Vízügyi Közlemények, 1960 (42. évfolyam)

4. füzet - VI. Képek a Föld különböző részeinek vízépítési munkáiról

(57) is balanced by the dead weight of the device and of one or more variable counterweights. Water from the canal is distributed by distributing structures. Water admitted to the latei'als and the ditches of the farmers is controlled by the mantle type distributor, which delivers under headwater levels varying between certain limits, a discharge depending solely upon the width of the aperlure, but constant in relation to unit width. A controlled water level can be maintained on rice plots by surface controlling diversions. Excess water is carried away by emergency syphons. Various types of this kind of equipment are manufactured in series to satisfy every water demand. The surface regulators are the Amil and Avis surface stabilizers, for controlling the headwater, respectively tailwater level. The istallations consist of a gate leaf and an air tank (float), with the latter floating in the water to be controlled. The two devices are carried on the common shaft, which is mounted at the device shown in Fig. 5., while actual installations are illustrated in Figs. 2 to 4. Main dimensions of various types are compiled in tabulated form, while the relationship between discharge and head-loss in the case of full gate conditions is plotted on log-log chart in Fig. 9. The discharge coefficient M in the formula Q = M Fjh is 6,4 for the Amil, 4,0 for the Avio and 5,0 for the Avis equipments. The purpose of the double- or mixed type surface regulator is to maintain a constant tailwater level, yet to permit variations therein in the case of violent spate or recesses (Fig. 15). The rice plot surface stabilizer (Fig. 18) is capable of maintaining a constant water depth over the plot regardless of the canal surface. The saddle syphons (Figs. 19.) used for this purpose are self-priming and start to operate at very slight changes in the water level. Mantle-type distributors consist of intake apertures placed side-by-side (Fig. 20). The small gates are either entirely opened, or fully closed. The structure is a combination of a bottom sill and agate sluice. The distributor is installed depending upon expected level fluctuations around the intake and is preceded, when necessary, by an Af/o-type sluice. Shooting movement in the distributor (Fig. 24) permits the division of flow according to a fixed ratio, i. e. the ratio of cross-sectional areas. These installations are used in irrigation systems controlled from the upstream (Fig. 28), or downstream (Fig. 30) side. Upstream control is suggested where water is scarce, but downstream control should be used where water is abundantly available. In the latter case the water demand acting against the sense of flow controls the amount of water diverted. Both basic systems have their particular advantages and drawbacks, so that any choice should depend upon local conditions. Regulation from the downstream side controlled also from above is made possible by the double surface regulators, which appear to be the most practicable devices. (Translated by Z. Szilvássy с. eng.) 4. ОРОСИТЕЛЬНЫЕ СИСТЕМЫ ВО ФРАНЦИИ M. Габри (Рисунки см. на 428 стр. венгерского текста) На территории Франции приблизительно на площади 2,5 милл. га ведётся орошение. Сельскохозяйственное управление ныне ведёт усовершенствование старых оросительных систем, а частично через кооперативы строит новые. Автор на основании опытов научной командировки, проведенной в 1959-ом году описывает три интересные системы: I. Система «Trieastin» получает воду из канала гидроузла Донзер-Мондрагон, созданного на р. Рон. Характерные данные водозабора даются в табл. 1. Сеть главных каналов была построена из сборных, железобетонных оболочек. Распределение воды и его измерение ведётся на принципе верхнего регулирования уровня воды. Проектирование автоматических устройст, регуляторов уровня воды, не удалось.