Ureditev ribjega prehoda na Demšarjevem jezu na Poljanski Sori : master thesis no.: 68/II. VOI

Lesjak, Simon (author), Rusjan, Simon (mentor), Vidmar, Andrej (comentor)

Pomembno vlogo pri ohranjanju biotske raznovrstnosti ima vzdolžna povezanost vodotokov, saj s prehajanjem rib in ostalih vodnih organizmov vzdolž struge prihaja do oblikovanja različnih življenjskih združb. To področje ureja tudi zakonodaja, ki predpisuje zagotavljanje prehodnosti za vodne organizme na prečnih vodnih objektih. V nalogi smo obravnavali stanje na Demšarjevem jezu na Poljanski Sori, kjer je v skladu z vodnim dovoljenjem za delovanje mHE potrebno urediti ribji prehod, kar pa predstavlja velik izziv. Jez se namreč nahaja na iztočnem delu desnega rečnega zavoja, zaradi česar prihaja do neenakomernih razporeditev hitrosti vodnega toka in strižnih napetosti, poleg tega pa ima vodotok tudi izrazit hudourniški značaj. Desna brežina je tako izpostavljena povečanemu toku premeščanja plavin, na nasprotni strani pa prihaja do prostorskih omejitev, saj se ob strmi levi brežini že nahaja konstrukcija mHE. V iskanju ustrezne rešitve smo skušali uporabiti celosten pristop, pri tem pa slediti smernicam za načrtovanje ribjih prehodov in hkrati upoštevati dinamiko naravnih procesov v vodotoku. Na podlagi teoretičnih izhodišč in analize območja smo naredili tri variantne predloge, katere smo podrobneje opisali ter izpostavili njihove prednosti in slabosti.

• Language: Slovenian
• Keywords: gradbeništvo, magistrska dela, VOI, ribji prehod, Demšarjev jez, Poljanska Sora, ribe, vzdolžna povezanost, mHE, prenos plavin, ribja splavnica
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [S. Lesjak]
• Year: 2020
• Number of pages: XII, 126 str., 6 f. pril
• PID: 20.500.12556/RUL-121207
• UDC: 626.882:627.132(497.4)(043.3)
• COBISS.SI-ID: 38853123
• Publication date in RUL: 01.10.2020

Secondary language

• Language: English
• Title: Designing a fish pass at Demšar weir on Poljanska Sora stream : magistrsko delo št.: 68/II. VOI

Abstract

Longitudinal connectivity of watercourses has an important role in the conservation of biodiversity, as the movement of fish and other aquatic organisms leads to the formation and existance of different biological communities along the river. This area is regulated by legalisation requiring the provision of passability for aquatic organisms at transverse water structures. In master thesis we discussed the situation at Demšar weir on Poljanska Sora stream, where, in compliance with the water permit for SHP operation, it is necessary to arrange a fish pass, which presents a great challenge. The weir is located at the outflow part of the right river bend, where uneven distribution of water flow velocity and shear stress occurs. In addition, the watercourse also has a pronounced torrential character. The right bank is thus exposed to intensive processes of sediment transport, while on the opposite side there are spatial restrictions, as the SHP structure is already located along the steep left bank. In search of a suitable solution, we tried to use an integrated approach, following the guidelines for the design of fish passes and at the same time taking into account the dynamics of natural processes in the watercourse. Based on the theoretical background and the analysis of the area, we designed three variants, which we described in detail and highlighted their advantages and disadvantages.

• Keywords: civil engineering, master thesis, fish pass, Demšar weir, Poljanska Sora, fish, longitudinal connectivity, SHP, sediment transport, fish lock