Abstract: An air inflation/deflection weir having an air bag made of a flexible film attached to the bed and the vertical bank of a river. The weir is adapted to be inflated and deflated by charging and discharging air into and out of the air bag, wherein the effect of the change of the atmospheric air temperature on the inner pressure of the air bag is eliminated and the inner pressure of the air bag is always maintained at predetermined valve. This inflates and raises the weir to a predetermined height in accordance with the detected water levels upstream and downstream of the weir. Maintaining the pressure inside the air bag, avoids abnormally high or low inner pressure of the air bag that would otherwise cause the air bag to burst or buckle resulting in a flood.

Abstract: A set-up/down plural-span weir assembly is made of flexible sheets and comprises a plurality of single-span weirs coupled to each other through pillars across the stream of a river. A pressure medium is introduced into the bags of the single-span weirs to inflate them to set up the single-span weirs and also discharged therefrom to deflate them to set down the single-span weirs. The upstream water of the weir assembly is directly introduced from an upstream water level detection pipe into a bucket or float container of at least one of the single-span weirs, and is indirectly introduced from the upstream water level detection pipe into the bucket or float container of at least another one of the single-span weirs through the bucket or float container of the former one of the single-span weirs or through that of still another one of the single-span weirs.

Abstract: A dam with a flexible cover attached to a bottom sheet by fittings with corrugations formed between the fittings so that upon deflation the cover conforms to the surface of the corrugations, minimizing any floating cover portion. The corrugations may be formed as pipe-like members, as molded portions integral with the bottom sheet or as part of the concrete foundation. Preferably the length between the fittings measured along the corrugation surfaces is at least 1.1 times the linear length therebetween. The corrugations are also preferably recessed to extend no higher than the bottom of the riverbed.

Abstract: An inflatable and collapsible dam arrangement including a flexible membrane weir element positioned so that when it is inflated, it will block a flow of water. The control chamber for the weir is divided into upper and lower sections. The upper section has at least a portion above ground and contains an apparatus for inflating the dam and making the weir element self-supporting. The lower control section includes at least a portion positioned underground and includes an apparatus for collapsing the dam.

Abstract: A dam with a flexible cover atached to a bottom sheet by fittings with corrugations formed between the fittings so that upon deflation the cover conforms to the surface of the corrugations, minimizing any floating cover portion. The corrugations may be formed as pipe-like members, as molded portions integral with the bottom sheet or as part of the concrete foundation. Preferably the length between the fittings measured along the corrugation surface sis at least 1.1 times the linear length therebetween. The corrugations are also preferably recessed to extend no higher than the bottom of the riverbed.

Abstract: A storage tank 1 is divided into oil and ballast water chambers 3, 4 by an elastic partition membrane 2. To prevent the membrane from blocking the oil and water intake/discharge ports 5, 6 during the final stages of loading or unloading, the internal edges and corners of the tank are chamfered by apertured partition plates, supported wire mesh screens or the like, and the intake/discharge ports communicate with the spaces defined behind such plates or screens.