Title of the project: Removal of the migration barriers for aquatic organisms on the river Wisłoka and its tributaries – Ropa and Jasiołka
Aim of the project
The aim of the project is a restoration of the possibility of free migration of fish and other aquatic organisms down and up the river Wisłoka and its tributaries, with the simultaneous maintenance of the stability of water intake and other elements of the infrastructure. The strategic aim of the project is an improvement of the ecological state of the Wisłoka water according to the requirements of the Water Framework Directive. This is one of the statutory duties of the Regional Water Management Board in Cracow and is an element of the Plan of the water management in the area of the upper Vistula basin.
Origin of the project
One of the characters of the natural river environment is a patency of the watercourse, it means lack of the barriers preventing the migration of fish and aquatic organisms. Fish in particular year seasons and life periods migrate along the river in search of food, appropriate shelters and places for spawning. Partition of the river with weir or other artificial barrier disturbs these processes what negatively affects number and condition of fish, and in extreme cases when access to spawning areas situated upstream is cut off, can lead to extinction of the whole populations.
The construction of damming buildings and regulation works carried out in riverbeds in the second half of the XX century lead to vanishing of the specific habitats necessary for spawning, spawn incubation, fry growth and also feeding and wintering of adult organisms. It finally resulted in the extinction of sturgeon, salmon, sea trout and vimba whereas the populations of other fish species requiring shorter, one-environment migration were heavily cut down. For this reason it is necessary to restore the patency of the flow what in practice means the necessity of removal or modernization of the weirs in a such way that they don’t cause an obstacle for aquatic organisms.
Project works were preceded by the precise stocktaking of the hydrotechnical buildings and the consultations of such technical solutions which ensure an liquidation of migration barriers for aquatic organisms while maintaining the previous functions of the modernized objects. Close to nature solutions have been adopted imitating conditions occurring in the natural river. They ensure whole ecological river continuity i.e. uninterrupted water flow, constant possibility of transport of bottom sediments and guarantee two-way, up- and downstream, migration of aquatic organisms.
In the projects migration requirements of different fish species were considered covering: dimentions, swimming speeds, typical behaviors, migration periods. It was assumed that technical solutions have to provide optimum migration conditions namely:
- possibility of quick, safe crossing the barriers (at most to several hours) by all taking migration developmental stages of aquatic organisms (ichthyofauna) occurring in rivers and streams within limits of operational flow device i.e. in flow range from the lowest (NNQ – the lowest of the lowest noticed) to fairly high because equal to two and a half times of mean flow (SSQ – mean flow calculated for the long-period average);
- assurance of minimum depths for different fish species in fish pass reservoirs, from 0.4 m (brown trout) to 1 m (sturgeon) in the lowest flows (NNQ);
- assurance of minimum transit depths in apertures, overflows and inlets of designed devices, from 0.2 m (brown trout) to 0.3 m (barbel, bream, perch, pike, salmon, sea trout) in the lowest flows (NNQ).
Some of these building have fish passes but they don’t ensure possibility of migration of different fish species in various age both in high and low water levels. Hence necessity of their modernization.
The project includes the following ventures:
Dębica (km 56+180 river Wisłoka) – modernization of existing chamber fish pass with a building of stone ramp at the dam;
Mokrzec (km 69+720 river Wisłoka) – building of bypass;
Gorlice I (km 32+300 river Ropa) – building of a fish pass designed as bottom ramp and slope with embedded boulder bars;
Gorlice II (km 34+250 river Ropa) – building of a fish pass in the form of stone ramp;
Ropica Polska (km 39+400 river Ropa) – building of a fish pass designed as bottom ramp and slope;
Jedlicze (km 19+100 river Jasiołka) – building of a fish pass in the form of stone ramp;
Szczepańcowa (km 27+960 river Jasiołka) – building of bypass.
First stage of the project
Planned actions constitute continuation of the project “Restoration of patency of the ecological passage of the river Wisłoka and its tributaries” realized by the Regional Water Management Board in Cracow in the years 2010-2015. The works carried out then have initiated improvement of the ecological state of the Wisłoka waters – the patency of the middle stretch of the river was restored (two barriers in Jasło were liquidated), gravelly habitats for lithopholous fish species on the stretch from the weir in Mokrzec to Pustków locality were reproduced and stockings with salmon and vimba were carried out.
Terms of implementation and costs
Total cost of the project: 28.7 milion Polish zloty including the European Union support of 24.4 milion Polish zloty (85%) from the Cohesion Fund under Operational Program Infrastructure and Environment 2014-2020.
Duration of the project: 2018-2021
Państwowe Gospodarstwo Wodne Wody Polskie
Regionalny Zarząd Gospodarki Wodnej w Krakowie – Project beneficiary
- Przedsiębiorstwo Produkcyjno-Usługowo-Handlowe WOLIMEX
- WTU Sp. z o.o.
- Ośrodek Usług Inżynierskich STAAND Sp. z o.o.
- Zakład Badań Ekologicznych
- Biuro Obsługi Budownictwa „Bień” Jan Bień