Laboratory Tests of Water Level Regulators in Ditches of Irrigation Systems

Abstract

Observed changes in hydrological conditions indicate the need for economical use of water. This pertains to water management on a national scale, river basins and drainage systems. The outflow of water can be extensively regulated after various forms of retention in the catchment. The water level regulators presented herein enable the damming of water in drainage networks and the adjacent ground. Their advantages include their simple structure and operation principles and also the ability to adapt to currently existing devices in sub-irrigation systems. Laboratory tests were conducted to determine the hydraulic characteristics and operating conditions of three innovative regulator solutions. They focused on changing water damming heights by the closure of successively placed beams in order to obtain the required water level in the given hydrometeorological conditions. The structures of the regulators were made of plastics and rectilinear fillings for securing S-type excavations and elements of sheet piling with a developed shape in the plan of U and Z types, offering advantages compared to traditional materials (with respect to installation, operation and durability). All tested regulators were characterized by the effective flow Qe, caused by water leaks due to the lack of tightness of the regulator elements. The regulator with rectilinear beams of S-type closures offered the highest effective flow, which was 4 ÷ 5 times higher than in other regulators. U- and Z-type regulators were better at facilitating the regulation of the water table and the flow than the S rectilinear regulator. This led to both: the greater tightness of connections and the use of an overflow with a developed crest in the plan. The U and Z controllers had the highest hydraulic efficiency, expressed as the flow increase coefficient, at overflow layer heights of up to 5.0 cm. For tested fillings larger than 5.0 cm, U-type beams with a cylindrical corner shape had a lower flow increase coefficient (kq = 1.25) than Z-type beams with an angular corner shape, for which kq ∈ <1.35 ÷ 1.38>.