Abstract
The research assessed the necessity for modification of management variables when treated wastewater (TW) is used for an existing border irrigation in lieu of normal water (NW). The infiltration parameters, characterized by Kostiakov equation, for normal water and treated wastewater were firstly obtained utilizing the double-cylinder infiltrometer. Secondly, the performance parameters considering the low quarter concept were computed through simulations for certain ranges of input data which included three roughness coefficients; three field slopes; three applied depths; and two field lengths. The zero inertia model was utilized to simulate flow along free outflow borders with longitudinal slope. The infiltration rate and consequently its amount were found to decrease with application of treated wastewater. The declined infiltration led to a decrease in the application efficiency equal to nearly 15% as a contrast to an increase in the runoff ratio from 7% for normal water to 31% for treated water. Moreover, the low quarter depths were 150 and 125 mm for normal water and treated water, respectively, indicating that there was less water stored in the field low quarter. It was ultimately evident that the management parameters, application rate and time, need to be modified when treated wastewater is alternatively used in lieu of normal water for which the system was supposedly designed to obtain maximum efficiency.