This document proposes two general solutions to ensure fish passage around discharge sills where riverbeds have been concreted or not. Solution I involves installing a variable geometry metal sheet pile downstream of the sill, attached to hydraulic cylinders. When lifted, the sheet pile can overflow the sill to the required height for fish to pass. Solution II is for non-concreted riverbeds, reinforcing the area with wood or metal sheets to allow safe water level increases over the sill using manually operated winches and cables to adjust the sheet pile height. Diagrams provide details on construction and operation of the sheet pile systems.

1. 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

2. 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

3. 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).

4. 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.

5. 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

6. 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

7. 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.

8. 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
winches
metal cables
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

9. All rights reserved
Bucharest
2014