Shape Factor During Advance Phase in Border Irrigation
AL-Rafdain Engineering Journal (AREJ),
Volume 22, Issue 5, Pages 24-34
AbstractThe present study proposed a new single shape factor to be used in volumetric balance equation. The new single shape factor combines the surface shape factor (0.77) and the subsurface shape factor (Kiefer factor) in one shape factor. By depending on hypothetical design factors: border length, border slope, inflow rate per unit width of border, manning coefficient, as well as soil type, the power function of water advance, the subsurface shape factor and single shape factor have been found respectively. The study introduced an equation to calculate the single shape factor as a function of water advance distance, border length, border slope, inflow rate per unit width of border , manning coefficient and the exponent of infiltration function without needing to data for water advance or the exponent of advance function (b), which is used to calculate the subsurface shape factor (Kiefer factor). Generally, the study demonstrated that the variation limits of the values of the single shape factor are (0.73-0.76) with average of 0.75 when the ratio of advance distance to total border length greater than or equal to 0.4.
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