AIR CONTENTS IN SOILS ABOVE A HIGH WATER TABLE — APPLICATION TO DRAINAGE CLASSIFICATION OF SOILS

1973 ◽  
Vol 53 (3) ◽  
pp. 325-330 ◽  
Author(s):  
K. MICHALICA ◽  
M. A. ZWARICH ◽  
C. F. SHAYKEWICH

Studies were conducted at 10 sites with a high water table with a view to classifying soil drainage status from a knowledge of water table depth and water retention properties of the soil. The parameter used to assess soil drainage status was air-filled porosity. The average error in predicting air-filled porosity in the field from water retention data was 2.3%. It was found that air-filled porosity in the water retention samples could be predicted from soil components to within 3.4–5.9% of the actual value (on the average). This suggests that where water retention data are not available, a knowledge of soil components and water table depth may be sufficient to obtain an estimate of air-filled porosity. A system of soil drainage classification based on air-filled porosity is proposed.

2016 ◽  
Vol 47 (S1) ◽  
pp. 293-312 ◽  
Author(s):  
Xiuli Xu ◽  
Qi Zhang ◽  
Yunliang Li ◽  
Xianghu Li

Groundwater plays an important role in supplying water to vegetation in floodplain wetlands. Exploring the effect of water table depth (WTD) on vegetation transpiration is essential to increasing understanding of interactions among vegetation, soil water, and groundwater. In this study, a HYDRUS-1D model was used to simulate the water uptake of two typical vegetation communities, Artemisia capillaris and Phragmites australis, in a floodplain wetland (Poyang Lake wetland, China). Vegetation transpiration was compared for two distinct hydrological conditions: high water table (2012) and low water table (2013). Results showed that vegetation transpiration in the main growth stage (July–October) was significantly influenced by WTD. Under high water table conditions, transpiration of A. capillaris and P. australis communities in the main growth stage totaled 334 and 735 mm, respectively, accounting for over 90% of the potential transpiration. Under low water table conditions, they decreased to 203 and 510 mm, respectively, due to water stress, accounting for merely 55% of the potential transpiration. Scenario simulations found different linear relationships between WTD and the ratio of groundwater contribution to vegetation transpiration. An increase of 1 m in WTD in the main growth stage may reduce the ratio by approximately 25%.


1971 ◽  
Vol 61 (3) ◽  
pp. 579-590 ◽  
Author(s):  
William Enkeboll

abstract Soil and water conditions had an effect on the degree of damage to structures. Most structures were located on alluvium with a high water table. Settlements occurred in dike and causeway fill in Chimbote harbor. Severe problems to communication occurred in some areas through embankment failures and road slides.


1991 ◽  
Vol 34 (6) ◽  
pp. 2445-2452
Author(s):  
C. R. Camp ◽  
M. L. Robbins ◽  
D. L. Karlen ◽  
R. E. Sojka

1989 ◽  
Vol 16 (5) ◽  
pp. 615-626 ◽  
Author(s):  
M. D. Haug ◽  
D. J. L. Forgie ◽  
S. L. Barbour

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.


1979 ◽  
Vol 20 (6) ◽  
pp. 493-505 ◽  
Author(s):  
R.P. Tripathi ◽  
B.P. Ghildyal

2013 ◽  
Vol 50 (4) ◽  
pp. 435-450 ◽  
Author(s):  
Christopher T.S. Beckett ◽  
Charles E. Augarde

Several models have been suggested to link a soil's pore-size distribution to its retention properties. This paper presents a method that builds on previous techniques by incorporating porosity and particles of different sizes, shapes, and separation distances to predict soil water retention properties. Mechanisms are suggested for the determination of both the main drying and wetting paths, which incorporate an adsorbed water phase and retention hysteresis. Predicted results are then compared with measured retention data to validate the model and to provide a foundation for discussing the validity and limitations of using pore-size distributions to predict retention properties.


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