The fish ladder in Smołdzino is now ready.

Details

The construction site for the “Restoration of wildlife corridor in the Łupawa River by constructing a fish ladder” project was handed over a year ago.

What was its purpose? How long did it take to complete preparatory and construction work?

Let us take a look!

The “Restoration of wildlife corridor in the Łupawa River by constructing a fish ladder” project, as its very name suggests, was mainly aimed at constructing a fish ladder at the Smołdzino barrage, along with accompanying infrastructure. The latter includes a biometric fish monitoring station and an electric barrier.

The LIFENaturaSlowinskaPL project was launched in early January 2015. In this context, 2 January 2015 can be considered the official date when the Project Team began preparations for investment implementation. However, arrangement procedures for fish ladder construction, involving Energa OZE S.A. as the land owner, had started much earlier, and so had the development of the investment concept.

 

The construction site for the “Restoration of wildlife corridor in the Łupawa River by constructing a fish ladder” project was handed over a year ago.

What was its purpose? How long did it take to complete preparatory and construction work?

Let us take a look!

The “Restoration of wildlife corridor in the Łupawa River by constructing a fish ladder” project, as its very name suggests, was mainly aimed at constructing a fish ladder at the Smołdzino barrage, along with accompanying infrastructure. The latter includes a biometric fish monitoring station and an electric barrier.

The LIFENaturaSlowinskaPL project was launched in early January 2015. In this context, 2 January 2015 can be considered the official date when the Project Team began preparations for investment implementation. However, arrangement procedures for fish ladder construction, involving Energa OZE S.A. as the land owner, had started much earlier, and so had the development of the investment concept.

When it comes to investment preparatory work, it is not the concept or building permit design that take longest, but obtaining the necessary decisions, permits and arrangements. In fact, these procedures took nearly 3 years.

Eventually, upon overcoming several difficulties that had come up quite unexpected, the construction site was handed over on 25 June 2019, and construction work could finally begin.

One should bear in mind that no two fish ladders are the same, as their length, width and location depend on numerous factors. So, there is never a ready-made solution that could fit all situations without a detailed analysis being performed first. Some of the factors to be taken into consideration include the range of aquatic animals found in a given watercourse and the height of the damming structure. At present, some of the new fishways being built are, so to say, added to the existing structures. This triggers the need to pay special attention to the amount of space to be occupied by the fish ladder. Its location is no less important as aquatic creatures must feel the drift of water flowing from the fish ladder.    

There is a wide range of fishway structures. Along with more natural types, one can distinguish chamber-type fishways, baffle fishways or vertical-slot fish passages.

If you are interested in various types of already built fish ladders, you may want to visit the websites of the following projects:

Active protection of water-crowfoots habitats and restoration of wildlife corridor in the River Drawa basin in Poland [klik].  

Creating a blue wildlife corridor in the Rega basin [klik].

The fish ladder in Smołdzino is a rock fishway. This implies that a number of rocks were arranged vertically in the river basin, forming locks which dam up water. Each lock is accompanied with an oval concrete pillar for water flow regulation. In addition, stones were placed at the riverbed to reduce flow velocity.

The fish ladder structure is 83 metres long and has 24 two-metre-wide chambers (including the monitoring and inlet chambers). To obtain adequate sloping and provide limited space on the islet, the ladder was built as a single-twisted structure.

Given the presence of eels in the Łupawa River, an eel ladder was also constructed in the form of a trough with nylon brushes mounted inside.

For fish migration analysis and species identification purposes, a biometric fish monitoring station was erected in the first chamber at the water level before the structure. Aquatic locomotion monitoring at the fish ladder is based on an HSMR hydroacoustic system which uses two detection methods. One is a hydroacoustic method based on hydroacoustic transducers, and the other is an optical method based on optical cameras. A special chamber was designed to house the station, which is narrowed down to 1 metre at the assembly point. The station location, while not disturbing the free passage of aquatic animals, provides excellent observation conditions. The technical design of the monitoring chamber, and the profiling of its edges so as not to disturb water flow, are also of utmost importance for observations. All these objectives have been accomplished in Smołdzino.

To minimise fish migration towards the power station grating, an electric barrier (NEPTUN) was erected at the water level before the structure, on the power station’s inlet channel and the eastern weir. Again, given the presence of eels in the Łupawa River, the barrier features a three-electrode-row system with a negative electrode row, a positive electrode row, and a mixed (positive/negative) electrode row.

The construction work went smoothly, taking less than 6 months. Given the need to obtain adequate decisions and permits, this can be considered very quick. While some unexpected problems could not be avoided, the contractor’s vast experience and close collaboration allowed for these to be promptly overcome.  

Contractor: RUSIECKI Hydrotechnical Services Adam Rusiecki.

Subcontractor: PROCOM SYSTEM S.A. (the electric barrier and the biometric fish monitoring station).

Another subcontractor: ESCORT Sp. z o.o. (the biometric fish monitoring station).

Was it possible to restore patency of the wildlife corridors at that section of the Łupawa River?

We can now give you an affirmative answer. If you want to know why, see the provided videos. They clearly show that the fish ladder is effectively used by both larger (salmonid) and smaller fish species. As we have observed, some fishes tend to come back to the ladder and dwell there a bit longer, instead of treating it merely as a passage.

As you can see below, the ladder is used not only by fish species but – much to our surprise – also by beavers or otters.

For anyone interested, the fish ladder can be well viewed from the concrete bridge in Smołdzino.

Photos from the construction process, as well as images of the ready-to-use infrastructure can be seen below.

Videos can be seen in the multimedia tab. [link]

 

View the embedded image gallery online at:
https://lifenaturaslowinska.pl/index.php/en/news/180-udrazniamy-korytarz-ekologiczny-rzeki-lupawy-3?tmpl=component&print=1&layout=default&page=#sigProId383436a5b2