General solutions to ensure fish fauna passage upstream – downstream

of discharge sills Solution I Ph.d Răzvan Voicu

rzvnvoicu@yahoo.com.getiiliberi@gmail.com

A solution for fish fauna migration is suggested for areas where river beds are

covered with concrete and where there are various discharged sills. Downstream of the

discharge sill (distance is calculated according to the discharge sill requirements) a metal

sheet pile is fixed to two or three telescopic hydraulic cylinders and also to three metal

hinges or bearings (figure 1). The unfolded sheet pile with variable geometry (at the

initial level) is under the water level, downstream of the discharge sill (figure 1).

Bearings are disposed vertically and attached to a metal bar, which belongs to the metal

sheet pile (figure 2).

discharged sill

metal sheet pile with variable geometry

bearings telescopic hydraulic cylinder

Figure 1 Positioning of the unfolded sheet pile-indicative scheme

metal sheet pile

bar for supporting the bearings

Figure 2 Bearing fixing in concrete riverbed-indicative scheme

The metal sheet pile is welded to the bearings top, which allows the sheet pile a circular

motion (figure 3).

metal sheet pile

bearing

bar for supporting the bearings

Figure 3 Attaching metal sheet pile to bearings-indicative scheme

When lifting the hydraulic telescopic cylinders, the metal sheet pile can be folded

up to the maximum peak: H height (figure 4). At that point the metal sheet pile will close

perfectly the whole water course and will cause the river to overflow the discharge sill as

much as needed so fish fauna can freely migrate above the spillway. Some metal brackets

are attached to both concrete banks in order to stop both the sheet pile and any seepage

downstream of the sheet pile (figure 5).

discharged sill

H max

bar for supporting the bearings

Figure 4 Sheet pile maximum height -indicative scheme

metal sheet pile with variable geometry

discharged sill

bearing telescopic hydraulic cylinder (maximum level)

Figure 5 Maximum flow supported by the metal sheet pile-indicative scheme

Two crenels should be built into the metal sheet pile for the water level to remain

constant over the discharge sill. The two crenels, which should not necessarily be

identical, are positioned at the top of the sheet pile (figure 6).

left bank right bank

metal bracket

metal sheet pile

metal grating

crenel crenel

right bank left bank

Figure 6 Positioning of the two crenels-indicative scheme

If necessary, several crenels will be created on the metal sheet pile (sluiceway) so

that the flow through the left bank crenel to be lower. A metal basin for fish fauna resting

will be positioned next to this crenel. The metal basin will also be attached to the metal

sheet pile (figure 7) a side of one of its surface being perpendicular to the oblique sheet

pile.In order for fish to reach only the crenel provided with the migration system, the

other crenels have metal grids preventing fish from moving downstream. Fish can also be

redirected through a system of electromagnetic fields created by floating generators or

fixed to metal poles which, in turn, are fixed in the river bed upstream of the discharge

sill.

metal sheet pile left bank

metal basin

support bar

Figure 7 Metal basin positioning in regard to the metal sheet pile-indicative scheme

To the metal basin a rectangular canal will be fixed which, in turn, will be secured to the

left bank by some metal dowels(figure 8).

mal stang

metal basin

rectangular canal

support bar

left bank

Figure 8 Rectangular canal positioning on the left bank-indicative scheme

The metal basin is rectangular parallelepiped shape and it is connected to the

water body (Fig. 9 – concrete left bank, , metal rectangular canal, metal basin positioning

in regard to the water level) in order to facilitate fish fauna migration or it will just be

connected to the rectangular basin (figure 10). The window through which fish will

migrate is under water and is calculated for local migratory species. The water discharge

flowing through the crenel into the metal sheet pile is greater than the water discharge

flowing through the window for fish fauna migration. The water discharge excess will

flow over the metal grating or through a window specially made into the metal basin and

it is positioned above the water level downstream of the sheet pile.

metal sheet pile concrete left bank

the water level downstream of the discharge sill

metal basin

Figure 9 Metal basin positioning in regard to the water level-indicative scheme

metal sheet pile left bank

crenel

the water level downstream

of the discharge sill

metal basin

metal rectangular canal

Figure 10 Metal rectangular canal positioning in regard to the water level-indicative

scheme

Solution II

For riverbeds whose discharged sills are not covered by concrete (figure 11) the

same method can be used, but only after the bed has been reinforced with some wood,

metal, durable plastic or concrete sheet piles. Approaching this option, the riverbed will

not be eroded when the water level rises, allowing a smooth flow of water above the

discharge sill. The places where the banks cannot sustain an increase in water level close

to the discharge sill level, there the banks can be arranged by increasing their height in

proportion to the discharge sill. Being an area without electricity, the sheet pile will be

folded manually using cables attached to some winches, which in turn are attached to a

semicircle shaped metal bar (figure 12). Cables will be wrapped on some metal cylinders

equipped with metal handles and therefore the metal sheet pile can be raised or lowered.

The two sheet piles attached to the banks ensure increased water levels upstream and

downstream of the discharge sill. To ensure the mobility of the metal sheet piles, other

mechanisms can be used, such as gears made of jagged wheels and positioned on both

banks. This solution can be successfully applied anywhere in the world.

left bank without concrete cover

right bank without concrete cover

watercourse

riverbed without concrete cover

Figure 11 Riverbed without concrete cover – cross section-indicative scheme

metal bar

metal sheet pile riverbeds arranged with concrete metal sheet pile

metal sheet pile

metal sheet pile (sluiceway)

Figure 12 The metal bar positioning-indicative scheme

metal cables

winches

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Bucharest

2014