Can scientists preserve one of the few remaining untouched rivers in Europe from being impacted by 50 dams?
At the base of a deep valley, located near the mountain settlement of Ulog in Bosnia and Herzegovina, rests the glistening blue-green Ljuta river, which feeds into the Neretva. The upper portion of the Neretva is considered to be one of Europe’s most untouched rivers, giving off an impression of untouched nature.
The country’s forested slopes are strewn with dangerous landmines left over from a decades-long conflict, making it hazardous for wild dogs to roam the trails. Using a map from the country’s mine action center, ecologist Gabriel Singer, a professor at the University of Innsbruck’s Institute of Ecology, carefully evaluates the safest path. The map reveals red and black lines indicating the location of mines on both sides of the Neretva River, leaving only one treacherously steep slope that can be crossed.
Hiking through hills filled with landmines is not a common task for the average ecologist, but Singer and his colleague Kurt Pinter were determined to complete the journey in June. Their goal? To protect the Neretva River. This 140-mile (225km) river, stretching from the Dineric Alps to the Adriatic Sea, is home to a variety of endangered species such as bears, wolves, lynx, and many others. It is considered one of the most thriving and untouched rivers in Europe, but experts warn that it is also at risk of being destroyed.
Scientists warn that the proposed construction of over 50 dams, with one already in progress, poses a significant threat to the waterway, its inhabitants, and the surrounding ecosystem. The construction of dams would greatly alter the physical characteristics of the waterway, replacing natural, turbulent sections with stagnant bodies of water. This disruption can impede fish migration and significantly decrease the flow of sediment necessary for fish reproduction. Such impacts typically result in harm to river ecosystems, leading to the loss of important aquatic species and ecological processes.
Singer and Pinter were among 70 scientists from 17 countries who descended on Ulog for Neretva Science Week in the summer. Experts on bats, mammals, insects and fungi waded through rivers and braved underwater caves to record rare species here, gathering samples of eDNA – the genetic material shed by organisms into the environment – to examine its biodiversity.
The duo collected samples from the Ljuta in hopes of finding proof of what they had heard from nearby fishermen: that the stream served as a breeding site for the rare soft-mouth trout (Salmo obtusirostris), a threatened species highly valued by fly fishermen in Bosnia.
According to Pinter, a freshwater ecologist from the University of Natural Resources and Life Sciences in Vienna, the fish in the Neretva river system is considered the “holy grail.” He explains that this river is one of the few remaining habitats for this unique species in the Balkans, as it is at risk of disappearing.
The Ulog construction site, located a short distance upstream from the Ljuta, will soon be home to a 35-megawatt hydropower plant featuring a 53-metre-high dam. Roads have been built through the surrounding mountains and the nearby valley has been cleared of trees to create a 5km reservoir.
“According to Pinter, the Ulog hydropower plant’s proximity to this location would undoubtedly have an impact on the nursery areas. He explains that the soft-mouth trout spawn in and their larvae burrow into the gravel. However, the construction of a dam’s weir prevents sediment from flowing downstream, resulting in a decrease in available gravel and therefore, fewer areas for spawning.”
According to Pinter, a lack of gravel will affect the ability of trout to reproduce.
The Guardian gathered samples from the Upper Neretva river to study the biodiversity of eDNA, which is genetic material released by organisms into the surrounding environment.
Upon finishing the examination of the eDNA samples, Pinter sent an email to the Guardian stating, “Karen! We have obtained soft-mouth trout. All three samples are positive.” He is optimistic that these findings will aid in preventing the construction of eight hydropower plants on the Ljuta River and potentially halt the Ulog plant as well.
I wish to demonstrate to the citizens of Bosnia that this species has significant habitats in that region, making it a valuable asset. While hydropower is the most ancient form of renewable energy, it also has a severe impact on ecosystems. It is important for them to understand what they stand to lose.
The singer believes that the current biodiversity and climate emergency requires scientists to do more than just publish their findings. He states that there is a debt of extinction, as 80% of our freshwater ecology has been lost in the past few decades. Building dams not only leads to the loss of aquatic species, but it also affects the surrounding landscape, terrestrial ecosystem, and forest biodiversity.
He suggests that we must change our approach and communicate with the general public and those in political positions.
Benjamin Barca, the conservation leader at NatureMetrics, examined eDNA samples from the Upper Neretva for the Guardian. His analysis revealed evidence of beech martin, chamois, vole, dormouse, roe deer, and frogs. Despite the small size of the samples, Barca concluded that the river is in a pristine state. He noted, “Compared to other locations in the UK, it is particularly distinct and varied.”
According to a 2020 study by the EU, Europe has the highest amount of barriers in its river landscape, with an estimated number of over 1 million dams, weirs, and fords. These barriers are a major contributing factor to the significant decrease of 80% in freshwater biodiversity and 55% in migratory fish populations in European rivers.
In 2021, 37% of Bosnia’s electricity was generated by hydropower. The Balkans are home to some of the cleanest and most natural rivers in Europe, but they are at risk due to the construction of 3,300 hydropower plants. Proponents of these dams claim they provide jobs and income for rural areas that lack both. Ulog, a town that used to have 400 residents, now only has 12.
A representative from EFT, the company responsible for constructing the Ulog dam, stated that the environmental impact assessment (EIA) and permit have established suitable measures to reduce or eliminate the project’s environmental impact. However, they refused to disclose specific information on these measures. They also mentioned that previous EIA reports and ongoing environmental monitoring have not detected the presence of soft-mouth trout in the HPP Ulog project site.
The 2022 report from the committee of the Bern Convention, an international treaty for safeguarding plants and animals, found that the EIA for the Ulog dam had inadequate and outdated baseline information and suggested mitigation measures that were deemed unfeasible.
According to a spokesperson, the Ulog project has the potential to create jobs and generate income in an underdeveloped area of Bosnia and Herzegovina. Additionally, the project will involve an investment of €90m (£78m) and is expected to reduce CO2 emissions by 87,846 tonnes.2
He stated that the emissions produced annually are equal to those of fossil fuels, aiding in the efforts to address the climate crisis.
In June, Radomir Sladoje, the mayor of Kalinovik, admitted to a group of scientists in Ulog that the dam had been approved by the local government. However, he also stated that the area required the compensation offered by the company responsible for building the dam.
In June, he expressed to the Guardian that it may have been a mistake. He initially approved the idea, but was convinced by the argument that protecting the river could lead to revenue from tourism activities such as rafting and mountain biking in the Upper Neretva. He now states that he will personally protest if anyone attempts to interfere with the upper portion of the river.
From a vantage point in the mountains, with the valley bare of trees and the Ulog dam being built below, Ulrich Eichelmann, CEO of Riverwatch, expresses concern that it may be too late.
According to him, protecting the unspoiled areas of the river and its smaller streams is a cause worth fighting for. Recently, conservationists were successful in gaining the backing of the Bern Convention committee. The committee members advised the government of Bosnia and Herzegovina to stop the building of Ulog and to cancel any plans for hydropower plants in the upper section of the river.
In July, agreements for 15 minor hydropower facilities on the Neretvica, a branch of the Neretva river, were terminated, marking a triumph for the local demonstrations against them.
According to Eichelmann, the information collected during Science Week will be crucial in the upcoming lawsuits against the Ljuta and other hydropower developments. He believes it will provide strong evidence against all dams, including the Ulog, as it is imperative to prevent the destruction of one of Europe’s most diverse and stunning rivers.
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