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Discussion on Comprehensive Improvement of Xinzui River Section in Hanshou County
Liu Aiguo,
Peng Jiuhua,
Cao Lijun,
Wu Feng,
Zhou Shangong
Issue:
Volume 5, Issue 1, March 2019
Pages:
1-8
Received:
9 November 2018
Accepted:
4 December 2018
Published:
29 January 2019
Abstract: The river channel of the Xinyizui to the car brain flood control embankment in the south of the Hanshou Lake in the Dongting Lake area is a typical bifurcation channel. Big After the first and second phases of the Dongting Lake area, the embankment was affected by the quality conditions of the embankment and the river regime. There were still dangers such as bank collapse, leakage and piping during the flood season. Analyzed the causes of the dangerous situation, and proposed comprehensive measures to strengthen the river control, static water filling and other measures. After the treatment, there was no danger in the levee of the river section in the flood in 2017, and the treatment effect was remarkable. Governance measures have certain reference significance for river regulation, embankment control and flood control in Dongting Lake area.
Abstract: The river channel of the Xinyizui to the car brain flood control embankment in the south of the Hanshou Lake in the Dongting Lake area is a typical bifurcation channel. Big After the first and second phases of the Dongting Lake area, the embankment was affected by the quality conditions of the embankment and the river regime. There were still dange...
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Evaluation of Soil Contamination in Mining Areas of Rwanda
Hubert Hirwa,
François Xavier Nshimiyimana,
Emmanuel Ngendahayo,
Beatha Akimpaye,
Lamek Nahayo,
Olivier Militery Ngamata,
Jean de Dieu Bazimenyera
Issue:
Volume 5, Issue 1, March 2019
Pages:
9-15
Received:
28 December 2018
Accepted:
24 January 2019
Published:
19 February 2019
Abstract: Soil serves as a great geochemical reservoir for contaminants as well as a natural buffer for transportation of chemical materials and elements in the atmosphere, hydrosphere and biosphere. This study aimed at evaluating the physical and chemical parameters of soil and understanding the features of the pollution in Gifurwe mining area, Burera District of Rwanda. The soil samples were randomly collected in seven locations of the study area. The soil samples were analyzed for selected physico-chemical parameters: pH values, Arsenic (As), Chromium (Cr) and Lead (Pb) concentrations using standard analytical techniques. The contamination factors and pollution load indices were calculated. The pH values of soil ranged between 4.2 and 8.2. The results showed that the As concentrations increase up to 531 mgkg-1 downstream of the tailings dam (farm fields) which is extremely high above the maximum concentration levels allowed by Canadian Standards (12 mgkg-1) for industrial zones. The results also revealed that the mean concentrations of Cr and Pb in soil samples exceed the recommended level by Germany Soil Regulation (50 mgkg-1 and 25 mgkg-1 respectively). The analysis concluded that the soil at Gifurwe mining site is strongly polluted by Arsenic and moderately polluted by Chromium and Lead. Hence, the downstream farmland of Gifurwe is declared as a contaminated site and prevented from other land use. Therefore, sustainable environmental management and contamination control strategies in Gifurwe mining areas are highly recommended.
Abstract: Soil serves as a great geochemical reservoir for contaminants as well as a natural buffer for transportation of chemical materials and elements in the atmosphere, hydrosphere and biosphere. This study aimed at evaluating the physical and chemical parameters of soil and understanding the features of the pollution in Gifurwe mining area, Burera Distr...
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Optimizing Emitters’ Density and Water Supplies in Trickle Irrigation Systems
Hammami Moncef,
Zayani Khemaies
Issue:
Volume 5, Issue 1, March 2019
Pages:
16-21
Received:
9 December 2018
Accepted:
30 January 2019
Published:
28 February 2019
Abstract: The usual approaches for designing trickle irrigation systems are based upon empirical estimation of the emitters’ density and the moistened soil volume. The objective of this paper is to implement a quasi-analytical approach that allows the inference of these two parameters. The emitters’ density is determined so that the rooted soil volume would be moistened even at the peak period. The proposed approach enables to adjust the irrigation time in order to replenish the rooted soil volume up to a threshold for an optimal plant growth. The required inputs are: the water retention curve, the hydraulic conductivity at the wetting front, the radius of the moistened spot at the soil surface, and the rooted soil depth. The method is assessed with respect to study cases for sandy and silty soils. The used emitters’ discharge were 2 l/h and 4 l/h. The present approach has the advantage of preserving the mass conservation as well as the dynamic aspect of irrigation management. For design purpose, the irrigation time is set equal to the time required to attain a quasi-state flow conditions within the rooted zone. Nevertheless, irrigation time should vary so that design errors are adjusted for irrigation scheduling needs.
Abstract: The usual approaches for designing trickle irrigation systems are based upon empirical estimation of the emitters’ density and the moistened soil volume. The objective of this paper is to implement a quasi-analytical approach that allows the inference of these two parameters. The emitters’ density is determined so that the rooted soil volume would ...
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Hydrological Risk Assessment of Gibe III Dam by Using L-Moment
Sintayehu Yadete Tola,
Abdella Kemal,
Daniel Reddythota
Issue:
Volume 5, Issue 1, March 2019
Pages:
22-28
Received:
22 January 2019
Accepted:
7 March 2019
Published:
8 April 2019
Abstract: A hydrological analysis for assessing the risk of dam overtopping is required for both dam designing and dam safety checking. There is enormous amount of water to be stored in the reservoir to provide valuable service such as hydroelectric power generation and flood control. However dams can cause catastrophic damage to both life and property if they experience performance failures due to overtopping and inadequate spillway design. The hydrological risk was computed from historical peak flow data of Gilgel Gibe near Abelti, Gojeb near Shebe and Wabi near Wolkite, of major rivers flowing towards Gibe III Dam, respectively. From the flood statistics of rivers, the general extreme value (GEV) distribution was fitted to peak flow using L-moment. In this research made an attempt, the extreme event or probability of maximum discharge occurrence at dam site analyzed by associating peak occurrence with the service life of Dam and estimated the hydrological risk at Gibe III Dam. It finds PWM method is very suitable for three river flow condition flowing toward Gibe III Dam. The hydrological risk at Gibe III predicted for 50, 100 and 150 years with respect of Discharge range of 2730m3/s to 3180m3/s was observed there is a risk decreases as return period increases.
Abstract: A hydrological analysis for assessing the risk of dam overtopping is required for both dam designing and dam safety checking. There is enormous amount of water to be stored in the reservoir to provide valuable service such as hydroelectric power generation and flood control. However dams can cause catastrophic damage to both life and property if th...
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The Research of the Flow Characteristics in Spiral Membrane Separator
Zhou Xiantao,
Liu Hui,
Wan Xuhui
Issue:
Volume 5, Issue 1, March 2019
Pages:
29-36
Received:
24 January 2019
Accepted:
17 March 2019
Published:
8 April 2019
Abstract: The spiral membrane separator is a novel module proposed for reducing the concentration polarization and membrane fouling of membrane separation process. This membrane separation process benefits from dean vortices produced by centrifugal instability in enhancing fluid mass transfer. A numerical stimulation of this membrane separation is presented and used to analyze the fluid flow characteristics and thoroughly understand the separation mechanism. The numerical model consists of a spiral flow path with rectangular sector. As the simulation with infiltration, the fluid domain of the ceramic membrane tube was as a porous medium domain. The standard momentum equation, added with the momentum equation source term which composed of the viscosity loss term and the inertia loss term, are figured out through the experimental characterization. In the simulation of spiral membrane separation, the Dean secondary flow structure is identified and found to enhance fluid mass transfer and to increase the permeate flux. The critical unstable state of spiral membrane separation is accordingly De=246 without the flow permeation and De=863 with the permeation, where Dean vortices cause collisions and the mixing of fluid particles. Then in the case of permeation, the fluid in separator at De=1232 is numerically simulated to show that the higher flow velocity and a large fluctuating trend of wall shear stress near the membrane surface (inside), which mainly contributed to alleviate concentration polarization and membrane fouling.
Abstract: The spiral membrane separator is a novel module proposed for reducing the concentration polarization and membrane fouling of membrane separation process. This membrane separation process benefits from dean vortices produced by centrifugal instability in enhancing fluid mass transfer. A numerical stimulation of this membrane separation is presented ...
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