Building of a fish pass in the form of stone ramp
Ropa River – km 34+250
Planned term of start:
IIIth quarter 2019
Planned term of end:
Ith quarter 2020
955 471 Polish zloty
Why do we interfere in a river?
Built in the central part of Gorlice, a concrete weir stabilizes the riverbed of the Ropa River and protects sewer pipelines situated at the bottom of a watercourse. The existing structure is an impenetrable obstacle for aquatic organisms therefore its modernization is necessary.
A structure consists of a two-step concrete weir damming water to the height of 1,1 m and located 14 m away from a concrete diaphragm wall leveled with bottom. Due to its significant height, the weir does not allow for a free fish migration. River banks on the whole stretch between the weir and the diaphragm wall are strengthened by retaining walls. The technical state of the existing device is poor.
As part of modernization, a liquidation of the existing weir is proposed as well as a building of a stone ramp made with boulders of various dimensions scattered irregularly. Their purpose will be on the one hand a water damming and on the other a decrease of the water flow which will create suitable conditions for a migration of fish and aquatic organisms.
The ramp will be finished with a diaphragm wall made with from erratic boulders and a stilling basin in order to decrease water energy. As the closure of the stilling basin, the existing diaphragm wall will be used in which a cutting for low flow water will be made.
Wires of an inactive rainy sewer will be dismantled and wires of a sanitary sewer will be moved above the ramp and along the river bottom. An existing retaining wall will be also reconstructed.