Water Use Conditions Research Articles

ОЦЕНКА АНТРОПОГЕННОЙ НАГРУЗКИ НА ВОДОСБОР БАССЕЙНА РЕКИ ТОБЫЛ ОТ ИСТОЧНИКОВ ЗАГРЯЗНЕНИЯ С МАТЕМАТИЧЕСКИМ МОДЕЛИРОВАНИЕМ КАЧЕСТВА ПОВЕРХНОСТНЫХ ВОД

Based on a systematic analysis of the structure and dynamics of water resource usage in the catchment area of the Tobyl River basin, the dynamics of the formation of geoecological conditions of water use in the economic sectors within the Kostanay region of the Republic of Kazakhstan were studied. The analysis revealed a significant load from return waters and pollutants, indicating a high and potentially catastrophic pressure that requires regulation of both natural and anthropogenic activities to ensure the region’s sustainable development in the future. A generalized water use scheme for the Kazakh part of the Tobyl River basin was developed, which facilitates the formation of mathematical, physical, and chemical indicators for water management and hydrochemical balance equations. This, in turn, allowed for the creation of a mathematical model of water quality and the determination of the maximum permissible discharge volume of return waters in the river basins. The model ensures compliance with sanitary-epidemiological standards and helps preserve the ecological state of water bodies while supporting the planning of water protection measures to achieve the desired level of water quality in the river.

Assessment of the biological effect of natural silicon when entering the body of experimental animals with drinking water. Part 1

Introduction. The biological effect of natural silicon (Si) and its hygienic regulation in drinking water still remain subjects of controversy in the scientific literature and in the practice of providing favourable conditions for water use by the population. In this regard, an assessment was made of the effect of natural silicon contained in drinking water in concentrations close to the maximum permissible concentration on the body of laboratory animals.
 Materials and methods. Drinking waters containing natural Si at MPC levels in water were studied, their effect was assessed in a three-month experiment on 80 white outbred male rats. Observations were made of the general condition, appearance of the animals, body weight dynamics, water consumption. 
 The morphological composition of whole blood was studied. Biochemical indices of the condition of internal organs, including the liver, were determined 
 in serum samples (the ALT and AST activity, the level of total protein and albumin), pancreas (α-amylase activity), kidneys (creatinine content), as well as lactate dehydrogenase activity as a nonspecific indicator of tissue damage.
 Results. In animals received 17±3.4 mg/L silicon with drinking water at a hardness of 2.25±0.47 mg-eq/L, a significant decrease in ALT activity was found on the 30th and 90th days of the experiment, AST – on 90th day, increase in the content of total protein and albumin in the serum on the 30th day of the experiment. Drinking water with silicon concentrations of 20.5±4.1 mg/L and hardness 3.55±0.76 mg-eq/L decreased ALT activity and serum creatinine concentration on the 30th day and increased amylase activity on the 90th day of the experiment. The animals had the highest water consumption and intake of silicon from drinking water over the first month of the experiment.
 Limitations. Limitations of the study are related to the short duration of observation and the small number of points for determining biochemical parameters over time.
 Conclusion. Consumption of drinking water containing natural silicon for 90 days led to changes in biochemical indices, largely indicating the positive effect of the element in concentrations of 17±3.4 mg/L and 20.5±4.1 mg/L on the body of laboratory animals.

Agroclimate‐centric irrigation water quality guidelines

AbstractThe suitability of a given water source for irrigation warrants the diagnosis of potential salinity, sodicity and toxicity hazards. Region‐specific irrigation water quality standards and guidelines formulated worldwide are too conservative. After a comprehensive assessment of newer insights from re‐analysis of the available data and examination of the associated evidence covering diversified conditions of saline water use, existing guidelines are updated to adjust for site‐specific conditions. The updated versions for rating both saline and alkali waters include the chemical composition of irrigation waters, soil type (texture, clay mineralogy), salt tolerance rating of crops and rainfall for broader adaptability. As modified by soil texture and rainfall, crop salt tolerance is the decisive factor for fixing upper salinity limits in hyper‐arid, arid, semi‐arid and semi‐humid regions. The customized recommendations include conjunctive use, leaching/rainfall management, irrigation methods, ionic ratios, fertilizers and manures. Guidelines for sodic/alkali waters are based on both crop responses and sodicity‐induced water infiltration problems. The amendment requirements stand defined. In view of the increasing water scarcity, the established guidelines are expected to promote saline and alkali water irrigation in arid and semi‐arid regions while safeguarding the environment.

Microplastics pollution in water is a threat for human health and the environment (literature review)

Microplastics pollution of water bodies and drinking water is a relevant problem caused by wide use of plastics in multiple industries, agriculture, manufacturing of household chemicals and medicines. Microplastics pose a threat for human health both due to physical effects and chemicals in their structure as well as microorganisms that can occur on their surface. Some foreign studies describe how microplastics are formed and how they can occur both in marine and fresh water. There are also studies confirming microplastics to be present in seas and rivers in the Russian Federation. Studies that address microplastics in tissues of water organisms are scarce. According to some foreign authors, micro-plastics can be absorbed by mollusks, starfish, actiniae, crabs, etc. Russian researchers provide evidence of considerable quantities of microplastics found in the digestive spruce fish caught in the Tom River. Several foreign studies have established effects produced by microplastics on reproduction, eating behavior as well as declining survivability in crustaceans and fish. Fish products are a well-known significant source of microplastics in human diets. Microplastics bioaccumulation in aquatic biota is considered a potential health threat for organisms at higher trophic levels, including humans at the top of the food chain. Unified water sampling techniques are absent; studies that address effects of microplastics on the human body are scarce; there is no available methodology for hygienic standardization of microplastics in water. All this makes it necessary to have some research aimed at identifying sources and causes of microplastics pollution in water bodies including sources of drinking water supply, to assess public health risks, and to provide safe conditions for water use.

A monthly distributed water and salt balance model in irrigated and non-irrigated lands of arid irrigation district with shallow groundwater table

Water scarcity and soil salinization are two major problems threatening the sustainability of irrigation districts in arid regions with shallow groundwater table. To study water and salt balances in arid irrigation districts, we developed a monthly distributed water and salt balance model for arid irrigation district (DAHMID-S) with shallow groundwater table by integrating models of major hydrological processes and the associated salt transport processes, including irrigation, evapotranspiration, soil water and groundwater and salt balances, drainage of water and salt through ditches, and interior drainage of water and associated dry drainage of salt between irrigated and non-irrigated lands. The model was successfully applied to the Hetao Irrigation District (HID), the largest irrigation district in the arid region of China. Results indicate that evapotranspiration is the dominant water consumption component in the HID and accounts for about 95% of the total irrigation and precipitation, while drainage through ditches accounts for 10.5% of the total irrigation. Only 49.4% of the introduced salt is discharged from the HID through drainage ditches. Consequently, most parts of the HID are in the state of salt accumulation except the northern Wulate sub-irrigation district, and the problem of salt accumulation is more serious in the western and southern HID under more favorable conditions of water use. Dry drainage plays a crucial role in salt balance of both irrigated and non-irrigated lands, which results in desalinization in most irrigated lands while salt accumulation in non-irrigated lands. Appropriate measures should be taken to solve water and salt-related problems to improve the sustainability of the HID. In the western HID, irrigation water diversion should be decreased, and the drainage system should be further improved to decrease the salt accumulation to a lower level. Meanwhile, the irrigation water diversion can be increased in the southeastern HID by planting more corn and wheat. Besides, irrigation management should be improved to reduce the surface water return flow to increase the groundwater drainage capacity, especially in the southwestern HID.

On the hygienic scientific provision of the Water strategy of the Russian Federation

Increased competition between producers has now become one of the critical features of the country’s economy. Within the framework of the Water Strategy of the Russian Federation, technological issues play a significant role both in the protection of water resources and in compliance with the safety requirements and favourable quality of the water used. For more than 20 years worldwide, there has been a transition from a hazard-oriented to a risk-oriented approach in the organization of nature and water protection activities. The use of a risk-based approach determines the mandatory monitoring of all pollutants and calculation methods for assessing various types of toxicity of a substance, their hazardous concentrations based on knowledge of the structure and information about the hazard of substances from international databases and registers. Based on the analysis of the main provisions of the Water Strategy of the Russian Federation until 2020 in conjunction with the conditions of water use affecting the health of the population, the priority problems of technological development in the water protection sector and their medical and preventive support were identified. Measures have been outlined to ensure the compliance of the technology for the protection of water bodies, sources of household and drinking water supply to the population and industrial development for monitoring the effectiveness and efficiency of hygienic regulation, sanitary and epidemiological examination of project documentation and a risk-oriented approach to ensuring the activities of business entities on the territory of sanitary protection zones of drinking water sources: water supply, wastewater treatment from point and diffuse sources of pollution.

On the creation of databases to assess the impact of chemicals on the organoleptic and general sanitary limiting signs of the harmfulness in the water of water bodies

Introduction. Information on the MPC (TAC) value and the limiting hazard sign is important for the analysis of the hazard of chemicals in the water of water bodies for the health of the population, serves as the basis for the development of preventive measures to ensure safe conditions for water use by the population. For the purpose of specifying the possible adverse effects of the influence of chemicals on the hygienic conditions of water use of the population, information is needed on the entire spectrum of the effects of chemicals on water quality indicators. Materials and methods. The object of the study was indicators characterizing the effect of chemicals on the organoleptic properties of water and the general sanitary regime of water bodies, algorithms for analyzing primary data to determine threshold concentrations for the effect on odor, color, turbidity, foaming, pH, general sanitary regime of water bodies - biochemical oxygen consumption, concentration of nitrogenous connections. To organize the databases, the standard apparatus of the Excel subBD electronic tables was used. The mathematical apparatus of data analysis, grouping and selection of critical indicators of limiting signs is presented. Conclusion. It is concluded that the use of databases allows to study the relationship “concentration - effect”, increases the reliability and accuracy of substantiating the threshold concentration of pollutants in water by the influence of limiting signs of harmfulness.

IS FEATURES OF THE LEGAL REGIME OF WATER FACILITIES USED FOR THE NEEDS OF HYDRO POWER

The article examines the features of the legal regime of water bodies used for hydropower. The water potential of the state is the natural basis of its economic development, social and environmental well-being. One of the main consumers of water resources is hydropower, which is one of the most promising areas of alternative energy. It was found that the category of legal regime occupies a special place in the system of legal regulation of public relations. It lays the foundations for the use and protection of water resources in general and water bodies used for hydropower in particular, taking into account the general and specific features inherent in legal regimes. It is established that Art. 66 of the Water Code of Ukraine is devoted to the peculiarities of special water use and use of water bodies for hydropower needs, but the provisions of this article do not disclose all features of the legal regime of water use for such purposes, and its practical significance is limited due to its reference to other water, land, tax legislation, technical regulations, etc. The legal regime of water bodies used for hydropower needs is characterized by such elements as ownership, management in the field of use and protection of water bodies, their legal protection, legal regulation of the use of such objects, legal liability for violations of the law in in this area, etc. The special features are that the use of water bodies for the needs of hydropower is carried out for a fee without a permit, without the removal of water resources from the water body, is indefinite. Water users are obliged to: adhere to the established rules of operation of reservoirs, conditions of special water use, modes of accumulation and operation of water reserves, environmental requirements; take measures to reduce water consumption (especially drinking); to ensure the regimes of fluctuations of water levels in the upper and lower reaches and the passage of water through hydroelectric power stations, uninterrupted passage of vessels and fish to spawning grounds in accordance with the projects of fish pass structures, etc.

Geospatial Assessment of the State of the Samara River Floodplain in the Area of Coal Mining in Western Donbas

The discharge of highly mineralized mine waters of the Western Donbass negativelyaffected the Samara Bay area, which is of great fishery importance. Mine water storage pondswere built in deep erosional cuts in the territories of mine fields in the gullies of Kosminnaya,Taranova, Glinyana and Svidovok. The screening of the bottoms was not performed in any pond.The soils that make up the bottom are not aquicludes, which contributes to intensive filtration ofmine waters and pollution of aquifers. Artificial ponds built without waterproofing of bottoms,rock dumps, mine water discharge routes and other sources of pollution are actively involved inthe zone of influence of mine drainage and worsen the quality of drinking water, the reserves ofwhich in the Western Donbass are limited. There is flooding and flooding by groundwater, as wellas increasing (compared to the period before the violations) areas of land temporarily floodedduring floods on rivers in the valleys of the rivers Samara, Velyka Ternivka and such large beamsas Svydovok, Taranova, Kosminna due to subsidence of the earth’s surface. Differences in theconditions of formation of mine waters determine the nature and degree of their impact on theenvironment. The main difficulties making complicated accurate comparison between calculatedand field data in Samara river floodplain are following: a) changes in parameters of mining andpumping rates of water used for local needs; b) hydrological changes including formation ofnew channels, bed deformation; c) transformation of the monitoring network; d) increasing leakagethrough the clayey bottom of the ponds. The main objective is to provide a comprehensivegeo-ecological assessment of the state of the Samara river floodplain in the area of coal miningin the Western Donbass. Multispectral imagery of Sentinel-2 satellite system was used for remoteassessment within the study area. Geomorphologic assessment of the studied area was performedusing Sentinel-1 satellite radar interferometry. Flooding of the territory is observed due to minedrainage and subsidence of the earth’s surface. The risk of salinization of soils under the conditionsof water use from the beam “Glynyana” and from the Samara river is estimated as insignificant,from the beam “Kosminna” ‒ average. The SAR value of mine waters in “Taranova” and“Svydovok” beams corresponds to a high level of salinity. Samara river waters belong to the 3rdclass and are characterized as highly mineralized, sometimes unsuitable for irrigation. Intensivenatural overgrowth of the mine dumps that have passed the stage of mining reclamation has beenrecorded near the “Heroyiv of Space”, “Pavlogradska” and “Samarska” mines. The rate of selfgrowthof the land cover around the mine “Ternovska” and “Blagodatna” is estimated as average.The self-healing levels of the “Ternovska” and “Blagodatna West Donbasska” mines are ratedfrom low to high. The greatest risk of salinization of soils under conditions of use of water forirrigation is possible at a fence from artificial ponds located in Taranov’s and Svidovok’s beams.The conturs of “Verbsky”, “Ternivsky”, “Bogdanovsky” and “Boguslavskiy” piscicultural pondscan be corrected with map of remote sensing of Samara river floodplain geomorphology. The dataobtained can be useful during development of econetwork of promising ecological corridors inthe floodplain part of the Samara River as well..

Land consolidation and creation of water user organizations for sustainable use and restoration of irrigation

The article presents the results of system analysis of the problems in irrigated agriculture and irrigation restoration in Ukraine. The results of classification of water and land use conditions within the irrigation systems are given in this paper. The methodological approaches to the development of integrated plans for consolidation of water and land resources have been elaborated. Based on the surveys and questionnaires in the studied regions, 5 groups of land fragmentation problems were identified, which are outlined in this study and illustrated on some examples with using maps. The following types of conditions of water use were distinguished: lease of land plots by one large farm or agroholding within the area of one or more water distribution channels of large irrigation systems; the using of lands of intra-farm irrigation systems, which typically belong to the territories of individual village councils and are served by several water intake structures, and a large number of medium and small tenants; the using by several tenants of an area serviced by one water intake structure or one pumping station; fragmentation of land use and land ownership conditions within a single field; the presence of land plots with different leases terms within the individual fields, used by one agricultural enterprise. According to the types of land use conditions, three options for integrated land consolidation plans for irrigation systems were proposed. In order to develop integrated land consolidation plans and to restore irrigation, a complex analysis of land use maps and maps of the projected irrigation area will be needed. Therfore, it is necessary to establish a dialogue with stakeholders, namely with all farms, farmers and individual landowners on drawing up the most economically and environmentally optimal land consolidation plan within irrigation restoration areas. When drawing up such a plan, it is necessary to carry out an expert evaluation of the different scenarios of irrigation restoration, taking into account the composition of crops, probable techniques and methods of irrigation. Once the consolidation plan has been agreed, it is important to have a permanent land users association in place to attract and invest in irrigation restoration and to operate the irrigation infrastructure after the restoration. The issues of creating Water User's associations (WUA) in the irrigation areas was considered; the role of associations and land consolidation in restoring the on-farm irrigation network was determined. The list of functions of Water User’s associations has been provided, the main one of which is the exploitation of on-farm irrigation systems and water distribution between water users.

Assessment of land use change in Kon - Ha Thanh rivers catchment using landsat images

Analysis of land use maps will provide important information upon which most management and intervention policies rely.Land use changes may have major impacts on the use of resources such as conditions for land and water use. However, land use map is often scarce for large area due to expensive statistics measurement work. In this study, the land use of Kon – Ha Thanh rivers catchment is mapped from 1990 to 2017 using remote sensing and geographic information system (GIS). It is found that the land use map generated in this study is in good agreement with the actual map provided by Binh Dinh Province Department of Planning and Investment (2017). Land use maps and the trend of conversion between soil types are analyzed and presented in detail during 1990-2017. The study outcomes can provide essential information for planning and sustainable development activities in the context of rapid industrialization and urbanization epoch.

Hydrodynamics of the Onega River tidal estuary as a basis for ecosystem monitoring

Tidal river mouths are very complicated objects for hydrological and ecosystem research. Moreover, river mouth areas are characterized by unique and vulnerable ecosystems with great biodiversity. Water quality and hydrological monitoring is essential for their preservation in conditions of intensive water use. We provided comprehensive field observations of the flow dynamics in the Onega River estuary during winter and summer period. Field data analysis has shown flow velocity and flow direction variability over a tidal cycle and depending on river runoff, wind conditions and ice cover. We investigated flow velocity profiles and cross-section velocity distribution over a tidal cycle. Also, water levels and salinity were measured over a tidal cycle at multiple locations along the estuary. All the collected data can be used for designing an ecosystem monitoring program and setting up a hydrodynamic model of the Onega River estuary.

Weather-induced economic damage to upland crops and the impact on farmer household income in Northeast Thailand

In Thailand, climate change has a direct effect on the export of food and agricultural products, which is one of the main revenue sources of the country. Furthermore, agriculture is the main income basis of local farmers; especially, in Northeast Thailand, the ratio of irrigated agricultural land was only 7.6%, and others were rainfed so that climate change makes agricultural production increasingly unstable and inflicts serious damages on the societies and economies of rural areas. In this study, we focused on weather-induced economic damages of upland crops, such as sugarcane and cassava. Firstly, we evaluated the effect of the seasonal rainfall amount and pattern on upland crop yields through correlation analysis using meteorological and agricultural statistical data. The sugarcane yield had a significant positive relationship with 4 months of accumulated rainfall. The cassava yield had a significant negative relationship with 5 months of accumulated rainfall. Secondly, a household survey was conducted to grasp the farmers’ conditions of water use, cultivation, income balance, etc. The average household income was 341,160 Baht/year, 122,433 Baht/year derived from agriculture and 218,727 Baht/year from non-agricultural work. The variation in farmers’ income in each province by crop changing was evaluated using interview results. For farmers’ livelihood, a monoculture system should be avoided because of the system’s normally high risk and its vulnerability. As a result of analysis, mixed farming of sugarcane and cassava is recommended to stabilize farming incomes both in flood and in drought years.

Productividad de Stevia rebaudiana Bertoni con diferentes láminas de riego e inoculantes microbianos

Las hojas son el órgano más importante en la planta de Stevia rebaudiana Bertoni, debido a que en ellas se encuentra la mayor cantidad de edulcorante. La emisión de hojas está determinada por el adecuado crecimiento de raíces y la cantidad de agua disponible en el suelo. El objetivo del presente estudio fue evaluar la respuesta de plantas de S. rebaudiana Bert. a cuatro láminas de riego calculadas a partir de la evapotranspiración de referencia (ETo) en interacción con inoculantes microbianos. Los tratamientos consistieron en regar con el 60, 80, 100 y 120% de la ETo estimada con un tanque evaporímetro tipo “A” en plantas previamente inoculadas. Se evaluaron como inoculantes una mezcla de Bacillus spp. y Azospirillum brasilense, Rhizophagus intraradices y un testigo (sin inocular). Se utilizó un diseño de bloques completos al azar con arreglo bi-factorial y cuatro repeticiones. Se evaluaron parámetros de crecimiento, producción y distribución de biomasa seca, intercambio de gases y uso eficiente del agua. Se encontró diferencia estadística (P≤0.05) por factores separados. Se obtuvo la mejor altura con 120% ETo, aunque fue estadísticamente igual (P≤0.05) a 100% ETo registrando 42.86 y 40.58 cm respectivamente, el 120% ETo se registró mayor área foliar. El tratamiento con Rhizophagus intraradices mostró diferencias significativas (P≤0.05) en la longitud de raíz contra el testigo, pero no contra la mezcla de rizobacterias. De igual forma R. intraradices mejoró el volumen de raíz registrando 2.49 cm3 con respecto al testigo, y permitió reducir un 20% la aplicación de la ETo para obtener la mayor producción de biomasa seca de hoja y raíz. La interacción R. intraradices + 80% ETo favoreció la asimilación del CO2 con 5.41 µmol m-2 s-1, de esta manera se proporcionó mejores condiciones para la transpiración y el uso eficiente del agua (1.87 µmol CO2 mmol-1 H20). El factor riego mostró efecto en la altura, área foliar, diámetro del tallo y rendimiento de hoja seca, mientras que el factor inoculante sólo afectó la longitud de raíz, volumen de raíz, relación MSV/MRS y rendimiento. Por último, la interacción de los dos factores solo fue significativa en los parámetros de producción de biomasa seca e intercambio de gases.

Прогноз изменения качества воды в реке Зеравшан в условиях Узбекистана

The purpose of the research is to develop measures for the protection of the Zeravshan river, which is used as an industrial and drinking water supply for the population of several regions of the Republic. Studies have established that the main source of river pollution is industrial enterprise «Navoiazot», which produces mineral fertilizers for needs of agriculture. Discharge of wastewater into the water, leads to pollution of water, and the quality does not correspond to the state standard specification about sources of centralized drinking water supply, about hygienic, technical requirements. At the same time, harmful chemicals are found in the water of the Zeravshan river, which are 2...9 times higher than the MPC installed on them. The medium-term forecast showed that by 2025 the ecological state of the Zeravshan river will not be improved, due to the fact that the production of mineral fertilizers is planned to be increased. In this regard, recommendations on the protection of the Zeravshan river have been developed, which will help to improve the monitoring of the state of the water body and improve the conditions of water use of the population.

The Landscape/geographical Method of Spatial Assessment of Water Resources Potential for the Purposes of Recreational Use

Provisions of the landscape/geographical method of spatial assessment of a water resources potential for recreational water use are presented. The water resources potential has been considered as a set of water and around-water conditions that determine principal possibility and its degree for the water bodies’ and coastline use for water recreation Spatial boundaries of the water resources potential spreading at the regional level have been identified on the basis of summing up and analysis of traditional methods of the water resources recreational assessment. Concurrently the list and indicators of the integral assessment criteria have been developed. Areas with similar conditions for recreational water use have been proposed to be considered in connection with the landscape structure and to limit them by the floodplain and valleys landscapes. Physiognomic, functional, and psychological assessment criteria are presented as integrated physical/geographic characteristics coupled with the data of the landscape, topographic and geological/geomorphological maps. Testing and approval of the method have been carried out with the Altay Kray territory as a study case. Partial criterial and integrated assessments of the water resources potential have been performed for this region. The assessment values were depicted by mapping. Correspondence of the calculated outputs to the actual regional situation was confirmed by the expert review.

Pricing Unmetered Irrigation Water under Asymmetric Information and Full Cost Recovery

The objective of this study is to define an efficient pricing scheme for irrigation water in conditions of unmetered water use. The study is based on a principal-agent model and identifies a menu of contracts, defined as a set of payments and share of irrigated area, able to provide incentives for an efficient use of the resource by maximizing social welfare. The model is applied in the case study of the Çukas region (Albania) where irrigation water is not metered. The results demonstrate that using a menu of contracts makes it possible to define a second best solution that may improve the overall social welfare derived from irrigation water use compared with the existing pricing structure, though, in the specific case study, the improvement is small. Furthermore, the results also suggest that irrigation water pricing policy needs to take into account different farm types, and that appropriate contract-type pricing schemes have a potential role in providing incentives to farmers to make irrigation choices to the social optimum.

Reliability of lumped hydrological modeling in a semi-arid mountainous catchment facing water-use changes

Abstract. This paper explores the reliability of a hydrological modeling framework in a mesoscale (1515 km2) catchment of the dry Andes (30° S) where irrigation water use and snow sublimation represent a significant part of the annual water balance. To this end, a 20-year simulation period encompassing a wide range of climate and water-use conditions was selected to evaluate three types of integrated models referred to as A, B and C. These models share the same runoff generation and routing module but differ in their approach to snowmelt modeling and irrigation water use. Model A relies on a simple degree-day approach to estimate snowmelt rates and assumes that irrigation impacts can be neglected at the catchment scale. Model B ignores irrigation impacts just as Model A but uses an enhanced degree-day approach to account for the effects of net radiation and sublimation on melt rates. Model C relies on the same snowmelt routine as Model B but incorporates irrigation impacts on natural streamflow using a conceptual irrigation module. Overall, the reliability of probabilistic streamflow predictions was greatly improved with Model C, resulting in narrow uncertainty bands and reduced structural errors, notably during dry years. This model-based analysis also stressed the importance of considering sublimation in empirical snowmelt models used in the subtropics, and provided evidence that water abstractions from the unregulated river are impacting on the hydrological response of the system. This work also highlighted areas requiring additional research, including the need for a better conceptualization of runoff generation processes in the dry Andes.

Optimal use of chlorine in water distribution networks based on specific locations of booster chlorination: analyzing conditions in Mexico

Water distribution networks (WDNs) could present problems of pathogen intrusion that affect the health of consumers. One solution to diminish this risk is to add more disinfectant to the water at the drinking water treatment plant (DWTP). However, this increases the cost of water treatment and may also cause the formation of trihalomethanes. Mexico has the largest bottled water market in the world. Also, most houses are built with individual storage containers due to intermittent service, which generates a greater residence time of the water before use. This paper shows an alternative to guarantee minimum disinfection along WDNs and diminish the use of disinfectant at the DWTP considering the conditions of water consumption and use in Mexico. We propose a model based on Genetic Algorithms to obtain scenarios where free chlorine is maintained at the minimum permissible concentration throughout the day. In addition, Water Managers could optimize the use of disinfectant by implementing booster chlorination stations (BCSs). The results show that chlorine use could be reduced by 38%, therefore guaranteeing the chlorine concentration limits along the WDN.

Obliczenia hydrologiczne w warunkach korzystania z wód regionów wodnych górnej Wisły, Czarnej Orawy i Dniestru

Obliczenia hydrologiczne w warunkach korzystania z wód regionów wodnych górnej Wisły, Czarnej Orawy i Dniestru