River Water Salinity Research Articles

Development of halotolerant multi-pesticides degraders for wastewater treatment

The biotreatment performance of high saline wastewater containing multiple pesticides is significantly reduced because the growth and metabolism of activated sludge microbial communities are severely impaired by high osmotic pressure and joint toxicity of multiple pesticides. In this study, Halomonas cupida J9 was metabolically engineered by chromosomal integration of three different pesticide hydrolase genes, to create a halotolerant multi-pesticides degrader. In batch degradation experiments, the finally constructed strain J9U-PVG was able to simultaneously degrade chlorpyrifos (organophosphate), carbaryl (carbamate) and α-cypermethrin (pyrethroid) in mineral salt medium supplemented with 4 g/L glucose and 60 g/L NaCl. Total cell lysate of J9U-PVG showed obvious degradation activity against chlorpyrifos, carbaryl and α-cypermethrin. Moreover, introduced Vitreoscilla hemoglobin (VHb) can enhance oxygen-sequestering capability of J9U-PVG and introduced green fluorescent protein (GFP) can be used as a biomarker to track the activity and movement of J9U-PVG in natural environments. More importantly, J9U-PVG could simultaneously and completely degrade chlorpyrifos, carbaryl and α-cypermethrin in high saline river water. Here, we demonstrate for the first time the successful construction of a halotolerant multi-pesticides degrader. This study underscores the value of H. cupida J9 as a promising chassis for the development of a halotolerant pesticide bioremediation platform. In the future, synthetic biology may serve as a powerful tool for expanding the catalytic repertoire of extremophiles for bioremediation of extreme environments.

The effect of irrigation water quality on the growth of maize plants, electric conductivity and pH of the soil

The research aims to determine the response of the Maize crop to irrigation with salt water during the growth stages, and to study the accumulation of salts in the soil, the degree of their interaction, and the efficiency of water use. Three types of irrigation water with salt concentrations (1.5, 4.5, 6.5) dSm-1 with three replicates for every kind water. The Randomized Complete Blocks Design was used in the experiment, and it was statistically analyzed using SPSS. Statistically significant differences were found at the 5% level according to Duncan's method. Statistical analysis showed that there were significant differences attributed to the salinity of irrigation water at the level of 4.5 dsm-1 (T2), which caused about 50% damage in plant height, root growth, leaf area per cob length, weight of 500 seeds, grain yield, and soil. Compared to salinity if irrigated with 1.5 dsm-1 (T1) salinity of river water. Using water with a salinity of 6.5 dsm-1 (T3) as wastewater resulted in a reduction of all apparent plant characteristics by 75%. An increase in soil salinity was also observed at the end of the experiment compared to its salinity at the beginning of the experiment, and this damage increases with an increase in the electrical conductivity of the water used in irrigation operations. It has been observed that soil PH decreases with increasing soil salinity.

Can crop production intensification through irrigation be sustainable? An ex-ante impact study of the south-central coastal zone of Bangladesh

In Bangladesh’s south-central coastal zone, there is considerable potential to intensify crop production by growing dry winter season ‘Boro’ rice, maize, wheat, pulses and oilseeds using irrigation from southward flowing and predominantly freshwater rivers. However, the impacts of surface water withdrawal for sustained irrigation and its safe operating space remain unclear. We used field measurements and simulation modeling to investigate the effects of irrigation water withdrawal for Boro rice–the most water-consumptive crop–on river water flow and salinity under different climate change and river flow scenarios. Under the baseline conditions, about 250,000 ha could potentially be irrigated with river water that has salinity levels below 2 dS/m. The impact on river water salinity would be minimal, and only between 0.71 to 1.12% of the cropland would shift from the 0–2 dS/m class to higher salinity levels. Similarly, for the moderate climate change scenario (RCP 4.5) that forecasts a sea level rise of 22 cm in 2050, there would be a minor change in water flow and salinity. Only under the extreme climate change scenario (RCP 8.5), resulting in a sea level rise of 43 cm by 2050 and low flow conditions that are exceeded in 90% of the cases, the 2 dS/m isohaline would move landward by 64 to 105 km in March and April for the Tentulia and Buriswar Rivers. This would expose an additional 36.6% of potentially irrigable cropland to salinity levels of 2 to 4 dS/m. However, Boro rice will already be well established by that time and can tolerate greater levels of salinity. We conclude that there is considerable scope to expand irrigated crop production without negatively exposing the cropland and rivers to detrimental salinization levels while preserving the ecosystem services of the rivers.

Effect of Physico-Chemical Parameters and Inorganic Nutrient Ions in Relation with Seasonal Algal Diversity of River Ichhamati, West Bengal, India.

The present study reflects seasonal algal diversity as a source of food for fishes in the river Ichhamati during October 2021 to August 2022. To understand the seasonal algal pattern in the river Ichhamati, physicochemical parameters of river water such as Hardness, Conductivity, pH, Total Dissolve Solids, Turbidity, Dissolve Oxygen, Salinity, Turbidity, Total Alkalinity, Salinity, Biological Oxygen Demand as well as biologically significant inorganic ion concentrations in river water namely sodium, potassium, calcium, carbonate, bicarbonate, nitrate, chloride were also evaluated during study period. It is found that physico-chemical parameters and inorganic ions in river water play an important and significant role in seasonal algal growth. Throughout the study period it was established that river Ichhamati is not very rich in floral diversity. During study time it was observed that dominant group of algae in this river are Chlophytes, Cyanophytes and Bacilariophyceae, including Species of Oscillatoria Nostoc, Klebsormidium, Spirogyra, Lyngbya, Chlorococcum, Chlorella, Diatoms in all seasons. During spring, summer and monsoon Conductivity, salinity, TDS and hardness of river water is high. Ichhamati contained adequate Na+, K+ and NO3- in summer and monsoon season. High rate of bio-mineralisation during winter was found due to presence of high calcium ion concentration and also high TDS along with high salinity as well as high hardness of river water.

Coccolithophore Distribution in the Western Black Sea in the Summer of 2016

Coccolithophores are an important component of phytoplankton abundance and biomass in the brackish environments of the Black Sea. Here, the abundance, composition, and distribution of coccolithophores were investigated in water samples taken from the first 50 m at 18 stations in the western Black Sea during a coccolithophore bloom, in June 2016. The total cell abundances ranged from 2 to 763 × 104 coccospheres L−1; Emiliania huxleyi was the most dominant species, but also Syracosphaera spp. (S. dilatata and S. molischii), Acanthoica (A. acanthifera and A. quattrospina), and Algirosphaera robusta displayed remarkably high concentrations. The formation of the seasonal thermocline significantly affects the vertical distribution of coccolithophores. Emiliania huxleyi, Syracosphaera spp., and Acanthoica spp. were restricted to the upper part of the water column, whereas high abundances of Algirosphaera robusta occurred below the thermocline. Overall, our results show significant differences in the vertical (ANOSIM R = 0.50, p = 0.0001) and spatial (ANOSIM R = 0.18, p = 0.0006) distribution of coccolithophores. Higher abundances of E. huxleyi and Syracosphaera spp. were recorded in the northwestern inner shelf region when compared to the open-sea samples. The observed coccolithophore spatial distribution is suggested to be mostly associated with the influx of less saline river water with high nutrient concentrations.

Prediction of river salinity with artificial neural networks

This paper presents the development and evaluation of an Artificial Neural Network (ANN) based on the model for predicting the salinity of the Warta River. The study focused on the prediction of river water salinity, expressed in terms of electrical conductivity (EC), using the proposed ANN structure of 7-10-1. The network showed a satisfactory ability to capture the interrelationships between the input data: sulphates, chlorides, calcium, magnesium, total hardness, pH, and total dissolved solids. The correlation coefficient (R) values for the training, validation and test sets were 0.99444, 0.96988 and 0.97174, respectively. From the results, it can be concluded that the developed model is suitable for predicting the EC of the river.

Analysis of the Salinity of the Vistula River Based on Patrol Monitoring and State Environmental Monitoring

Background: Secondary salinity of river water reduces the value of ecosystem services, negatively impacting the entire aquatic ecosystem and reducing the possibility of water use. In Poland, significant anthropogenic salinity of rivers and water reservoirs is usually associated with mining activity consisting of pumping salty mine water into settling ponds or often directly into rivers. However, to assess the reasons for the salinity of the Vistula waters, it is necessary to identify all sources of salt in surface waters, enabling the assessment of the salt load in the waters. Methods: The paper presents four sources of data which have been compiled to propose a valuable method for analyzing the threat of the river. Patrol monitoring was one method of data acquisition, and State Environmental Monitoring data ware also used. Clustering and correlation statistical techniques were used for analysis. Results: Of the 20 physical and chemical parameters analyzed, chloride, calcium sulphate and magnesium ions are important for salinity. Measurements with multi-parameter probes allowed for the identification of increased salinity pressure sites, while flow analyses were required to calculate the load. Conclusions: The Vistula River had the highest concentrations of the analyzed ions in the Silesia Region. The use of patrol monitoring can be highly useful in determining the causes of emerging problems with water quality and supporting State Environmental Monitoring.

Rice-based Cropping System Intensification in the Coastal Saline area of Bangladesh: Problems and Prospects

The coastal zone environment of Bangladesh is characterised geographically by river deltas and estuaries, where tidal and riverine flooding and varying salinity levels affect agriculture and livelihoods. In this area, the land and agricultural productivity is very low because of several constraints, particularly waterlogging, high salinity of soil and water, freshwater scarcity for crop irrigation and natural disaster. In this review, the objectives are to focus on the limiting factors for crop intensifying and highlighting the opportunities to increase coastal agriculture while enhancing farmer’s livelihoods. Some recent studies demonstrated many opportunities for increasing cropping systems that have not yet been exploited extensively. Rainwater or low saline river water storing in the internal canal can fulfil the water requirement for dry season rice and non-rice crops, thereby increasing growth and yield. Early establishment of “Rabi” crops (non-rice) can utilize maximum low-saline soil water and escape high salinity/drought or heat/storms at later period of the growing stages, but this early sown Rabi crops needs early harvest of Aman rice around 15-30 days earlier than farmer practices. Moreover, early sowing by zero tilled dibbling (such as sunflower, maize, wheat, and potato) in wet soils results in higher yield potential. Using rice straw mulch ~5 t ha-1 has been shown to be highly beneficial for ameliorating soil constraints. A recent study revealed that straw mulch application on soil surface increased soil water and soil solute potential in the upper root zone, reduced soil salinity, soil strength, and cracking which attributed to higher yield. Considering the successful dry season crop establishment and yield potential requires early drainage to remove excess soil water and a drainage system that mitigates waterlogging from heavy rainfall events during the growing season. We expect this review will facilitate the future research planning and execution in this vulnerable coastal environment. Bangladesh Rice J. 25 (2) : 31-43, 2021

ПРОГНОЗ ДИНАМИКИ ПЕРВИЧНОЙ ПРОДУКЦИИ ОРГАНИЧЕСКОГО ВЕЩЕСТВА И ЗАГРЯЗНЕНИЯ ПРИОРИТЕТНЫМИ ТОКСИКАНТАМИ АЗОВСКОГО МОРЯ НА КРАТКОСРОЧНУЮ ПЕРСПЕКТИВУ

Background. Modern climate changes and increasing anthropogenic water withdrawal in the Azov Sea river basins have led to a reduction in freshwater runoff and a record increase in the sea salinity. Relevance. Salinization of the Azov Sea leads to a transformation of the structure of biological communities and a decrease in primary productivity, which inevitably has a negative impact on fish productivity. Another important factor in the stock formation of aquatic biological resources is the quality of their habitat. Aim of this work is to make a short-term forecast of the hydrochemical foundation of biological productivity and toxicological status of the Azov Sea up to 2030. Methods. This study was based on the long-term data on the level of primary production, hydrochemical regime and accumulation of priority toxicants in the Azov Sea ecosystem. Results. In the present period, adaptation of the Azov Sea ecosystem to increasing water salinity is manifested in a decrease in the level of primary production. In recent years, during the summer season, an unfavorable physiological state of phytoplankton has been observed due to the high content of pheophytin in the cells. In the Azov Sea, from 1986 (the peak of industrial development and anthropogenic load) up to the present, in the water, bottom sediments and muscles of commercial fish species, has been observed a decrease in the average annual concentration of the majority of monitored toxicants. Conclusions. Under the most likely forecasted scenario for the river flow and water salinity (14.5–16.5 ‰), a further decrease in the level of primary production is expected. It is possible that the ecosystem will adapt to the increase in water salinity; phytoplankton will be characterized by a more favorable physiological state in the summer. No deficiency of biogenic elements is predicted. If the existing anthropogenic load remains unchanged (the most likely scenario), the level of sea pollution by anthropogenic toxicants is predicted to be low, and in certain areas—Taganrog Bay, the waters of the Yeysk and Temryuk Sea Ports—it is expected to be moderate. The quality and safety of aquatic biological resources as a food product will meet regulatory requirements.

A CPSOCGSA-tuned neural processor for forecasting river water salinity: Euphrates river, Iraq

Salinity is a classic problem in water quality management since it is directly associated with low water quality indices. Debate continues about selecting the best model for water quality forecasting, it remains a major challenge and causes much uncertainty. Accordingly, identifying the optimal modelling that can capture the salinity behaviour is becoming a common trend in recent water quality research. This study applies novel combined techniques, including data pre-processing and artificial neural network (ANN) optimised with constriction coefficient-based particle swarm optimisation and chaotic gravitational search algorithm (CPSOCGSA) to forecast monthly salinity data. Historical monthly total dissolved solids (TDS) and electrical conductivity (EC) data of the Euphrates River at Al-Musayyab, Babylon, and climatic factors from 2010 to 2019 were used to build and validate the methodology. Additionally, for more validation, the CPSOCGSA-ANN was compared with the slime mould algorithm (SMA-ANN), particle swarm optimisation (PSO-ANN) and multi-verse optimiser (MVO-ANN). The results reveal that the pre-processing data approaches improved data quality and selected the best predictors’ scenario. The CPSOCGSA-ANN algorithm is the best based on several statistical criteria. The proposed methodology accurately simulated the TDS and EC time series based on R2 = 0.99 and 0.97, respectively, and SI = 0.003 for both parameters.

Ice conditions in northern Norwegian fjords: Observations and measurements from three winter seasons, 2017–2020

Freshwater provided by rivers beginning deep within the mountains, feeds into fjords along the coast of Norway, often forming a brackish surface layer that will change in its salinity, thickness, and extent throughout the year. As temperature drops below freezing, ice can form from this layer along the entire coastline from 71° N down to 58° N. The influence of freshwater combined with changing weather and oceanographic conditions, can lead to ice that varies not only in its thickness and extent but its properties including crystal fabric, bulk salinity, and pore structure. Resultantly, how ice interacts with the surrounding environment including communities that use the ice for winter activities, boats transiting through fjords, pollutants like oil, and the biota living within the ice and fjord waters, will be impacted.To enhance understanding of the drivers of ice formation and resultant properties in Norwegian fjords, seven fjords located in northern Norway were monitored over three winter seasons between 2017 and 2020. Measurements of ice thickness, stratigraphy, bulk salinity, and δ18O were gathered along with measurements of ocean salinity, temperature, and δ18O of both snow and river water. Ice thickness ranged from non-existent up to 0.8 m with the proportion of congelation to granular ice changing between seasons and fjords. While ocean salinities directly below the ice on the day of measurement were primarily above 31 psu, ice bulk salinity varied from 0 psu to 5.6 psu with values of δ18O between −13.3 ‰ and 0.2 ‰, indicating ice frozen from fresh water as well as seawater. Findings support that ice conditions in a single fjord or in a geographic region should not be generalized, with substantial variations measured between years and locations. We examine openly accessible interpolated weather and runoff data obtained through seNorge for possible causes for the variable ice conditions observed. Results reveal freezing degree days are not a dependable predictor of ice thickness when applied to Norwegian fjords, and substantial consideration of the date of onset of ice formation and snow cover are needed. Freshwater runoff and snowfall as well as the timing of weather and oceanic conditions throughout the three winter seasons are also presented to highlight their potential to influence ice formation considerably.

Impact of Climatic Change and Shortage of Water Flow on the Euphrates River Water Salinity between Al-Hindyia and Al-Nasiriya, Southern Iraq

Although the increase in water pollution, the amount of water consumption also increased in population and their activities. The effect of climatic changes are considered as the main effect on Iraqi water resources on its quality and quantity. The goal of the present research is to explain the negative effect of the decreasing of water flow and climate change on the quality of water over the years 2005 to 2010 along the Euphrates river starting from AlHindyia Barrage through Al-Samawa to Al-Nasiriya sites. Historical climatological data of rainfall and temperature for the period 1990 to 2020 and hydrological data of discharge and hydrochimecal analysis for the period 2005 to 2010 were applied in this research. Three gauging stations were chosen on the stretch of the Euphrates River, Al-Hindyia Barrage, Al-Samawa and Al-Nasiriya city. The discharge of Euphrates river is correlated with the Total Dissolved Solids, the major cations (Na+, Ca2+, Mg2+ and K+) and anions (Cl-, SO42-, HCO3-). It was found that the decrease of discharge due to shortage of water resources and climate change led to increase salinity, Total Dissolved Solids and major ions were became higher with time. The concentration of Total Dissolved Solids increased significantly to reach about 846 ppm in Al-Hindyia Barrage and this rate continue to rise in Samawa to about 2545 ppm and Nasiriya 2724 ppm. it was found that the ions Na+, So42- dominated in Al-Hindyia Barrage water while Na+ and Cl- dominated in Samawa and Nasiriya city water.

Impact of Flood Mitigation Project on the River Water Salinity

The impact of flood mitigation project in the Kemaman River Basin was assessed in this study. Salinity intrusion was simulated in the study area by 1D numerical model. A 1-D hydrodynamic model coupled with a salinity model was used to analyze the salinity intrusion within Chukai River after the implementation of the flood mitigation project. The model was calibrated and validated using the data measured in Chukai River at 3 points from January 2007 until August 2013. Water quality simulation of salinity has been carried out once an excellent hydrodynamic model was established. The simulated river flow was reasonably matched to the measured data with R2 value 0.88, 0.92 and 0.82, respectively. Results suggest that after the realignment of Chukai River, the seawater intrudes further to the upstream river, causing the increasing salinity in the river about 10 - 15 ppt. However, with the floodway development, the channel would allow more water from Kemaman River being discharged into Chukai River. Increased in the volume of water in Chukai River has led to seawater dilution. Further, it invades the unique stretch of Chukai River and takes the salinity back to the initial state. Findings from the implementation of the flood mitigation project in the Kemaman river basin has benefitted the local society, watershed, and the surrounding biota ecosystems. Importantly, a greater prevention with the risk of repetitive flood damage to the buildings and structures in Kemaman area which has significantly achievable.
 HIGHLIGHTS
 
 Salinity model is used for flood mitigation project
 High salinity in Chukai river resulted from seawater intrusion
 Hydrodynamic model is to assess the water quality simulation

Comparative Assessment of Individual and Ensemble Machine Learning Models for Efficient Analysis of River Water Quality

The prediction accuracies of machine learning (ML) models may not only be dependent on the input parameters and training dataset, but also on whether an ensemble or individual learning model is selected. The present study is based on the comparison of individual supervised ML models, such as gene expression programming (GEP) and artificial neural network (ANN), with that of an ensemble learning model, i.e., random forest (RF), for predicting river water salinity in terms of electrical conductivity (EC) and dissolved solids (TDS) in the Upper Indus River basin, Pakistan. The projected models were trained and tested by using a dataset of seven input parameters chosen on the basis of significant correlation. Optimization of the ensemble RF model was achieved by producing 20 sub-models in order to choose the accurate one. The goodness-of-fit of the models was assessed through well-known statistical indicators, such as the coefficient of determination (R2), mean absolute error (MAE), root mean squared error (RMSE), and Nash–Sutcliffe efficiency (NSE). The results demonstrated a strong association between inputs and modeling outputs, where R2 value was found to be 0.96, 0.98, and 0.92 for the GEP, RF, and ANN models, respectively. The comparative performance of the proposed methods showed the relative superiority of the RF compared to GEP and ANN. Among the 20 RF sub-models, the most accurate model yielded the R2 equal to 0.941 and 0.938, with 70 and 160 numbers of corresponding estimators. The lowest RMSE values of 1.37 and 3.1 were yielded by the ensemble RF model on training and testing data, respectively. The results of the sensitivity analysis demonstrated that HCO3− is the most effective variable followed by Cl− and SO42− for both the EC and TDS. The assessment of the models on external criteria ensured the generalized results of all the aforementioned techniques. Conclusively, the outcome of the present research indicated that the RF model with selected key parameters could be prioritized for water quality assessment and management.

Recharge mechanism and salinization processes in coastal aquifers in Nam Dinh province, Vietnam

In Nam Dinh province, in the Red River delta plain in Northern Vietnam, groundwater in the shallow Holocene aquifer shows elevated total dissolved solids up to 35 km from the coastline, indicating a saltwater intrusion from the Gulf of Tonkin. High groundwater salinities have been encountered below and adjacent to the Red River in the deep Pleistocene aquifer. Since 1996, large-scale groundwater abstraction was initiated from the deep aquifer, and the observed elevated salinities now raise concerns about whether the groundwater abstraction is undertaken sustainably. We have conducted a study to obtain a fundamental understanding of the recharge mechanisms and salinization processes in the Nam Dinh province. A holistic approach with multiple methods including transient electromagnetic sounding and borehole logging, exploratory drilling, sampling and analyzing primary ion and stable isotope compositions of water and pore water, groundwater head monitoring, hydraulic experiments laboratory of clay layers, and groundwater modeling by using the SEAWAT code. Results reveal that saline river water is leached from the Red River and its distributaries into the shallow aquifers. The distribution and occurrence of salty pore water in the Holocene aquitard clay shows that meteoric water has not been flowing through these low permeable clay layers. Marine pore water has, however, been leached out of the Pleistocene clay. When this layer is present, it offers protection of the lower aquifer against high salinity water from above. Salinity as high as 80 % of oceanic water is observed in interstitial pore water of the transgressive Holocene clay. Saltwater is transported into the Pleistocene aquifer, where the Holocene clay is directly overlying the aquifer.

Modular Concept for High Saline River Water Desalination by Combining Low-Pressure Reverse Osmosis (Lpro) and Membrane Capacitive Deionization (Mcdi): Performance Study of a Pilot Plant in Vietnam

Modular Concept for High Saline River Water Desalination by Combining Low-Pressure Reverse Osmosis (Lpro) and Membrane Capacitive Deionization (Mcdi): Performance Study of a Pilot Plant in Vietnam

Modular Concept for High Saline River Water Desalination by Combining Low-Pressure Reverse Osmosis (Lpro) and Membrane Capacitive Deionization (Mcdi): Performance Study of a Pilot Plant in Vietnam

Modular Concept for High Saline River Water Desalination by Combining Low-Pressure Reverse Osmosis (Lpro) and Membrane Capacitive Deionization (Mcdi): Performance Study of a Pilot Plant in Vietnam

Fishing in Salty Waters: Poverty, Occupational Saline Exposure, and Women’s Health in the Indian Sundarban

Collecting wild tiger prawn seedlings, also known as prawn post-larvae (PL), from rivers and creeks is an important occupation for more than 100,000 poor women in India’s Sundarban estuarine delta. Prawn PL collecting requires many hours of immersion in saline river water. This paper uses a large household survey to explore the determinants of poor women’s engagement in this occupation and the health impacts. The results reveal high significance for two variables: (i) the opportunity wage, proxied by years of education and (ii) child-care demands, proxied by the household child-dependency ratio. Together, these variables are sufficient to distinguish between women who have no engagement with prawn PL collecting and those with many years of engagement. The probability of self-reported health problems is also significantly higher for women with more saline exposure from prawn PL collecting and whose drinking water is from tube wells with higher salinity.

Regulation of the water-salt regime of irrigated lands in the lowerof the Syrdarya River

In general, the salinity of the water of the Syrdarya river, the current soil-reclamation state of the irrigated lands located in the lower reaches of the Syrdarya river are very poor. Soil salinity and salinity of collector-drainage waters are very high. For example, the average annual salinity of river water at the Tomenaryk gauging station is 2.0-2.5 g / l, and at the Kazalinsky gauging station - 3.0-3.5 g / l. Moreover, the process of soil salinization took place practically throughout the entire territory of the region. For example, according to the latest data, the area of ​​saline irrigated land in the Kyzylorda region is about 225 940 hectares, of which slightly saline - 87 574 hectares, moderately saline - 73 302 hectares, strongly and very strongly saline - 65 064 hectares. The Kyzylorda region is mainly engaged in the cultivation of rice (as well as alfalfa, corn for silage, sunflower, etc.). Considering this, secondary salinization was observed in rice fields due to poor performance of collector-drainage systems. After all, all of this is known to have a negative impact on crop yields. Therefore, we can get the best results only with the right watering with the right measures and capabilities. To optimize this issue, the article presents the current state of irrigated lands in the lower reaches of the Syrdarya river in the Kyzylorda region, as well as the results of work on regulating the water-salt regime. For this purpose, research work was carried out on 71.15 hectares of agricultural land Bidaikol (formerly Gigant), belonging to the Zhanakorgan-Shieli irrigation massif. It provides for the analysis of the amount of salts entering the soil with irrigation water and the release of salts from the soil by collector-drainage waters, measures to improve the ecological-reclamation state of the soil. And also the positive results of studies carried out on the site to improve the water-salt regime of the soil are presented. According to the research results, it was optimal to provide the fields with water through a specially prepared biofield planted with dense reed plants. It has been proven that purified irrigation water from the biofield is effective for irrigating forage crops. In addition, the reed itself is widely used in the republic as a fodder crop. Young reeds collected in August (at this time the reeds will be soft, and the leaves are green) are finely chopped and stored using a press using a special technology. Due to the growing importance of winter forage, the price of cane has increased significantly in the southern and southwestern regions of the country. For example, this year the price of 1 cane press fluctuated within 650-850 tenge. In addition, this spring there was a shortage of feed in the western regions (Aktau, Mangistau). Considering all these problems, the technology of water supply for irrigation through the biofield is more efficient.

Evaluate River Water Salinity in a Semi‐Arid Agricultural Watershed by Coupling Ensemble Machine Learning Technique with SWAT Model

AbstractThis study is to establish a new approach to estimate river salinity of semi‐arid agricultural watershed and identify drivers by using hydrologic modeling and machine learning. We augmented the limitations of the Soil and Water Assessment Tool (SWAT) to model salinity by coupling with eXtreme Gradient Boosting (XGBoost), a decision‐tree‐based ensemble machine learning algorithm. Streamflow, precipitation, elevation, main reach length, and dominant soil texture of the top two layers were used along with NO3, NO2, and total phosphorus (TP) output from a calibrated SWAT model are used as predictors to Total Dissolved Solids (TDS) in the XGBoost algorithm. Then, the SWAT model simulations of streamflow, NO3+NO2, and TP from 2000 to 2015 are used as inputs of the XGBoost model to predict monthly water TDS distribution along the river. The predicted river water TDS showed a higher concentration as going downstream from El Paso (inlet) through the Hudspeth canal to Fort Quitman (outlet). Finally, this study carried out cause analysis focusing on soil physical characteristics. The soil salinity level is directly affected by the soil permeability and irrigation water. As a result, the highest TDS is shown in sites with silt loam, whereas the lowest TDS was shown in sites with very cobbly soil. Silt soils can hold more water and are slower to drain than soils of a sand type. These analyses can be used to better understand the mitigation of water salinity.