Sodicity, conventional drainage and bio-drainage in Israel

Soil Research ◽  
2001 ◽  
Vol 39 (6) ◽  
pp. 1269 ◽  
Author(s):  
Avi Gafni ◽  
Yechiel Zohar
Keyword(s):  
Drainage System ◽  
Eucalyptus Camaldulensis ◽  
High Water ◽  
Groundwater Table ◽  
First Year ◽  
Broken Hill ◽  
Water Tables ◽  
Direct Infiltration ◽  
Artesian Aquifer ◽  
Rates Of Growth

Years of intensive irrigated farming in the inland valleys of northern Israel have caused secondary salinity in vast areas. Soil salinity/sodicity surveys, conducted after the problem was recognised, showed relatively high levels of sodium adsorption ratio (SAR) in the active soil layers. In a sample of 7 affected fields, 92.5% of the 1584 SAR measurements on cored soil samples had values >5, and 39% had values >15. Two ameliorative approaches were conceived to reverse the evident salinity/sodicity trends in the Yizre’el Valley: (a) a gravitational, newly engineered, subsurface drainage system; and (b) bio-drainage, using eucalypts as a means to control the high water tables. Both approaches were very successful according to the chosen criteria. The drainage system, comprising 3 drain components, effectively controlled excess water from 3 sources: direct infiltration, lateral subsurface flow, and a deep, presumably upward-seeping, artesian aquifer. The groundwater table response to the installation of the applied drainage system was immediate. In the next rainy season, there was an associated and appreciable deep leaching of Cl– and somewhat less of Na+. More than 3000 ha of land has been drained in this way in the past 10 years in the northern, salinity-prone, inland valleys. The bio-drainage approach, tested in 5 different waterlogged and salinity-affected sites in the Yizre’el Valley, also proved very successful. The rates of growth of Eucalyptus camaldulensis provenances was impressive from the first year. In the best plot, in the fifth year, biomass production reached 30 t/ha.year for the Broken-Hill ecotype (NSW) and peaked at 57 t/ha.year for the Hadera (Israel) ecotype. The annual transpiration of selected trees at Nahalal was 1360 mm, or 3 times the local average annual precipitation. The groundwater table dropped to below 3 m in the summer of the fifth year—sufficient to provide saltflushing conditions. In a related study at the Nahalal site, it was demonstrated that E. camaldulensis screens out the salts while consuming soil water. That, coupled with prolonged stresses of salinity and flooding, can be detrimental to eucalypts. In conclusion, despite sodic conditions, which are ‘formal’ by definition and which prevail in much of the area of our northern valleys, drainage, whether conventional or biological, if well-designed and implemented, is a viable means for controlling local hydrology and restraining salinitysodicity trends.

scholarly journals Long-Term Changes in Floristic Diversity as an Effect of Transforming the Lake into a Retention Reservoir

2021 ◽  
Vol 13 (14) ◽  
pp. 7642
Author(s):  
Joanna Sender ◽  
Danuta Urban ◽  
Monika Różańska-Boczula ◽  
Antoni Grzywna
Keyword(s):  
Drainage System ◽  
High Water ◽  
Diversity Indices ◽  
Habitat Diversity ◽  
Peat Bogs ◽  
Ecological Index ◽  
Natural Lakes ◽  
Lighting Conditions ◽  
Low Reaction Temperature

The Łęczna-Włodawa Lake District is one of the most valuable natural regions in Europe. It is an area of numerous lakes, peat bogs, swamps and forests, which has been undergoing intensive transformation for decades. Among the largest projects were the creation of the Wieprz Krzna Canal system along with the drainage system and the transformation of natural lakes into retention reservoirs. Among the transformed lakes is Lake Wytyckie. The land was used for analyses near the lake, and floristic and habitat analyses were carried out within the boundaries of the contemporary embankment. The studies were carried out from the 1950s, when the lake functioned as a natural reservoir, through to the 1980s (the transformation of the lake), to the 2020s. Lake Wytyckie was transformed into a retention reservoir by increasing its size and flooding the areas inhabited mainly by peat bog, meadow and forest vegetation, which contributed to the impoverishment of both species and habitat diversity of the area, while it increased the nutrient richness of the water. This was reflected both in the decline in the value of individual diversity indices as well as in the ecological index numbers. In the first period of the research, the area was dominated by wetlands, not drained, with a large variety of species that preferred good lighting conditions. Additionally, the habitat was characterized by low reaction, temperature and trophic values. In the following period, there was an increase in the depth of the water of the reservoir, characterized by high water visibility values, which contributed to the presence of protected species, as did the low moisture content of the areas within the embankment and a neutral pH. The factors currently influencing the formation of the vegetation structure are the high humidity of the entire embankment area, the increase in pH, and the significant increase in the share of built-up areas in the immediate vicinity.

scholarly journals Combined measurements of Subglacial Water Pressure and Surface Velocity of Findelengletscher, Switzerland: Conclusions about Drainage System and Sliding Mechanism

1986 ◽  
Vol 32 (110) ◽  
pp. 101-119 ◽  
Author(s):  
Almut Iken ◽  
Robert A. Bindschadler
Keyword(s):  
Functional Relationship ◽  
Water Pressure ◽  
Drainage System ◽  
High Water ◽  
Water Levels ◽  
Surface Velocity ◽  
Glacier Surface ◽  
Measured Velocity ◽  
Sliding Mechanism ◽  
Velocity Variations

AbstractDuring the snow-melt season of 1982, basal water pressure was recorded in 11 bore holes communicating with the subglacial drainage system. In most of these holes the water levels were at approximately the same depth (around 70 m below surface). The large variations of water pressure, such as diurnal variations, were usually similar at different locations and in phase. In two instances of exceptionally high water pressure, however, systematic phase shifts were observed; a wave of high pressure travelled down-glacier with a velocity of approximately 100 m/h.The glacier-surface velocity was measured at four lines of stakes several times daily. The velocity variations correlated with variations in subglacial water pressure. The functional relationship of water pressure and velocity suggests that fluctuating bed separation was responsible for the velocity variations. The empirical functional relationship is compared to that of sliding over a perfectly lubricated sinusoidal bed. On the basis of the measured velocity-pressure relationship, this model predicts a reasonable value of bed roughness but too high a sliding velocity and unstable sliding at too low a water pressure. The main reason for this disagreement is probably the neglect of friction from debris in the sliding model.The measured water pressure was considerably higher than that predicted by the theory of steady flow through straight cylindrical channels near the glacier bed. Possible reasons are considered. The very large disagreement between measured and predicted pressure suggests that no straight cylindrical channels may have existed.

Design of a hydrodynamic leachate containment system

1989 ◽  
Vol 16 (5) ◽  
pp. 615-626 ◽  
Author(s):  
M. D. Haug ◽  
D. J. L. Forgie ◽  
S. L. Barbour
Keyword(s):  
Contaminant Transport ◽  
Water Table ◽  
High Water ◽  
Groundwater Table ◽  
Cutoff Wall ◽  
Transport Modelling ◽  
High Water Table ◽  
Cutoff Walls ◽  
A Site

This paper presents the design concept for a case study sanitary landfill on a site that would not normally have been approved owing to the presence of a high water table. In this design, the base of the landfill was intentionally placed below the water table. A massive 2.5 m wide, 2.5 m high cutoff wall and a 0.3 m thick liner with hydraulic conductivities of approximately 5 × 10−10 m/s were constructed of recompacted glacial till to limit both groundwater intrusion into the landfill and leachate migration out of the landfill. In this case study, the landfill base was placed below the water table to (i) provide a relatively inexpensive source of cover material and (ii) use the hydrodynamic gradient from the high water table to help contain the leachate. Finite element modelling of the seepage and contaminant transport, for alternate designs for lined and unlined landfills placed above and below the groundwater table, is shown to confirm a previous, less-sophisticated, estimation that placing a lined landfill below the groundwater table has definite advantages in reducing both leachate seepage and contaminant transport. Key words: landfill, leachate, hydrodynamic containment, liners, compacted earth cutoff walls, seepage and contaminant transport modelling.

On the relative growth and development of various breeds and crosses of sheep

1921 ◽  
Vol 11 (4) ◽  
pp. 367-407 ◽  
Author(s):  
John Hammond
Keyword(s):  
Alimentary Canal ◽  
Live Weight ◽  
The Body ◽  
First Year ◽  
Fat Percentage ◽  
Early Maturity ◽  
Relative Growth ◽  
Fodder Crops ◽  
First Year Of Life ◽  
Rates Of Growth

Records of the live and carcase weights of sheep exhibited at the Smithfield Show from 1893 to 1913 have been treated statistically. The results show the average weights, rates of growth, and proportions of the carcase in the different breeds of sheep at 9 months and at 21 months of age (see Tables II and V).On the average of all breeds the rate of growth declines from 4·7 lbs. per week from birth to 9 months of age to 1·7 lbs. per week from 9 to 21 months of age.The carcase percentage increases with age on the average from 61 per cent, at 9 months to 65 per cent, at 21 months and with it the percentage of fat from 5·7 per cent, at 9 months to 64 per cent, at 21 months. On the other hand the proportions of pluck, skin and alimentary canal (“Unaccounted for”) decrease with age.Ratios of early maturity are given for the various breeds and the factors which affect it are discussed.The average weights, rates of growth and proportions of the carcase are given for the different crosses of sheep (see Tables IX and XIII).From a comparison of crossbreds with pure breeds it would appear that crossing leads to increase in live weight and probably more early maturity. There is an indication that the proportions of carcase, fat and pluck are less but the proportions of skin and alimentary canal are greater in crossbreds than in the pure breeds of sheep.There is greater variation in live weight in the Cheviot and Blackface breeds than in the Leicester, Southdown, Hampshire and Suffolk breeds; in the latter breeds variability decreases but in the former breeds it increases with age.Variability in live weight at 9 months old has steadily increased from 1893 to 1913 but at 21 months old there has been little change.Some parts are more variable in their proportion to live weight than are others. Fat and alimentary canal are most variable, skin and pluck slightly less variable, while the proportion of carcase is less variable even than live weight.The variability of the proportions of carcase, pluck and alimentary canal increase while the variability of the proportions of fat and skin decrease with age.Within a breed and among animals of the same age the heaviest sheep generally have the highest carcase and fat percentage and the lowest percentage of pluck, skin and alimentary canal.A high proportion of carcase is correlated with a high proportion of fat and a low proportion of skin and alimentary canal at 9 months old. At 21 months old the same holds true with the exception that the sheep with the highest carcase percentage have not the most fat.The proportion of pluck does not appear to be correlated with any other part of the body except inversely with the live weight.During the period 1893–1913, although individual breeds show differences, the majority have increased in live weight at 9 months old but at 21 months old have remained practically constant in weight.The sheep exhibited in 1840 were very much fatter than those shown in the Carcase Classes of to-day and are probably comparable with those of the present-day Live Classes. Since 1840 Leicesters have shown a great increase and Southdowns a small increase in weight.The carcase percentage of sheep both at 9 and 21 months of age has steadily decreased during the period 1893–1913; this has been attended by an increase in the proportion of pluck, skin and alimentary canal.There is an indication that the influences which affect sheep in their first year of life (store period) affect their ultimate size.The seasonal variation in the weight attained by sheep is dependent on the rainfall; a high rainfall through increased root and fodder crops causing increased live weight.

scholarly journals Determinants of Flooding and Strategies for Mitigation: Two-Year Case Study of Benin City

Geosciences ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 136 ◽  
Author(s):  
Giuseppe Cirella ◽  
Felix Iyalomhe ◽  
Paul Adekola
Keyword(s):  
Flood Hazard ◽  
Drainage System ◽  
High Water ◽  
Benin City ◽  
Close Proximity ◽  
Risk Reduction Measures ◽  
And Migration ◽  
Transportation Routes ◽  
The City

Recent flood disasters in Benin City, Nigeria have claimed a number of lives, damaged property, and threatened the overall livelihood of residents. The economic burden of such events has forced a vast reallocation of monetary resources for clean-up and recovery, as well as forcibly altered and suspended internal trade via devastated transportation routes. Secondary trends include inflation and migration concerns. As a result, the aim has been to prioritize mitigation by examining easily read, rapidly accessible flood hazard maps, as well as assess and identify areas within the city prone to flooding. We used a number of data sources and conducted a questionnaire surveying three of the local government areas of Benin City over a two-year period. Findings indicate excessive unsustainable land use and land cover change and a flat and high water table area with close proximity to the Atlantic Ocean make the city susceptible to flood risk. Heavy rainfall and drainage system blockage are leading causes of flooding which have destroyed property and houses—two major side effects. A number of mitigation and disaster risk reduction measures were, hereafter, recommended to reduce flooding occurrence in Benin City or lessen its effects on inhabitants.

Engineering geology of Quaternary soils: II Methods of treatment

1991 ◽  
Vol 7 (1) ◽  
pp. 39-62 ◽  
Author(s):  
F. G. Bell
Keyword(s):  
Thermal Stabilization ◽  
High Water ◽  
Ground Freezing ◽  
Wide Range ◽  
Water Tables ◽  
Pore Water Pressures ◽  
Engineering Problems ◽  
Electro Osmosis ◽  
Introductory Paper ◽  
Methods Of Treatment

AbstractThe various soils of Quaternary age present a wide range of engineering problems such as low density, low strength, high compressibility, high permeability, collapsibility and high swell/shrink potential, as well as difficulties caused by the presence of high water tables and zones of high pore water pressures. This introductory paper describes a number of methods of ground treatment that can be used to alleviate these problems including exclusion techniques, grouting, ground freezing, drainage and groundwater lowering techniques, electro-osmosis and electro-chemical stabilization techniques, compaction and reinforcement, and methods of chemical and thermal stabilization.

scholarly journals Theoretical Analysis and Experimental Study of Subgrade Moisture Variation and Underground Antidrainage Technique under Groundwater Fluctuations

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Liu Jie ◽  
Hailin Yao ◽  
Pan Chen ◽  
Zheng Lu ◽  
Xingwen Luo
Keyword(s):  
Groundwater Table ◽  
Richards Equation ◽  
Natural Factor ◽  
Capillary Action ◽  
Moisture Variation ◽  
Study Results ◽  
Water Tables ◽  
Groundwater Fluctuations ◽  
The Stability ◽  
Drainage Effect

Groundwater is a main natural factor impacting the subgrade structure, and it plays a significant role in the stability of the subgrade. In this paper, the analytical solution of the subgrade moisture variations considering groundwater fluctuations is derived based on Richards’ equation. Laboratory subgrade model is built, and three working cases are performed in the model to study the capillary action of groundwater at different water tables. Two types of antidrainage materials are employed in the subgrade model, and their anti-drainage effects are discussed. Moreover, numerical calculation is conducted on the basis of subgrade model, and the calculate results are compared with the experimental measurements. The study results are shown. The agreement between the numerical and the experimental results is good. Capillary action is obvious when the groundwater table is rising. As the groundwater table is falling, the moisture decreases in the position of the subgrade near the water table and has no variations in the subgrade where far above the table. The anti-drainage effect of the sand cushion is associated with its thickness and material properties. New waterproofing and drainage material can prevent groundwater entering the subgrade effectively, and its anti-drainage effect is good.

scholarly journals The Biology of Balanus balanoides. III. The Soft Parts

1935 ◽  
Vol 20 (2) ◽  
pp. 263-277 ◽  
Author(s):  
Hilary B. Moore
Keyword(s):  
Dry Weight ◽  
High Water ◽  
Mantle Cavity ◽  
Tissue Growth ◽  
First Year ◽  
Summer Period ◽  
Tidal Level ◽  
Tissue Weight ◽  
Low Levels ◽  
Balanus Balanoides

1. The relation between the dry weight of the decalcified barnacle and its shell volume has been determined in its relation to age, season and tidal level, at Port Erin, with the following results: (a) In immature barnacles, tissue growth continues throughout the year, but is most rapid in the spring and autumn, (b) In mature barnacles which produce a considerable amount of larvæ there is a heavy drop in tissue weight during the summer period of high temperature, and another slighter drop during the winter, the latter being apparently associated with the presence of developing larvæ in the mantle cavity.2. Gonad samples were examined seasonally. At low levels on the shore the barnacles mature in their first year. Above this level they do not commence to mature until over a year old. The sequence of changes in the gonads is described. A condition of senility is found in many of the largest high-water barnacles.3. The naupliar content was estimated in relation to size and tidal level, counts of up to 13,000 larvæ per individual being obtained. The dry weight of a fully developed nauplius was determined to be 7·5×10-4 mgm.

Gravel Soil Landslide Sliding Mechanism and Stability Analysis Based on Fluid-Solid Coupling

2011 ◽  
Vol 255-260 ◽  
pp. 3535-3538
Author(s):  
Zhi Bin Sun ◽  
Xiao Li Yang
Keyword(s):  
Drainage System ◽  
High Water ◽  
Underground Water ◽  
Soil Slope ◽  
Rainfall Condition ◽  
Monitoring Result ◽  
Sliding Mechanism ◽  
Gravel Soil ◽  
Underground Water Level ◽  
Level Monitoring

The developed groundwater pipe network drainage system in the gravel soil slope has a significant impact to its stability. Considering the underground water level monitoring result, this paper simulates the xikengkou slope after the excavation and rainfall conditions based on fluid-solid coupling. The result presents that excavation at toe of slope damaged the groundwater discharge path. In the rainfall condition, the groundwater level increases significantly, which leads displacement occurring within the gravel soil slope. On the other hand, the displacement makes the drainage system be further destroyed and the permeability coefficient continues decreasing. Finally, the high water table leads the slope stability decreasing considerably, even to instability.

scholarly journals DRAINAGE OF AN IRRIGATED SALINE SOIL IN ALBERTA

1982 ◽  
Vol 62 (2) ◽  
pp. 387-396
Author(s):  
D. R. BENNETT ◽  
G. R. WEBSTER ◽  
B. A. PATERSON ◽  
D. B. HARKER
Keyword(s):  
Water Table ◽  
Crop Production ◽  
Saline Soil ◽  
Soil Depth ◽  
Drainage System ◽  
High Water ◽  
Coarse Sand ◽  
Irrigation Period ◽  
Dilution Effects ◽  
Sand And Gravel

A shallow subsurface drainage system effectively controlled a high water table and reduced salinity in an irrigated soil near Magrath, Alberta. Plastic corrugated tubing was installed in 1976 at depths of 1.1–1.5 m and spacings of 15 and 30 m in a moderately saline soil. During the irrigation period, the water table rose to within 0.3 m of the surface but was lowered to pre-irrigation levels within 48 h. The water table was maintained at, or below, the depth of the drains between irrigations. The 15- and 30-m spacings of the drain lines were equally effective in providing water table control in this lacustrine soil which was underlain by a coarse sand and gravel layer. Salinity levels were decreased substantially only within the surface 0.3-m soil depth. Quality of the drainage effluent remained constant throughout the growing season with only small dilution effects detected during irrigations. Barley yields increased to 3900 kg/ha in 1978, 2 yr following drainage of this saline soil which had been out of crop production for 20 yr.

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