Hasil untuk "River, lake, and water-supply engineering (General)"

leila zameni, fardin sadeghzadeh, Bahi Jalili et al.

Introduction Nitrate pollution in groundwater and drinking water reservoirs has increased alarmingly in different parts of the world. The high concentration of nitrate in surface and groundwaters is due to the excessive use of chemical fertilizers and improper disposal of wastes caused by human activities and animal manure. Due to its high mobility, nitrate anion is easily washed from the soil and enters the surface and groundwaters. If the concentration of nitrate exceeds the limit (50 mg l-1), it causes the disease of children with methemoglobinemia, as well as the formation of carcinogenic nitrosamines. Various methods have been proposed to remove nitrate. These methods besides having side effects on water, are not economically viable. In recent years, the development of effective technologies for keeping nitrates in the soil has received much attention. Adding biochar to the soil is one of the effective ways to reduce nitrate leaching. Biochar is a carbon-rich and porous substance, that is produced by heating biomass such as organic waste, animal manure, plant residues, sewage sludge, wood, etc. in limited or oxygen-free conditions. Due to its high specific surface area, high porosity, and diverse functional groups, biochar increases the water retention capacity, cation exchange capacity, and surface absorption capacity after adding it to the soil. Therefore, this research aims to investigate the effect of biochar and biochar coated with trivalent iron on the amount of nitrate absorption from aqueous solution. Materials and Methods Biochar can be produced from materials with low economic value and is a suitable and inexpensive adsorbent for nitrate removal from water sources. According to the studies conducted for biochar production, the temperature and duration of storage in the furnace are the most important factors controlling the quality and strength of biochar in nitrate removal. In this research, four types of rice straw, rice husk, sugarcane bagasse, and dicer wood chips were used to produce biochars. First, the samples were passed through a 2 mm sieve and dried in an oven at 70°C for 24 h. Then they were converted to biochar for 3 h at 300 and 600°C in an electric furnace under oxygen-free conditions. To determine the best adsorbent with maximum nitrate absorption, 0.5 gr of each adsorbent was weighed and poured into a 50 ml centrifuge tube. Then, it was contacted at a constant time (60 min) at an initial concentration of 50 mg l-1 of nitrate solution. After determining the best adsorbent, kinetic experiments were done to determine the equilibrium time, optimum pH, and adsorbent dosage. The adsorption isotherms were conducted for soil, rice husk 300˚C (RSB 300), and Fe-coated RSB 300. Results and Discussion The results showed that among the eight types of biochar produced at two temperature conditions of 300 and 600 ˚C, RSB 300, with the initial concentration of nitrate solution of 50 mg l-1 and contact time of 60 min, had the most amount of nitrate absorption. The kinetic experiments were continued on this type of biochar. The kinetic experiment results showed adsorption nitrate with an initial concentration of 50 mg l-1 an equilibrium time of 90 min, pH 7, and an adsorbent dosage of 1.25 g l-1 was 23580 mg kg-1. The result of the adsorption isotherms study showed that the adsorption of nitrate on RSB and Fe-coated RSB were fitted to the Langmuir isotherm model. This result indicates the uniform or single-layer distribution of active sites on the absorbent surface. The maximum adsorption capacity of nitrate by RSB and Fe-coated RSB were 38.16 and 43.66 mg g-1, respectively. ConclusionThe use of cheap absorbents can be a suitable solution for removing environmental pollution. In general, biochar can absorb pollutants and nutrients by its potential physicochemical properties, including high specific surface area, high porosity, high cation and anion exchange capacity, high surface charge density, low volume mass, and the presence of functional groups. The results showed that among the eight types of biochar tested, RSB with the initial concentration of nitrate solution of 50 mg l-1 and contact time of 60 min, had the highest absorption rate. The optimal conditions for nitrate absorption are estimated at 90 min of contact time, pH 7, and adsorbent dosage of 1.25 g l-1. The results showed that wastewater treatment by surface absorption process using biochar produced from vegetable waste is a very useful and effective method. Besides, the results of isotherm adsorption on the nitrate adsorption test data by biochar produced from RSB and Biochar Fe-coated RSB showed that nitrate adsorption on these adsorbents according to its correlation coefficient (R2=0.994) is consistent with the Langmuir isotherm model. The maximum absorption capacity RSB is 38.16 mg l-1, which is more absorbable than other studies. Now, when the above biochar was coated with Fe, the maximum nitrate absorption capacity increased by 43.66 mg g-1, which is a very high absorption. It can be concluded that RSB, especially when it has a Fe-coating, is a suitable adsorbent for removing nitrate from water. Therefore, it is suggested to investigate the effect of biochar covered with different cations on the mobility of other pollutants that are in anionic form.

HAO Yuetong, XIAO Hong

The evolution of landslide surge chain-generated hazards involves complex landslide-stream interactions, and the application of fluid-solid coupling methods at the granular scale is becoming more and more prominent. In order to study this problem in depth, this study adopts the CFD (Computational Fluid Dynamics)-DEM (Discrete Element Method) fluid-solid coupling method at the granular scale. The UDF is written to improve the disadvantage that the discrete phase model in the Computational Fluid Dynamics software FLUENT can only perform momentum exchange but cannot consider the drainage effect. This not only improves the volume replacement problem between landslides and fluids, but also overcomes the limitation of the critical size ratio of mesh particles. In the simulation of particle accumulation body collapse-surge test, the maximum surge height obtained by numerical simulation is 8.67 cm, which is more consistent with the physical test results, proving that the improved CFD-DEM fluid-solid coupling model proposed in this paper can effectively restore the particle motion state and the fluctuation change of the surge, and it can meet the needs of the coarse-grained material modeling of landslides in the simulation of the landslide surge process and the high-resolution real topography grid in the simulation of landslide surge process.

Matheus Sant’Anna, Rui Gabriel Souza, Guilherme Prudente et al.

ABSTRACT Swift detection and repair of leaks in water distribution networks are essential to ensure the operational efficiency of the system. It’s not viable, both financially and technically, to scour the entire extension of the system to look for leaks, therefore it’s important to narrow down areas prone to leakage. Hydraulic techniques are useful to that end, since hydraulic data can be used to identify anomalies and guide efforts on field campaigns. Among these techniques, those based on the transient state are used to infer about the actual condition of the system by causing controlled disturbances, such as closing a valve, as to reveal anomalies like leaks, deposits or illegal connections. In this paper, the software OpenFlows Hammer, was used to model the transient state and generate the transient state data. This data was then analyzed based on signal theory. The results show that it’s possible to identify the presence of leaks, even minor ones, and their location in relation to the monitoring point. However, further studies are needed to better establish metrics relevant to characterize the behavior of the data in the frequency domain.

Kassym Duskayev, Ainur Mussina, Javier Rodrigo-Ilarri et al.

The article presents the outcomes of an assessment of hydrographic network changes within the Almaty city, utilizing geographic information system (GIS) technology and Earth remote sensing data. Two gauge stations were selected along the main rivers within the Almaty city. To identify distinctive alterations in these rivers, hydrological data series encompassing the maximum runoff from 1970 to 2021 were collected and subjected to statistical analysis. Differential integral curves were constructed to pinpoint periods corresponding to peak and trough runoff levels. For each of these identified periods, the processing of satellite imagery allowed for the computation of meandering coefficients for the river channels. Additionally, refinements were made to the slope values of the rivers during these same timeframes, and connectivity graphs were established to elucidate the relationship between slope and liquid runoff for each period. The analysis encompassed an assessment of the impact of anthropogenic factors on both artificial and natural bodies of water while also considering shifts in the boundaries of the Almaty city. The findings derived from this study have practical applications in the planning and design of water supply systems and in the implementation of measures aimed at mitigating the adverse effects of anthropogenic factors on water bodies. HIGHLIGHTS The changes in the hydrographic network of Almaty city in Kazakhstan were assessed.; Hydrological time-series and differential integral curves were analyzed.; The changes in channel outlines were identified and the riverbed modifications over decades were assessed.; The influence of anthropogenic factors on artificial and natural water bodies was analyzed.; The obtained results can be used to support the development of sustainable water management.;

Jiramate Changklom, Phakawat Lamchuan, Adichai Pornprommin

Frequent saltwater intrusions in the Chao Phraya River have had an impact on water supply to the residents of Bangkok and nearby areas. Although relocation of the raw water station is a long-term solution, it requires a large amount of time and investment. At present, knowing in advance when an intrusion occurs will support the waterworks authority in their operations. Here, we propose a method to forecast the salinity at the raw water pumping station from 24 h up to 120 h in advance. Each of the predictor variables has a physical impact on salinity. We explore a number of model candidates based on two common fitting methods: multiple linear regression and the artificial neural network. During model development, we found that the model behaved differently when the water level was high than when the water level was low (water level is measured at a point 164 km upstream of the raw water pumping station); therefore, we propose a novel multilevel model approach that combines different sub-models, each of which is suitable for a particular water level. The models have been trained and selected through cross-validation, and tested on real data. According to the test results, the salinity can be forecasted with an RMSE of 0.054 g L\({^{-1}}\) at a forecast period of 24 h and up to 0.107 g L\({^{-1}}\) at a forecast period of 120 h.

Patrice Carbonneau, Simone Bizzi

Abstract Much progress has been made over the last decade to build global inventories of freshwater resources. However, existing freshwater inventories are generally produced for a fixed period in time and/or do not discriminate lakes from rivers. The emergence of deep learning methods and Big Data platforms such as Google Earth Engine offers a potential solution. Here we present a unique raster dataset at 10 m spatial resolution which classifies freshwater into rivers and lakes for a study site covering 89% of the terrestrial landmass and for the months of April, July and October 2021. This data gives us the first global-scale direct count of lakes larger than 1 hectare as ~7.3 million. We also present the first intra-annual ranges for the areas distinctly occupied by rivers and lakes where we find that basins influenced by the Asian summer monsoon (e.g. the Ganges) closely followed by the Amazon display the largest intra-annual range of river area per unit basin area. Finally, we find that whilst maximum of lake water surface occurs in October 2021, the maximum river surface is in July 2021 leading us to conclude that the global maximum occurrences of river water and lake water are not synchronous.

Tatyana N. Zimina, Alevtina G. Ardabyeva, Andrey V. Kotelnikov

Th e article presents a list and characteristics of invasive species based on literary sources and own materials and discusses their role in shaping the bio/productivity of the Caspian Sea. Th e purpose of our work is to determine the most favorable conditions for the development of invasive species, their qualitative and quantitative indicators, as well as their role in the trophic chain of the Caspian Sea. A brief taxonomic description of the phytoplankton of the Caspian Sea is considered.

DAI Xiaoping, ZHANG Xiaohong, WAN Fubing

Adjustment of the Yellow River Water Allocation Scheme (“Scheme 1987”) is vital for the water resource management of the Yellow River Basin and is a good example to explore the method of river water allocation adjustment.Most researchers analyzed government adjustment methods while market adjustment methods were not fully discussed.This paper put forward a new water allocation scheme based on unused water permits.In the new scheme,assignable water resources will be calculated by subtracting ecological water needs from changed river runoff.Unused water permits will be canceled and returned to the Yellow River Basin Commission and the canceled water permits will be sold to different provinces by auction.The water allocation ratio of provinces will be calculated by the sum of left permits and bought permits.The canceled water permits of Shaanxi Province,Shanxi Province,Henan Province,and Hebei Province and Tianjin City were calculated to be 662,1 417,154,1 362 million m³ respectively.Cancellation of water permits will have a greater impact on Shanxi Province than other provinces.The loss of these provinces should be compensated with the investment of the central government and the fund of water permit auction.This new water scheme adjustment method can provide a novel idea for river water allocation adjustment.

Jin-Yong Lee, Jihye Cha, Maimoona Raza

In this study, the current state of groundwater development and use and groundwater quality has been examined based on official groundwater data collected from the Republic of Korea. The groundwater data indicate a steady increase in the number of groundwater wells and an increase in groundwater pumping. The well diameters also increase with increasing well depth, owing to the development of drilling technology. Although groundwater is predominantly used for agricultural and living purposes, the former has recently outnumbered the latter. According to the groundwater quality monitoring stations covering the entire country, the groundwater levels, dissolved oxygen, and oxidation–reduction potential decrease with a steady increase in the water temperature, pH, and electrical conductivity, indicating an aggravating groundwater environment in this region. The most concerning contaminants found are nitrate, ammonia, arsenic, zinc, toluene, xylene, chloroform, and fluoride. Thus, based on these observations, we propose three essential tasks for sustainable groundwater use: a paradigm shift in groundwater management, conjunctive use and integrated management of groundwater and stream water, and groundwater governance and data quality control. HIGHLIGHTS Groundwater development and use have steadily increased in Korea.; Groundwater wells are becoming bigger and deeper.; Groundwater quality is gradually deteriorating.; Groundwater management strategies are required for sustainable use.;

FU Xuhui, WANG Shuo, TANG Dingdan et al.

This paper conducts field observations of near-shore waves in the Dachang section of theDaning River Basin, a tributary of the Three Gorges Reservoir area, observes the heights of near-shorewind and ship waves at a water level of 160 m in the reservoir area by high-definitiondigital cameras and rulers, carries out the parameter test, Weibull distribution fitting andgoodness-of-fit test on more than 1 000 sets of measured wave height data by Minitab software, andanalyzes the spatial and frequency characteristics of near-shore waves. The results show that: 1)The height of the waves caused by wind varies within a range of 0~5 cm, and the distribution ofwaves is uniform; 2) The height of the ship waves varies within a range of 1~12 cm; 3) The measuredeffective wave heights of the four groups of different banks are fit well with the Weibulldistribution. The height of near-shore ship waves is mainly 6~10 cm, accounting for 90%; while thatof near-shore wind waves is mainly 2~4 cm, accounting for 85%. The results provide effectivesupport for the analysis of wave erosion on the bank slope in the water-level-fluctuating zone ofthe Three Gorges Reservoir area.

Yayu Gao, Xiaoyou Zhang, Xinmin Zhang et al.

Among the most widespread structures for successfully retaining water and checking erosion on the semi-arid portions of China's Loess Plateau, check dams retain silt at slower than projected rates, leading to flood control issues. Meanwhile, the shortage and the uneven distribution of time and space of water resources in semi-arid areas can easily cause droughts and floods, which seriously restricted the rapid development of the socioeconomic. However, some of the high-quality rain and flood resources accumulated in the check dams can be used to alleviate part of the water resources crisis instead of causing flood. With the goal of holistically maximizing a projected check dam array's water resource, ecosystem and socioeconomic benefits, a Check Dam Benefit Maximization Model (CDBMM) was first developed. The CDBMM was first applied to the Si Jiagou Basin, and the model showed the total costs represent 7.07% of the total and rather significant benefits. Water resources benefits accounting for 45.40% of the total benefits, indicating that the water resources benefits were substantial and should be considered as the main influencing factors in the basin's ecosystem-friendly design and construction. Use of the CDBMM in watershed planning will allow a more efficient use of water and soil resources and greatly alleviate water crises in the semi-arid area. It can further provide a reference for both check dam system planning and the system benefits analysis. HIGHLIGHTS A Check Dam Benefit Maximization Model (CDBMM) is proposed.; CDBMM maximize the overall benefits of the check dam system and efficiently use water resources.; For the first time, CDBMM considers water resource benefits of the check dam system in the check dam construction.; Provide new ways for the sustainable development of semi-arid areas and the construction of water-saving and ecological check dam systems.;

Claudinei Garcia, Fabiano Tomazini da Conceição, Anna Silvia Palcheco Peixoto

The lack of situational studies on groundwater resources in Piracicaba where the increasing demands show a bottleneck situation until 2035, aligned the search for the assessment of the intrinsic vulnerability of groundwater in the municipality of Piracicaba through the GOD method(Groundwater hydraulic confinement; Overlaying strata; Depth to groundwater table), based on the cadastre of deep wells granted, the pedological and lithological characterization, and soil use data worked in a computational environment. The results generated by the deterministic tool, reveal that 86% of the area of the municipality has intrinsic vulnerability with indices between insignificant and low. The results obtained, although contextual, aim in synthesis to identify the places where it is pertinent to intensify resources and efforts for complementary and conclusive studies, and they constitute important first step for the characterization and evaluation of the risks to the local underground water resources.

Paulo Henrique Ferreira Galvão, Eliene Lopes de Souza, Roseli de Almeida et al.

A área de estudo é a Província Petrolífera de Urucu, município de Coari/AM. A pesquisa contribui para o conhecimento hidrogeológico da região norte do Brasil, onde pesquisas sobre isotópos ainda são incipientes. O objetivo foi determinar, via isótopos estáveis 18O e 2H, interrelações entre águas superficiais e subterrâneas para compreender a origem da recarga do lençol freático e descarga do aquífero. Amostras de água da chuva, água superficial e subterrânea foram coletadas entre junho de 2008 e maio de 2009 para as análises dos isótopos estáveis. Os resultados mostraram águas superficiais tipicamente leves e com origem meteórica. A recarga das águas subterrâneas é por infiltração de chuva direta, com a evaporação primária antes de atingir o lençol freático no Sistema Aquífero Içá-Solimões.

D. Leong, S. Donner

Boris Chaves Freimann, José Geraldo das Virgens Alves, Marcos Welby Correa Silva

Foi realizada uma correlação de perfis geofísicos de poços das áreas de captação da Companhia de Saneamento do Pará (COSANPA) perfurados no município de Salinópolis para o abastecimento local. O estudo foi realizado em várias áreas de captação, abrangendo 15 poços. Os parâmetros utilizados na correlação foram Potencial Espontâneo (SP), Resistência Elétrica (RE) e Raios Gama (RG). Também, para efeito de controle, utilizaram-se os perfis litológicos dos poços, obtidos através de amostras de calha. Essa correlação teve por objetivo avaliar a continuidade lateral das camadas permeáveis e impermeáveis, a fim de se elaborar seções da sub-superfície com alta precisão. Constatou-se a provável existência de dois grandes aquíferos que se encontram abaixo do horizonte 60 metros em relação ao nível do mar e que apresentam continuidade lateral por toda extensão da área estudada. Constatou-se, também, que o topo do embasamento na região estudada oscila em torno de 120 metros abaixo do nível do mar. Tais conclusões são de extrema importância para uma melhor avaliação construtiva e locação de futuros projetos de abastecimento na sede do município de Salinópolis-Pa.