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

GAO Yangyang, CHEN Zhuo, LIU Ke et al.

Hydropower development is one way to efficiently harness the energy of rivers. However, damming limits the upstream reproductive behavior of migratory fish, and fish passage facilities are now an important means of restoring connectivity. Flow velocity is an important factor for fish to perceive the environment and maintain swimming behavior. The reservoir in front of the dam has become a near-hydrostatic environment that significantly changes the river properties. Reduced velocity may make it difficult for fish released into the reservoir area by fish passage facilities to find the flow direction, reducing their migratory success rate. This paper takes the Wudongde reservoir as an example and uses numerical simulation to analyze the characteristics of the flow field in the reservoir at different flow levels. It takes the induced velocity of fish as the threshold value to analyze the river sections in the reservoir affected by the reduced velocity. The results show that the flow velocity in the reservoir area decreases significantly from the end of the reservoir to the front of the dam; the flow velocity in the main reservoir is more homogeneous in the direction of water depth, and the tributary estuaries present non-uniform distribution. Under the conditions of low flow (February), medium flow (May), and high flow (August), a certain range of the river section is below the induced velocity of the fish (0.2 m/s), and the suitable locations for migratory fish stocking are located in the upper part of Wudongde Dam, 102, 96, and 38 km, respectively. The results provide technical references for the selection of release sites for fish passage facilities in high dams and large reservoirs, and are of great significance for the protection of water ecology in the dam-built river reaches.

Rashmi Ranjan, Himanshu Kaushik, Rajesh Kumar Ranjan

ABSTRACTThis manuscript presents the first inventory of dissolved ions (cations and anions) and trace metals (Pb, Mn, Cr, Co, Ni, Cu and Zn) in the Punpun River water to assess its irrigational suitability, pollution sources and hydrogeochemical processes. For this, the physicochemical parameters and trace metals in river water were analysed in the pre- and post-monsoon seasons. The results showed that the concentrations of cations and anions were Ca2+ > Na+ > Mg2+ > K+ and HCO3− > SO42- > Cl− > NO3− > PO43-, respectively, in both the pre- and post-monsoon seasons. However, trace metal concentration in pre- and post-monsoon followed the trend of Pb > Mn > Cr > Ni > Cu > Zn > Co and Pb > Ni > Mn > Cr > Zn > Co > Cu, respectively. The results reveal that combined effects of rock weathering and evaporation-concentration influence hydrochemistry, along with anthropogenic factors like industrial effluents, urban domestic sewage and agricultural runoff. Piper and Durov plots suggest that the river water is dominated by Ca–Mg–HCO3− type, and the processes were governed by simple ion dissolution and mixing. However, the Gibbs plot shows that silicate and carbonate weathering govern the hydrochemical properties. Irrigational indices like sodium adsorption ratio, %Na, residual sodium carbonate, Kelly's ratio, magnesium hazard, and trace metals indicate that most of the water samples are suitable for irrigation. Comprehensive pollution index values suggest that the river water quality ranges from sub-clean to slightly to moderately polluted.

Piotr Kacorzyk, Mirosław Kasperczyk, Barbara Wiśniowska-Kielian et al.

The aim of the study was to improve the habitat conditions in the initial development of a grass-legume mixture sown in the reconstructed river embankments along the Uszwica River in Kwików and the Vistula River in Kraków, Poland. For this purpose, after sowing the seeds, NPK fertilisation was used, along with the application of a hydrogel to limit the evaporation of water from the soil. Additionally, a non-woven fabric was used to cover the soil. The study was conducted in two stages. In the first stage, polymeric and five biodegradable non-woven fabrics were evaluated in laboratory conditions for their water absorption and retention capabilities. After this assessment, two biodegradable and one polymeric non-woven fabrics were selected for the second stage of field research. A grass- legume mixture consisting of five species of seeds: Lolium perenne L., Poa pratensis L., Festuca rubra L., Festuca arundinacea Schreb. and Trifolium repens L. was used for sowing the embankments. This study takes into account the concept of green economy aimed at addressing the challenges of securing difficult terrains, such as river embankments. The non-woven fabrics used to cover the soil had a positive effect on the initial development of plants, accelerating their emergence, and the degree of soil coverage. After two months post-sowing, the soil surface coverage under the non-woven fabrics was 50% higher compared to areas without such coverage. However, the type of non-woven fabrics and the hydrogel used did not have a significant impact on the initial development of seedlings.

Thoriq Teja Samudra, Yoshimasa Amano, Motoi Machida

This study aimed to control the buoyancy of Microcystis by increasing the growth rate and simultaneously reducing the cellular carbohydrate content under various light and temperature regimes. Microcystis was precultured in continuous dark (0 µmol·m−2·s−1) or light conditions (135 µmol·m−2·s−1) for 48 hours at 30°C and 35°C. After preculture, Microcystis was cultivated in a burette to observe the difference in the buoyancy. The buoyancy was evaluated by relative buoyancy of 25% (RB25), defined as the percentage of Microcystis cell number in the upper 25% layer to the total cell number in the burette. The result showed that preculture under the dark condition at 30°C had higher RB25 (43.8 ± 3.5%), than under the light condition (23.8 ± 2.8%). In addition, Microcystis precultured in the dark condition at 30°C also had the lowest cellular carbohydrate (3.1 ± 0.3 pg/cell). The reduction of cell ballast would promote the buoyancy of Microcystis. These results indicate that the buoyancy of Microcystis can be controlled by reducing cellular carbohydrate using preculture under the dark condition at high temperature. Thus, artificial control to increase Microcystis buoyancy could be a useful method for removal of Microcystis blooms, especially in water purification plants.

Ganga Shrestha, Bijay Man Shakya, Mohan Bikram Shrestha et al.

The rapid urbanization and land-use change prominently decreased groundwater recharge areas. Infiltration occurring through permeable areas is responsible for groundwater recharge. However, detailed studies of infiltration in low-income countries especially in human-encroached recharge areas are limited. Thus, this study mainly aims to measure the infiltration rate in the major recharge areas of the Kathmandu Valley (KV) using a double-ring infiltrometer (concentric ring size 30 and 15 cm). It also aims to estimate the volume of groundwater recharge with respect to the decrease in permeable areas in the northern part of the KV. The results revealed the infiltration rate ranging from 0.01 to 37.2 cm/h with an average of 7.3 ± 8.4 cm/h. The infiltration is found to be dependent upon land-use among different categories and organic matter among different soil properties. Additionally, the volume of water recharge in 2010, 2020, and 2030 was estimated as 67.73, 59.05, and 51.5 million cubic meters per year (MCM/year), respectively, which clearly showed a decrease in water recharge with respect to a decrease in the permeable areas. Hence, the findings would be useful for policymakers, stakeholders, and urban planners regarding the preservation and conservation of permeable areas for sustainable water resource management and urban flood management. HIGHLIGHTS The importance of permeable land for groundwater recharge and sustainable water resource management.; Up to now, there are no data for the infiltration rate of the Kathmandu Valley.;

WANG Qiuliang, SUN Xiang, GAN Dufen et al.

Dongguan is an important city in the Guangdong-Hong Kong-Macao Greater Bay Area,which is a major contributor to the economic development of this area.However,its urban planning,rational allocation of water resources,flood prevention and disaster reduction are severely affected by torrential rain and floods,and thus its high-quality economic development is seriously hindered.Therefore,by using the 32-year daily rainfall data of 30 hydrological stations in Dongguan,this paper adopts methods such as GIS,the Mann-Kendall test,moving average,and cumulative anomaly to discuss the temporal and spatial distribution of rainfall in Dongguan.The results reveal that in the past 32 years,the temporal and spatial distribution of annual rainfall has gradually increased from west to east with a significant rising trend over time.During the flood season,the rainfall increases sequentially from west to east and gradually decreases from the central part to west,and from the central part to east,it drops before it rises.Rainfall in the flood season accounts for about 60%~95% of the annual total.The rainfall in the non-flood season is prominent in the central part,with great differences between east and west,namely that the rainfall in the central part tends to decrease gradually to both sides,and the southwestern part registers the smallest.The center of the maximum rainfall in the four seasons moves from the central part to the northeast,east,and central,and the southwest still records the minimum rainfall.The monthly average rainfall generally shows an increasing trend from west to east:Many years of data indicates that the average rainfall in June is the largest,accounting for 18.58% of the rainfall all year,while December sees the smallest,accounting for 1.88% of the yearly total.The research results can provide reference and support for the later development of Dongguan.

Bedassa Dessalegn Kitessa, Semu Moges Ayalew, Geremew Sahilu Gebrie et al.

This study aims to understand the long-term (2020–2050) urban water–energy–food (WEF) resources access and sustainability in Addis Ababa city through a nexus modeling approach. Several feasible scenarios in line with improving WEF resources supply and access through conservation, system rehabilitation and technology input are explored. The water system scenarios include rehabilitation and conservation scenario, water supply enhancement scenario, technology input scenario and integrated water improvement scenario. The energy scenario includes energy conservation scenario and new renewable supply enhancement scenarios and integration of both scenarios as integrated energy scenario. The food system scenarios include crop yield productivity and irrigation water use efficiency scenarios of urban agricultural system. The integrated WEF nexus scenario is the integration of all scenarios under one nexus framework. The results are evaluated against baseline scenario. At a system level, the integrated water scenario result provides a water saving potential of 26 and 52% from the baseline scenario by 2030 and 2050, respectively, whereas the integrated energy use scenario saves energy by as much as 22 and 48%. For respective years, under the integrated WEF nexus scenario, the integrated water use scenario for low energy intensity reduces the energy use for urban water system by 23 and 72% from the baseline scenario. Similarly, urban food production have also shown enhancement. Urban food production system in Addis Ababa city is relatively small and does not significantly affect the food import from other parts of the country. Overall, the results WEF nexus modeling approach revealed the importance of exploring integrated nexus approach to sustainable urban water energy and food development and management as a first attempt at the urban scale. HIGHLIGHTS Water, energy and food are interdependent.; Water–energy–food nexus studies help policymakers to make decision to efficiently use these utilities.;

Hao-yuan Liu, Amir M. Kaynia

Monopile response under undrained conditions in sand is gaining increasing interests owing to the recent development of offshore wind farms in seismic regions. Pore pressure evolution in liquefiable soil can significantly reduce the strength and stiffness of the soil which in turn affects the structural dynamic response. Several numerical models have been developed in the last two decades to enhance understanding of the mechanism of monopile–soil interaction with the existence of pore water pressure. In this study, the effects of geometry and static vertical load on monopile lateral response were studied using three-dimensional finite element methods that consider the existence of lateral cyclic load-induced pore water pressure. To achieve reliable simulation results of pore pressure development and pile displacement accumulation during cyclic loading, the simple anisotropic sand model with memory surface for undrained cyclic behavior of sand was adopted. For piles with the same diameter, a accumulated pile head displacement during lateral cyclic loading decreased linearly with increasing pile embedded length but increased with increasing eccentricity. Static vertical load had minor effects on pile cyclic lateral response. The distributions of mean effective stress and pore water pressure in the soil domain were presented. The pile reaction curve (cyclic soil reaction against pile defection) of the monopile was extracted. The numerical results aim to provide reference for optimized engineering design procedures.

ZHOU Wenzhong, GU Yanchang, HUANG Haibing et al.

The small probability method for typical monitoring effect quantities is a common methodfor establishing early warning index based on monitoring data, but this method has someshortcomings. If the dam has not encountered the most unfavorable load or the data time series isshort, the effect quantity samples will not cover the monitoring effect quantity for the mostunfavorable load combination.This paper describes the theoretical method of determining damdeformation safety monitoring index by using the typical small probability method, proposes animproved typical small probability method by transforming the normal distribution calculation todecompose different load components with query for the standard normal distribution table, andcombined with an example of prototype observation data of a reservoir, determines the safetymonitoring index for radial displacement of section 11 of the dam. The analysis of the results ofdeformation safety monitoring index shows that the improved typical small probability method notonly is convenient for calculation but also fully considers the most unfavorable loadcombination,which increases the reliability of monitoring indexes.

Gustavo Simão, Jader Lima Pereira, Nadja Zim Alexandre et al.

The city of Criciúma was impacted by decades of coal mining exploration and tailings disposal. These activities directly interfere with natural resource systems, causing the contamination of ground and surface water resources through acid mine drainage (DAM).The definition of geochemical background values is a strategy to quantify and qualify the impact of mining activities on natural resources. The present paper aimed to establish geochemical background values in groundwater from springs distributed in the city of Criciúma/SC. The water quality data were evaluated using the Exploratory Data Analysis (EDA) and cumulative frequency representation methods. Thus, the work allowed to determine the background values for the analytical parameters pH, Iron, Manganese and Sulphate, when it was confirmed that values for pH found within the range of 5.5 to 7.9 can be considered normal for the groundwater. Iron and manganese had background concentrations of 2.58 and 0.30 mg / L respectively, while sulfate had concentrations between 2.0 and 20.0 mg / L. The background in many cases can of course supplant legally regulated limits, a fact observed in this study for manganese, which has a background concentration three times higher than that recommended by MS Ordinance n. 5/2017 which deals with water potability.

Juliana Broggio Basso, Chang Hung Kiang

Hydrodynamic dispersion coefficient (Dh) and the retardation factor (Rd) to chemical species of K+, Cu2+ and Cl- were evaluated in sandy and clay-rich residual soils of Itarare Subgroup, collected from Mogi Mirim and Capivari counties respectably, located in the eastern region Sao Paulo State. Laboratory tests were carried out percolating of potassium chloride and copper chloride solutions of variable concentrations (250 mg/L, 500 mg/L and 1000 mg/L of K+ and Cu2+), through saturated soil columns and steady-state flux. Breakthrough curves (BTC) were constructed and transport parameters were calculated by fitting theoretical curve to the experimental data using the STANMOD software. Mineralogical alterations and precipitates were examined in soil samples using scanning electronic microscope. The calculated Rd for cations ranged from 9 to 3.9 in sandy soil and from 5.7 to 3.5 in clay-rich soil. For chloride it varied from 4.6 to 2.4. Hydrodynamic dispersion coefficients showed values ranging from 0.02 to 0.31 cm2/min for cations and from 0.01 e 0.11 cm2/min for chloride. The column tests showed that ionic retention was highly influenced by pore volume on soil, by flux velocity. Mineralogical analyses of the percolated soil samples did not indicate dissolution and precipitation of minerals.

Sandra Garcia Gabas, Giancarlo Lastoria, Leonardo Tadaaki Tsuge et al.

Um caso de contaminação de chumbo a partir de uma indústria de reciclagem de baterias localizado em Campo Grande (MS) é discutido a partir de dados contidos em processo junto ao órgão ambiental municipal. A indústria operou de 1999 a 2008 com uma produção anual de lingotes de chumbo da ordem de 150 toneladas, tendo efetuado a disposição de resíduos e efluentes do processo de maneira inadequada. Valores acima dos limites recomendados pela legislação brasileira vigente para o metal potencialmente tóxico foram constatados em resultados analíticos do monitoramento. Ocorreu a contaminação do solo (concentração de 245 mg.kg-1 de Pb) e da água subterrânea (até 0,29 mg.L-1), bem como da vegetação (633,34 mg.kg-1) de uma área vizinha, com consequente morte comprovada devido à intoxicação por chumbo de trinta e quatro bovinos. A indústria está com suas atividades paralisadas desde 2008 e um projeto de pesquisa está em andamento para verificar a situação atual da contaminação por este metal e seus impactos na área de influência do empreendimento.

WANG Si

Clarice Araújo Mattos, Alfredo Akira Ohnuma Júnior

A urbanização não controlada em bacias urbanas produz um aumento na frequência das inundações devido a impermeabilização das superfícies [3]. No intuito de identificar os pontos críticos na capacidade de permeabilização da bacia hidrográfica do rio Piranema, foi utilizado o modelo de simulação hidrológica IPHS-1. A partir de imagens de sensoriamento remoto, foi possível extrair dados da classificação de uso do solo que expressam características físicas da bacia e posterior determinação da capacidade máxima da camada superior do solo, representado pelo parâmetro CN. O resultado final relatou as condições hidrológicas da bacia quanto ao risco de inundações, apresentando um CN 78,77.

Antonio Abel Carrasquilla, Sérgio L. Fontes

A geophysical pilot study has been undertaken in the Northern Coastal Plain of Rio de Janeiro State (Brazil), near Rio das Ostras Town, 200 km NE from Rio de Janeiro City. This region is characterized by both scarcity of drinking water and the existence of saline intrusions, which is caused mainly by the presence of a complex Quaternary geology and excessive aquifer exploitation. The research was performed by employing magnetic and electromagnetic methods (time - TEM and frequency - FEM domains), in order to evaluate the effectiveness of these methods under these particular geological conditions, and thus to allow the formulation of a more comprehensive hydrogeological research in the region in future. FEM profiles and one-dimensional (1D) interpretation of TEM data were capable of depicting different geological formations, to locate the main aquifer and to reveal the fresh-saline water contact. On the other hand, the magnetic method showed the presence of a NE-SW direction geological fault, which is located just in the geological contact between sand and clay, coincidentally with the fresh-saline water contact. Our results evince a promising future for using electromagnetic geophysical methods in this region in small scale surveys, as well as it confirmed that a precursory regional survey, chiefly using the magnetic method, is essential in the indication of most suitable places to locate productive fresh-water wells.

LIU Zhi-min, HUANG Guo-ru, GAO Shi-you