Bioengineering Solutions for Restoring Lotic Ecosystems
Method I In order to ensure fish migration (upstream and downstream) over dams up to 30m height, a two-circular channel mechanism of variable geometry can be set. This mechanism is rectangular (Fig.1), and the two circular channels are made of metal or hard plastic and attached to two metal rails (metal frame) (Fig. 2). The channel for ichthyofauna migration is made of metal or hard plastic modules. Each module has a durable attaching system fixed to the metal rails.
The two channels can be also built (fixed) diagonally on the bar supporting the bearings, which are usually able to adapt to any condition (Fig. 3 and 4).
The loading chamber or the rectangular basin has a light frame of aluminum, but it is extremely resistant to shocks and extreme temperatures. This basin is provided with unbreakable glass surfaces so fish have a suitable resting environment. All metal modules are joined so ichthyofauna can pass without any obstacles downstream or upstream. The size of the rectangular basin is proportional to the migratory fish species. The two channels, Channel I and Channel II, for fish migration have the same size and compounding material.
A 30cm wide threshold having the same length as the rectangular basin right in the basin is attached to the supporting bar of the metal rails (Fig.6). The threshold is a few centimeters below the water level in the tank and is designed to help fish climb toward the metal channel. For dams higher than 15m and up to 30m, such rectangular basins can facilitate fish migration upstream and downstream and can be fixed on the slopes and in the riverbed (Fig.7).
The loading chamber or the rectangular basin is fixed on four telescopic hydraulic cylinders, which, in turn, can be fixed on any type of soil so the loading chamber remains vertical (Fig.8).
Telescopic hydraulic cylinders operate independently as they are supplied with electricity produced by mobile generators. Thus, they can be fixed on very inclined, rocky slopes. Channel I will be fixed on the concrete dam by means of a weatherproof rubber sleeve. The rubber sleeve has the form of the dam where the ichthyofauna migration project is operated (Fig. 9). The rubber sleeve is fixed on the dam by means of metal dowels (Fig.10).
Two supporting bars are provided with two metal springs (silencers) for Channel I (Fig. 11).
To ensure protection of Channel I and, therefore, of the entire ichthyofauna migrating system, a semicircle floating system made of wood, plastic or rubber should be installed in order to redirect floating elements on the lake or stream. If the ichthyofauna migrating system is fixed on one end of the dam, then the floating semicircle system will be fixed on the dam and one bank (Fig.12). Migratory species are not disturbed by this system because it can be easily avoided.
This system is maintained convexly by means of metal springs inside the floating plastic. Floating elements redirected by this floating system should be collected periodically. This engineering method for ensuring the ichthyofauna migration can be successfully applied on all continents.
Method II: Slope Stabilization. One possibility to support slopes is fixing into the soil a wooden mattress of variable geometry with both vertical and horizontal elasticity (Fig. 1). All parts of these mattresses, namely wooden bars, are fixed together using flexible and weatherproof rubber cords (Fig. 2).
These mattresses are also fixed together by means of weatherproof rubber cords. Due to the cords, mattresses can stop (independently or together) any force able to dislocate the slope. These mattresses should be entirely fixed inside the slope on different angles and in different ways depending on the slope’s specificity (Fig. 3). Mattresses should be fixed on resistant slope structures (frames, trees or, especially, rocks) to operate at maximum performance. All of these will be performed according to detailed calculations.
This engineering method for slope stabilization can be successfully applied on all continents.
Method III. In order to stabilize the river bed, a linearization should be performed on an inclined plane, thus lowering the slope gradient (Fig. 1).
Once the bed has been linearized, a prism made of coconut fibers or thin rods will be fixed on both banks (Fig.2).
On its top, this prism for bank stabilization (Fig.3) is provided with a drain, which takes excess water over the stabilized sector and redirects it downstream. This drain does not allow water to get inside the prism made of coconut fibers or thin rods. The system stabilizing the river banks is fixed on the banks by means of wooden or plastic dowels.
The advantages of this solution are its convenient cost and high durability over time due to its hydro-dynamic shape during great floods. If this prism is made of twigs, they must be connected and bonded so they remain compact during weathering. This engineering method for strengthening river banks can be successfully applied on all continents.
All rights reserved