs, while still keeping the same safety level.

Generalized Beta Distribution of the Second Kind for Flood Frequency Analysis

Estimation of flood magnitude for a given recurrence interval T (T-year flood) at a specific location is needed for design of hydraulic and civil infrastructure facilities. A key step in the estimation or flood frequency analysis (FFA) is the selection of a suitable distribution. More than one distribution is often found to be adequate for FFA on a given watershed and choosing the best one is often less than objective. In this study, the generalized beta distribution of the second kind (GB2) was introduced for FFA. The principle of maximum entropy (POME) method was proposed to estimate the GB2 parameters. The performance of GB2 distribution was evaluated using flood data from gauging stations on the Colorado River, USA. Frequency estimates from the GB2 distribution were also compared with those of commonly used distributions. Also, the evolution of frequency distribution along the stream from upstream to downstream was investigated. It concludes that the GB2 is appealing for FFA, since it has four parameters and includes some well-known distributions. Results of case study demonstrate that the parameters estimated by POME method are found reasonable. According to the RMSD and AIC values, the performance of the GB2 distribution is better than that of the widely used distributions in hydrology. When using different distributions for FFA, significant different design flood values are obtained. For a given return period, the design flood value of the downstream gauging stations is larger than that of the upstream gauging station. In addition, there is an evolution of distribution. Along the Yampa River, the distribution for FFA changes from the four-parameter GB2 distribution to the three-parameter Burr XII distribution.

Estimating the index flood with continuous hydrological models: an application in Great Britain

Abstract Estimating peak river discharge, a critical issue in engineering hydrology, is essential for designing and managing hydraulic infrastructure such as dams and bridges. In the UK, practitioners typically apply the Flood Estimation Handbook (FEH) statistical method which estimates the design flood as the product of a relatively frequent flow estimate (the index flood, IF) and a regional growth factor. For gauged catchments the IF is estimated from observations. For ungauged catchments it is computed through a multiple regression model. While the FEH IF method provides peak flow estimates that are statistically robust, it does not readily take into account catchment heterogeneity or effect of environmental change on river flows. This study presents a new methodology to estimate the IF at national scale using continuous simulation from a physically based hydrological model (Grid-to-Grid). The methodology is tested across Great Britain and compares well with IF estimates at 550 gauging stations (R2 = 0.91). The promising results for Great Britain support the aspiration that continuous simulation from large-scale hydrological models coupled with increasing availability of global weather and climate products, could be used to estimate design floods in regions with limited gauge data or affected by environmental change.

Experimental floods: A new era for Spanish and Mediterranean rivers?

The provision of human-designed floods in regulated rivers is still an incipient worldwide practice. However, these floods have already been shown to have relevant effects on the ecogeomorphic integrity of rivers altered by flow regulation. In Spain, experimental floods were legally established in 2008 and were stipulated in two subsequent Basin Management Plans as compulsory practice for improving the functioning of strategic river reaches. Since that time, a number of flooding events have been carried out in rivers of Mediterranean condition. This paper reviews the main consequences of experimental flood releases in three Spanish river sites downstream of major hydraulic infrastructures. In each case, the ecologic and geomorphic effects of the releases are analysed in parallel with their causes and consequences, thereby providing a detailed understanding of the dynamics of each scenario. The Spanish examples and the lessons learned from them are contrasted with examples of experimental floods from other countries (U.S.A., Switzerland, Australia). Lastly, recommendations are proposed to improve the implementation of future experimental floods in Spain and other Mediterranean countries.

Iran’s Socio-economic Drought: Challenges of a Water-Bankrupt Nation

Iran is currently experiencing serious water problems. Frequent droughts coupled with over-abstraction of surface and groundwater through a large network of hydraulic infrastructure and deep wells have escalated the nation’s water situation to a critical level. This is evidenced by drying lakes, rivers and wetlands, declining groundwater levels, land subsidence, water quality degradation, soil erosion, desertification and more frequent dust storms. This paper overviews the major drivers of Iran’s water problems. It is argued that while climatic changes and economic sanctions are commonly blamed as the main drivers of water problems, Iran is mainly suffering from a socio-economic drought—i.e. “water bankruptcy,” where water demand exceeds the natural water supply. In theory, this problem can be resolved by re-establishing the balance between water supply and demand through developing additional sources of water supply and implementing aggressive water demand reduction plans. Nevertheless, the current structure of the water governance system in Iran and the absence of a comprehensive understanding of the root causes of the problem leave minimal hope of developing sustainable solutions to Iran’s unprecedented water problems.