A study on the occurrence and depth of impermeable layers in a newly reclaimed area at west Nile Delta and its effects on spacing calculation between field drains
Abstract: The current study was conducted on a newly reclaimed area of about 200 feddans at the Interagro Farm, Nubaria Agricultural Development Region, West of the Nile Delta, to study the occurrence and depth of the impermeable layers and their effects on field drain spacings. Field investigation were carried according to grid system to initiate a number of 20 investigation points, with an area of about 10 feddans for each one. Each point was opened 2m deeps using auger hole to collect the soil samples and measuring the hydraulic conductivity. To identify the depth of the impermeable layer the experimental points of 2m deep were boring to reach 5m depth. Also, soil samples from barrier were collected.
The results show that, the dominant texture class of the studied area is mainly sandy clay loam and sandy loam. Soil calcium carbonate content in the investigated soil samples ranged between 5.14 and 18.78%, but it reached 29.79% in the barrier, and it is moderate to high affects most of physical characteristics of the soil.
The obtained data of the hydraulic conductivity revealed that its values ranged between 0.1 and 4.9 m/day. This wide range covers the different classes of hydraulic conductivity, due to the influence of the impermeable layers upon the water flow pattern in the soil, since it limits the flow movement.
Therefore, the soil survey information is then applied to determine a reliable impermeable layer values and these values will be used in drainage equations to identify proper field drain spacings. Hence, the occurrence and depth of impermeable layers are of the greatest parameter in the design of a drainage system. The impermeable layer depths are divided into five classes: less than 1, 1 - 2, 2 - 3, 3 - 4, 4 - 5 and more than 5m depth. These classes represent 0.0, 15, 35, 30, 10 and 10%, of the total investigated points respectively. It is noteworthy that there was no impermeable layer throughout a depth less than 1m in the studied points. At the same time, the majority of the impermeable layers are found between the depth of 2m and 4m. The dominant texture class of the impermeable layers was sandy clay loam. While, percentages of calcium carbonate ranged between 8.24 and 29.79% for the impermeable layer. The data reveal that, the percentage of CaCO3 content increased in the impermeable layers as compared with that found in the upper zone of this layer. The data showed also that, the salt content of barrier still be considered low and Ca++ is the dominant cation. Whereas, the chloride was the dominant anion followed by sulfates. Most of the salts are present in the forms of CaCl2 and CaSO4 in the impermeable layers under study.
Also, the data showed that, the distance between lateral drain increased with increasing the depth of impermeable layers, where the calculated spacing between laterals ranged between 23-29m when the depth of impermeable layer ranged between 1 and 2m from the soil surface, and the distance reached to 161m in case of 5m depth for impermeable layer. Also, it noticed that when the impermeable layer depth increased from 1 – 2 to 2 – 3m, the lateral spacing increased three folds but when the depths of the barrier reached 4 and 5m, the drain spacing becomes 4 and 6 times as compared with the depth of 1 – 2m . Finally, it is recommended that, to design a suitable drainage system in the newly reclaimed areas, information survey must be given in all these areas, especially the occurrence and depth of impermeable layers
Publication year 2006
Pages 325-337
Availability location Soils, Water and Environment Research Institute, ARC
Availability number
Organization Name
City Zagazig
serial title Egyptian Journal of Applied Sciences
ISSN 1110-1571
Department Field Drainage Research
Author(s) from ARC
Agris Categories DrainageSoil erosion, conservation and reclamation
AGROVOC
TERMS		 Drainage. Permeability. Reclamation. Soil surveys.
Publication Type Journal
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