I . Field of Invention

The present invention is related to a dam built of a flexible and inflatable material to be used to temporarily isolate sections of lakes, bays and even streams with low water flowrates.

II . Background of Invention

To our knowledge, there are no similar systems for temporary containment of waters, employing the process described in this document or any other process.

The only other known system is the one employing inflatable surface floats, used to isolate oil spills on aqueous surfaces. These systems, however,are used to isolate suspended material at the water surface level only and do not isolate the column of water located between the surface and t bottom of the basin.

Usually, water containment in dams is undertaken by permanent or semi-permanent structures, using rocks or steel structures . The drawback of such structures is that they require a sizable amount of civil works and lengthy construction period, have associated high costs, cannot be reused, alter the local topography and have a permanent environmental impact.

III. Summary of the Invention

To avoid such drawbacks , a flexible dam was developed and is the object of the present invention. Its installation i very simple and practical, containment is achieved in a short period of time and at costs considerably lower than those associated with other permanent solutions.

The dam is suitable for temporary containment to assis in the undertaking of various activities, for example, dredgi of material from the bottom of the basin, without contaminati of the sorrounding water by suspended matter. The dam installation does not require any alterations

the submerged or land topography, avoiding eventual permanent damages to the environment and preserving the local environme

Due to its modular feature and ease of assembling and disassembling, it can be used at different locations, that is it is reusable.

The dam is constituted by a guide pipe, made of a flexible material, which dimensions and physical resistance must be specified for each particular case.

Both ends of the pipe are supported on the ground. The pipe is filled, by pumping, with a high density pulp. The pul density is specified for each particular case to ensure prope anchorage of the dam.

The guide pipe is encased by a layer of flexible and inflatable material that constitute a screen elevating from t bottom of the aquatic basin to a level above the water. This layer is constituted by a synthetic material, whose resistanc must be specified, and it is made up of inflatable cushions, whose dimensions must also be specified for each case.

The inflatable layer's cushions are filled with water, injected under pressure. The upper cushions, close to the wat line, are filled with air, also injected under pressure.

The anchorage of the system is provided by the adhesio of the guide pipe to the surface of the basin. The pipe diameter, as well as of the volume and density of the filler pulp are specified to withstand the shear stress and buoyancy forces.

If required, a grid of cables supported on the ground and on the aquatic basin can be used to keep the dam in place. This grid, installed on the exterior of the system, can preve excessive bending of the inflatable layer or even its draggin due to movements of the column of water, wind action, surface of submerged currents.

The following schematic figures of the proposed invention are provided to assist in the understanding of the invention:

- Figure 1 - cross section of lateral view of the dam.

- Figure 2 - perspective of the dam erected in a lake.

IV. Detailed Description

As can be observed in these figures, the flexible dam, object of the present invention, is constituted by a high density polyethylene guide pipe (1) , completely filled with a pulp made of a baryte emulsion (2) , the said guide pipe (1) encased by an inflatable layer (3) made of PVC or similar material, containing inflatable cushions (4) filled with wate and inflatable cushions (5) filled with air, all provided wit a valve.

The first step in the design the dam is the measuremen of all variables for the particular case under consideration. The size of the area to be contained, topography, characterization of the basin constituents, presence of currents, measurement of their energy, etc., are critical elements for the specification of materials to be used in the construction of the dam.

The information collected at the site is used to specify the guide pipe including: type of material, resistance and flexibility, diameter, density and composition of the filler pulp.

The length of the guide pipe must be chosen to allow ground support, in order to facilitate pumping and moving of the high density pulp. It must cover the entire perimeter of the area to be contained, following all changes in the topography of the basin.

The guide pipe (1) is completely encased by a flexible and inflatable layer (3) , made of a suitable material to be specified. This layer is composed by sections with appropriate dimensions, each containing a valve or pressurized air and liquid injection.

The flexible and inflatable layer must be sized to provide a screen that will completely isolate the area to be contained. The size of this layer is defined by the length of the guide pipe its elevation above the water line.

After the inflatable, flexible layer is installed, pressurized water is injected, in the lower section of the screen and pressurized air is injected in the section close t the water line. If required, the screen can be kept in a fixed positio by an anchorage system composed of stretched cabies, located either on the ground or submerged in the water. A grid of stretched cables can also be installed around the system, to prevent excessive bending of the screen, thus avoiding build of shear stress that may shift the position of the system. After installation, the dam remains in place in the containment area, requiring only periodic inspection. Repairs can be conducted on some of the sections without requiring deactivation of the dam. The dam can be dismantled following a reverse procedur that is, deflating the segments by removing its contents (wat or air) , removing the guide pipe filler by pumping the high density pulp and finally by removing the system from the basi After reconditioning, the flexible dam can be installe again, at another location requiring containment.

The flexible dam offers a large number of advantages. The following can be highlighted:

- quick installation and removal

- low construction, installation, maintenance and removal cos - it can be reused

- preservation of the original topography, with no alteration to the original basin contour

- environmental protection, as operations can be conducted in water bodies (lakes, lagoons, bays and rivers) with no contaminantion