Drainage Regimes Research Articles

УСТОЙЧИВОСТЬ ЗДАНИЙ И СООРУЖЕНИЙ ЗАПОРОЖСКОЙ АТОМНОЙ ЭЛЕКТРОСТАНЦИИ ПРИ ИСПОЛЬЗОВАНИИ АРТЕЗИАНСКОЙ ВОДЫ ДЛЯ ТЕХНОЛОГИЧЕСКОГО ПРОЦЕССА СТАНЦИИ

The article provides an assessment of ensuring safe operation, water supply, as well as the safety of personnel and the environment during the operation of the Zaporizhia NPP. It has been established that the exploitation of groundwater for the technical water supply of the NPP and its infrastructure facilities, both under constant and periodic drainage regimes, will lead to the formation of depression funnels, the size of which will depend on the magnitude (flow rate) of the water intake, the layout of water intake facilities and specific hydrogeological conditions of the groundwater deposit. It is shown that it is necessary to ensure not only the strength of the soils under the structures of buildings and structures of nuclear power plants, but also the reliable functioning of all systems that control the nuclear process. The necessity of monitoring the stability of geological and geophysical conditions in the area and at the sites of nuclear power plants in the monitoring mode has been determined. The monitoring is comprehensive. It includes geotechnical, surveying and geodetic, hydrogeological, and seismological observations. The forecast of the development of a depression funnel in time and space should be carried out by analytical methods or modeling, taking into account changes in the conditions of the relationship of aquifers with each other and environmental components. It has been revealed that extending the further operation of the NPP is an expensive and unsafe process. It is not possible to upgrade old power units to modern ones in terms of safety in nuclear energy. The power units of the Zaporizhia NPP are not ready for further operation, therefore, it is necessary to start developing a project for decommissioning power units No. 1-4 of the NPP.The research results can be useful in predicting the possible development of karst-suffusion processes under the influence of intensive groundwater drainage, organizing monitoring of the possible development of these processes, including them in the integrated monitoring of this facility. It will make it possible to justify the scale and regime of rational water extraction, taking into account the requirements for environmental protection and the specifics of further operation of the NPP.

Thin free-standing liquid films manipulation: device design to turn on/off gravity in flow regimes for thickness map control and for material structuring.

The manipulation and control of free-standing liquid film drainage dynamics is of paramount importance in many technological fields and related products, ranging from liquid lenses to liquid foams and 2D structures. In this context, we theoretically design and introduce a device where we can reversibly drive flow regime switch between viscous-capillary and viscous-gravity in a thin free-standing liquid film by altering its shape, allowing us to manipulate and stabilize the film thickness over time. The device, which mainly consists of a syringe pump, a pressure transducer, and a 3D-printed cylinder, is coupled with a digital holography setup to measure, in real time, the evolution of the local film thickness map, revealing characteristic features of viscous-capillary and viscous-gravity driven drainage regimes. By using polyvinyl alcohol/water concentrated solutions, we are also able to produce viscoelastic membranes after manipulation and water evaporation, which presents manipulation history-dependent geometrical properties. Furthermore, using a system composed of carboxymethyl cellulose, water, and rod-like zinc oxide nanoparticles, we show a clear effect of film manipulation on particle rearrangement. We believe this device could represent a starting point for the development of a useful and practical tool to study thin liquid film dynamics and to produce novel (patterned) 2D structures for the numerous scientific and technical fields where they are of use.

Effect of foam instability on drainage regime in forced drainage

Forced drainage has been widely used to study foam drainage regimes. Correct and accurate drainage regime of two phase foam is the base for better understanding the complicated three-phase froth. However, anomalies in data were uncovered in the presence of foam instability. Movement of bubbles in different foam instability conditions was firstly studied. Then, it was discussed that how the foam instability affected the power law relationship and the drainage regime. The power law index increased with the wider fitting range of liquid superficial velocity. Finally, the factors influencing foam instability and the power law relationship were analysed, including the position of imposed liquid, bubble size, and foam drying time. This paper advances our understanding of forced drainage in terms of foam instability.

Cd isotope fractionation in a soil-rice system: Roles of pH and mineral transformation during Cd immobilization and migration processes

Cd speciation in soil and its transport to rice roots are influenced by the soil pH, oxidation-reduction potential, and mineral transformation; however, the immobilization and migration of Cd in soil-rice systems with different pH values under distinct water regimes remain unclear. This study used Cd isotope fractionation, soil physical analysis, and root gene quantification to elucidate the immobilization and transport of Cd in different soil-rice systems. In drainage soils, the high soil pH enhanced the transformation and magnitude of negative fractionation of Cd from MgCl2 extract to FeMn oxide-bound pool; however, it favored Cd uptake and root-to-grain transport. Compared with drainage regimes, the flooding regimes shifted fractionation toward heavy isotopes from MgCl2-extracted Cd to FeMn oxide-bound Cd in acidic soils (∆114/110CdMgCl2 extract – FeMn oxide-bound Cd = −0.09 ± 0.03 ‰) and to light isotopes from MgCl2-extracted Cd to carbonate-bound Cd in neutral and alkaline soils (∆114/110CdMgCl2 extract – carbonate-bound Cd = 0.29–0.40 ‰). The submerged soils facilitated the forming of carbonate and poorly crystalline minerals (such as ferrihydrite), which were transformed into highly crystalline forms (such as goethite). These results demonstrated that the dissolution-precipitation process of iron oxides was essential for controlling soil Cd availability under flooding regimes, and the relative contribution of carbonate minerals to Cd immobilization was promoted by a high soil pH. Flooding regimes induced lower expressions of OsNRAMP1 and OsNRAMP5 to limit the uptake of light Cd isotopes from MgCl2-extract pool, whereas a teeter-totter effect on gene expression patterns in roots (including those of OsHMA3 and OsHMA2) limited the transport of heavy Cd isotopes from root to grain. These findings demonstrate that flooding regimes could exert multiple effects on soil Cd immobilization and Cd transport to grain. Moreover, alkaline soil was conducive to forming carbonate minerals to sequester Cd.

The CryoGrid community model (version 1.0) – a multi-physics toolbox for climate-driven simulations in the terrestrial cryosphere

Abstract. The CryoGrid community model is a flexible toolbox for simulating the ground thermal regime and the ice–water balance for permafrost and glaciers, extending a well-established suite of permafrost models (CryoGrid 1, 2, and 3). The CryoGrid community model can accommodate a wide variety of application scenarios, which is achieved by fully modular structures through object-oriented programming. Different model components, characterized by their process representations and parameterizations, are realized as classes (i.e., objects) in CryoGrid. Standardized communication protocols between these classes ensure that they can be stacked vertically. For example, the CryoGrid community model features several classes with different complexity for the seasonal snow cover, which can be flexibly combined with a range of classes representing subsurface materials, each with their own set of process representations (e.g., soil with and without water balance, glacier ice). We present the CryoGrid architecture as well as the model physics and defining equations for the different model classes, focusing on one-dimensional model configurations which can also interact with external heat and water reservoirs. We illustrate the wide variety of simulation capabilities for a site on Svalbard, with point-scale permafrost simulations using, e.g., different soil freezing characteristics, drainage regimes, and snow representations, as well as simulations for glacier mass balance and a shallow water body. The CryoGrid community model is not intended as a static model framework but aims to provide developers with a flexible platform for efficient model development. In this study, we document both basic and advanced model functionalities to provide a baseline for the future development of novel cryosphere models.

Stem Characteristic Associated with Lodging Resistance of Rice Changes with Varied Alternating Drought and Flooding Stress

A two-year field experiment was executed to investigate the impact of different controlled irrigation and drainage regimes on the morphological and mechanical traits related to the lodging resistance of rice in Jiangsu province, China. Three irrigation regimes were comprised of conventional flooding practices (CK), controlled irrigation and drainage mode I (CID-1), and controlled irrigation and drainage mode II (CID-2). Results indicated that there was no significant difference in the heights of rice plants under the three irrigation regimes, but the average diameter of CK treatment was 21% higher than that of CID-2 in the 2013 season. Similarly, the value of the section modulus of CK was significantly higher than that of CID-2 (p < 0.05). On the contrary, the length of basal internodes of CK and CID-1 was significantly lower than that of CID-2 in 2013 (p < 0.05). For both seasons, the safety factor against stem breakage (SFs) of CID-2 always had the lowest value under different irrigation regimes, which might be related to the significantly lower values of bending strength of culm at breaking (S) and the bending stress (BS) as well as lower ash content and cellulose content in CID-2 compared with CK and CID-1. Collectively, properly increasing the depth of water levels after heavy rain under the current water-saving mode (CID-1) would not increase the risk of lodging for rice plants, whereas if the water depth after heavy rain was kept higher than 20 cm (CID-2), the SFs would be significantly lower than that of CK, and the rice plants would be much more likely to undergo lodging.

Root adaptations of black spruce growing in water-saturated soil

Black spruce (Picea mariana (Mill.) BSP) is the main tree species growing within peatlands. The difficult growing conditions within peatlands are associated with low individual wood productivity, and only tree species tolerant to high ground water level can survive. We examine the effect of water-saturated soil on the growth potential of black spruce trees and specific adaptation of the root system. Experimental mesocosms were constructed with two drainage regimes (saturated and well-drained soil conditions). We measured biomass, height, and diameter at stem base of 55 black spruce saplings and noted the location of each horizontal root. Black spruce exhibited a very shallow root system located above saturated commercial peat 19 years after the experiment was initiated. Most roots were adventitious in the water-saturated mesocosms. Overall aerial and root biomass accumulation of the black spruce trees growing under saturated soil conditions was significantly lower than that of the well-drained mesocosms. Interestingly, root–shoot ratios were similar across the two drainage regimes. Soil conditions induced adaptation of the root system in black spruce trees, and physiological stress affected the entire individual with lower biomass productivity in all components (stem, branches, root system). However, biomass distribution remained similar to that of trees growing in well-drained mesocosms.

Regimes of drainage instability caused by wash water

Wash water is widely used in flotation to increase the gravity-driven drainage rate of water within the froth phase and the efficiency of removing entrained (hydrophilic) particles. At a high rate, it can disturb the froth. Here, we investigate the drainage instability caused by wash water using the forced drainage experiments. We quantitatively confirm that foam suffers from convective instability when a sufficiently high flow rate of wash water is employed. A comparison between the theoretical onset predictions of convective instability and experimental results shows that some available drainage experiments might have suffered from convective instability. Our new experimental results show three drainage regimes and structures associated with increased flow rate of wash water: (1) stable foam structure, (2) relative motion of bubbles and (3) convective roll. Our study presents both theoretical analysis and experimental results for quantifying convective instability, which can be eliminated to improve flotation.

Response of soil compaction to the seasonal freezing-thawing process and the key controlling factors

The seasonal freezing-thawing process can alleviate saline farmland soil compaction, and improve soil aeration and soil water retention. However, the response of soil compaction to the seasonal freezing-thawing process and the key factors affecting soil compaction are still unclear. Therefore, in this study, we conducted a regional monitoring of soil compaction and other soil physical and chemical properties before and after the 2016–2017 seasonal freezing-thawing period in Yongji Irrigation Area, Hetao Irrigation District, North China. We used a combination of genetic algorithm-projection pursuit evaluation, grey relational analysis and stepwise regression to analyze the measured soil physical and chemical properties and their variations during the freezing-thawing period. Using this method combination, we obtained one projection value to represent the whole-profile soil compaction, and found the most important influencing soil physical and chemical properties—soil water content, groundwater level and total inorganic nitrogen. Ultimately, we developed a regression model to predict soil compaction given the values of the predictive variables (soil water content, groundwater level and total inorganic nitrogen) at the same depth and time. The importance of autumn irrigation and planting structure, as well as the spatial heterogeneity of field management regime on the relationship between freezing-thawing processes and soil compaction were highlighted. Our findings provide solid foundations for regional field management policies, especially irrigation and drainage policies. Future studies are recommended to focus on the effect of different irrigation regimes, different drainage regimes and different nitrogen fertilizer application regimes on the relationship between the seasonal freezing-thawing processes and saline farmland soil compaction.

On the effect of the approach velocity on the coalescence of fluid particles

The effect of the constant relative approach velocity of two Newtonian fluid particles on their coalescence is investigated via a film drainage model. The interfaces are deformable and allowed to have any degree of mobility. The thinning equation is derived based on the lubrication theory, and the tangential velocity of the interface is determined via the Boundary Integral Method (BIM). The details for the treatment of the inherent singularity in BIM are provided. As the approach velocity increases, regardless of the strength of the van der Waals forces and the value of the viscosity ratio (or the degree of the interfacial mobility), three types of behavior of the coalescence time are identified: the linear slow, the dimpled and the multiple-rim drainage regimes. In the first two regions the coalescence time decreases with the approach velocity, eventually passes through a minimum and starts to increase in the third region. The slope in the linear region and the critical velocities separating the regimes are used to quantify the behavior, and given as functions of the Hamaker constant and the viscosity ratio. The results are shown to be in good agreement with several recent experimental studies in the literature.

Dip-Coating perfluoropolyether lubricants on rigid magnetic disks

Abstract Dip-coating is used to apply a boundary lubricant film of perfluoropolyether (PFPE) on rigid magnetic disks. At lower solute concentration and lower withdrawal speeds, solvent evaporation is faster than the motion of the drying line leading to capillary feeding during film formation. At higher solute concentrations and higher withdrawal speeds, film formation is described by the Landau-Levich drainage model modified for evaporation. The minimum in the deposited film thickness versus withdrawal speed is attributed to a mixed regime corresponding to a crossover between the capillarity and drainage regimes. The solute concentration and therefore solvent type is a strong determinant of which regimes are observed. The dip-coating process is well-described by semi-experimental equations. The relationship between solute concentration and solvent compatibility, a determinant in the dip-coating process, is explained on the basis of solvent power and solubility parameters.

Suitability of open-access elevation models for micro-scale watershed planning.

Watershed planning is a major issue in Turkey and other parts of the world. Surrounded by seawater on almost three-quarters of its international borders and by sheer mountains along the coastal regions and throughout the country, Turkey experiences a range of climatic changes, which constantly shape its topography. Recently, the occurrences of floods, landslides, and torrents have increased, forcing decision-makers to come up with solutions to manage and rehabilitate the upper watersheds in order to stop or limit the impact of disasters on downstream areas. Possible solutions should reduce flow coefficients, erosion, and sedimentation and increase reservoir capacities. It is expected that torrent volumes will decrease, drainage regimes on slopes will be better organized and adjusted, thawing snow will be better deposited and delayed, evapotranspiration will increase, surface runoffs will be delayed, and water regimes will be better managed, meaning that flood and torrent control will be achieved. For the reasons mentioned above, watershed parameters need to be firmly set. In the scope of this study, the elevation, slope acreage, and reservoir capacity of a small watershed, as extracted from open-access elevation models, were compared to a real-time kinematic (RTK) global positioning system (GPS)-generated point cloud and the resulting elevation model through various geospatial and analytical means. The Shuttle Radar Topography Mission (SRTM) C-band digital elevation model (DEM) (version 3) proved to be a satisfactory method in making residual, correlation, mean, and reservoir capacity comparisons. An L-band Advanced Land Observing Satellite (ALOS) phased-array-type synthetic aperture radar (PALSAR) and an X-band DLR_SRTM ASTER were slightly superior methods in terms of defining a greater number of slope categories than the other models. Finally, DLR_SRTM and SRTMv3 could match a greater number of slope façades than the other models. Seventeen years after its acquisition, SRTM and its derivatives have continued leading the topographic definition of the Earth.

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The effective mitigation of greenhouse gas emissions from rice paddies without compromising yield by early-season drainage

Global rice production systems face two opposing challenges: the need to increase production to accommodate the world's growing population while simultaneously reducing greenhouse gas (GHG) emissions. Adaptations to drainage regimes are one of the most promising options for methane mitigation in rice production. Whereas several studies have focused on mid-season drainage (MD) to mitigate GHG emissions, early-season drainage (ED) varying in timing and duration has not been extensively studied. However, such ED periods could potentially be very effective since initial available C levels (and thereby the potential for methanogenesis) can be very high in paddy systems with rice straw incorporation. This study tested the effectiveness of seven drainage regimes varying in their timing and duration (combinations of ED and MD) to mitigate CH4 and N2O emissions in a 101-day growth chamber experiment. Emissions were considerably reduced by early-season drainage compared to both conventional continuous flooding (CF) and the MD drainage regime. The results suggest that ED+MD drainage may have the potential to reduce CH4 emissions and yield-scaled GWP by 85–90% compared to CF and by 75–77% compared to MD only. A combination of (short or long) ED drainage and one MD drainage episode was found to be the most effective in mitigating CH4 emissions without negatively affecting yield. In particular, compared with CF, the long early-season drainage treatments LE+SM and LE+LM significantly (p<0.01) decreased yield-scaled GWP by 85% and 87% respectively. This was associated with carbon being stabilised early in the season, thereby reducing available C for methanogenesis. Overall N2O emissions were small and not significantly affected by ED. It is concluded that ED+MD drainage might be an effective low-tech option for small-scale farmers to reduce GHG emissions and save water while maintaining yield.

Improving temperature interpolation usingMODIS LSTand local topography: a comparison of methods in south east Australia

ABSTRACTAvailable climate data for south east Australia is reliant upon elevational lapse rates, which do not account for mesoscale processes that can affect temperatures, such as cold air drainage. Additional predictor variables are available for generating new climate datasets such as topographic indices and Moderate Resolution Imaging Spectroradiometer land surface temperature (MODIS LST); however, these have not been thoroughly tested to date. In this study, the relative benefits of including a localized topographic index and standardizedMODIS LSTvalues for temperature interpolation were assessed using partial bivariate splines, full and partial trivariate splines, and regression kriging. Trivariate splines provided the best interpolation performance in most cases; however, the partial bivariate spline with a fixed dependence upon elevation performed marginally better than the full trivariate spline for minimum temperature. The local topographic index improved theRMSEof minimum temperature climate normals by 17% in comparison to the best performing elevation only model. A further improvement for minimum temperature performance was achieved by including standardized night timeMODIS LSTvalues as covariates (34–39% reduction inRMSE). Standardized day timeMODIS LSTvalues improved maximum temperature interpolation performance; however, the improvement was only marginal in comparison to the full trivariate spline (6% reduction inRMSE). Cross validation of daily maximum and minimum temperature anomalies reflected performance trends shown in the climate normal analysis. Results suggest that the use of alternative approaches to interpolating temperature data may have significant implications for the calculation of bioclimatic variables and provide new opportunities to study extremes at high spatial and temporal resolutions using existing weather station networks. Furthermore, improving minimum temperature surfaces by accounting for temperature inversions driven by cold air drainage regimes may improve our ability to incorporate mesoscale temperature variability into a variety of applications, such as deriving temperature dependent climatic variables, species distribution modelling and assessments of fire risk.

Protocol of the Australasian Malignant Pleural Effusion-2 (AMPLE-2) trial: a multicentre randomised study of aggressive versus symptom-guided drainage via indwelling pleural catheters

IntroductionMalignant pleural effusions (MPEs) can complicate most cancers, causing dyspnoea and impairing quality of life (QoL). Indwelling pleural catheters (IPCs) are a novel management approach allowing ambulatory fluid drainage and...

Potential effects of different irrigation and drainage regimes on yield and water productivity of two potato varieties under Estonian temperate climate

To examine the potential effect of water management on potato yields, the crop model POMOD (POtato MODel) was used. The effects of irrigation, drainage and two-way water management (irrigation+drainage) were simulated with and without natural outflow (percolation to deeper soil layers and runoff). Calculations were performed for two Estonian mainland locations (subcontinental Tallinn for the period 1920–2011, continental Tartu, 1901–2011) and one insular, maritime region (Kuressaare, 1923–2011) as well as for an early and a late potato variety, ‘Maret’ and ‘Anti’, accordingly.In the reference series without water management, the average yields were 18% higher for the late variety compared to the early variety. The mean reference yield in Kuressaare was 8% lower than in mainland locations. The mean water productivity (WP) calculated per evapotranspiration was nearly 45kgmm−1ha−1 (dry mass), somewhat higher for the late variety compared to the early variety. The highest and most statistically significant (P<0.05) increase of yield was achieved from the two-way water management. In the case of natural outflow (water losses to deep percolation and runoff exist), the effect of irrigation prevailed over drainage in all locations. Without outflow, the effects of irrigation and drainage were comparable in the mainland, but the effect of drainage remained negative in Kuressaare. Generally, a positive effect on tuber yield occurred more often from irrigation than from drainage. However, in the case of restricted outflow in the mainland locations, the maximum yield gain from drainage exceeded the yield increase from irrigation by approximately two-fold. The extra yield depended on the amounts of irrigation or drainage by a second order polynomial, while the productivity of irrigated or drained water was, on average, markedly lower than the WP calculated per evapotranspiration, which had a linear relation. Irrigation and drainage water amounts under 50mm did not have any positive effect on yield.The need for irrigation is highest in maritime climate covering Estonian islands and Western and Northwestern coast. In these regions, irrigation increases the mean yield by 18–26% and decreases its variability two-fold. In continental locations, if natural outflow is restricted, implementation of two-way water management projects should be considered, as its effects on yield quantity as well as on stability exceed the sum of separate effects from irrigation and drainage.

CAUSES AND EFFECTS OF MELIORATIONS IN THE NORTH BLACK SEA REGION: DRAINAGE SYSTEMS

The drainage of irrigated areas has led the improved condition of lands the Northern Black Sea. The stabilization of groundwater levels, their desalination, the reduction of areas of saline lands occurred. In this article the actual data on the number of vertical drainage wells, the squares of drained lands in the region, the quantity of drainage water and their mineralization are given. The analysis of the negative effects of constant use of drainage wells was made. The factual amount of drainage water discharge into the bays of the Black Sea shown. The need for integrated management of irrigation and drainage regimes proved. The author describes the current state of drainage systems and accentuates the need for technologies that spare the resources.

Andean growth and monsoon winds drive landscape evolution at SW margin of South America

In the Atacama Desert, the driest place on Earth located at the subduction margin of the Andes, the landscape evolves very slowly and changes in tectonic or erosion processes remain for a long time in the memory of topography. At latitude ∼19°30′S, a threshold between exoreic and endoreic drainage regimes is clearly associated with the latitudinal gradient imposed by the modern monsoon (carrying humidity from the Atlantic) and disposed obliquely over catchments draining the Andes to the Pacific. We summarize the geomorphic, geological and climatic data in the threshold area. We then use these data to constrain numerical experiments of drainage evolution. Data and experimental results are consistent with the development of a flat low-energy morphology, close to sea level, interrupted at ≤10 Ma by tectonic uplift prevailing to the present suggesting trench-ward relief growth by incorporation of the coastal Atacama region to the Andes mountain belt.

Relating relative hydraulic and electrical conductivity in the unsaturated zone

Numerical modeling was used to generate pore-scale structures with different structural properties. They were partially saturated according to wetting and drainage regimes using morphological operations for a range of saturations. The hydraulic and electrical conductivities of the resulting partially saturated grain packs were numerically computed to produce relative hydraulic conductivity versus saturation and relative electrical conductivity versus saturation curves. The relative hydraulic conductivities were then compared to the relative electrical conductivities for the same saturations and it was found that relative hydraulic conductivity could be expressed as relative electrical conductivity to a power law exponent, β. This exponent β was not correlated to porosity, specific surface area, or tortuosity. It did change according to whether the soil was wetting or draining. However, a β value of 2.1 reproduced relative hydraulic conductivity from relative electrical conductivity with little added error. The effects of surface conduction on the observed power law relationship due to either low fluid electrical conductivity or increased clay content were analyzed. The relationship was found to hold for fluid conductivities typical of groundwater and for clay content of less than 5% if the clays were layered perpendicular to electrical flow. The relationship breaks down for electrical flow parallel to clay layers, which makes the choice of electrode arrangement important in cases where clay may be present. This relationship can be used with secondary pressure or saturation data to characterize a soil's hydraulic conductivity curve.