Contrary to its name, the Paks Weir can only be accessed from the opposite bank, in Dunaszentbenedek. The term ‘accessible’ must be taken literally here, as the barrier placed on the riverside of the stone embankment blocks off barely a quarter of the full cross-section from ‘disaster tourism’, and as there are no uniformed guards, nobody takes the sign with the screaming face seriously. A well-trodden path winds round it on both the right and left, so you can easily walk right out to the end of the weir, into the middle of the Danube, as the big blocks of natural stone have been covered with fine-grained gravel. This river regulation structure is a distinguished memorial to the absolute hydrological catastrophe of 2026. Judging by the number of international film crews passing through here, it is probably a global sensation. One could list our dried-up lakes and streams on it, and lay wreaths there every year in remembrance of the devastation caused by the drought – say, on a special autumn day when the Danube’s water gauges will record, for the fifth or sixth time, the lowest water level ever measured on the river.
Around midday on Sunday, 4 October 2026, at least 20 cars pulled up in quick succession on the dusty, sun-baked bank at Szentbenedek, whilst dozens of disaster tourists ensured a steady stream of customers at the Pillangó (Butterfly) diner, which is otherwise situated in a rather pleasant spot. At that time, the water gauge at Paks showed a water level of –116 centimetres, 24 centimetres above the lowest water level ever recorded. Those 24 centimetres demonstrated that the weir was working and doing the job for which its construction had begun in mid-August: ensuring a supply of cooling water for the Paks nuclear power station. To provide context, it is important to note that at the same time, one gauge station further upstream, at Dunaföldvár, a new record low was recorded, whilst one gauge station further downstream, at Baja, the situation was the same.
In this situation, the visible surface level of the weir was approximately half a metre higher than the impounded upstream water, whilst the downstream water was, naturally, considerably lower. The water rushing through the narrow gap in the submerged weir between the two levels created the altered drop. It is important to note that there is also a bed of stones at the bottom of the Danube here; otherwise, the current would erode the structure from both sides. However, water flow is not limited to this opening alone. Due to the difference in the structure and the water level, water also flowed through the weir. Upstream, the gaps between the larger stones absorbed the water of the Danube, which reappeared in the depressions on the far side of the bottom sill, like a sort of inverted "Donaversickerung". The volume of water flowing beneath the road, which is covered with finer gravel, has been steadily decreasing since the completion of the construction, as algae colonising the stones and the sediment caught on them are continuously narrowing the gaps between the stones.
Barely a month after its completion, the naturally shallower shoals on the left bank, on the convex side of the river bend downstream of Paks, became visible due to the water level remaining extremely low. This section is an area of intense sediment accumulation due to the altered flow conditions. The riverbank shoals, with their varied topography, can be found on both sides of the weir. Whilst on the upstream side a wide, flat area of rather unusual colour (specifically greenish-brown) is visible, in the section beneath the wire, water flowing over the area during a previous period of higher water levels has formed well-defined sand dunes. Originally, these dunes were connected to the side of the stone structure; however, seepage water severed this connection. The seepage water flows parallel to the sill for several tens of metres, and its current has successively cut through the bases of the sand dunes, creating interesting truncated shapes. Beyond the dunes, in the lower section too, a barren, desert-like expanse of sand stretches all the way to the horizon, where the waves of the Danube would normally be rolling grains of sand.
In addition to the sediment accumulation zones, intense scouring has occurred between the rock outcrops – which most closely resemble spurs – extending from both banks, due to the increased water velocity caused by the altered flow conditions. According to some reports, in places the riverbed deepened by more than 10 metres downstream, which also threatened the stability of the weir. On the one hand, this was a calculated move; on the other, monitoring of the downstream riverbed is ongoing, and even on Sunday there was noticeable activity from motorboats and survey vessels on the Danube. This means that action can be taken immediately in the event of any sudden changes. On the Dunaszentbenedek side, the embankment has also been reinforced with huge concrete blocks transported from Dunakiliti, as the lateral erosion caused by water flowing over the sill could lead to the erosion of the loose, sedimentary section of the bank below the Pillangó diner.
Finally, here are a few thoughts that cannot go unmentioned regarding the Paks Weir. The first and most important lesson is that this structure will stand as a monument to a downward ecological spiral. Throughout human history, nature conservation has always been given the lowest priority. One result of this approach is, for example, this summer, which ultimately made this intervention at Paks necessary. In other words, when dealing with the problems arising from the neglect of nature conservation, we are increasingly unable or unwilling to take nature conservation into account. Where will this lead? The ever-deepening pessimism of the Danube Islands blog stems from this realisation.
We could also discuss nuances such as the members of the French BatoLabo expedition who became stranded at Harta, whose plan to sail from France to the Danube Delta has probably been thwarted for good. It would be good to know whether the sill was intended as a permanent or temporary structure. And one might also mention that this weir was built exactly where, in 1887, more than two hundred people perished at sea when the Biskó ferry capsized with them on board. But that is another story altogether...
Translated with DeepL.com (free version)
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