| 摘要 |
A permanent structure with temporary use to generate a headloss in a river "HLG Boom" was developed to provide a means to control the level, the velocity or the discharge of the water in the river at a specific site. The potential applications for the "HLG Boom" is to modify the amount of water discharged into the out flowing rivers from a lake (Figure 1a), to increase or decrease the amount of water diverted from a river into a tributary or a can al (Figure 1b), or to increase the water level in a river, thus reducing the current velocity (Figure 1c). The "HLG Boom" is designed using several self contained boom units connected together with chains to resist the water and generate. a headloss. Each boom unit consists of two steel pontoons joined with chains and where a rubber curtain blocks the gap in-between. The dimensions of the rubber curtain and the pontoons depend on the range of water depth and curre nt velocity expected in the river. The pontoons are chained together and anchored at the boom ends and laid across the river. The top pontoon (called "Pontoon 'T") is designed to provide the buoyancy th at produces the desired headloss. The bottom pontoon (called "Pontoon B") is filled with wat er during the boom deployment to sink and rest firmly on the river bottom. The diameter of the Pontoon T, the length of the rubber curtain and its width are directly related to the desir ed headloss to be accomplished. This "HLG Boom" can be designed to operate effectively during the dry season where the water discharge is low. For this case, the effect of the "HLG Boom" on the natural flow of the river gradually diminishes when the water discharge increases and the effect becom es negligible during flooding. If desired, the effect of the "HLG Boom" can be completely neutralized by sinking the top pontoon "Pontoon T" or by completely removing the "HLG Boom" from the water. The "HLG Boom" is designed so minimal retention of debris behind the boom ca n occur. The "HLG Boom" is designed to be resistant to floating and grounded ice impa ct for use in northern rivers on a year-round basis. The "HLG Boom" is designed so it can be deployed for any desired length of time. When the "HLG Boom" is no longer needed, it is removed from sight and re-deployed whe n it is required again. It can be removed by two methods by either re-floating all the boom units or by storing the HLG Boom under water (as described in Patent Application No. 2,252,197). Conventional systems used to modify the river discharge or the current velocity, are usually permanent structures. These methods include blasting the rocky bottom or filling the river bottom with rocks, concrete or sheet piles. Control darn and others similar structures are also used. Most of these options are permanent solutions that represent a problem when the water discharge increases. They are also costly to remove and can alter the water circulatio n in the river permanently. These options are also relatively expensive to design and build . Approval of these types of structures requires comprehensive environmental impact studies, particularly in environmentally sensitive areas.
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