Water resources are becoming scarce due to climate change and anthropogenic activity, necessitating immediate action. The first step in conserving our water supplies is to manage them mindfully and sustainably. To achieve this, water sources must be monitored, mapped, and evaluated regularly. Updating national water maps using conventional methods can be a challenging task. Most of the obstacles have been addressed due to recent breakthroughs in the remote sensing field. In this study, we benefit from the remote sensing data integrated into Google Earth Engine (GEE) for developing an application for mapping Turkey's national inland water bodies. To achieve this, we explored the recently developed Multi-Band Water Index (MBWI) in GEE using Sentinel-2 satellite imagery and then applied it over the research area. The results showed that GEE is a promising application for dealing with large amounts of satellite data and can accurately extract water bodies on a national scale. The results might be helpful for various administrative applications that require up-to-date water information. The developed application can be used over different study areas and for spatiotemporal analysis.

This work assessed the potable water savings potential for different scenarios in a flat in Florianópolis, Brazil. An uncertainty analysis was also performed to understand which parameters most influenced the results. First, it was necessary to evaluate the water consumption and calculate the water end-uses during a home-office period due to the Coronavirus pandemic. The water end-uses were obtained by monitoring the users’ consumption for sixteen days and compared with the water meter on a daily basis. The results were very close to those measured using the water meter, with an average absolute error of 5.6%. The base consumption was, on average, 249.2 litres per capita per day. With a home-office regime and uninterrupted occupation, the Coronavirus pandemic can be postulated to justify the more intense consumption patterns. Regarding the percentage of non-potable end-uses, an average of 25.8% was obtained. Potable water savings were simulated using the computer programme Netuno, version 4. Seventy scenarios were evaluated, including different rainwater catchment areas and water and rainwater demands. The main results were that the rainwater harvesting through a reduced area, 17.5% of the roof, obtained significant results compared to the simulation with the whole roof, with a potable water savings potential of 16%.

For Water Service Providers (WSP) the safety and quality of drinking water provided are of paramount importance. To ensure drinking water safety a WSP must understand the potential hazards of the supply system all the way from catchment to tap [1]. For drinking water source protection, ecosystem services in the catchment area play a vital role in managing source water contaminants. Leveraging off these services and viewing catchment areas as water treatment assets has the potential to complement conventional engineering solutions such as water treatment, as well as reducing public health risks to consumers [2]. This research focuses on riparian buffers specifically as a subprocess of the wider catchment area. These buffers interrupt the movement of contaminants and sediments from non-point source sources such as agricultural land to surface waters [3].

There are many examples exist where stream buffers have been used to improve water quality outcomes [4] [5]. However, when it comes to wider implementation further research is required to establish practical approaches for management that capitalises on ecosystem services [3]. Good practice catchment management is guided through multiple information sources such as water quality data, land use, compliance action, etc. Core to effective management is understanding monitoring data and responding appropriately in the context of protecting water quality can be complicated. This study uses System Theoretic Process Analysis (STPA) to systematically examine the sociotechnical structures involved us managing vegetated buffers in surface water catchments using a theoretical scenario representative of typical surface water supplies. STPA is a hazard analysis methodology based on System Theoretic Accident Modelling Processes (STAMP), which, being founded on systems theory views safety as the emergent property of the system [6]. Using STPA to examine the complex sociotechnical systems involved in managing stream buffers provides a comprehensive set of requirements for appropriate monitoring and management measures as well as leading indicators of safety.

This example provides a valuable test of how taking a highly systematic approach to identifying management requirements using STPA can help to better understand management requirements. Such processes can be used to give more certainty to management approaches and potentially overcome the common bias toward more costly investment in water treatment infrastructure.

References

[1] World Health Organisation, Guidelines for drinking-water quality: fourth edition incorporating the first addendum, Geneva: WHO, 2017.

[2] J. R. Vincent, I. Ahmand, N. Adnan, W. B. Burwell III, S. K. Pattanayak, J.-S. Tan-Soo and K. Thomas, “Valuing Water Purification by Forests: An Analysis of Malaysian Panel Data,” Environmental Resource Economics, no. 64, pp. 59-80, 2016.

[3] M. L. Stutter, W. J. Chardon and B. Kronvang, “Riparian buffer strips as a multifunctional management tool in agricultural landscapes,” Journal of Environmental Quality, no. 41, pp. 297-303, 2012.

[4] F. K. Yeboah, F. Lupi and M. D. Kaplowitz, “Agricultural landowners’ willingness to participate in a filter strip program for watershed protection,” Land Use Policy, vol. 49, pp. 75-85, 2015.

[5] C. Buckley, S. Hynes and S. Mechan, “Supply of an ecosystem service—Farmers’ willingness to adopt riparian buffer zones in agricultural catchments,” Environmental Science and Policy, vol. 24, pp. 101-109, 2012.

[6] N. Leveson, “A new accident model for engineering safer systems,” Safety Science, vol. 42, no. 4, pp. 237-270, 2004.

The present study assesses the vulnerability of groundwater seawater intrusion using the GALDIT method in the rural and coastal Almyros basin, in Thessaly, Greece. Excessive groundwater abstractions, mainly for irrigation, have degraded the quality and quantity of Almyros basin’s aquifer. Seawater intrusion vulnerability indices have been estimated for the period 1992-2015 using the original GALDIT method and the modified GALDIT method with the weights being estimated through the Analytical Hierarchy Process (AHP) (GALDIT-AHP). The weights in the modified GALDIT-AHP have been estimated based on the pairwise table responses of 15 experts. The average, median and the mode of the 15 experts have been used to find the final weights in the modified GALDIT-AHP method and three variations of the method have been applied (i.e. GALDIT-AHP (Average), GALDIT-AHP(Median), and GALDIT-AHP (Mode)). The GALDIT and modified GALDIT-AHP results have been validated against observed Cl concentration measurements in the Almyros basin aquifer, using the Spearman's rank correlation coefficient. The results indicate that the weights of the original GALDIT index and the modified GALDIT-AHP indices differ affecting the estimated vulnerability in seawater intrusion. All indices's values range from low to high vulnerability at the Almyros aquifer and the coastal area, respectively, for all the studied periods. The original GALDIT index, the modified GALDIT-AHP (Average) and the modified GALDIT-AHP (Median) present similar results. It seems that the most appropriate method for the estimation of the vulnerability in seawater intrusion is the modified GALDIT-AHP (Mode) index because it exhibits the highest correlation to the observed Cl concentrations.

Hydrological dam safety analyses should assess the frequency curve of maximum reservoir water levels in flood events, by routing a large set of inflow hydrographs in the reservoir. Routing processes in the reservoir will depend on several variables, such as flood peak and hydrograph volume. Therefore, bivariate analyses are required for hydrological dam safety analyses. In addition, hydrometeorological simulations are required to generate possible hydrograph shapes that characterise the catchment response in flood events. Adequate hyetograph shapes will be required as input data for calibrating the model.

In this study, the Cuerda del Pozo Dam in central Spain is selected as case study. Hydrographs associated with the annual maximum peak flows lead to storm durations of several days. Therefore, hyetographs of several days based on intensity-duration-frequency curves are required to generate the runoff volumes given by the univariate frequency curve of hydrograph volumes. Design hyetographs of several days with a short time step can generate sharp hydrographs that require unreasonable model parameter values to smooth flood peaks. Design hyetographs with long time steps could lead to excessively smooth hydrographs with lower flood peaks than observed. A sensitivity analysis is carried out to identify the most suitable hyetograph shape to calibrate flood peaks and hydrograph volumes with reasonable model parameter values.

The calibrated rainfall-runoff model is used to generate a set of possible synthetic hydrograph shapes. A bivariate analysis is performed to generate random pairs of peak flow and hydrograph volume that fit the univariate frequency curves. A given synthetic hydrograph shape is assigned to each pair of peak flow and hydrograph volume. Hydrological safety of the Cuerda del Pozo Dam is assessed by using a long set of 500 000 inflow hydrographs.

Recent surge in pharmaceutical micro-pollutants in water bodies calls for an efficient method to neutralize wastewater to sustain the ecosystem. One of the ways to degrade drug molecules is through photocatalytic degradation using UV rays. ZnO is known to be a common catalyst in the degradation of contaminants found in wastewater. However due to its toxicity to the environment, there is a need to objectively re-evaluate its necessity and alternatives. In addition, most studies are focused on utilization of UVA/UVB rays for the photocatalytic degradation process, as such, there are currently limited studies evaluating the efficacy of UVC for such purpose. In this work, we provide a comparative analysis of photodegradation of drug molecules using UVC ray with and without the ZnO catalyst. Ibuprofen (IBP) and clotrimazole are used for analysis. We found that the use of ZnO catalyst does not always produce better results. In some case, we found that IBP was degraded up to 94.8% more than that with the ZnO up to 91.4% in 60 mins. However, without ZnO we observed secondary metabolite by-products of IBP that require longer treatment period to fully degrade. The inferior degradation strength for treatment with ZnO can be explained by increasing turbidity from adding greater concentrations of ZnO which decreases the UV transmission to the IBP solution. To support the results, an investigation on the photocatalytic degradation of clotrimazole, an antifungal, with varying concentrations of ZnO as catalyst was also carried out. The optimum ZnO concentration was determined to be ~1000 ppm, above or under which the efficiency of the degradation suffers. Thus, the use of ZnO catalyst require strict dosage control. Such tight regulation is not required for the system using just UVC ray, but it would require a longer treatment time to completely degrade drug molecules and its by-products.

Despite the demand for clean water, it is commonly deficient. In the past two decades, there has been renewed interest in the development of clean water generation processes from atmospheric moisture. Atmospheric water generation is a 2-stage process; in the first stage, the moisture is accumulated in an absorber material, and in the second stage, the absorbed moisture is recovered to a vessel by thermal and/or mechanical processes. One of the keys to achieving high efficiency in such processes is the moisture-absorbing agent, which works passively without electricity. Several materials are currently under research, such as metal-organic frameworks (MOF) and hygroscopic salts. However, most approaches would likely be challenging to scale up from technical and economic perspectives. This work aims to develop a commonly accessible, cost-effective, environmentally friendly, and highly effective moisture absorber. Calcium chloride was chosen as the main salt of interest due to its deliquescence; however, it is known to suffer from agglomeration upon repeated absorption-desorption trials which decreases efficacy. To overcome this problem, a simple infusion of the salt into the sponges significantly reduced the agglomeration problem of the salt while also improving its absorption rate and maximum water uptake by ~30 % at 27°C and 80% relative humidity (RH) compared to a sample without the cellulose sponge. To elucidate the science behind this synergistic interaction, time-dependent water uptake measurements at controlled conditions were carried out using a microbalance in an environmental chamber. Then the data was analyzed using a double exponential equation. A physical model of the moisture absorption mechanism in the salt/sponge system was proposed. Finally, a complete atmospheric water generation device prototype was demonstrated by incorporating the salt/sponge absorber into a custom-designed Peltier-based distillation chamber.

The distribution of potable water is an important aspect of a water supply scheme. The water must be available with sufficient pressure head and flow velocity while maintaining the standard quality and minimization of losses. The current study aims at the review of the use of EPANET 2.0 for the water distribution system modeling. The factors that can serve as the decision variables while aiming at an optimal design have been reviewed. A review of the studies pertaining to the performance evaluation and the leakage modeling of a designed network was reviewed. It was found that EPANET 2.0 is a great tool in cases where a modest degree of accuracy along with cost efficiency is required. To obtain an optimal design solution, the decision variables for the hydraulic design need to be constrained to standard values, the cost efficiency has to be validated and the efficiency of performance has to be estimated.

Highly managed Mediterranean river basins are facing considerable environmental management challenges. Water resource managers are increasingly concerned about the allocation of limited water resources, environmental quality concerns and planning under present and future climatic change and uncertainty. Conventional siloed approaches are not always adequate to address multiple environmental challenges regarding water resources at the watershed scale. In this study, we implemented a watershed-scale eco-hydrological model on the Cervaro river basin (Southern Italy) using the Soil and Water Assessment Tool (SWAT+) model to evaluate the influence of anthropogenic management on water balance components, nutrients and sediment loads from 1990 to 2019. A high-precision land use map derived from administrative sources was used to grasp detailed information regarding landscape patterns. The efficacy of the model is evaluated by comparing modelled and observed streamflow data by assessing the goodness-of-fit objective function values such as Nash-Sutcliffe efficiency (NSE), the percent of model bias (PBIAS), root mean square error (RMSE) and coefficient of correlation (R). Preliminary results indicate good model performance reproducing the water balance in the watershed. The calibrated model will be used to analyze the effects of alternative best management practices scenarios on water quality, sediment loads and soil erosion. Future work will be oriented to evaluate the impacts of climate change using data from high-resolution Regional Climate Model projections under different representative concentration pathways.

This study estimates the effect of climate change on water resources efficiency and crop/agronomic productivity at the coastal agricultural Almyros basin, in Greece. Groundwater resources in the studied basin are intensively mined for irrigation, whereas their quantity and quality are highly downgraded. Multi-model climate projections for Representative Concentration Pathways (RCPs 4.5 and 8.5) from the Med-CORDEX database for precipitation and temperature have been used to evaluate the impacts of climate change on the studied area. The multi-model climate projections have been bias-corrected with Quantile Empirical Mapping. Simulation of coastal water resources has been performed using a calibrated Integrated Modelling System (IMS) consisting of coupled and interconnected models of surface hydrology (UTHBAL), groundwater hydrology (MODFLOW), nitrate leaching/crop growth (REPIC), nitrate pollution (MT3DMS), and seawater intrusion (SEAWAT) for the historical period of 1991–2018, and the projected future period 2019-2100. Analysis of the simulation results for the various water resources management and crop/agronomic scenarios have been evaluated using the Standardized Chloride Hazard Index (SCHI), the Crop Water Productivity (CWP) index for crop yields and irrigation water, the Nitrogen Use Efficiency (NUE) index, and the Economic Water Productivity (EWP) index for the gross profits of irrigation water, based on historical and projected growth ratios until 2100. The results indicate how the various water resources development, and the agronomic scenarios will affect the water use and agricultural production management and help to develop adaptive and sustainable agricultural and water resources management plans under climate change.