scholarly journals Evaporation-Induced Water and Solute Coupled Transport in Saline Loess Columns in Closed and Open Systems

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-26
Author(s):  
Jian Xu ◽  
Wei Lan ◽  
Yanfeng Li ◽  
Wen-Chieh Cheng ◽  
Jun Yuan ◽  
...  
Keyword(s):  
Water Supply ◽  
Open Systems ◽  
Atmospheric Temperature ◽  
Soil Salinization ◽  
Coupled Transport ◽  
Basic Law ◽  
Initial Stage ◽  
Moisture State ◽  
External Water ◽  
Water And Solute Transport

Evaporation-induced water and solute coupled transport is a significant cause for soil salinization that leads to a series of engineering and environmental problems. In the artificial evaporation environment, including relative humidity, atmospheric temperature, atmospheric pressure, radiation intensity, and wind speed, evaporation of loess columns with sodium sulfate, temperature profile, and water and solute transport in closed and open systems were investigated. In the former case, a range of stability was noted in the lower part of the column where the heat, water, and solute coupled transport only exhibited a weak response to a specified evaporation environment. As the environment was more favorable for evaporation, or at a higher gradient of temperature, this range extended downwards, while above this range the heat, water, and salt profiles in the evaporation-affected domain changed dramatically, characterized by a basic law that solutes moved with water and were then retained with water desalinated. Evidences were found from the profiles that the water contents in the evaporation-affected range decreased but the salt contents increased, especially in the surface. In an open system, by contrast, there was little difference in temperature but greater in water and salt profiles. Three stages were found from the supply of external water during evaporation. In the initial stage, the higher gradient formed between the initial moisture state and the preset external water level led to a rapid supply of external water. As the evaporation proceeded, a relatively stable water profile was reached as the intensity of water supply approached to that of evaporation, accompanied by a continual migration of solutes towards the surface. Due to the accumulation of precipitated salts, water transport was slowed down, and the intensity of water supply decreased. The changes in soil suction may account for the above behavior.

Effects of the use of drainage-/ infiltration systems in the Pleistocene uplands of the Netherlands

2021 ◽  
Author(s):  
Janine A. de Wit ◽  
Ruud P. Bartholomeus ◽  
Gé A.P.H. van den Eertwegh ◽  
Marjolein H.J. van Huijgevoort
Keyword(s):  
Waste Water ◽  
The Netherlands ◽  
Boundary Conditions ◽  
Water Supply ◽  
Field Experiments ◽  
Crop Yields ◽  
Scale Model ◽  
Groundwater System ◽  
External Water ◽  
The Impact

<p>The Netherlands is a low-lying, flood prone country, located in a delta. Most Dutch agricultural fields are drained to quickly get rid of excess water to increase crop production. Additionally, the freshwater demand of different sectors (agriculture, industry, drinking water) increases, causing an increased pressure on the groundwater system. The combination of fast drainage and increased use of groundwater for human activities led to declining groundwater tables in the Dutch Pleistocene uplands. Given the changing climate resulting in prolonged dry periods, solutions for water retention are needed to decrease the pressure on the groundwater system to guarantee the future water supply for different sectors.</p><p>One of the solutions could be to modify the current drainage systems to drainage-infiltration (DI)-systems with a dual purpose. First, the DI-system stores water during (heavy) rainfall in the soil, but if the risk of flooding increases, the DI-system discharges water. Second, (external) water is actively pumped into the drainage network to raise groundwater tables (subirrigation). Through efficient use of the available external water source (treated waste water, industrial waste water, surface water or groundwater) the pressure on the groundwater system reduces.</p><p>We focus on the data and model results of several field experiments using subirrigation conducted in the Dutch Pleistocene uplands (± 2017-2020). The effects of subirrigation on the groundwater table and soil moisture conditions will be shown, including water supply rate and hydrological boundary conditions. We also provide both the set-up and results of field scale model simulations (SWAP; Soil-Water-Atmosphere-Plant model) to i) quantify the impact of subirrigation on all components of the (regional) water balance (including transpiration, drainage and groundwater recharge), ii) quantify crop yields, and iii) optimize the configuration and management of subirrigation systems for different soil types, hydrological boundary conditions, and climate scenarios.  </p>

Water relations of germination in the recalcitrant seeds of Quercus robur L.

1994 ◽  
Vol 4 (3) ◽  
pp. 315-322 ◽  
Author(s):  
W. E. Finch-Savage ◽  
H. A. Clay
Keyword(s):  
Water Supply ◽  
Water Relations ◽  
Quercus Robur ◽  
High Moisture Content ◽  
High Moisture ◽  
Mature Fruit ◽  
Tissue Pressure ◽  
Radicle Growth ◽  
Physical Barriers ◽  
External Water

AbstractQuercus robur L. fruits are desiccation sensitive and shed from the plant at high moisture content (c. 48%). Water relations measurements were taken at intervals during the germination of prematurely-harvested immature fruits and naturally-shed mature fruits. In fruits from both harvests the pericarp and seed coat delayed germination by providing physical barriers to emergence of the radicle and by restricting the rate of imbibition. Although immature fruits could germinate in the absence of water they germinated more rapidly in the presence of an external water supply. The fully-mature fruit required a supply of external water, but germination was more rapid than in immature fruits. Substantial physiological changes, resulting in the accumulation of solutes, and increased axis size and extensibility occurred before splitting of the pericarp and subsequent germination of immature fruits. Such changes did not occur in fully-mature fruits, but fruits, from both harvests imbibed water and splitting of the pericarp appeared to result from increased embryo size and tissue pressure. Splitting was minimal prior to germination in immature fruits without an external water supply. It is suggested that the resulting reduction in Ψp when the pericarp splits was greater in the axis than in the cotyledons because of its greater capacity for expansion. This would create a Ψw gradient driving water flow to the axis from the cotyledons allowing continued radicle growth for germination.

scholarly journals MODERNIZATION OF THE CONSTITUTION OF RUSSIA (TO THE RESULTS OF THE DISCUSSION IN CONNECTION WITH THE 25TH ANNIVERSARY)

2019 ◽  
Vol 23 (2) ◽  
pp. 163-183
Author(s):  
Nikolay A. Vlasenko
Keyword(s):  
Russian Federation ◽  
Legal Status ◽  
Public Authorities ◽  
25Th Anniversary ◽  
Basic Law ◽  
Initial Stage ◽  
History Of ◽  
The Russian Federation ◽  
The One ◽  
Constitutional Construction

A quarter of a century has passed since the adoption of the Constitution of the Russian Federation by a national referendum. The jubilee gives a reason to talk about the optimality of constitutional provisions, their effectiveness, and somewhere practical expediency. The article aims to analyze the points of view expressed in this regard in the scientific press, newspaper periodicals and other media. However, the author first refers to the history of the emergence of the Constitution of the Russian Federation in 1993. It is noted that the Basic Law, on the one hand, was a result of military-political compromise between supporters of the parliamentary vision of the future structure of the country and supporters of a strong presidential power, on the other hand, allowed ultimately abolish the Soviet system and traditions. The mentioned situation and the factor of haste and hurry could not but affect the content and technical and legal quality of the document. The author has reduced the opinions expressed on the issue of modernization of the Constitution of the Russian Federation to three main positions: 1) The Constitution has not exhausted its potential and there is no reason to change its text; 2) a full-fledged constitutional reform is required, the current Constitution has exhausted its potential; 3) there is a need for precise partial changes and additions that can improve the Constitution. The article argues that the last position of the so-called precise partial changes is the most productive and allows to make the constitutional document adequate and relevant. In this regard, it is proposed to hold several round tables at the initial stage on the development of concepts for improving the constitutional foundations. One of them, the author calls promising and offers to prepare a list of proposals for the removal of ideologically and actually not confirmed in practical life provisions. These are provisions about Legal State (excluding the principle of separation of state power), Welfare State, etc. Another concept that also needs to be developed is institutional (the concept of the legal status of public authorities, their powers, checks and balances, etc.). These ideas, the author believes, should be a compromise between scientists, then become public and be implemented in the practice of constitutional construction.

Biochar manages salt-degraded land and conserves water: Effects and mechanism

2020 ◽  
Author(s):  
Xinqing Lee ◽  
Yimin Huang ◽  
Fang Yang ◽  
Ying Xing ◽  
Liang Xu ◽  
...  
Keyword(s):  
Water Supply ◽  
Application Rate ◽  
Soil Salinization ◽  
Water Evaporation ◽  
Degraded Land ◽  
Biomass Waste ◽  
Salt Leaching ◽  
Short Period ◽  
Water Effects ◽  
Soil Cracking

<p>Soil salinization represents a wide-spread land degradation in the world, especially in arid regions. Current management involves excessive water consumption. As a pyrolyzed residue of biomass waste, biochar has the potential to combat salinization at limited water supply, the effect and mechanism, however, remain to be clarified. We monitored the movement of salts and water in the profile of irrigation-silt soil during watering and evaporation in both laboratory and the field in Kashgar oasis in Xinjiang, China, and found that biochar exacerbates salinization within a short period of time after its application due to its high content of salts, nevertheless, it strengthens salt leaching in irrigation while intensifies salt accumulation in the top soil at the expense below during evaporation, all as results of invigorated movement of salts. Removing the top 2 cm before sowing, therefore, rejuvenates the soil well. Adsorption of biochar retards migration of salts in cation forms, but the effect is trivial. Due to increase to soil water content, biochar promotes evaporation before soil cracking. This is reversed, however, once the cracking occurs, which is inevitable in irrigated farmland and increases evaporation by 77%. Biochar counteracts soil cracking by alleviating soil compaction, lowering water evaporation by 43% at 10% of biochar application rate. Our results indicated that agriculture application of biochar creates salt distribution conducive to desalting in a mechanical way. In conjunction with the effect of anti-fracturing and enhanced salt leaching, it lowers water demand substantially, providing a new solution to the agricultural sustainability at reduced water supply.</p>

scholarly journals The Physiology of Sugar-Cane VI. Effects of Temperature, Light, and Water on Set Germination and Early Growth of Saccharum Spp.

1963 ◽  
Vol 16 (2) ◽  
pp. 416 ◽  
Author(s):  
PC Whiteman ◽  
TA Bull ◽  
KT Glasziou
Keyword(s):  
Water Supply ◽  
Sugar Cane ◽  
Early Growth ◽  
Subsequent Growth ◽  
Saccharum Spp ◽  
Effects Of Temperature ◽  
External Water

Freshly cut sets from irrigated cane gave 100% germination without an external water supply. Pre-soaking did not accelerate germination or subsequent growth.

Water resources management in central northern Namibia using empirically grounded modelling

2012 ◽  
Vol 2 (2) ◽  
pp. 112-123 ◽  
Author(s):  
M. Zimmermann
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
Large Scale ◽  
Driving Forces ◽  
Saline Groundwater ◽  
Water Supply Management ◽  
External Water ◽  
High Precipitation ◽  
System Variables

In this paper, a new methodology for the analysis and assessment of water supply regimes is presented. The problems of water supply management in developing countries are multidimensional and interdependent. Conventional methods, which only deal with separated and isolated issues, are not appropriate to deal with these problems. The method presented here, however, can comprehend the whole system. Therefore, using this method, conclusions for the management of adapted institutional and technological transformations can be drawn. In this study, relevant system variables of a problem context are identified, and their interdependencies are assessed and interpreted. This is done by using a method of qualitative interview analysis (grounded theory) and a cybernetic modelling approach (sensitivity analysis). In doing so, it is possible to identify outstanding variables which are essential to understand the system. These variables reveal the weakest links, driving forces, systemic stabilisers and the sustainability indicators of the system. The case study area is the Cuvelai-Etosha-Basin in central northern Namibia where a large-scale water supply system has been established. The water supply in the region is determined by the dependence on external water resources, high precipitation variability, absence of perennial rivers, saline groundwater, population growth and urbanisation.

scholarly journals Economic Effects of an Exhaustible Irrigation Water Supply: Texas High Plains

1973 ◽  
Vol 5 (1) ◽  
pp. 135-139 ◽  
Author(s):  
James E. Osborn
Keyword(s):  
Water Supply ◽  
Regional Development ◽  
Irrigation Water ◽  
Economic Effects ◽  
High Plains ◽  
Texas High Plains ◽  
Complementary Resources ◽  
Initial Stage ◽  
Derived Demand ◽  
Available Resources

Specialization by a region is determined primarily by resources available and the available markets for the products. In addition, specialization in the production of a product or in an industry is an initial stage of regional development but may not be sufficient. As firms locate in a region to produce with the available resources, a derived demand will develop for substitute and complementary resources.Input supply firms will locate in the region to satisfy the derived demand for resources. In addition, other firms will locate in the region to process some of the output of the emerging industry. As associated industries locate in the area, an interdependency will develop between the industry's supply requirements and/or markets for their products. Consequently, regional development has a tendency to include firms that are interdependent.

scholarly journals Effect of Frequency of Multi-Source Water Supply on Regional Guarantee Rate of Water Use

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1356 ◽  
Author(s):  
Shanghong Zhang ◽  
Jiasheng Yang ◽  
Zan Xu ◽  
Cheng Zhang
Keyword(s):  
Water Supply ◽  
Water Use ◽  
Main Body ◽  
Source Water ◽  
Water Supplies ◽  
Allocation Model ◽  
External Water ◽  
The Impact ◽  
Guarantee Rate ◽  
Regional Water

Multi-source, combined water supply models play an increasingly important role in solving regional water supply problems. At present, in the area of regional water supply, models are mainly used to study the problem of overall water guarantee rate, and do not take into account the impact of the uncertainty of multi-source water supplies on water supply risk. There is also a lack of research on how changes in multi-source water supplies affect sub-region and sub-user water guarantee rates. To address this knowledge gap, the encounter probability of different frequencies and a refined water resources allocation model of multi-source supplies were used. Using Tianjin as an example, this paper studies the quantitative relationship between the uncertainty of multi-source water inflows and the regional guarantee rate of water use. The objectives of the study are to analyze the changing trend of the water shortage rate and the main body of water supply in each region, and to quantitatively describe the influence of the variation of multi-source water supply on the main body of water supply for users. The results show that under the same requirement of guarantee rate for water use, as the number of water diversion sources increase, the probability of water supply meeting the water use rate increases significantly, and the risk to water supplies decreases. At the same time, suburban areas have a low dependence on external water supplies, while the change in the quantity of external water sources has a great impact on the water supply of the Zhongxinchengqu and Binhaixiqnu areas. The distribution and main body of water supply will change for different water users. Therefore, it is important to ensure a stable supply of external water for maintaining the guarantee rate of regional water use.

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