Bayurivka Dam, River Perkalaba, Ukraine

Demolition of a 120-year-old dam in Ukraine, despite the war

The River Perkalava
River Perkalaba is part of the Danube basin and runs through the Verkhovyna National Nature Park which is located in the Ivano-Frankivsk Region, next to the Ukrainian-Romanian borders. River Perkalaba is inhabited by several fish species, including the Brown trout (Salmo trutta), the endangered Danube salmon (Hucho hucho) and the Ukrainian brook lamprey (Eudontomyzon mariae). Terrestrial and semi-aquatic species are also present in the area, like the brown bear (Ursus arctos), the European mink (Mustela lutreola), the otter (Lutra lutra) and various birds. At the end of the 19th century and during the reign of the Austro-Hungarian Empire, the industrial forest harvesting initiated in the Ukrainian part of the Carpathians. Logged splash dams were constructed during that time to raise the water level of the shallow rivers in the region and thus enabling the transportation of timber rafts, from high mountains to the valleys downstream. This practice was used till August 1979, when the last timber raft was transported this way. Since then, all splash dams that had outlived their usefulness remain obsolete to fall in decay. However, many of them oppose significant barriers to fish migration and sediment transportation.  

Barrier removal
WWF Ukraine, with the financial support of the European Open Rivers Programme – a grant-giving organization dedicated to restoring rivers – moved forward to restore the longitudinal connectivity of the small Carpathian Rivers. Bayurivka Dam, a 120-year-old splash dam made of wood logs (Figure 1) at River Perkalaba on the territory of Verkhovyna National Nature Park (latitude: 47.744028; longitude: 24.926194), was removed in June of 2022 (Video 1). The removal aimed to eliminate the safety risks due to the dam’s decaying condition and to restore the ecological connectivity and biodiversity of the river and the fish migration (Figure 2).  

Figure 1. Bayurivka Dam at Perkalaba River on the territory of Verkhovyna National Nature Park (photos by (up) Yaroslav Zelenchuck and (down) WWF Ukraine)

Figure 2. Brown trout at the removal site of Bayurivka Dam in June 2022 (photo by Yaroslav Zelenchuck)

Video 1. Removal of the Bayurivka Dam in June 2022 (video by WWF Ukraine) 

Bayurivka Dam was built at the end of the 19th century and was used for timber transportation but remained obsolete for the past 40 years and was in risk of structural failure. The logs that formed the splash dam were sawed and removed by hand (Figure 3). Since the dam was located close to the Ukrainian-Romanian border, special permission was acquired beforehand by the State Border Service. The removal project costed ~ 20000 euro.  

Figure 3. Removal works of the Bayurivka Dam in June 2022 (photo by Yaroslav Zelenchuck) 

The removal of the Bayurivka Dam followed the demolition of other three splash dams within the territory of the Verkhovyna National Nature Park executed in 2020, the Lostunets (latitude: 47.851972; longitude: 24.82375), the Hostovets (latitude: 47.872923; longitude: 24.911758) and the Dobryn Dam (latitude: 47.889458; longitude: 24.704067) (Figure 4). Downstream the former Bayurivka Dam stands Perkalaba Dam (latitude: 47.787665; longitude: 24.944263) (Figure 4) which is unsurpassable for several fish species based on recent (2020-2022) ichthyological surveys executed by external experts of WWF Ukraine. 

Figure 4. Locations of the former Lostunets, Hostovets, Dobryn and Bayurivka dams and the existing Perkalaba Dam. The black rectangle on the map of Ukraine indicates the region of all these locations 

Ecological and community benefits
The qualitative and quantitative composition of fish upstream and downstream the Bayurivka Dam was analyzed the year prior to the dam removal, in September of 2021, and a few months after the dam demolition, in October of 2022 (Table 1). The latter surveys showed that the only fish species in this site is the Brown trout, most likely due to the Perkalaba Dam located further downstream that is unsurpassable by other fish species (e.g., Common minnow – Phoxinus phoxinus and European bullhead – Cottus gobio). It’s possible that the fish species composition of the site won’t be changed after the dam removal, but gene exchange is expected between the Brown trout populations that remained separate upstream and downstream of Bayurivka Dam before it was removed. This removal opened 27 km of River Perkalaba providing suitable spawning and feeding grounds for Brown trout and enabled the sediment transportation to sites further downstream. The foreseen boost in fish numbers is expected to lead to the return of predators in the area, such as the brown bear, the European mink and otter. Thus, the area has the potential to transform into a “biodiversity hotspot” in the Carpathians. WWF Ukraine has already removed seven obsolete dams in the Carpathian region since 2020 and thus reconnected over 530 km of river stretches. 

Table 1. Fish species composition and number of fish sampled upstream and downstream the Bayurivka Dam prior to and after the dam removal

Before & After photo pair

The removal site at River Perkalaba: (left) before and (right) after the removal operations of Bayurivka Dam (photos by Yaroslav Zelenchuck) 

The removal site at River Perkalaba: (left) before and (right) after the removal operations of Bayurivka Dam (photos by Yaroslav Zelenchuck) 

Written by Foivos A. Mouchlianitis