Water Policy Makers Research Articles

Boosting water conservation by improving campaign: Evidence from a field study in China

ABSTRACTSlogans advocating water conservation appear on all kinds of media. However, it is often not clear if and how much these campaigns can boost water-conserving behaviors, especially in developing countries. The current study tries to address this issue with a field randomized control trial (RCT) experiment in China. According to the longitudinal water consumption data, we found that 1) residents who received water conserving tips significantly reduced the subsequent water consumption relative to the residents who did not receive; 2) adding (vs. not adding) quantitative information into tips made the residents reduce water consumption; 3) adding (vs. not adding) norm information into tips failed to make the residents reduce water consumption. To our knowledge, this is the first study that quantitatively investigates the effect of water conservation campaigns on actual water consumption in developing countries. Our findings thus offer valuable insights on water efficiency information campaigns and policy-making.

Decentralized water reuse planning: Evaluation of life cycle costs and benefits

The objective of this paper is to comparatively evaluate the life cycle costs and expected monetary benefits of decentralized greywater reuse systems. Specifically, added life cycle costs and estimated life cycle monetary benefits of satellite and onsite greywater reuse systems are evaluated in comparison with the prevailing centralized systems. Centralized systems refer to the traditional form of water delivery where one centralized treatment plant treats and distributes potable water to a large service area through a water distribution network while a sewer network collects used water for treatment at a centralized wastewater treatment plant before the wastewater effluent is disposed into the environment. Satellite greywater reuse systems collect raw greywater at neighborhood or district level for treatment and re-distribution for non-potable uses within the same neighborhood or district. Onsite greywater reuse systems collect raw greywater for treatment on the premises of where it is produced after which it is re-distributed for permitted non-potable use on the same premises. Infrastructure needs and associated life cycle cost information for both types of greywater reuse systems are appropriately modeled or synthesized from literature. The skeletal layout of a real-world water distribution network is adapted for performing the cost-benefit analysis in this study. Finally, sensitivity of the cost-benefit tradeoff associated with satellite and onsite greywater reuse adoption scenarios is evaluated for various uncertainties associated with technological evolution, policy incentives, and planning schemes. Given that several states in the U.S. are expected to face water shortages in the near future, this paper will provide guidance to water utilities and policy makers in planning of future water supply alternatives.

A Perspective on Training Methods Aimed at Building Local Capacity for the Assessment and Implementation of Environmental Flows in Rivers

This paper describes the development and delivery of a global training programme for environmental flows in rivers. The programme was developed in South Africa, and formalised with WWF. It has been delivered at various levels of detail, to specialist teams of scientists and managers (as learning-by-doing), and to large numbers of post-graduate students, in more than 20 countries worldwide. The intention has been to build local capacity and initiate E flows implementation. The general format of the training is described, and a number of examples and case studies are used to demonstrate the successes and pitfalls of the process. The examples concentrate on the need for long-term commitment and persistence in the face of multiple impediments, chief among them the need to change mind-sets of water policy makers, managers, scientists, and all levels of stakeholders, who traditionally view rivers as resources to be used to the maximum extent, rather than as valuable assets to be protected. They also illustrate examples of misunderstanding and resistance to implementing E flows. Lessons from training and implementation over 25 years include: • The need for local champions, with a long-term commitment • The need for understanding and support from all levels of stakeholders • The need (at least initially) to simplify the process as much as possible, so as to foster understanding and support, and to demonstrate successes within a time frame that maintains that support.

Defining and evaluating the social value of regional water resources in terms of emergy

Abstract The social value of water resources must be considered when reforming water prices, improving water policy, protecting water resources and devising allocation methods. However, current social value theories for water resources are often unsound. The social value of water resources is defined here based on social system theory. Energy flow within a combined social–ecological system is analyzed, and an emergy analysis method for ecological economics is introduced for unified quantification and to improve the accounting method of the social value of water resources. Taking Zhengzhou in east-central China as an example, the social value of water resources is calculated for 2015. The water resources' total social emergy was 6.04 × 1021 solar equivalent joules (sej) and the unit value was 6.58 × 1012 sej/m3. This corresponds to 3.88$/m3, indicating that the social value of water resources is enormous. This paper proposes that the social value of water is an important component of its ecological economic value, and its social value should therefore be considered by water policy makers. Research of this type can be effective in helping to protect water resources and encourage efficient water use.

Security of deep groundwater against arsenic contamination in the Bengal Aquifer System: a numerical modeling study in southeast Bangladesh

Across the floodplains of southern Bangladesh deep (> 150 m belowground level, bgl) groundwater within the Bengal Aquifer System (BAS) has become widely used for domestic water supply as a de facto mitigation response to the presence of excessive arsenic (As), exceeding the World Health Organization standard of 10 µg L− 1, in shallow groundwater. Over the past 10 years, many hand-pumped tube wells and high-capacity municipal water-supply wells have been installed at this depth and at deeper regions of the BAS, which are almost uniformly free of excessive As. Concern for the security of the deep groundwater resource against possible invasion of As and saline water from shallow depths emphasizes the need for comparative assessments of groundwater abstraction strategies to guide water resource managers and policy makers. To this end, particle-tracking post-processing has been applied within a numerical groundwater flow model for an area of over 10,000 km2 in southeastern Bangladesh, one of the regions where the As issue is most acute. Criteria for describing the security of deep groundwater abstraction strategies over a 100-year time frame have been applied to the model outcomes for a range of scenarios. Our analyses suggest that deep groundwater will remain secure against invasion of As across the entire region if it is restricted to domestic use, even under domestic demand projected for 2050. Our approach can be applied in other regions and in similar Asian mega-deltas where As contamination of groundwater is recognized as a grave concern for sustainable water resources development.

Review of studies on hydrological modelling in Malaysia

Hydrological models are vital component and essential tools for water resources and environmental planning and management. In recent times, several studies have been conducted with a view of examining the compatibility of model results with streamflow measurements. Some modelers are of the view that even the use of complex modeling techniques does not give better assessment due to soil heterogeneity and climatic changes that plays vital roles in the behavior of streamflow. In Malaysia, several public domain hydrologic models that range from physically-based models, empirical models and conceptual models are in use. These include hydrologic modeling system (HEC-HMS), soil water assessment tool (SWAT), MIKE-SHE, artificial neural network (ANN). In view of this, a study was conducted to evaluate the hydrological models used in Malaysia, determine the coverage of the hydrological models in major river basins and to identify the methodologies used (specifically model performance and evaluation). The results of the review showed that 65% of the studies conducted used physical-based models, 37% used empirical models while 6% used conceptual models. Of the 65% of physical-based modelling studies, 60% utilized HEC-HMS an open source models, 20% used SWAT (public domain model), 9% used MIKE-SHE, MIKE 11 and MIKE 22, Infoworks RS occupied 7% while TREX and IFAS occupy 2% each. Thus, indicating preference for open access models in Malaysia. In the case of empirical models, 46% from the total of empirical researches in Malaysia used ANN, 13% used Logistic Regression (LR), while Fuzzy logic, Unit Hydrograph, Auto-regressive integrated moving average (ARIMA) model and support vector machine (SVM) contributed 8% each. Whereas the remaining proportion is occupied by Numerical weather prediction (NWP), land surface model (LSM), frequency ratio (FR), decision tree (DT) and weight of evidence (WoE). Majority of the hydrological modelling studies utilized one or more statistical measure of evaluating hydrological model performance (R, R2, NSE, RMSE, MAE, etc.) except in some few cases where no specific method was stated. Of the 70 papers reviewed in this study, 16 did not specify the type of model evaluation criteria they used in evaluating their studies, 17 utilized only one method while 37 used two or more methods. NSE with 27% was found to be the most widely used method of evaluating model performance; R and RMSE came second with a percentage use 24% each. R2 (20%) was recorded as the third most widely used model evaluation criteria in Malaysia, MAE came fourth with 16% while PBIAS is the least with 11%.The findings of this work will serve as a guide to modelers in identifying the type of hydrological model they need to apply to a particular catchment for a particular problem. It will equally help water resources managers and policy makers in providing them with executive summary of hydrological studies and where more input is needed to achieve sustainable development.

Modification to the DRASTIC framework to assess groundwater contaminant risk in rural mountainous catchments

Mountainous headwater catchments are safeguards of quality groundwater and hence require special protection against contamination by anthropogenic sources. However, methods currently handling contamination risk fail to produce reliable results in mountainous watersheds because they overlook the influence of downhill flows and contaminant transport in the validation process. To overcome this difficulty, a new model based on so-called “concentration profiles” is presented that combines the DRASTIC framework for evaluation of intrinsic vulnerability, the categorization of land uses for evaluation of specific vulnerability to nitrate and Processing Modflow graphical user interface for simulation of nitrate transport. This model was tested in a mountainous region of Northern Portugal. The risk of groundwater contamination by nitrate was generally classified as moderate. The risky areas are regions used for agriculture and livestock production. These activities have raised nitrate concentrations of spring water (15–25 mg·L−1) downstream the risky areas. The Modflow simulations linked the risky areas (contaminant sources) to actual nitrate plumes (contaminant sinks) and modeled nitrate distributions at specific groundwater travel times. Winter plumes could be simulated for the 1-year stress period, and hence are flushable in a short time span. Spring and summer plumes could only be explained by contaminant transport during 10–20 years. In these cases, even if contaminant sources were immediately neutralized, the washout of nitrate would take decades. These results may hold back the fulfillment of sustainable development goals related to water and sanitation until 2030, and hence deserve reflection by water planners and policy makers. The modeling exercise provided extra evidence that safeguarding the catchment headwater is the keystone of groundwater quality protection in mountainous catchments. Therefore, application of this modified DRASTIC to other mountainous areas may not need to resort to Processing Modflow. The study comprises the main paper (this paper) and a MethodsX companion paper.

Increased fire hazard in human-modified wetlands in Southeast Asia.

Vast areas of wetlands in Southeast Asia are undergoing a transformation process to human-modified ecosystems. Expansion of agricultural cropland and forest plantations changes the landscape of wetlands. Here we present observation-based modelling evidence of increased fire hazard due to canalization in tropical wetland ecosystems. Two wetland conditions were tested in South Sumatra, Indonesia, natural drainage and canal drainage, using a hydrological model and a drought-fire index (modified Keetch-Byram index). Our results show that canalization has amplified fire susceptibility by 4.5 times. Canal drainage triggers the fire season to start earlier than under natural wetland conditions, indicating that the canal water level regime is a key variable controlling fire hazard. Furthermore, the findings derived from the modelling experiment have practical relevance for public and private sectors, as well as for water managers and policy makers, who deal with canalization of tropical wetlands, and suggest that improved water management can reduce fire susceptibility.

Modeling the carbon-energy-water nexus in a rapidly urbanizing catchment: A general equilibrium assessment

Energy and water systems are interdependent and have complex dynamic interactions with the socio-economic system and climate change. Few tools exist to aid decision-making regarding the management of water and energy resources at a watershed level. In this study, a Computable General Equilibrium (CGE) model and System Dynamics and Water Environmental Model (SyDWEM) were integrated (CGE-SyDWEM) to predict future energy use, CO2 emissions, economic growth, water resource stress, and water quality change in a rapidly urbanizing catchment in China. The effects of both the CO2 mitigation strategies and water engineering measures were evaluated. CO2 mitigation strategies have the potential to reduce 46% CO2 emissions and 41% energy use in 2025 compared with reference scenario. CO2 mitigation strategies are also found to be effective in promoting industrial structure adjustment by decreasing the output of energy- and water-intensive industries. Accordingly, it can alleviate local water stress and improve water environment, including a 4.1% reduction in both domestic water use and pollutant emissions, a 16.8% water demand reduction in the labor-intensive industry sector, and 4.2% and 4.4% decrease in BOD5 and NH3-N loads in all industrial sectors, respectively. It is necessary to implement water engineering measures to further alleviate water resource stress and improve water quality. This study improves the understanding of the feedbacks of CO2 abatement on water demand, pollutant discharges, and water quality improvement. The integrated model developed in this study can be used to aid energy, carbon, and water policy makers to understand the complicated synergistic effects of proposed CO2 mitigation strategies on water demand and pollution emissions, and to design more effective policies and measures to ensure energy and water security in the future.

Evaluating Hydrological Responses to Urbanization in a Tropical River Basin: A Water Resources Management Perspective

The present study investigates the hydrological response of increase in urbanization on water stressed Upper Bhima River basin which lies in a semi-arid climatic zone of Maharashtra state, India. Land Use Land Cover (LULC) changes due to urbanization, industrialization and anthropogenic activities have reconfigured the waterscape of the river basin, which has affected its regional hydrology. Influence of urbanization on key hydrological components is studied using Soil and Water Assessment Tool model. Firstly, Object Based Image Analysis approach was used to prepare time series LULC maps of the years 1992, 2002, 2009 and 2014. Overall classification accuracy of 92.48% and Kappa Coefficient (K) of 0.87 were achieved. Urbanization indicators, e.g. population urbanization level (Up) and spatial urbanization level (Us), were used to quantify the growth patterns in population and urban areas respectively. Mann–Kendall trend test was performed on the average annual rainfall data (year 1985–2014) to study rainfall trends across the region. Further, combination of statistical analyses including correlation analysis and multivariate analysis of variance were performed to comprehend the causative connection and interrelationships between Us and hydrological parameters. The results reveal that during 1992–2014, with increase in Us of 0.05, the average annual surface runoff increased to 10.4 mm [standard deviation (σ) = 4.40; sum of squares (SS) = 58.20], whereas percolation decreased to 14.5 mm [σ = 6.06; SS = 110.10], and base flow decreased to 11.7 mm (σ = 4.90; SS = 72.00). These hydrological parameters are highly influenced by increase in urbanization. This study is relevant for various stakeholders such as water sources planners and policy makers for assessment of water resources to ensure sustainable development in the urbanizing tropical river basins. Remedial measures are suggested to minimize the adverse effect of urbanization on hydrological processes.

Understanding the Impacts of Climate Change in the Tana River Basin, Kenya

Abstract. In the Tana River Basin in Kenya, six Regional Circulation Models (RCMs) simulating two Representative Concentration Pathways (RCPs) (i.e., 4.5 and 8.5) were used as input to the Soil and Water Assessment Tool (SWAT) model to determine the possible implications for the hydrology and water resources of the basin. Four hydrological characteristics – water yield, groundwater recharge, base flow and flow regulation – were determined and mapped throughout the basin for three 30-year time periods: 2020–2049, 2040–2069 and 2070–2099. Results were compared with a baseline period, 1983–2011. All four hydrological characteristics show steady increases under both RCPs for the entire basin but with considerable spatial heterogeneity and greater increases under RCP 8.5 than RCP 4.5. The results have important implications for the way water resources in the basin are managed. It is imperative that water managers and policy makers take into account the additional challenges imposed by climate change in operating built infrastructure.

Assessing the impacts of urbanization on hydrological processes in a semi-arid river basin of Maharashtra, India

This study investigates the influence of changes in spatial urbanization on the hydrological processes of Upper Bhima River basin of Maharashtra state, India using Soil and Water Assessment Tool hydrological model based simulations. The simulated and observed monthly stream flow rates at the basin outlet were compared for calibration (1985–2004) and validation (2005–2014) of the SWAT model. For both the periods, Nash–Sutcliffe efficiency values were > 0.70, root mean square error observations standard deviation ratio (RSR) values were < 0.50 and percent bias values were < 10. Hence, with coefficient of determination (R2) of 0.89 and 0.96 both the periods showed good agreement between simulated and observed stream flow rates. Urbanization indicators viz. population urbanization level (U p ) and spatial urbanization level (U s ) were estimated to quantify the growth patterns in population and urban areas respectively. Further, correlation analysis and Multivariate analysis of variance were performed between U s and hydrological variables to study the influence of spatial urbanization on hydrological components for comprehending the existing relationships between them. Results reveal that from 1992 to 2014 with increase in U s of 1.44 to 6.31, the average annual surface runoff increased from 438.22 to 448.61 mm [standard deviation (σ) = 4.40; sum of squares (SS) = 58.20], whereas percolation decreased from 153.53 to 139.08 mm (σ = 6.06; SS = 110.10). These hydrological parameters are highly influenced by increase in urbanization. This study is relevant for water sources planners and policy makers for assessment of water resources for sustainable development in the urbanizing semi-arid river basins.

Impact of Climate Change on Flood Frequency and Intensity in the Kabul River Basin

Devastating floods adversely affect human life and infrastructure. Various regions of the Hindukush-Karakoram-Himalayas receive intense monsoon rainfall, which, together with snow and glacier melt, produce intense floods. The Kabul river basin originates from the Hindukush Mountains and is frequently hit by such floods. We analyses flood frequency and intensity in Kabul basin for a contemporary period (1981–2015) and two future periods (i.e., 2031–2050 and 2081–2100) using the RCP4.5 and RCP8.5 scenarios based on four bias-corrected downscaled climate models (INM-CM4, IPSL-CM5A, EC-EARTH, and MIROC5). Future floods are modelled with the SWAT hydrological model. The model results suggest an increasing trend due to an increasing precipitation and higher temperatures (based on all climate models except INM-CM4), which accelerates snow and glacier-melt. All of the scenario results show that the current flow with a 1 in 50 year return period is likely to occur more frequently (i.e., 1 in every 9–10 years and 2–3 years, respectively) during the near and far future periods. Such increases in intensity and frequency are likely to adversely affect downstream population and infrastructures. This, therefore, urges for appropriate early precautionary mitigation measures. This study can assist water managers and policy makers in their preparation to adequately plan for and manage flood protection. Its findings are also relevant for other basins in the Hindukush-Karakoram-Himalayas region.

Public Attitudes toward Water Management Measures and Droughts: A Study in Southern Spain

In a context of climate change and more severe and frequent droughts, in order to achieve efficient and sustainable results, water-governance models must take into consideration different alternative management measures and the degree of social approval of each alternative. In this context, the present work analyzes public perceptions concerning water management- and climate change-related issues, especially in relation to the degree of social approval attained by six water management measures in Andalusia (southern Spain). These issues were included in the Ecobarómetro between 2004 and 2013, a period which was marked by the 2005–2008 drought. This analysis aims to increase our understanding of the state of public opinion in Andalusia on the basis that such knowledge is a necessary tool for political decision-making processes. The results and the conclusions have significant implications for water policy makers.

Liquid futures: Water management systems and anticipated environments

Climate change and its impact on hydrological dynamics have become key topics of concern among water managers and policy makers in many parts of the world. Yet while practitioners often frame adaptation to a climate‐changed future as a novel issue, ideas about future environments have long influenced systems of water management. Reviewing ethnographic and historical accounts of waterscapes across the globe, this article examines the relationship between imagined environmental futures and the policies, practices, infrastructures of water management and legal frameworks. We show, first, how conflicting ideas about environmental stasis and perturbation have been built into water networks across space and time. In some cases, notions of radical landscape change have underpinned these systems, as in programs dedicated to land “reclamation” or interbasin water transfer schemes. In other contexts, water systems have developed based on visions of long‐term sociohydrological stability. Second, we highlight how contrasting notions of human capacity to change environmental outcomes have played into water management systems. In some cases, there has been an assumption of the potential for and desirability of full human control; in others, there has been more recognition of the limits of such mastery. Exploring the wide range of environmental imaginaries mobilized through water management, we contextualize contemporary efforts to build resilient, “climate proof” waterscapes. WIREs Water 2018, 5:e1274. doi: 10.1002/wat2.1274This article is categorized under: Human Water &gt; Water as Imagined and Represented Science of Water &gt; Water Quality

The changing water cycle: impacts of an evolving supply and demand landscape on urban water reliability in the Bay Area

The San Francisco Bay Area is no stranger to the emerging water challenges of climate change and population growth. As California bounces back from one of the most severe droughts in the state's history, utilities are forced to look for more resilient ways to manage their water resources. In the search for enhanced water reliability and resiliency, water providers must identify viable and innovative ways to increase water supplies and decrease demands. These decisions will be highly dependent on local characteristics, and the population dynamics that greatly affect supply, demand, and adaptation capacity in each region. This article explores the evolving supply and demand dynamics in 26 interconnected water utilities in the Bay Area. These utilities reflect not only the challenges that much of the state is facing due to the ongoing drought, but also the stresses of a growing population and shifting socioeconomic characteristics. The region has made significant investments in water efficiency and conservation that have helped increase resilience during the current drought, but conservation can only go so far and many uncertainties remain about future directions for supply and demand management. We explore: (1) how the supply and demand landscapes have evolved in these utilities over the past few decades, (2) what the main drivers have been, and (3) identify opportunities for the region to move forward in response to changing dynamics. The result is a holistic perspective that can help inform water managers and policy makers in preparation for the future. WIREs Water 2017, 4:e1240. doi: 10.1002/wat2.1240This article is categorized under: Engineering Water &gt; Planning Water Human Water &gt; Rights to Water Science of Water &gt; Water and Environmental Change

A Historical Review of the Benefits and Hypothetical Risks of Disinfecting Drinking Water by Chlorination

This review examines the benefits and alleged risks associated with the disinfection of drinking water by chlorination, through critical appraisal of the historical saga of chloroform as the main disinfection by-product (DBP). The author maintains that the provision of clean drinking water is a survival issue for humankind and supports unreservedly the recommendation by the World Health Organization (WHO) of the United Nations to disinfect by chlorination, for the reasons stated herein. The author aims to lead water professionals to a deeper understanding of the public health issues concerning chloroform and how the corpus of knowledge was attained by colossal multi-disciplinary effort on a global scale.Origins of the alleged risks of chlorination are traced and the assumptions behind these allegations are questioned. The author welcomes and encourages innovations for improved methods of water treatment insofar that the standards of potability set out by the WHO are met in the very least, but argues that the commencement point of research into new techniques should be an acknowledgment of the development of disinfection up to contemporary times, on the part of water engineers and policy makers. There must be a clear recognition of the horrific consequences of failure to eliminate pathogens and toxic substances. To this effect, landmark tragedies are described to emphasize the point.Significantly, this work addresses topics which are sine quo non to the debate over chlorination but which are often lacking in public discourse, namely: differences in the way cytochrome P450 enzymes oxidize carbon tetrachloride which is not normally a product of chlorination, and chloroform, which is a disinfection by-product; the role of free radical scavengers in protecting the human body; the difficulties of extrapolating experimental results from rodents to humans; the awareness of the complex relationship between governments, chemical industries, special interest groups and the public. Also introduced are the aetiologies of some cancers (e.g., Hepatitis B and C viruses as the instigators for hepatocellular carcinoma) to juxtapose claims that chloroform in drinking water is the sole culprit responsible for liver, bladder, colorectal cancers and birth defects etc. Other well known human carcinogens and a few inorganic compounds known to cause harm are also depicted. Lastly, a structured approach towards integrating the overarching concepts in the analysis of alleged carcinogenicity is applied to chloroform and the inferences discussed.The literature reviewed spanned the years 1848 – 2017.

Testing the detection and discrimination potential of the new Landsat 8 satellite data on the challenging water hyacinth (Eichhornia crassipes) in freshwater ecosystems

Detecting and monitoring the spatial distribution, configuration and propagation rates of aquatic water weeds (i.e. water hyacinth) in freshwater ecosystems, is arguably important to water resources managers, hydrologists and policy makers, for sustainable water resources management and planning purposes. The principal objective of this work was to develop a model that can satisfactorily detect and map the spatial distribution and configuration of water hyacinth (Eichhornia crassipes) in freshwater ecosystems, using both visible, near-infrared and thermal band information derived from the Landsat 8 multispectral sensor. Statistical analysis was done, using two machine learning classification ensembles, which are the Discriminant Analysis (DA) and Partial Least Squares Discriminant Analysis (PLS-DA). Our results have shown that the spatial distribution and configuration of water hyacinth can be accurately detected and mapped with an overall classification accuracy of 95% using Landsat 8 data. The results have further shown that the different growing stages (i.e. young, intermediate and old water hyacinth) could be spectrally detected and mapped, using the new Landsat 8 sensor. In addition, the findings of this study have demonstrated that Landsat 8 bands 5, 6, 7, 8, 10 and 11 are the most influential in detecting and mapping water hyacinth in freshwater ecosystems. Furthermore, allocation of agreement results showed that the DA classification algorithm outperformed PLS-DA in the detection and mapping the distribution and spatial configuration of water hyacinth in freshwater ecosystems. Overall, the derived water hyacinth maps provide critical information required for the development of effective and robust water hyacinth control and eradication programmes.

Temporal Hydrologic Alterations Coupled with Climate Variability and Drought for Transboundary River Basins

Climate change (CC) and drought episode impacts linked with anthropogenic pressure have become an increasing concern for policy makers and water resources managers. The current research presents a comprehensive methodology but simple approach for predicting the annual streamflow alteration based on drought indices and hydrological alteration indicators. This has been achieved depending on the evaluation of drought severity and CC impacts during the human intervention periods to separate the influence of climatic abnormality and measure the hydrologic deviations as a result of streamflow regulation configurations. As a representative case study, the Lesser Zab River Basin in northern Iraq has been chosen. In order to analyse the natural flow regime, 34 hydrological years of streamflow (1931–1965) prior to the main dam construction were assessed. The Indicators of Hydrologic Alteration (IHA) method has been applied to quantify the hydrological alterations of various flow characteristics. In addition, an easy approach for hydrological drought prediction in relatively small basins grounded on meteorological parameters during the early months of the hydrological year has been presented. The prediction was accomplished by implementing the one-dimensional drought examination and the reconnaissance drought index (RDI) for evaluating the severity of meteorological drought. The proposed methodology is founded on linear regression relations connecting the RDI of 3, 6, and 12 months and the streamflow drought index (SDI). The results are critical for circumstances where an early exploration of meteorological drought is obtainable. Outcomes assist water resources managers, engineers, policy makers and decision-makers responsible for mitigating the effects of CC.

Impact of potash mining in streams: the Llobregat basin (northeast Spain) as a case study

Potash mining is significantly increasing the salt concentration of rivers and streams due to lixiviates coming from the mine tailings. In the present study, we have focused on the middle Llobregat basin (northeast Spain), where an important potash mining activity exists from the beginning of the XX century. Up to 50 million tonnes of saline waste have been disposed in the area, mainly composed of sodium chloride. We assessed the ecological status of streams adjacent to the mines by studying different physicochemical and hydromorphological variables, as well as aquatic macroinvertebrates. We found extraordinary high values of salinity in the studied streams, reaching conductivities up to 132.4 mS/cm. Salt-polluted streams were characterized by a deterioration of the riparian vegetation and the fluvial habitat. Both macroinvertebrate richness and abundance decreased with increasing salinity. In the most polluted stream only two families of macroinvertebrates were found: Ephydridae and Ceratopogonidae. According to the biotic indices IBMWP and IMMi-T, none of the sites met the requirements of the Water Framework Directive (WFD; i.e., good ecological status). Overall, we can conclude that potash-mining activities have the potential to cause severe ecological damage to their surrounding streams. This is mainly related to an inadequate management of the mine tailings, leading to highly saline runoff and percolates entering surface waters. Thus, we urge water managers and policy makers to take action to prevent, detect and remediate salt pollution of rivers and streams in potash mining areas.