INFLUENCE OF WATER TABLE FLUCTUATION IN THE TAIL OF DRAINS AND IRRIGATION CANALS ON CHEMICAL AND PHYSICAL PROPERTIES OF SOIL IN THE NORTH NILE DELTA REGION

Abstract

The objectives of the present study were to determine the fluctuation effect of water table level in tail ends of drains and irrigation canal on chemical and physical properties of the soil in North Nile Delta region. Six soil profiles from Kafr El-Sheikh were excavated at each location in two lines under investigation. The studied area is located between EL-Gharbia main drain and Nashart drain, since it was started from Kafr El-Sheikh towards the Mediterranean Sea in the north for the first line. Three locations were chosen on Nashart drain at a distance of 5, 10 and 20 km from Burullus Lake towards Sedi-Salim district. The second line of study was EL-Gharbia main drain. Three locations were selected on a distance of 5, 20 and 30 km from the sea towards Kafr- El-Sheikh city. Three observation wells at 10, 50 and 100 meters distance for each profile were installed and the fluctuation of water table depths were recorded, table fluctuation of water were recorded. The obtained results illustrated that the values of hydraulic conductivity increased with increasing depth of water table level. Also, data revealed that the values of hydraulic conductivity decreased with decreasing the distance from the sea and increased with increasing the distance from the drain. Data showed that the fine clay content (<1μ) increases in the 30-90 cm layer, while in shallow water table profiles the aggregation parameters were decreased due to fluctuation of water table level. The values of electrical conductivity, SAR, ESP, pH, soluble cations, anions and total calcium carbonate in the studied soil, were increased gradually towards the tail of the drains and water irrigation canals due to reuse of drainage water and the intrusion of sea water with groundwater. Cation exchange capacity (CEC) decreased gradually towards the tail of drains and irrigation canals, and increased with increasing water table depth. These results declared that the values of organic matter increased when the distance was far from the tail ends of drains and irrigation canals and decreased with shallow water table profiles, while the values of NPK increased with increasing the distance from BurullsLake due to increasing of groundwater salinity.