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

Dawid Kudas, Agnieszka Wnęk, Ewelina Zając

Soil sealing is a threat to soil and its ecosystem services. One of the main drivers of soil sealing is land degradation resulting from the expansion of urban areas, where it leads to such problems as the growing risk of flooding and local inundations, urban heat islands, or water shortages. The article focuses on analyses and quantification of the general degree of soil sealing in 2012–2018 in eight functional urban areas (FUA) in Poland, taking into account their division into the urban core (UC) and the commuting zone (CZ). We used the high resolution layer imperviousness density (HRL IMD) data to quantify soil sealing as well as data on land cover and land use with different spatial resolutions, i.e. from the European Urban Atlas project (UA) and the National Database of Topographic Objects (BDOT10k) to quantify artificial surfaces. The research determined the spatial differentiation of UCs and CZs in terms of the degree of soil sealing. We further observed higher average growth of sealed land in CZs. Quantitative and spatial analyses determined the spatial patterns of soil sealing in the FUA in Poland. Soil sealing intensified from 2012 to 2018. The process should be expected to continue in the coming years in light of the continuous transformation of vegetated areas into artificial ones. The conclusions should be considered valuable for the implementation of the spatial policy concerning sustainable land use and soil protection in suburban areas.

Evgeniya Ushakova, Elena Menshikova, Tatiana Karavaeva et al.

Atmospheric deposition, vehicular transportation and de-icing agents are major sources polluted snow in urban. This study investigates the current trace elements concentrations of snow and de-icing using ICP-MS, and phytotoxicity using three vascular plants in snow. The study assesses the contamination, classification and phytotoxicity of snow quality removed from roads of residential areas and piled on children’s playgrounds in residential territories. The research found that according to Russian environmental quality standard for water has been identified the exceeding trace elements in snow by W, Se, Mn, Cu, V, Mo, Ni and Zn. The pollution indices ( PLI, CF and Zc) were identified pollution level of snow piles from moderate contamination to very high contamination. Based on average germination index values for Sinapis alba L., Lepidium sativum L., and Triticum aestivum L., the degree of inhibition in snow piles varied from no inhibition to strong inhibition. The trace elements content in de-icing “Galit А” and salt sand mix are defined in the following descending order: Zn > Mn > Ba > V > Rb > Sr and Mn > Ba > Cr > V > Sr > Ni, respectively. High concentrations of trace elements in snow piles are a source of environmental pollution. To prevent snow storage and disposal in residential areas should be involved in future studies of environmental pollution and circular economy, so that environmental managers can reduce threats to the environment and public health, as well as initiate circular economy projects in urban areas.

Yanyu Dai, Fan Lu, Benqing Ruan et al.

Quantitative differentiation of climate and human activities on runoff is important for water resources management and future water resources trend prediction. In recent years, runoff in the middle reaches of the Yellow River (MRYR) has decreased dramatically. Many studies have analyzed the causes of runoff reduction, but there is still a lack of understanding of the spatial differences in runoff contributions and their causes. Therefore, this study quantitatively distinguishes the contributions of climate and human activities to runoff changes in nine sub-basins of the MRYR based on the Budyko framework and analyses the differences in the contributions of different basins and their causes. The results show that the runoff in the nine sub-basins decreases significantly and the precipitation increases from northwest to southeast. The contribution of human activities to runoff is greater than that of climate change, especially in the Huangfuchuan (HF) River and Kuye (KY) River basins, where the contribution of human activities to runoff exceeds 90%. The greater impact of human activities in HF River and KY River is due to the significantly higher water use growth rate and normalized vegetation index trends than in other areas. HIGHLIGHTS Spatial differences in the causes of runoff variation in nine small watersheds in the middle reaches of the Yellow River were analyzed.; The influence of NDVI and human water extraction cannot be ignored.;

YUAN Shengyan, ZHU Aiping, ZENG Hongping et al.

To investigate the hydrochemical characteristics and water quality of the shallow groundwater in Guangzhou and the potential human health risks posed by the nitrates in the shallow groundwater,this study collected 132 shallow groundwater samples in Guangzhou during November 2014 to February 2015.The hydrochemical characteristics of the shallow groundwater in Guangzhou were analyzed by the Piper trilinear diagram.The water quality of the groundwater and the health risks caused by nitrate pollution were assessed by the Nemerow comprehensive index method and a health risk evaluation model,respectively.The results showed that the main chemicals in the shallow groundwater in the study area were Ca-Na-HCO₃,Ca-HCO₃,Ca-Mg-HCO₃,and Ca-Na-HCO₃-Cl.The groundwater quality was generally poor,and manganese,ammonia nitrogen,nitrates,and pH were the main factors behind the poor water quality of the groundwater.The results of health risk assessment revealed that the health risks for children exposed by nitrates via drinking water intake and skin contact were both significantly higher than those for adult females and males.Furthermore,the health risks caused by drinking water intake were much higher than those caused by skin contact.Those all indicated that the health risks exposed by nitrates for different groups of people in the study area were mainly through drinking water intake.Therefore,serious attention should be paid to the potential human health risks posed by long-term drinking of the groundwater in the study area.

ZUO Daxing, ZANG Chuanfu, WANG Lina

Evaporation is an important link in the water cycle,and in-depth studies on the influence of various meteorological factors on evaporation changes are of great significance for climate change,ecological restoration,and utilization of water resources.In this study,the Penman-Monteith model modified by the Food and Agriculture Organization of the United Nations (FAO) is used to calculate the potential evaporation (ET₀) in the Pearl River Basin from 1980 to 2019.The Mann-Kendall non-parametric test method and inverse distance weighting method are used to analyze the spatial and temporal distribution characteristics of the ET₀,and the principal component analysis method is used to analyze the influencing factors.The results show that:① The average ET₀ of the Pearl River Basin is 1 145.8 mm,and the growth rate is 1.37mm/a,which shows an increasing trend.In terms of four seasons,the growth rate increases in spring (0.56 mm/a),autumn (0.4 mm/a),and winter (0.44 mm/a) but decreases in summer (-0.03 mm/a).② In terms of spatial distribution,the annual average ET₀ of the Pearl River Basin is high in the east,west,and south but low in the middle andnorth.The distribution of ET₀in summer,autumn,and winter is similar.However,the distribution of ET₀ in spring is opposite to that in summer,autumn,and winter.③ Temperature,average water vapor pressure,and altitude are the leading factors of ET₀ changes.Factors such as temperature,average water vapor pressure,sunshine duration,and wind speed make positive contributions to ET₀,while altitude,latitude,and relative humidity make negative contributions to ET₀ changes.

Lan Fang, Yong Fu, Shaojian Chen et al.

Ensuring food security in China is the primary task in solving the problems of ‘agriculture, countryside, and farmers’. Based on Chinese provincial panel data from 2009 to 2018, this paper evaluates the impact of a water rights trading pilot policy (WRTPP) on food security and examines its underlying mechanism. To overcome the estimation bias existing in previous studies, we use the difference-in-differences method, which can separate time effects from policy treatment effects and is an effective tool to compare the effect before and after policy implementation. We, therefore, use this method to evaluate the net effect of the WRTPP on food security. It is found that the WRTPP can help ensure food security. This effect reaches its maximum in the fourth year after the policy's implementation. It is further found that the WRTPP can improve the adoption of agricultural water-saving irrigation technology to increase the grain yield. Our conclusions complement existing evidence on the factors influencing food security. From the perspective of improving farmers’ water-saving irrigation technology, we confirm that the mechanism of the water rights trading pilot policy helps ensure food security. HIGHLIGHTS Water rights trading pilot policy can help guarantee food security.; The policy help guarantee food security by improving the adoption of water-saving irrigation technology.; This effect reaches its maximum in the fourth year after the implementation of the policy.; The policy will have a long-term effect on helping guaranteeing food security.; The research does not violate the parallel trend assumption of the difference-in-differences method.;

Andrey V. Bogomolov, Vladimir Yu. Filatov, Maksim S. Dyakov et al.

The article studies the impact of mercury-containing bottom sediments on the pollution of the surface water body – the Elkhovka River, which for a long time was affected by the enterprises of the Kirovo-Chepetsk industrial hub, to assess the possibility of ensuring the standard water quality in the Elkhovka River. Based on the data obtained as a result of determination of the mercury content in water samples, bottom sediments and measurements of the second-long water flow in the Elokhovka River along the watercourse length calculation of the mercury migration processes in the “water-bottom sediments” system has been carried out. It has been established that the decisive role in the formation of pollution belongs to migration processes in the system «water – bottom sediments», and the bottom sediments themselves have a dominant effect on the pollution of the Elkhovka River with mercury in concentrations exceeding MPC in fishery water. Migration of mercury from bottom sediments in the Elkhovka river riverbed in the coming years will not allow to ensure the standard water quality (MPC in fishery water) in the water body. A possible solution to this problem may be the laying of a new river channel with subsequent reclamation of the old channel.

Laura Aguilera, Paulo Cesar Colonna Rosman, Claudio Freitas Neves

ABSTRACT The design of monopile foundations for offshore wind farms, the estimate of wave loads, and the effect of the structures on the environment usually consider one single vertical cylinder. This choice is based on the size of the ratio cylinder diameter to wavelength, and on the large distances between turbines. However, for large arrays of monopiles, the ensemble effect must be investigated. This study addresses monochromatic wave propagation through a rectangular array of four cylinders 800 m and 300 m apart, considered here as the fundamental geometry for an arbitrary array of monopiles turbines. Results for bottom velocities, mean water level, mass transport, and radiation stress tensor in the presence of the array are compared with those for a single cylinder. The numerical model WAMIT® is used to compute the potential velocity solution. Relevant spatial variations were found, especially for radiation stresses, for different periods and directions of propagation. Diffraction effects on the wave field by the array are significantly stronger than the superposition of individual effects of isolated cylinders under the same conditions. Impacts of the entire wind farm on bottom morphodynamics near the foundations, on the design loads, and on the wave climate past the wind farm are discussed.

LI Shuai

Distribution of groundwater and accumulated soil stress is an important factor for the deformation stability and failure mode of composite interface slope.Based on the typical geological section of Dongjiashan landslide,this paper generalizes a geomechanical model of composite interface slope,analyzes the development and evolution results of the equivalent plastic zone of the slope at different groundwater levels by finite element software,mainly explains the stress and deformation characteristics of the slope,slip zone and central soil in natural state,and reveals the deformation and failure mechanism of the composite interface slope.The numerical calculation results show that under natural and heavy rain conditions,the equivalent plastic zone of the slope first penetrates integrally and gradually develops towards the middle of the slope,and finally forms the secondary plastic penetrating surface in the upper middle part of the slope.The groundwater level reduces the stability of the composite base slope,and there is a higher possibility of secondary sliding on the upper part of composite interface slope during heavy rain.The shape of the horizontal displacement change curve of the slip zone and slope is similar to that of the composite interface,and the non-monotonic change potential slip surface affects the deformation distribution and failure mode of the slope at the geotechnical composite interface.

LI Jiadi

In the absence of physical conversion parameters, this paper establishes the conversionmodel of relative soil humidity and volumetric soil water content by the regression analysismethod, and converts the observed data of relative soil humidity in China into the volumetric soilwater content. The results show that: There was a significant linear correlation between theobserved values of volumetric water content and relative humidity of soil in 33 of the 35coincident stationsat the same time, with the overall average correlation coefficient of 0.819 1.The error between converted value and observed value is very small. The mean relative error(MRE) of most stations and soil layers is within±5%, and the root mean square error (RMSE) isless than 5.0. In this method, the observed data of relative soil humidity in China from 1991 to2013 is converted into the volumetric soil moisture content, which expandes the time range of theobserved data of volumetric soil water content in China from 1981—1999 to 1981—2013.

Luan Marcos da Silva Vieira, Andrea Sousa Fontes, André Luiz Andrade Simões

ABSTRACT The impacts caused by flood waves due to dam ruptures usually cause irreversible damages to the resident population, and, the loss of body equilibrium in floods contributes to aggravate this scenario. In this context, this work aimed to analyse the influence of consideration of physical mechanisms that cause instability in the human body on the definition of hazard zones. Therefore, it was developed simulation of the propagation of the flood wave due to the hypothetical rupture of Santa Helena Dam in Bahia, using the hydrodynamic model HEC-RAS. The results of flow velocities and heights were related and compared to different criteria of hazard zonings and mechanisms that cause body instability. It was verified that the consideration of instability mechanisms of the human body can contribute to hazard management, through the knowledge of areas in which different individuals may topple or slide. It was confirmed that in supercritical flow regimes is more likely for the individual to slide and that in subcritical regimes the individual will topple. Moreover, the consideration of parameters such as buoyancy force and the angle related to the human body's adaptive ability in a flooding influence on the definition of zones.

Jorge Luis Martinez, Malva Mancuso, Manuela Simões Ribeiro

This research compared the applicability of remediation technologies to reduce nitrates in groundwater in a coastal aquifer at Terras da Costa de Caparica, Portugal. The purpose of the study was to select a pilot area in Terras da Costa in order to assess the applicability of the following in situ remediation technologies: Fitoremediation, Permeable Reactive Barrier and Enhanced In Situ Biodenitrification. Advantages and disadvantages of each technology were discussed and presented in a comparison matrix for decision and proposal of future pilot tests. It was concluded that no technical or practical factors would impede the application of the above technologies in the pilot area.

Milton Antonio da Silva Matta, Glória Lorena Sousa Sena, Itabaraci Nazareno Cavalcante et al.

Este estudo mostra uma avaliação da qualidade da água subterrânea do município de Curuçá, através do cadastramento de 36 poços de água entre as obras de captação disponíveis no âmbito do município. Foram selecionados 12 poços, utilizando como principal critério, a utilização para abastecimento humano e distribuição areal, para a realização das análises físico-químicas das amostras. Analisou-se um conjunto de parâmetros como indicativos da qualidade das águas subterrâneas, incluindo pH, condutividade elétrica, sólidos totais dissolvidos além dos principais cátions e anions. As águas analisadas foram coletadas do aqüífero mais superior da área, do sistema hidrogeológico Barreiras e os resultados mostraram que, de uma maneira geral a água é de boa qualidade físico-química e adequada para o consumo humano, não parecendo estar refletindo a baixa qualidade sanitária mostrada durante os trabalhos de campo. Esse fato pode estar associado ao período no qual foram coletadas as amostras de água dos poços para análise, de baixa precipitação pluviométrica, associado à existência de um pacote argiloso de cerca de 8m acima das camadas arenosas que constituem o aqüífero superior, pode dificultar a passagem dos contaminantes, protegendo-o durante esta época do ano.

Amélia João Fernandes, Carlos Henrique Maldaner, Alain Rouleau

A motivação que levou ao estudo da geologia física e química dos basaltos de Ribeirão Preto foi investigar a existência de recarga do Sistema Aqüífero Guarani (SAG) através dos basaltos do Aqüífero Serra Geral (ASG), objetivo do projeto abreviadamente denominado de FRATASG. Além de métodos hidrogeológicos, a pesquisa demandou uma investigação geológica de detalhe, a qual é essencial para a elaboração de modelos conceituais de circulação de água subterrânea em aquíferos complexos, caso dos basaltos do ASG. Assim, o estudo englobou levantamentos estruturais de detalhe e a análise de fraturas horizontais e verticais o que levou à identificação de quatro eventos tectônicos. Concluiu-se que o fluxo vertical de água subterrânea é importante até a profundidade de 10m e, secundariamente, até 25m. Há predomínio de fluxo horizontal o qual ocorre, preferencialmente ao longo de fraturas subhorizontais, presentes nos contatos entre os basalto 2 e 3 ou próximas a estes. Sugere-se que fluxo vertical mais profundo é muito localizado e deve ocorrer preferencialmente segundo a direção NE.

Adilson de Chaves, José Luiz Silvério da Silva

No sistema de monitoramento a avaliação do nível da água subterrânea permite a determinação da direção de fluxo, identificação de zonas de recarga e avaliação da dispersão de contaminantes. O presente trabalho constitui parte de um estudo de monitoramento das águas subterrâneas em um reservatório de combustíveis no município de Santa Maria/ RS, instalado em uma zona de afloramento ou recarga direta do Sistema Aqüífero Guarani (SAG) na Depressão Periférica do Estado do Rio Grande do Sul. Avaliou-se a variação do nível estático dos poços de monitoramento no período de 12 meses. Evidenciou-se que ocorreram variações de nível da água nos poços de monitoramento avaliados, indicando estarem situados em área de recarga direta do Sistema Aqüífero Guarani/SAG, constituído no local pelo Aquiclude da Formação Santa Maria Membro Alemoa. Também, construiu-se o fluxo da água subterrânea quatro períodos, sendo que a principal observação indica que em caso de vazamento de combustíveis os fluxos subterrâneos mostram que o Rio Vacacaí-Mirim será afetado.

YAO Zhangmin, LIU Zhisen, WU Weiqiang

Iara Brandão de Oliveira, Francisco Inácio Negrão, Alessandra Gomes Lopes Sampaio Silva

Este trabalho verificou a aplicabilidade do Índice de Qualidade Natural das Águas Subterrâneas (IQNAS), para os domínios aqüíferos do Estado da Bahia. O IQNAS foi construído à semelhança do Índice de Qualidade da Água IQA-CETESB para classificar a qualidade das águas superficiais. O cálculo do IQNAS foi elaborado com base em pesos e gráficos de intensidade da variável, versus qualidade da água, ou nota, definido pelos autores, com critério semelhante ao estabelecido para o índice IQA-CETESB, ou seja: de 80-100, ótima; de 52-79, boa; de 37-51, aceitável; e de 0-36, imprópria. Os parâmetros utilizados para o cálculo do IQNAS foram: cloreto, pH, resíduo total, dureza, nitrato e flúor, obtidos das análises químicas de 8.725 poços do Estado da Bahia, cadastrados no Banco de Dados da CERB, e de 05 amostras de águas minerais do Recôncavo, tomadas como padrão. Essas informações foram consolidadas em banco de dados com 1.899 poços nos seguintes Domínios Aqüíferos: Sedimentar, Metassedimentar, Cárstico e Cristalino. O objetivo do IQNAS é facilitar a visualização espacial da qualidade das águas. Os valores do IQNAS encontrados para os quatro Domínios Hidrogeológicos do Estado, quantificaram adequadamente a qualidade das águas subterrâneas das regiões estudadas, confirmando positivamente a metodologia adotada.

Cesar Bianchi Neto, Fernando Wili Bastos Franco Filho, Flavio Luis Fernandes

O incremento na aplicação de revestimentos em PVC, ao longo dos últimos anos, revelou a necessidade de ajustes no manejo e aplicação deste tipo de material, com mudanças em procedimentos anteriormente adquiridos no emprego de tubos de aço. A partir da experiência no emprego deste material em poços da SABESP, em conformidade com as normas dos fabricantes, foi possível reunir neste trabalho, propostas para a utilização e emprego deste material de foram mais segurança.

WALDIR DUARTE COSTA, ALMANY COSTA SANTOS

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