Water Supply Research Articles

Removal of pyrene from domestic water supply using styrene-based imprinted polymer

Pyrene removal from domestic water supply (DWS) is important due to its mutagenicity, toxicity, and carcinogenicity. Use of molecularly imprinted polymer for pyrene removal is scarce, therefore the study developed polystyrene to complement conventional water treatment methods for pyrene removal. Bulk polymerisation was used to synthesise Pyrene imprinted polystyrene (PIP) and its non-imprinted analogue (NIP). Monoliths were characterised using SEM–EDX, FT-IR, and XRD. Extraction and concentration of pyrene were determined using GC–MS. Adsorption experiments on simulated solutions of pyrene with different concentrations, pH, adsorbent dosage, time, and temperature using PIP and NIP with equilibrium studies were done. Recovery was performed, while pyrene was adsorbed using simulated experiment best conditions. Used PIP and NIP were characterised. Pre-adsorption characterisation confirmed PIP and NIP while post-adsorption showed a clogged surface for NIP, but PIP was pyrene-selective. Pyrene concentration (0.05 mg/L) in DWS was > WHO standard (0.0002 mg/L) with 100% recovery. Adsorption efficiencies ranged from 25–100% and 15–100% with varied parameters for PIP and NIP respectively. However, best adsorption conditions are pH-9, time-1 h, adsorbent dosage-0.8 g, concentration-0.001 mgL−1, and temperature-27 °C with ΔG° (KJmol−1)13.48, 13.70, 13.94 for NIP and 21.24, 21.60, 21.95 for PIP. NIP ΔH° -0.3233 KJmol−1 and ΔS, 0.046 KJmol−1 k−1, while PIP ΔH° -0.0717KJmol−1 and ΔS, 0.071 KJmol−1 k−1. Adsorption fits Langmuir isotherm compared to others with R2 of 0.9140 and 0.9540 for PIP and NIP respectively. The study showed that both PIP and NIP removed pyrene from DWS with excellent efficiencies. However, PIP showed greater selectivity for pyrene removal.Graphical

Management Planning Water Resources in Balikpapan City, Indonesia in East Kutai Regency, Indonesia: A Case Study

This study aims to investigate the role of water resource management in Balikpapan City, Indonesia, focusing on how the city government implements sustainable development and water governance practices. Using a qualitative approach and literature review, this research examines Balikpapan’s strategies for addressing water challenges amid climate change, population growth, and its role within the Indonesian Capital City (Ibu Kota Nusantara, IKN) area. Findings reveal that Balikpapan’s regional development plan has adopted a sustainable approach, emphasizing prevention and mitigation efforts to secure long-term water resources. In addition to constructing new infrastructure, Balikpapan is exploring collaboration with neighboring administrative areas to ensure a reliable water supply in the future. Nonetheless, there is a need for stronger partnerships with the private sector, especially to support technological innovations that, while potentially costly, could enhance water management. Public participation is also essential to prevent social conflicts and to ensure that development progresses fairly and inclusively. By engaging diverse stakeholders—including the government, private sector, and community—in planning and implementation, Balikpapan and IKN Nusantara can work towards sustainable development goals that prioritize environmental responsibility and meet the needs of all communities. This collaborative approach can foster sustainable, equitable solutions that align with global goals, supporting a resilient and water-secure future for Balikpapan and its surrounding areas.

Localization of hidden leaks in water supply networks by hydraulic methods

AbstractThe hydraulic gradient method is an effective approach for localizing hidden leaks in water supply networks. Relative errors in leakage location depend significantly on head measurement errors, necessitating the use of high-precision pressure gauges with an accuracy class of 0.25 or better. An optimization function, defined as the ratio of the localization relative error to the probability of detection, was used to determine the optimal location for the control section. Dependencies of localization relative error on the pressure gauge accuracy class, section length, and piezometric head are obtained. Presented multi-leakage estimation model enables the assessment of the multi-leakage probability, enhancing decision-making efficiency for emergency repairs in water supply networks.

Water distribution pipelines inside the monastery of El Escorial during the sixteenth century

AbstractThis article addresses the study of the internal hydraulic infrastructure of the Royal Monastery of San Lorenzo del Escorial. The vast network of pipes that supplied water to the numerous fountains, tanks, and other devices in the building. The methodology was based on two fundamental pillars: an analysis of the historical sources related to water and a cataloguing of the preserved architectonical remains of the infrastructure. A new sketch of the water supply network of the building has been drawn using ArcGIS Pro software. In doing so, this article provides a more accurate and detailed knowledge of the building's plumbing system.

Building trust with stakeholders in water supply management

Building trust with stakeholders in water supply management

Biotechnology of groundwater purification for water supply systems, using Gallionella and Lepthothrix ferrobacteria

Aim. The aim of the study was to consider the possibility of using the consortia of chemolithoautotrophic ferrobacteria from Gallionella genus and heterotrophic bacteria from Lepthothrix genus for the biological method of groundwater purification. Methods. The photocolorimetric method to determine the concentrations of ammonium and iron ions, the titrimetric method to determine the hydrocarbon and total alkalinity, the method of determining the permanganate oxidizability using the Kubel method, the potentiometric method to determine the values of рН and Еh, the electronic microscopy using the X-ray spectral analysis of matrix structures of bio-minerals, microbiological and statistical methods. Results. The main technological parameters of the water deironing process were defined as follows: the filtration velocity of the bioreactor – 7–11 m/h, and of the filters – 3.5–5 m/h; the filter-cycle duration – 48 h. It was found that the application of the two-stage technology of biological deironing in the bioreactor and filters provided for the possible removal of Fe2+ compounds up to 5.0 mg/cdm, ammonium nitrogen — up to 1.5 mg/cdm, soluble organic substances by PO – up to 6.0 mg O2/cdm. It was determined that the optimal parameters for the process of biological purification of neutral groundwaters, containing increased concentrations of Fe2+ cations were as follows: рН 7.0–7.2; hydrocarbon alkalinity 2.5–2.2 mmol/cdm; content of soluble oxygen – 1.5–2.0 mg/cdm. The ability of concentrated (Dos 200 mg/cdm) matrix structures of Gallionella and Lepthothrix ferrobacteria to remove Cr6+ ions from natural groundwaters was determined. The study found no considerable differences in the efficiency of applying disinfectants, produced using polyhexamethylene guanidine chloride (PHMGchl) or polyhexamethylene biguanidine chloride (PHMBchl). In concentrations of 0.25–0.5 %, they effectively disinfect pathogenic microorganisms, including Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The same was found true for the bacteria, most common in the systems of technical reverse water supply, the systems of water circulation, plant watering, and fire tanks, including Aeromonas hydrophila, Aeromonas salmonicida, Pseudomonas sp., E. coli, Flavobacterium columnare, Micrococcus lysodeikticus. Conclusions. This was the first study on the possibility of applying the biotechnology of groundwater purification from excessive amounts of iron in conditions of uneven hydraulic burden, notable for the water supply systems of rural areas and most agricultural enterprises in the north-western and northern regions of Ukraine. The specificities and perspectives of PHMGchl application in the systems of water preparation were studied. It was found that from the standpoint of safety and efficiency, the use of the water deironing processes involving iron bacteria was reasonable in the systems of water consumption and technical water supply, and the disinfection of water using PHMG was possible only in the second case, due to some toxicity of the preparation. The optimal parameters for the process of biological purification of neutral groundwaters, containing increased concentrations of Fe2+ cations were determined.

Biodiversity and Abundance of Angiosperms and Environmental Resilience in the Tidal Range of Yuanjiang Dry–Hot Valley, Southwestern China

Yuanjiang dry–hot valley is located in the southwest of mainland China. It is a sparsely vegetated area with a fragile arid ecosystem. Although the valley previously had forest cover, it has become a tropical montane savannah in recent decades. Mechanisms controlling plant species distribution in such dry–hot valleys are unclear. Clarifying this will be beneficial to sustainable ecosystem management in dry–hot valleys. This study explored the relationship between diversity patterns of plant species and their environments in the lowland of this dry–hot valley. To achieve this, transects and plots were arranged along the river channel. Alpha and beta diversity indices were calculated to quantify biodiversity changes between species and environments. Estimated species, rarity, and abundance indices were also utilized to examine the correlation among species, their population size, and their environment: Species_estimated (expected number of species in t pooled plots), Singletons (the number of species with only one individual in t pooled plots), Uniques (the number of species living in one plot in t pooled plots), ACE (species richness estimator with coverage-based abundance), ICE (species richness estimator with coverage-based incidence), and Chao2 (species richness estimator extrapolated from Singletons). Fifty years of meteorological records, including temperature and precipitation, were utilized as climate variables. The results indicated the following findings: (1) alpha diversity was higher closer to the river, whereas the beta diversity was higher towards the lower sections of the river (Bray–Curtis < 0.5), but this trend was reversed in the perpendicular transects; (2) total phosphorous (TP) and total potassium (TK) were higher on flatter ground, tending to be associated with raised nitrogen (TN) and organic matter (OM); (3) soil nutrients were higher towards the lower sections of the river, corresponding to an increased number of species; (4) water supply determined plant distribution, with soil condition determining water retention; (5) the estimated species and their rarity and abundance indices were associated with proximity to the river, indicating heterogeneity of habitats and soil condition; and (6) fern species could be used as indicators representing the xeric environment of Yuanjiang dry–hot valley. Plant cover was reduced at low altitudes, with high temperatures and a low water supply. These results draw attention to the need for specific policy formation to protect the microhabitats and manage the environment of the Yuanjiang valley.

Water Use Attribution Analysis and Prediction Based on the VIKOR Method and Grey Neural Network Model: A Case Study of Zhangye City

Water consumption forecasting is a critical aspect of the increasingly strained water resources and sustainable water management processes. It is essential to explore the current status of water use patterns and future development directions in Zhangye City. In this study, 17 factors affecting water consumption in Zhangye City were selected to analyze changes in water consumption and to predict values from 2003 to 2022, utilizing the entropy weight–VIKOR model and the grey neural network model. The results indicate that agricultural water consumption and annual rainfall are the factors with the largest weights among the social and natural attribute indicators, respectively, significantly influencing water consumption in Zhangye City. As the proportions of water consumption for forestry, animal husbandry, fishery, livestock, urban public use, and ecological environment increase, while agricultural water consumption continues to decline, the overall water consumption trend in Zhangye City from 2003 to 2022 shows a positive trajectory. Each water consumption factor is tending toward greater balance, and the relationship between water supply and distribution is improving. The multi-year average relative error of the water consumption predictions for Zhangye City from 2003 to 2022 using the grey neural network model was 4.28%. Furthermore, the relative error values for annual predictions ranged from 0.60% to 5.00%, achieving an accuracy rate of 80.00%. This indicates a strong predictive performance. Ultimately, the model was used to predict a water consumption of 20.18 × 108 m3 in Zhangye City in 2027. The model can serve as a theoretical reference for short-term water consumption forecasting and for establishing a basin water resource allocation system in Zhangye City.

Women, gender and the ancient economy: towards a feminist economic history of the ancient Greek world

Abstract This article asks why women are ignored in debates about ancient economies and suggests a way forward. It argues that women performed a wide variety of diverse economic activities, though this is not particularly discernible from the scholarly literature, which mostly casts them as patrons or prostitutes and, despite the household being a basic economic unit to which women contributed, generally considers economic actors as male by default. However, by drawing on feminist economics, social history and gender studies, it is possible to reframe women’s varied activities in ways that acknowledge their labour, spotlight female agency, challenge the (gendered) categories of analysis and discourses that are predominantly used within ancient history, and recentre questions relating to the structures of inequality created by ancient economies. Three case studies explore some of the problems and raise new questions: Z3, a building in the Kerameikos the function of which is debated, the contribution of tax-farmers to sacrifices on Kos and the water supply in Athens. That is, this article argues that examining how ancient economies were gendered is a profitable way to think about both economic history and gender history.

Innovative Strategy for Rainwater Harvesting in Saline-affected Urban Areas: A Case Study of a Sports Complex in Delhi

Water scarcity remains a critical global challenge, requiring immediate, sustainable management strategies, particularly in areas with an increasing disparity between water supply and demand. In India, and especially in Delhi, this issue is acute. In response to growing environmental concerns and the urgent need for sustainable water resource management, rainwater harvesting has emerged as a practical and effective solution for water conservation. This study investigates the application of rainwater harvesting to sustainably support water needs for a sports complex located in a salinity affected region. The land, originally intended for agriculture, has been converted into a complex featuring hydro-landscape facilities, including swimming pools, water polo areas, diving pools, toddler pools, and leisure pools. These facilities require an initial water input of 6,754.5 m³ and an annual replenishment of 7,957.28 m³ due to evaporation and seepage. By calculating the total rainwater harvesting potential based on the runoff coefficient, annual rainfall intensity, and the complex's catchment area, the study reveals that 29,693.8 m³ of rainwater can be harvested annually, providing a surplus of 14,981.7 m³ of potable water. This analysis demonstrates the viability of designing sports complexes in saline areas using efficient land use and rainwater harvesting, and presenting a scalable model for sustainable water management in similar regions worldwide.

Assessment of socioeconomic and ecological impacts on integrated rice cultivation in Africa: a systematic review and meta-analysis

ABSTRACT Integrated rice-fish (RF) is seen as a valuable system to increase food production and farmers’ income in Africa. To date, no research has been conducted to comparatively assess integrated RF, rice, and fish monoculture systems in Africa. This study aimed to evaluate the agronomic and economic performances and identify constraints and enabling conditions for large-scale adoption of RF systems in Africa. Systematic review and meta-analysis were performed using papers collected from January 1999 to December 2023 and 30 pair-observations. The results showed a significant effect on FGR (+6%) in integrated RF compared to fish monoculture. The production cost increased by 300 USD/ha in integrated RF, but the gross revenue increased by more than 600 USD/ha resulting in an increase in net income by 300 USD/ha compared to rice monoculture. NUE, soil properties, and control of weeds, pests, and diseases were enhanced in the integrated RF compared to rice monoculture. Land ownership, water supply unreliability, access to fish feed and fingerlings, and lack of funding were the major factors limiting integrated RF adoption by farmers. Due to the limited data identified in this study, more field observations and long-term monitoring are necessary on land suitability and management practices for integrated RF.

Conceptual and terminological features and legal content of environmental quality standards for water bodies in Ukraine and EU

The article investigates the compliance of Ukrainian and European water legislation in the part of legal instruments, which are the standards for determining, for assessing the ecological status and for regulating the quality of surface waters. Such instruments are included in the main environmental and legal institutions of these legislations. The relevance of the study is determined by the transition of Ukrainian water legislation to the phase of practical support for the implementation of European river basin management. The use of these legal instruments should be envisaged in the first Ukrainian river basin management plans. The purpose of the article is to determine the terminological correctness and conceptual conformity for standards of environmental regulating to ensure that Ukrainian river basin management plans are provided with European equivalents (or analogues) of legislative means to combat environmental status degradation and for surface water pollution, in particular, as a result of the impacts of point sources. The study is based on a comparative analysis of the legal requirements of Ukrainian and European water legislation. Numerous inconsistencies have been identified that impede the harmonization of the both legislations. The most significant of these inconsistencies concerns the recently created Ukrainian ecosystem-based framework of environmental and chemical standards (and corresponding classifications) for surface water bodies. These standards have significant terminological inconsistencies and inconsistencies with the water legislation of Ukraine in terms of the concept of environmental water quality standards. It is determined that the European term and concept of environmental quality standards does not correspond to the Ukrainian concept of the environmental water quality standard and does not allow implement of European regulation of pollutant discharges without changes in legislation. In addition, find inconsistencies create significant obstacles to compliance with the requirements of Ukrainian legislation in the field of drinking water and drinking water supply. It is noted that the principle of building a Ukrainian analog of the European system of environmental quality regulations complicates the policy of nationwide unification of activities in the areas of environmental safety and economical use of aquatic ecosystems.

Experimental study of advanced phase change materials to optimise the thermal storage performance of radiant floors: Towards a low-carbon energy system for grassland pastoral settlements

Building on the advancements in integrating phase change materials (PCM) within building envelopes to enhance thermal performance, this paper explores the use of slag cement combined with PCM to significantly improve the heat storage performance of radiant floors. The study involved the preparation of a heat storage composite mortar by mixing 0–10 % PCM into slag cement mortar using a specialized process. The thermal performance test shows that the thermal conductivity and thermal diffusivity of radiant floor decreased by 9 % and 10 % respectively with 1 % increase of PCM. Through SEM and DSC analysis, it was determined that incorporating more than 4 % PCM markedly enhances the mortar's thermal storage capacity, with 7 % identified as the optimal maximum addition. The utilization of an experimental platform within an environmental chamber to test a radiant floor module with a 5 % PCM replacement (3.26 wt%) demonstrated a 12.5 % increase in heating efficiency and a 15 min delay in peak heat flow during the exothermic process. Additionally, adding 10 % PCM increased the surface temperature of the radiant floor by 18 %, and a water supply temperature of 45 °C further elevated the surface temperature by 21 %. These findings suggest that the PCM improves the thermal insulation, the heat transfer efficiency and heat storage performance of the radiant floor, facilitates the integration of abundant renewable resources, and further integrates the system with the solar energy, thus providing a way to solve the energy-environmental balance of grassland pastoral dwellings.

Detection of Aquifer Infiltration Zones Using Resistivity and Induced Polarization Methods

Infiltration zones that are water providers for aquifers are often neglected, resulting in the sustainable use of groundwater resources will be disrupted. The research is intended to determine rainwater catchment areas as water suppliers for aquifers on the coast of East Tondano Beach. The location of the research is in the coastal area of East Tondano, Minahasa Regency. Exploration of subsurface rock layer detection using the resistivity geoelectric method and induced polarisation, dipole-dipole configuration, 10 m space. Data acquisition using multielectrode resistivity and IP meter MAE type X612-EM. The measurement line of the two methods is the same, the data was measured on 2 lines, with line 1 being 240 m long and line 2 being 360 m long. A rainwater infiltration zone with a resistivity of 48<ρ<192 Ωm was identified, on track 1 there was a infiltration zone at meters 105-135, a layer with low resistivity was identified at meters 70-150 with a resistivity of 3-48 Ωm and a depth of ≥ 15 m.. Based on the results of the IP meter, no suspected groundwater aquifer was found, so rainwater is estimated to flow directly into the sea. On line 2, the infiltration zone was detected at meters 80-105 and meters 275-315. The layer with a low resistivity value at 100-275 meters with a resistivity of 3-48 Ωm, has a depth of ≥ 20 m. The results of the IP measurement, layer with low chargeability ≤ 0.8 ms are found on the 180-200th meter. Suspected groundwater aquifer at 180-200 meters with a depth of 45-65 m. Keywords: Aquifer; resistivity; infiltration zones

Improving the technology of drinking water purification at the water treatment facilities of the Chernorechensk reservoir during the flood period

The paper considers the natural and technical aspects that contribute to the supply of substandard quality water to the water treatment facilities of the city of Sevastopol during the flood period, which caused repeated shutdown of water treatment facilities. Options for retrofitting the existing water supply and purification scheme are considered, with the determination of the enlarged cost. The paper presents a technological justification for the application of a two-stage sedimentation scheme, which can be implemented within the framework of existing equipment and a small technological re-equipment.

Identifying the gap in assessing activities of daily living in resource-constrained rural settings: An integrative review of existing frameworks and instruments

Introduction: The non-availability of indoor piped water and electricity results in alternate forms of personal care and domestic tasks in resource-constrained rural settings. This article examines the applicability of existing measures for the contextual assessment of basic and instrumental Activities of Daily Living (bADLs and iADLs) in these settings. Method: An integrative review guided by the approach of Lubbe et al (2020) was conducted. Structured database searches of CINAHL, Scopus and Sabinet identified published articles which were subjected to eligibility criteria. Microsoft Excel was used to synthesize data. Results: The search strategy yielded 591 articles that met the inclusion criteria, from which 187 ADL instruments were identified. Three instruments suited to resource-constrained rural settings were identified. Conclusion: Occupational therapists should consider that existing ADL frameworks and instruments appear silent on the impact of limited access to household amenities in resource-constrained settings. This constitutes epistemic injustice as many rural households globally do not have potable water or adequate household energy supply. Global South occupational therapy curricula must include contextually relevant ADL frameworks and development of contextually relevant instruments should be prioritised. Implications for Practice The findings suggest that existing ADL instruments have limitations when utilised in the Global South, particularly in resource-constrained rural settings. As such, occupational therapists practicing in such settings need to interpret instrument scores with caution and apply contextual clinical reasoning in the best interests of service users. Furthermore, training institutions in the Global South must ensure that the limitations of existing ADL frameworks, models and instruments are made overt within curricula and that research efforts are directed towards the development of contextually relevant ADL instruments.

An Assessment of Drinking Water Quality in the Chief Albert Luthuli Local Municipality, South Africa: A Case Study of the Elukwatini Water Supply Scheme

This study analysed the water quality of 156 samples collected from 13 different points within the Chief Albert Luthuli Local Municipality between January and December 2021, focusing on compliance with the South African National Standard 241 (SANS 241). Microbiological assessments revealed widespread contamination, with heterotrophic plate counts (HPCs) exceeding the recommended range in nearly all samples. The median HPC levels were particularly concerning, with the untreated source (RE000) exhibiting a median of 2555 CFU/mL. Total coliforms and Escherichia coli were present at alarming levels, indicating significant faecal contamination; the highest total coliform count, 2420 CFU/100 mL, was recorded at RE000. Physically, while all samples complied with electrical conductivity standards (0–70 µS/cm), turbidity levels showed variability, with nine samples exceeding the acceptable threshold of 1 NTU. The highest turbidity, 7.55 NTU, was recorded at the untreated source (RE000). Chemically, pH levels fell within safe ranges (6.0–9.0), with all samples being compliant with standards. However, only one sample (E001) met the free chlorine standard of 0.3–0.6 mg/L, suggesting inadequate disinfection practices. The untreated source was classified as ‘Unsuitable for drinking’ (WQI = 207.27). These findings highlight the critical need for enhanced monitoring and remediation strategies to improve drinking water safety in the region.

Drinking water is the urolithiasis development factor among the rural population of a single region

BACKGROUND: The urolithiasis incidence in the Nizhny Novgorod Region exceeds the national average that determines the importance of analyzing the causes of its development and creating preventive measures. AIM: To evaluate the relationship between the urolithiasis incidence and drinking water composition consumed by the rural population of the Nizhny Novgorod Region. MATERIALS AND METHODS: A chemical analysis of drinking water was performed in 50 rural districts of the Nizhny Novgorod Region (a total of 61 samples). Water was taken from centralized water supply sources, artesian wells and boreholes, and springs. The relationship between the urolithiasis incidence and chemical composition measures of drinking water was assessed. RESULTS: Differences in the impurity content of drinking water were found between districts with different values of urolithiasis incidence. Exceeding the standard values for impurities specified in the Sanitary regulations and standards (SanPin) was most commonly detected in water from districts with the highest incidence of urolithiasis. An increase in the calcium/magnesium ratio was the most commonly noted in drinking water from these districts. In 41 (67.2%) of 61 samples, an increase of calcium level was detected. The hardness of drinking water was higher than the standard in 33.3–38.8% of samples depending on the water intake source. CONCLUSIONS: Drinking water with a high level of hardness and mineralization is one of the etiological factors for the development of urolithiasis in Nizhny Novgorod Region. In rural areas of this region with a high incidence of urolithiasis, the monitoring of the state of central water supply sources and the impurity content in drinking water should be intensified.

Sources and Transformation of Nitrate in Shallow Groundwater in the Three Gorges Reservoir Area: Hydrogeochemistry and Isotopes

Nitrate is among the most widely occurring contaminants in groundwater on a global scale, posing a serious threat to drinking water supplies. With the advancement of urbanization and mountainous agriculture, the nitrate in the groundwater of Wanzhou District in the Three Gorges Reservoir Area has formed a complex combination of pollution sources. To more accurately identify the sources of nitrate in groundwater, this study integrates hydrochemical methods and environmental isotope techniques to analyze the sources and transformation processes in shallow groundwater nitrate under different land-use types. Furthermore, the Bayesian isotope mixing model (MixSAIR) is employed to calculate the contribution rates in various nitrate sources. The results indicate that nitrate is the primary form of inorganic nitrogen in shallow groundwater within the study area, with nitrate concentrations in cultivated groundwater generally higher than those in construction land and forest land. The transformation process of nitrate is predominantly nitrification, with little to no denitrification observed. In cultivated shallow groundwater, nitrate mainly originates from chemical fertilizers (36.3%), sewage and manure (35.4%), and soil organic nitrogen (24.7%); in forested areas, nitrate primarily comes from atmospheric precipitation (35.3%), chemical fertilizers (31.3%), and soil organic nitrogen (22.1%); while in constructed areas, nitrate mainly derives from chemical fertilizers (46.0%) and sewage and manure (32.2%). These results establish a scientific foundation for formulating groundwater pollution control and management strategies in the region and serve as a reference for identifying nitrate sources in groundwater in regions with comparable hydrogeological features and pollution profiles.

Stochastic optimization to maximize water supply index in conjunctive use of surface and groundwater

Systematic operation of water resources systems requires rules that consider the uncertainties affecting system performance. Here, stochastic dynamic programming (SDP) is used to structure and solve a full-scale surface and groundwater conjunctive use model to derive a multiparameter operational policy (rule) that maximizes the water supply index (WSI). The model uses a Markovian representation of inflows to account for hydrologic uncertainties. Both the reliability of allocated water and its vulnerability are employed to define the WSI. To overcome the computational burden inherent with SDP, infeasible solutions are identified and removed from the model solution process. Optimal expected values of WSI and surface and groundwater uses are assessed. The system simulation model with embedded rules is executed to assess the performance of the derived rules. The derived rules employ water rationing and account for long-term benefits during periods when the available surface and groundwater resources may suffice to meet demand. The simulation results demonstrate that the derived operational rules produce high WSI values for the long-term operation of the system and ensure sustainable groundwater use.