Average Monthly Water Research Articles

Spatio-Temporal Variability of Water Temperature of Arctic Rivers in Russia over the Past 60 Years

This article presents the findings of a comprehensive statistical analysis based on one of the largest and most up-to-date datasets on average monthly water temperatures at 286 hydrological stations from 1961 to 2021. Through this analysis, a detailed examination of the factors influencing temperature formation in different landscape-diverse regions in the Russian Arctic has been conducted. It has been determined that air temperature plays a crucial role in determining water temperature, although its influence is constrained by geographical factors, primarily geographical latitude. An analysis of discontinuities in uniformity and the presence of trends was carried out, along with a regression analysis of the relationships between air and water temperatures. The results of estimating changes in river water temperature were simultaneously compared both with respect to generally accepted climatic periods (1961–1990 and 1991–2020) and with respect to revealed change point years. The results of the statistical analysis indicate a relatively slow increase in water temperature in the Arctic rivers of Russia over the past 60 years, by 0.11–0.74 K/decade. These changes are mainly due to changes in air temperature (about 70% of cases), which in turn are influenced by the altitude of the location of the objects and other local factors.

Historical and Future Changes in Water Temperature in the Pilica River (Central Europe) in Response to Global Warming

This study analyzes changes in the water temperature in the Pilica River (Poland), encompassing both historical data (1958–2023) and projections extending to the year 2100. We use multi-model ensembles (MMEs) with Bayesian Model Averaging (BMA) to integrate various Global Climate Model (GCM) datasets for current and projected climate data. Additionally, a Random Forest (RF) machine learning method is applied to project future water temperatures in the Pilica River. It has been demonstrated that over a period of more than sixty years, the average annual water temperature has increased by nearly 2 °C. Further changes are expected to continue in a similar direction with a gradual rise in this parameter, reaching a temperature increase of 3 °C by the end of the 21st century (SSP585). In the distant future, with average monthly water temperature changes at the Przedbórz station ranging from 0.27 °C to 0.87 °C·decade−1 and at the Białobrzegi station from 0.22 °C to 1.06 °C·decade−1. The results of these changes are concerning, especially considering the crucial role of water temperature in shaping seasonality and the dynamics of processes occurring within the river. In the context of the sustainability of the river itself, but also of the entire catchment area, strategies developed by relevant public administration bodies are needed to mitigate the impacts of global warming observed in the thermal regime of the Pilica River.

Extreme weather characteristics and influences on urban ecosystem services in Wuhan Urban Agglomeration

In recent years, there has been a pronounced increase in the frequency of extreme weather events. To comprehensively examine the impact of extreme weather on ecosystem services within the Wuhan Urban Agglomeration (WUA), this study utilized meteorological station data, the Mann-Kendall (MK) test, and the Standardized Precipitation-Evapotranspiration Index (SPEI) to quantify the variation trends in heatwaves (HW) and droughts from 1961 to 2020. Then the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model was employed to evaluate and compare the differences in water yield and climate regulation ecosystem services under various HW, droughts, and HW-drought combination scenarios. The results show that over the past 60 years, the temperature, duration, and frequency of HW have significantly increased in the WUA. Specifically, the highest HW temperature, total HW days, HW frequency, and average HW temperature showed changing trend of +0.17 ℃/decade, +1.4 day/decade, +0.19 event/decade, and +0.07 ℃/decade, respectively. The year 2000 was identified as a mutation year for HW, characterized by increased frequency and heightened severity thereafter. The SPEI value exhibited an insignificant upward trend, with 1980 marked as a mutation year, indicating a decreasing trend in drought occurrences after 1980. Heatwaves have a weakening effect on both water yield and climate regulation services, while drought significantly weakened water yield and had a relatively modest effect on climate regulation. During HW-drought composite period, the average monthly water yield showed a notable discrepancy of 60 mm compared to humid years. Besides, as heatwaves intensify, the area of low aggregation for ecosystem services expands, whereas the area of high aggregation decreases. This study provides a preliminary understanding of the impact of urban extreme weather on urban ecosystem services under changing climatic conditions.

Assessment of household's willingness to pay for improved water supply services in emerging nations: a case study of Adama City, Ethiopia

Abstract Adama City grew rapidly due to its proximity to Addis Ababa, resulting in increased industrial, urban activities, and population growth. However, this expansion has resulted in drinking water shortages, which is a critical community's concern. The aim of this study was to determine households’ willingness to pay (WTP) for improved water supply services in Adama, with factors influencing WTP. To quantify households’ WTP, a contingent valuation (CV) technique was used and data from 435 respondents was gathered through field surveys, KII, and HHs interviews. A binary logistic model was utilized to examine variables that have a significant impact on households’ WTP. The analysis revealed several independent variables, such as gender, age, marital status, education level, and monthly income, additionally, water quantity, quality, availability, and affordability. The study found that 39.77 and 26.21% of residents of the city were dissatisfied with the quality and quantity of available water supply, respectively. The study discovered that 92% of households were willing to pay an additional $7.26 USD above their average monthly water cost of $3.58 USD to improve water delivery services. Factors that influence households’ WTP for improved water supply services should be considered. The study's findings can help legislators and water supply companies to design sustainable projects that meet community needs.

Enhancing the electricity and desalinated water production from solar chimney power plants through integration with nuclear power plants: A case study in Jordan

A new energy generation system combining a solar chimney power plant (SCPP) with a nuclear power plant (NPP) cooling tower has been developed and assessed in Irbid, Jordan. The surplus hot air from the NPP is directly routed into the SCPP collector, increasing the initial air temperature and boosting the air profile of the SCPP, improving the air velocity inside the chimney and boosting electricity and water production. The integration of these two systems (SCPP+NPP) has shown significant improvements in electricity and water production compared to a standalone SCPP. The integrated system provides reliable electricity production throughout the day (24/7), thanks to the contribution of heat from the NPP side. Key results include a maximum electricity production rate of about 238 kW at approximately noon, twice the productive value of a conventional SCPP. The average monthly water and electricity production increased from 9.44 ktons and 25.73 MWh in the SCPP to 22.96 ktons and 63.81.64 MWh in the integrated system. The SCPP+NPP system peaks electricity production of 69.4 MWh in December, underscoring the positive influence of the added nuclear heat. While March emerges as the month of the maximum of water production (25.6 ktons) in the SCPP+NPP system, the SCPP water production peaks at 14.9 ktons in July. The results also show that the integrated system demonstrates a remarkable monthly electricity and water production of 63.81 MWh and 22.96 ktons, surpassing the standalone SCPP's production (25.73 MWh and 9.44 ktons), respectively. These results demonstrate this innovative solution's potential for optimizing excess heat produced by the NPP and the potential to revolutionize the energy industry.

ГИДРОМЕТЕОРОЛОГИЧЕСКИЕ ФАКТОРЫ И ИХ ВЛИЯНИЕ НА СОДЕРЖАНИЕ ХЛОРОФИЛЛА-α В АЗОВСКОМ МОРЕ В 2006–2022 ГГ.

Background. Chlorophyll-α concentration is a key environmental parameter used to calculate the primary production of a water body, which, in turn, determines phytoplankton biomass. The fields with increased chlorophyll concentration can develop under the influence of various hydrometeorological factors considered in this work, such as air and water temperatures, cloud amount, wind-driven water mixing, and precipitation affecting the surface water layer. Relevance. Monitoring of chlorophyll distribution as it is influenced by hydrometeorological factors facilitates the rational fisheries management on account of their relation to the phytoplankton biomass providing fish and zooplankton with a food source. The aim of this work is to analyze the inter-annual variability of the average monthly hydrometeorological factors and their influence on the chlorophyll-α concentration in the Azov Sea (excluding Taganrog Bay) for the time range from 2006 to 2022. Methods. Spatial and temporal analysis of the average monthly water temperatures and chlorophyll-α concentrations has been conducted based on the daily satellite images of the sea surface taken by MODIS spectroradiometer in the Azov Sea; the analysis of the meteorological characteristics has been carried out using the weather observation data from international data exchange and reports (SYNOP, METAR) posted on the website pogodaiklimat.ru for the time range from April 2006 to September 2022. Results. It is shown that, for the entire investigated time range (2006–2022), the trends of the inter-annual variability of the average monthly air and water temperatures were not significant. An increase in water temperature that started in the middle of 1990s changed for the opposite in 2011, i. e. turned into a decrease. The wind velocity above the Azov Sea (excluding Taganrog Bay) over the investigated time range gradually decreased, which fell in line with the decrease in the chlorophyll-α concentrations. The average monthly cloud amount in the area has shown a weak inter- annual and considerable seasonal variability with relatively low values in the summer season and high values in the winter season. A positive trend of the monthly amount of atmospheric precipitation was observed, in contrast with the negative trend of the chlorophyll-α concentration. Conclusion. A significant positive correlation of the average monthly chlorophyll-α values with water and air temperatures has been identified, as well as a negative one with the wind velocity and cloud amount over the Azov Sea (excluding Taganrog Bay) — both in the individual investigated areas and in the sea as a whole.

Monthly stream temperatures along the Danube River: Statistical analysis and predictive modelling with incremental climate change scenarios

Abstract The aim of the study is to analyse changes and predict the course of mean monthly water temperatures of the Danube River at various locations for the future. The first part of the study involves conducting a statistical analysis of the annual and monthly average air temperatures, water temperatures, and discharges along the Danube River. The study examines long-term trends, changes in the trends, and multiannual variability in the time series. The second part of the study focuses on simulating the average monthly water temperatures using Seasonal Autoregressive Integrated Moving Average (SARIMA) models and nonlinear regression models (NonL), based on two RCP based incremental mean monthly air temperature scenarios. To assess the impact of future climate on stream temperatures, the historical long-term average of the monthly water temperature (1990–2020) was compared with scenarios S1 (2041–2070) and S2 (2071–2100). The simulation results from the two stochastic models, the SARIMA and NonL, showed that in scenario S1, the Danube River’s average monthly water temperature is projected to increase by 0.81/0.82°C (Passau), 0.55/0.71°C (Bratislava), and 0.68/0.56°C (Reni). In scenario S2, the models predict higher increases: 2.83/2.50°C (Passau), 2.06/2.46°C (Bratislava), and 2.52/1.90°C (Reni). Overall, the SARIMA model proved to be more stable and effective in simulating the increase in monthly water temperatures in the Danube River.

Potential of rainwater harvesting in the retail sector: a case study in Portugal

Water is a crucial resource for life, and it is increasingly scarce in many regions of the globe. In addition, retail water use is responsible for up to 19% of public water globally supplied. Hence, this study has set out to explore the technical and economic feasibility of rainwater harvesting systems as an alternative water source for a retail store located in southern Portugal. Water consumption data from 2018 to 2021 was collected from water bills, placing average monthly water consumption at around 400 m3. Next, rainfall data was collected from the nearest meteorological station, comprising 54 years of daily rainfall data between 1932 and 2008 with an annual average of 685 mm. The simulation of a rainwater harvesting system was performed, resorting to the mass-balance model. The optimal tank size was found to be 100 m3 considering simply the relation with the relative water savings variation on the graph relating the water savings with the tank size. Results show that the simulated rainwater harvesting system would allow saving 32–36% of the water consumed, despite the store’s location in a dry climate, representing a financial gain of €330–372 per month. Findings suggest a substantial potential for the technical and economic feasibility of rainwater systems in retail stores, which makes them relevant solutions to achieve important water-savings in the retail sector, thus positively influencing retailers’ direct water footprint.

The impact of COVID-19 and natural disasters on water consumption across sectors: case studies of Barbados and Trinidad and Tobago

Abstract The Small Island Developing States of the Caribbean (SIDS) are among the most vulnerable to natural hazards, particularly hydroclimatic and, in some cases, geological. In 2020, the COVID-19 pandemic added another layer of complexity to the already disruptive risk profiles of these countries. Understanding how these hazards, both individually and cumulatively, impact sectors, particularly essential sectors such as the water sector, is crucial. This paper examines the impact of the COVID-19 pandemic on water consumption along with concurrent natural hazards in two Caribbean countries: Barbados, and Trinidad and Tobago. The assessment indicated a marked influence on consumption levels in various sectors consistent with imposed public health restrictions. In the case of Barbados, monthly consumption decreased during the pandemic across all categories when compared to the pre-Covid period, except for residential consumption, which increased by approximately 9%. For Trinidad and Tobago, a decrease in average monthly water consumption across all categories, ranging from 3% to 13% was noted. Although available data did not permit conclusive analysis, we have discerned some general trends, identified gaps, and provided recommendations. Our findings can provide useful guidance for water utilities in the region to better understand consumer behaviour and address demand and supply issues.

Ecological and engineering solutions for the reconstruction of anti-mudflow hydraulic structures of the Crimea

The article studies the territorial features of the formation of a dangerous process - mudflows. The factors of mudflow hazard formation are described, the classification and characteristics of mudflows formed in the Crimea are given. The methods of studying mudflows are considered, the parameters of the mudflow are calculated on the example of the Shelen River, on the basis of which options for the reconstruction of existing mudflow protection structures are proposed. The purpose of the article is to substantiate environmental engineering solutions for the reconstruction of anti-mudflow hydraulic structures in mudflow-prone Crimean river basins. The object of research is the basin of the Shelen River typical for the South-Eastern rural area. The purpose of the research is to substantiate technical solutions for the reconstruction of anti-mudflow structures in the Shelen River basin. Research objectives: to study the conditions for the formation of Crimean mudflows, the history of research and classification; consider existing methods for studying mudflow hazard and calculation methods for determining the parameters of mudflows; to characterize the current state of anti-mudflow structures on the example of the Shelen river basin; justify decisions on the reconstruction of anti-mudflow structures and develop recommendations for their restoration. In the article, on the basis of field studies, hydrological flood flow rates, annual runoff volumes, water flow rates and volumes in years of different water content and average monthly water flow rates using the Shelen River basin as an example, the mudflow parameters are calculated. Anti-mudflow structures were identified and their condition was analyzed. Based on the results of the study, proposals and environmental engineering technical solutions for the reconstruction of existing anti-mudflow structures were developed

Probabilistic-forecasting method for determination of low flow discharge of Pivdennyi Buh, Black Sea area, and Lower Dnieper rivers

The aim of the study is to substantiate the probabilistic-forecasting method for forecasting the low flow discharge and its implementation for the Pivdennyi Buh, Black Sea area and Lower Dnieper rivers, taking into account climatic patterns of precipitation distribution and establishing probabilistic characteristics of low flow discharge in multi-year period. The study area is in a zone of significant risk due to the shortage of water resources, the formation of extremely low runoff in the dry flow period, which requires its definition and forecasting. The methodological basis of forecasts is to solve the equation in determining the components of the low flow of rivers by constructing regional dependences for forecasting the average decade summer-autumn low flow from previous water discharge (in runoff modules), establishing their probabilities water discharge for a number of intakes. Results. The paper substantiates the probabilistic-forecasting method for forecasting low flow discharge (in summer, autumn and winter periods) based on the construction of regional dependences of average decadal runoff modules on previous water discharge for groups of basins of studied rivers taking into account climatic dependences of precipitation distribution in the territory and the establishment of probabilistic characteristics of the low flow water discharge in a multi-year period. The methodology of territorial short-term forecasts of average decade water discharge of low flow of summer, autumn and winter river runoff is assessed as satisfactory with a margin of error of 70 % to 97 %, with a number of members of more than 500 points. To determine the cumulative probability of the forecast values of the average decade water discharge of the summer, autumn and winter dry weather flow, the empirical distribution of the average monthly water discharge in the limited seasons, which are generalized in the basins of the studied rivers of Ukraine, is established. Scientific novelty. For the first time for the zone of insufficient natural water content of rivers the method of territorial forecasts of low flow discharge, determination of their probability of occurrence in a multi-year period and cartographic representation of prognostic values have been developed and practically implemented. The practical importance is the use of forecast modules maps of low flow for spatial monitoring and assessment of low water levels on rivers in the whole region, including ungauged rivers, and their probabilistic characteristics – to assess the possible occurrence of low runoff, even when it reaches values close to the environmental runoff, which are critical for the functioning of the river ecosystem.

ОЦЕНКА ВЛИЯНИЯ РЫБХОЗА «КРАСНАЯ СЛОБОДА» НА СТОК РЕКИ МОРОЧЬ

A comprehensive assessment of the impact of the Krasnaya Sloboda fish farm on the hydrological regime of the Moroch River in the calculated areas was carried out. The following methods were used in the work: field research, desk data processing, geographical analysis, statistical analysis, regression analysis, water balance calculations. The analysis of the hydrological regime of the calculated sections of the river used for the needs of the fish farm made it possible to determine the minimum average monthly water consumption of 95% probability of excess and ecological runoff, taking into account the intra-annual distribution of runoff. For the central section of the Krasnaya Sloboda fish farm, the permissible volume of withdrawal of water resources from the Moroch River has been determined.

ASSESSMENT OF THE LAHVA FISH FARM IMPACT ON THE SMERD RIVER RUNOFF

A comprehensive assessment of the fish farm "Lahva" impact on the hydrological regime of the Smerd River was carried out. The following methods were used in the work: field research, desk data processing, geographical analysis, statistical analysis, regression analysis, water balance calculations. The analysis of the hydrological regime of the calculated sections of the river used for the needs of the fish farm made it possible to determine the minimum average monthly water runoff of 95% probability of excess and ecological runoff taking into account the intra-annual runoff distribution. The permissible volume of the water resources withdrawal from the Smerd River for the central section of the fish farm "Lahva" has been determined.

ДИНАМИКА ИЗМЕНЕНИЯ РЕСУРСОВ РЕЧНОГО СТОКА ТОБЫЛ -ТОРГАЙСКОГО ВОДОХОЗЯЙСТВЕННОГО БАССЕЙНА

The study presents results of assessing the resources of the river flow of the Tobyl - Torgai water management basin. The purpose of the work is to update the previously developed methodology for assessing the annual runoff resources of individual rivers and river runoff resources of the considered water management basin of the Republic of Kazakhstan. The calculations used the average monthly and average annual water discharge of the main rivers. Methods have been developed for determining and restoring the observed and natural runoff, long-term statistical characteristics and its values of probability of exceeding. The equations for determining the water resources of local runoff and water resources coming from other regions are obtained. As a result of the work done on the preliminary calculation, the total surface water resources for the Tobyl – Torgai water management basin, formed in Kazakhstan and coming from the territory of the Russian Federation for a long-term period from 1931 to 2019, on average amount to 1,67 km3, of which: resources formed within Kazakhstan - 1,33 km3, inflow – 0,34 km3. The runoff formed in the territory of the basin, for the disturbed period, relative to the conditionally natural period, decreased by 8%, the runoff coming from the Russian Federation decreased by 12%, and the total water resources by 9%

Новая методика расчета теплового стока рек при отсутствии данных наблюдений

In the paper, a comparative analysis of previously developed methods for calculating the heat flux of rivers in the absence of gauging-station data are given, and a new method for such calculations is proposed. It is based on the Maps of specific annual heat flux of zonal rivers and empirical dependencies of heat flux on the average height of the catchment area. An example of such a map is the “Map of specific annual heat flux (MT, 109× kJ/km2) of rivers in the northeast of the Asian part of Russia” plotted on the data for the period from 1950/1955 to 2018 and on the basis of data from 112 gauging stations. General recommendations for calculating the annual heat flux of medium-sized rivers that do not have posts, the intra-annual distribution of heat flux, the values of heat flux at the mouths of large rivers are set out in the paper. The values of heat flux calculated for the marine mouths of region large rivers and the sections of seacoasts between these mouths are given as an example of the implementation of the new recommendations. The list of new materials that help calculations includes new maps of average monthly water temperatures (May-October), the dependence of water temperature and heat flux on the average height of the catchment area, the division of the territory of the Northeast Asian part of Russia into 10 altitude-thermal zones, the relationship between heat flux and water runoff, the catchment area of the river and other materials. In total, data from 34 weather stations, 231 posts with water temperatures and 145 posts with water discharges were used in the research.

Variability of thermohaline regime of see water of the Gulf of Mexico in 2005-2017

The Gulf of Mexico is a large, productive, marine and coastal ecosystem providing the coastal residents and neighbouring regions with goods and services. The Gulf of Mexico's water area plays a significant role in shaping the climate across the coastal zone and the thermal state of the region's water also has a major impact on development of atmospheric processes over the Atlantic and Europe. Long-term climate variability throughout the Gulf of Mexico may affect both the strength of the Gulf Stream and heat transfer patterns within the ocean and the economic activity and environmental stability of the entire Northwest Atlantic Region. This work aims at determining the characteristics of variability of temperature regime and salinity of the Gulf of Mexico over recent decades.
 The study was conducted based on the Gulf of Mexico Regional Climatology (GOM RC) data, version 2, available at the website of the NOAA's National Centers for Environmental Information (NCEI). It analyzes the temperature and salinity values at different depths for the period of 2005-2017. According to the analysis, over 2005-2017 the spatial distribution of the average annual water temperature on the Gulf of Mexico's surface demonstrates its decrease from south to north. Its highest value is observed next to the northwestern coast of Cuba and along the coastal area of the Bay of Campeche, and the lowest temperature is observed at Apalachee Bay located in the northeastern part of the Gulf of Mexico. Though significant horizontal temperature gradients are observed in winter, during the warm period the temperature field is more homogeneous. The minimum average monthly water temperature on the surface is observed in January, the maximum one – in September. The most distinct seasonal changes in temperature are observed in the water of the northern part of the Gulf of Mexico next to the United States' coast. The distribution of average annual salinity of the most of the Gulf of Mexico is homogeneous with the exception of its northern part, especially in the area where the Mississippi River water flows into it, where salinity decreases sharply. Graphs of water temperature and salinity distribution at different depths across different areas of the gulf were constructed in order to determine the water stratification.

Statistical Assessment of the Runoff Variability of Small Rivers in the Middle Zeravshan Basin

The article deals with the issues of statistical assessment of the variability of the runoff of small rivers in the Middle Zeravshan basin. For this purpose, the average monthly and annual water discharges were used, taken into account at 11 hydrological stations located on small rivers and water resources in the Middle Zeravshan basin. Calculations to estimate the coefficient of variability of river runoff were carried out for two periods: the first calculation period includes the base climatic period (1961-1990), and the second calculation period includes 1991-2018. Based on the analysis of the results obtained, an increase in the value of the coefficient of variation (Cv) in the second calculation period relative to the first calculation period was revealed.

Households’ preferences for hydrological services in Veracruz, Mexico: The importance of outcomes vs. program design

Payments for Ecosystem Services (PES) are transfer payments that incentivize natural resource owners and managers to carry out environmental conservation efforts that promote ecosystem service provision. A common issue that PES programs face is long-term financial sustainability. In the case of payments for hydrological services (PHS), this may be achieved by introducing fees in the water bill of water users and using the money to pay landowners to conserve their forests and the hydrological services they provide. However, these fees are often minuscule and chosen arbitrarily without assessing households' preferences for the outcomes and design of the programs that manage them. While programs that improve water quality and regularity are universally desired, we know less about household preferences for who administers the program and who is eligible to enroll. We design a choice experiment survey to study preferences for attributes of a PHS program in Xalapa and Coatapec, Mexico. Expectedly, both cities' residents are willing to pay more to support a PHS program that improves water quality and water quantity regulation. Trust in the municipal government in the case of Xalapa and watershed awareness in Coatepec increase the likelihood of selecting the proposed alternative PHS programs. Households in both cities are willing to pay a premium if an NGO is involved in managing the program. While residents of Xalapa prefer keeping the PHS program land eligibility restricted to forests, the residents of Coatepec are willing to pay significantly more for a program that expands land eligibility to include shade-grown coffee. Overall, the WTP for a PHS program is estimated to be 16% of the current average monthly water bill for Xalapa households and 70% of the current water bill for Coatepec households. Our findings suggest that downstream water users can serve as a viable option for financing a PHS program to conserve forestland upstream. Attention needs to be paid to differences in WTP magnitudes and the population characteristics that affect differences in WTP across cities, such as trust in the government and watershed awareness.

Identifying High Influence Parameters using Genetic Algorithm (GA) Chromosomes for Water Consumption

Severe uncertainties climate changes course flood and droughts disaster have made clean water precious for domestic consumption. Thus, securing clean water is important. Wastage of water comes from water consumption such as from household usage. However, monitoring water consumption from household usage is tedious and time consuming. This work utilized Genetic Algorithm (GA) to optimize the coefficient of micro-components of water consumption (CMWC) values to determine high influential household routine parameters. Nine household parameters have been investigated namely, bath/shower, personal hygiene, flush toilet, wash cloth by hand, wash cloth by washing machine, food preparation, water plant, washing car and miscellaneous. These parameters are encoded as a chromosome data in GA to incorporate the CMWC values. The aim is to minimize the residential water consumption estimation error rates and subsequently enabling increased accuracy towards estimating and classifying the amount of residential water consumption. Data average monthly water consumption were collected from 80 households in Seremban. Water consumption has been categorized into three groups of low (L-PDWC), medium (M-PDWC) and high (H-PDWC). Comparison was made between per capita water consumption (PCC) and Domestic Water Consumption via Genetic Algorithm (DWC-GA) error rate’s values. The results are as follows; PCC method’s error rates of 9.49 and DWC-GA error rate is 1.05.

Interannual and intra-annual changes in the Volga River water discharge in the alignment of the Zhigulevsk hydroelectric complex

Interannual and intra-annual changes in river water flow play a decisive role in the formation of water quality and the functioning of aquatic ecosystems. For a quantitative assessment of long-term and seasonal changes in the water flow of the Volga River, an analysis of water discharge in the outlet section of the Kuibyshev reservoir (Zhigulevsky hydroelectric complex) for the period 1958-2019 was carried out. Almost the entire water flow of the Volga River passes through the bottom spillways of the hydroelectric power station and the overflow dam of the Zhigulevsky hydroelectric complex. The results of time series analysis showed that the average annual water discharge was 7,7 × 103 m3/s, the highest water discharge was 10,4 × 103 m3/s, and the lowest water discharge was 5,3 × 103 m3/s. Over a long-term observation period (61 years), it was established that the water content of the river is characterized by a change in low water and high-water periods. Statistical analysis revealed a positive trend for an increase in the average annual water discharge of the Volga River by 700 m3/s. Extremely low-water (1996, 1977, 1976, 1975, 1973, 1967) and extremely high-water (1994, 1991, 1990, 1981, 1979, 1966) years have been identified. The regulation of water flow at the Zhigulevsky hydroelectric complex has formed the seasonal variability of water discharge, which is characteristic of technical water bodies. Within the year, three periods are distinguished: winter low-water period (December-March), spring high water (April-June), and summer-autumn low-water period (July-November). The highest water discharges were observed during the spring flood (8,7-19,6 × 103 m3/s). During the winter and summer-autumn low-water period, the water discharge was 5,5-6,5 × 103 m3/s. The amplitude of fluctuations in the average monthly water discharge for the entire observation period was 2,1-33,5 × 103 m3/s.