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

Alejandra De Vera, Rafael Terra

Ante la creciente incorporación de energías renovables en Uruguay en un contexto de gran variabilidad climática, desde el 2019 se encuentra operativo un modelo hidrológico para simular los caudales de aporte a las centrales hidroeléctricas del río Negro, acoplado con la simulación del sistema eléctrico del país. En este trabajo se propone una técnica de bajo costo computacional basada en la combinación de “Time-Lagged Ensembles” (TLE) para mejorar el desempeño del pronóstico por ensambles de precipitación del modelo GEFS (NCEP-NOAA) en la cuenca del río Negro. En particular, se busca mejorar la representación de la incertidumbre que enfrenta el sistema en el horizonte inmediato, ya que durante los primeros días del pronóstico la dispersión del ensamble es excesivamente baja en comparación con su error medio. Para ello, se construyeron super-ensambles equiprobables a partir de múltiples pronósticos de precipitación inicializados en diferentes momentos. Esta metodología demostró una mejora en la distribución del ensamble sin deteriorar su error, mejorando el cociente SPREAD/RMSE (en comparación con el desempeño del ensamble de la última inicialización disponible). Esto sugiere que el enfoque TLE aporta información valiosa que va más allá de aumentar el tamaño del ensamble.

Maria Eduarda Rodrigues da Silva, Severino Martins dos Santos Neto, Rodrigo Lustosa Peronico et al.

ABSTRACT Simulation of water flow in the soil in semiarid regions is fundamental for managing scarce water resources. Aiming for more accurate results, the sensitivity analysis (SA) of the hydrodynamic parameters involved in the simulations is very relevant. This study aims to evaluate the influence of hydrodynamic parameters on the hydrological response of an alluvial deposit in the dry bed of the Capibaribe River using the Hydrus-1D. A global sensitivity analysis method proposed by Sobol was chosen to evaluate the sensitivity of the soil water infiltration curve. A convergence analysis was carried out to investigate the evolution of the indices with increasing sample size. Values of the sensitivity indices showed gross variations at the beginning of the simulations for the different parameters, but they converged within the set of 10,000 samples. For parameters whose sensitivity indices are closer to 0, it is noted that 1,000 samples (14,000 simulations) were sufficient for the index to converge to their final value. The total and first-order sensitivity index calculated with 10,000 samples present the parameters n and Ks as the most important, being expressly more influential than the others.

XU Xiaofeng, YU Hong, JIANG Kaiyun

The construction of concrete gravity dams is subject to various factors, of which the rational arrangement of the placing face significantly impacts the total duration. To seek an ideal duration under a variety of limitations, the BIM technology and Shell's sort are jointly applied in the visual simulation of the dam placement plan. A dam BIM model is built and stratified. The stratified dam block sequences are taken as the variable, and the placing intensity, vertical placing interval time, transverse placing interval time, maximum adjacent height difference, and flood control rule as constraints. The Shell's sort is then applied to find the optimal solution of the placing scheme under those constraints, a computer program was developed by the Revit API interface based on .Net framework and C# language. The visual simulation of the concrete-placement optimization sequencing process was achieved. According to the engineering application, the program can quickly obtain the optimal placing sequencing and total duration under different constraints. The finding is of great significance in guiding the mechanical equipment and can be applied to similar projects.

Ramin Mardani, Hossein Montaseri, Mehdi Fazeli et al.

IntroductionDrought is considered a complex hazard, whose severity depends on the climate and weather conditions of each region. In fact, drought is caused by dry and unusual weather conditions, among other things, lead to a change in vegetation characteristics. Since this dangerous phenomenon is caused by the lack of rainfall for a long period of time, it slowly and gradually leads to a natural disaster and conquers the environment compared to other environmental hazards. Therefore, it is not noticed and taken less seriously by people and authorities. Undoubtedly, the occurrence of drought and as a result the crisis of reduction and shortage of water resources is one of the main and most important risks of the natural environment that humans have faced since the past. Therefore, it can be stated that the possibility of this natural phenomenon also exists in humid areas. Drought causes unfortunate and in some cases irreparable damage to human life as well as the natural ecosystem which is very different from other natural events such as floods, storms, and earthquakes. So that it has caused wide and big problems in the economic, social, political, and cultural fields. Therefore, the impacts it causes are not only structural and the damage it causes affects different areas. Drought is one of the destructive phenomena of the natural environment that affects a significant number of countries and causes problems. Simultaneous droughts with the period of vegetation growth cause environmental ecosystem consumption, which results in biological compounds such as land surface, soil amount, and plant growth rate, that we need proper management and planning in order to deal with this phenomenon. Materials and MethodsIn the present study, drought in Marvdasht city was analyzed using remote sensing technology and satellite imagery as a time series. For this purpose, during the statistical period of 20 years (2000-2019), out of 460 satellite imagery of land surface temperature (LST) and vegetation cover (NDVI) were used in conjunction with the MODIS sensor of Terra satellite, from which to estimate the temperature condition index (TCI) and vegetation condition index (VCI) was used. The optimal index indicating the state of drought from satellite imagery, the SPI was also used. In this way, using the rainfall data recorded by synoptic and rain gauge stations in the study area, the SPI was calculated using MATLAB software for the period of 3, 6, and 12 months. One of the other goals pursued in this study is to determine the basic and optimal index, indicating the state of drought in the study area, which is based on TCI and VCI satellite drought indices. Thus, after calculating the SPI and its intervals for each station, the points of each ground station were placed on the maps produced from TCI and VCI satellite indicators. Then, by taking the numerical value of the corresponding points for each of the years of the investigated period, the obtained values were entered into SPSS 22 software and the amount of correlation coefficients between SPI and its intervals with TCI and VCI values was calculated. Results and DiscussionAccording to the drought maps extracted from the TCI, the highest amount of land area with very severe drought in 2016 was 118.90 km2, and then in 2018 with 112.25 km2, and in 2017 with an amount of 101.66 km2 has happened. On the other hand, the least amount of extreme drought area in the first place is related to 2006 with an area of 46.10 km2, and then 2002 with an area of 48.21 km2. In terms of the severe drought category, 2009 with an area of 433.71 km2 experienced the largest area and 2007 with an area of 45.78 km2 experienced the lowest amount of drought. According to the maps obtained from the TCI, a very severe drought situation is observed in the southern and southwestern parts, especially in 2016 and 2018. It is also consistent with the results of the different intervals of the SPI in 2016 and 2018. They are considered as the years in which the highest amount of drought occurred. In addition, the year 2013 has less drought than other years in all three ranges of the SPI. From the comparison of the average SPI values for the studied years with the values obtained from the two indices, TCI and VCI obtained from satellite imagery, the highest amount of correlation coefficient between TCI and six-month SPI was equal to 0.65, which indicates that the TCI satellite index is the optimal index to indicate the drought situation in Marvdasht city. ConclusionAccording to the maps obtained from the NDVI, the studied area has normal and semi-dense vegetation density, which is scattered in all its different areas, so it has more density in the central and northwestern parts. The results of the VCI for the studied area, in none of the years, has not faced very severe drought. In terms of medium aridity, they have experienced the highest amount of drought in 2010 with an area of 62.98 km2 and after that in 2019 with an area of 50.04 km2. In contrast, the lowest drought in this layer was in 2002 with an area of 5.09 km2. According to the maps showing the drought condition of VCI, the studied area has almost the same distribution pattern in all areas and except for a small part of the southern part of the area which has a medium drought condition, the other areas have a mild drought condition and are not dry in most areas.

ZHAO Lei, LIAO Yu

Zhi-lin Wang, Mahmood Sadat-Noori, William Glamore

Wetlands play an important role in the global carbon cycle as they can be sources or sinks for greenhouse gases. Groundwater discharge into wetlands can affect the water chemistry and act as a source of dissolved greenhouse gases, including CO2 and CH4. In this study, surface water quality parameters and CO2 and CH4 concentrations were evaluated in a tidal wetland (Hunter Wetlands National Park, Australia) using time series measurements. Radon (222Rn), a natural groundwater tracer, was used to investigate the role of groundwater as a pathway for transporting dissolved CO2 and CH4 into the wetland. In addition, water-to-air CO2 and CH4 fluxes from the wetland were also estimated. The results showed a high concentration of radon in wetland surface water, indicating the occurrence of groundwater discharge. Radon concentration had a strong negative relationship with water depth with a determination coefficient (R2) of 0.7, indicating that tidal pumping was the main driver of groundwater discharge to the wetland. Radon concentration also showed a positive relationship with CO2 and CH4 concentrations (R2 = 0.4 and 0.5, respectively), while the time series data revealed that radon, CO2, and CH4 concentrations peaked concurrently during low tides. This implied that groundwater discharge was a source of CO2 and CH4 to the wetland. The wetland had an average water-to-air CO2 flux of 99.1 mmol/(m2·d), twice higher than the global average CO2 flux from wetlands. The average CH4 flux from the wetland was estimated to be 0.3 mmol/(m2·d), which is at the higher end of the global CH4 flux range for wetlands. The results showed that groundwater discharge could be an important, yet unaccounted source of CO2 and CH4 to tidal wetlands. This work has implications for tidal wetland carbon budgets and emphasizes the role of groundwater as a subsurface pathway for carbon transport.

GU Guihua, LI Xuehui, YU Shoulong et al.

To study the annual variation characteristics of runoff in Yunnan Province and analyze the main influencing factors,based on the observed monthly and annual rainfall and runoff data of 9 representative hydrological stations in 6 major river basins in Yunnan from 1956 to 2016,this paper analyzes the annual runoff distribution in terms of the uniformity,concentration and relative variation range.The research shows that:①The uniformity coefficient (C_u) of runoff distribution in many years ranges from 0.55 to 1.21,and the concentration (C_n) ranges from 0.23 to 0.66,so the runoff is unevenly distributed in the whole province.②The C_u and C_n decrease in general.Especially after 2000,the annual distribution of runoff shows a trend of uniformity.③The runoff concentration is relatively high in the Yangtze River Basin and the Honghe River Basin,and the annual runoff distribution is flat in the Lancang River Basin and the Zhujiang River Basin.④The uniformity trend of annual runoff distribution is closely related to human activities in the basin.

Yun-ping Yang, Yi-tian Li, Yong-yang Fan et al.

In order to determine how the subaqueous delta evolution depends on the water and sediment processes in the Yangtze Estuary, the amounts of water and sediment discharged into the estuary were studied. The results show that, during the period from 1950 to 2010, there was no significant change in the annual water discharge, and the multi-annual mean water discharge increased in dry seasons and decreased in flood seasons. However, the annual sediment discharge and the multi-annual mean sediment discharge in flood and dry seasons took on a decreasing trend, and the intra-annual distribution of water and sediment discharges tended to be uniform. The evolution process from deposition to erosion occurred at the −10 m and −20 m isobaths of the subaqueous delta. The enhanced annual water and sediment discharges had a silting-up effect on the delta, and the effect of sediment was greater than that of water. Based on data analysis, empirical curves were built to present the relationships between the water and sediment discharges over a year or in dry and flood seasons and the erosion/deposition rates in typical regions of the subaqueous delta, whose evolution followed the pattern of silting in flood seasons and scouring in dry seasons. Notably, the Three Gorges Dam has changed the distribution processes of water and sediment discharges, and the dam's regulating and reserving functions can benefit the subaqueous delta deposition when the annual water and sediment discharges are not affected.

V. Danilov-Danilyan

Shan Li, Yanlong Liu

The purpose of this research is to change the microstructure of wood using ultrasonic processing, increase the connectivity between pores in the cell to improve the permeability of the wood; ultrasonic cavitation dye in the wood veneer by the instinstantaneous temperature, high pressure, high jet role in the infection rate has been markedly improved. In the same time under the conditions of the veneer Ultrasonic assisted dyeing dye than conventional high temperature dip. Veneer dyeing dye uptake an yeing rate increases with the enhancement of ultrasonic vibration time increases with the increase of dye concentration increased with the improvement of the dyeing temperature increase. With solid mu fu joins a floor board and furniture industry on dyeing timber demand increases, more than 3 mm thickness of the single homogeneous dyeing problem due to the increasingly prominent in wood for dye solution to move or penetrating horizontal channel is few, the greater the thickness of wood dyeing the more difficult to dye penetration of wood dyeing essence is dye in wood of infiltration and fixed with two process, if the wood permeability good, dye in sessile former is easy to reach inside and outside a uniform color. Dye penetration performance depends on the types of wood and its state dye molecular size and physical and chemical properties of medium physical and chemical properties and dyeing external conditions. Wood dyeing process is dye solution in wood surface wetting diffusion adsorption, and dye solution to wood internal penetration and fixation process. The lumber size is big, dye molecules in the wood mobile and penetration depth is the key to real wood dyeing. This study adopts ultrasonic auxiliary dyeing is the use of ultrasonic cavitation to change the wood conventional dyeing auxiliary dyeing to achieve the purpose of the article. Materials and methods Experimental material Wood Oak veneer (100 mm 100 mm 1.3 mm) 36 piece from the forest Jiao river. Agent Acid lake blue, penetrating agent sodium sulphate (Na2SO4· 10 h2o), all stain (NaCl). Instrument ltrasonic cleaning apparatus (origin: kunshan), TU 1810 uv-vis spectrophotometer (origin: Beijing general analysis universal instrument co., LTD.), 722 n visible spectrophotometer (origin: Shanghai save division instrument table co., LTD.),etc. Test method Veneer pretreatment Preparation 0.3% NaOH solution installed in 2000 ml beaker, beaker placed in water bath pot heating, until the temperature reaches 80 warm after temperature to the oak veneer completely submerged in NaOH solution, cooking 3 hours after treatment out put into this drying oven drying to moisture content 12 (1) %. Ultrasonic auxiliary dyeing This experimental design three kinds of pretreatment process for: (1)Different dyeing time the veneer of ultrasonic auxiliary dyeing test after drying to the thickness of 1.3 mm oak veneer as test materials, in the dye solution concentration was 0.1%, bath ratio for 1:30, in the dyeing temperature respectively for 70, 80 and 90 under the condition of cooking 12 hours for 12 hours 2 cycle of ultrasonic auxiliary dyeing. (2)Different shock time of ultrasonic auxiliary dyeing test after drying to the thickness of 1.3 mm 1419 2nd International Conference on Electronic & Mechanical Engineering and Information Technology (EMEIT-2012) Published by Atlantis Press, Paris, France. © the authors thick oak veneer as test materials, in the dye solution concentration was 0.1% temperature for 80, bath ratio for 1:30, at every hour shock time respectively for 10 min 20 min and 30 min under the condition of cooking 12 hours for 12 hours 2 cycle of ultrasonic auxiliary dyeing. (3) Different dye solution concentration of ultrasonic auxiliary dyeing test after drying to the thickness of 1.3 mm ring oak veneer as test materials, in the dye solution concentration were 0.05%, 0.1%, 0.15%, temperature for 80, bath ratio for 1:30, cooking 12 hours for 12 hours 2 cycle of ultrasonic auxiliary dyeing. Dyeing rate measurement The dye uptake rate defined as:

ROBERTO EDUARDO KIRCHHEIM, SHAIENE VIEIRA FIGUEIRA

À medida que a bacia hidrográfica se consolida como unidade de planejamento e gestão, a quantificação de suas demandas e disponibilidades hídricas subterrâneas torna-se indispensável. As principais demandas de água subterrânea na Bacia do Rio Ibicuí (BHIb) foram dimensionadas com base nas informações dos poços tubulares disponíveis no SIAGAS da CPRM. A maioria dos 1189 poços é utilizada para atendimento de demandas domésticas urbanas e rurais. As disponibilidades foram estimadas com base em métodos hidrológicos e a partir das propriedades dos aquíferos. Da razão entre as disponibilidades e as demandas avaliou-se o estado de stress hídrico subterrâneo da bacia. Este conjunto de informações é de extrema valia para os atores intervenientes na gestão e serve para refinar as políticas públicas na referida bacia. Trata-se de uma bacia estratégica devido à presença de SAG confinado.

A. Tiganescu

J. Ono, Daisuke Takahashi, Xinyu Guo et al.

Larissa Silva Silva, Itabaraci Nazareno Cavalcante, Ediu Carlos Lopes Lemos et al.

Este trabalho foi desenvolvido na porção centro-norte no município de Quixeré, Chapada do Apodi, Ceará. Teve por objetivo a avaliação e análise da situação das obras de captação das águas subterrâneas no meio carste Jandaíra através das características hidrodinâmicas, além de dados construtivos e uso dos poços. Dos 55 poços utilizados observou-se que 100% são para uso particular, cuja finalidade maior a irrigação, onde 82,6% são poços tubulares profundos, com vazão média de 147 m³/h, apresentando níveis estático e dinâmico médios de 7,3m e 8,5m, respectivamente.

S. Vomvoris, R. W. A. rews, G. Lanyon et al.