“Eight beavers built a dam in two days that took the Czech Republic seven years to build.” Are these “beavers”?

Beavers, cute large rodents, have been in the news recently. Several media outlets reported that a dam in the Czech Republic that had not been built for seven years was completed in one or two days by a nest of beavers, saving 9 million RMB in funding.

The picture comes from the Internet

After reading this, isn’t it hard not to sigh – this is “河(合)利(理)”???

The picture comes from the Internet

Are beavers really that powerful? Will we no longer need to manage rivers in the future? Will we just release a nest of beavers and solve the problem? Obviously, human engineering cannot be simply equated with animal behavior.

First of all, one thing should be made clear: many reports that the beaver dam was built overnight or in two days are certainly exaggerated - just like other "overnight city" stories in history. It usually takes several weeks for beavers to build a dam . However, when the dam is finally closed, the water level can rise in one or two days. If people nearby had not noticed the dam itself before, they might have mistakenly thought that the dam was built in one or two days.

This night of water storage probably didn’t happen recently. The official website of the Brdy Nature Reserve in the Czech Republic, where this “dam” is located, released news about beavers, which mentioned that they built a dam and changed the water level, and also included photos - but this news was published on January 25, 2024. Yes, it was a year ago.

News about beavers building dams on the official website of the Brdy Nature Reserve in the Czech Republic

The current state of the wetlands in the reserve after the beavers built the dam. Image source: Official website of the Brdy Reserve in the Czech Republic

In addition, the dam is not that big. Czech TV station CT24 interviewed zoologist Jiří Vlček about this matter. He said that if someone were to do the project, it would be done in a week. Judging from the photos of the beaver dam on the official website of the Brdy Nature Reserve, this is indeed not a large-scale project. It is just a normal beaver dam, with a height of about one meter and a width of no more than a few dozen meters.

So why is it said that 9 million RMB can be saved? This number itself has a source. The director of the Brdy Nature Reserve said in an interview that it can save about 30 million Czech crowns - about 9 million RMB. However, a dam that can be built in a week can't be that expensive, right?

After reading this, do you feel that there is something else behind this "beaver helping people" incident? That's right, the management of this stretch of water is mired in a long-running dispute.

A tree bitten by a beaver. Copyright image from the photo library. Reprinting and using it may cause copyright disputes.

Bejčková Marie, a student at the University of West Bohemia in the Czech Republic, wrote a dissertation in 2019 that sorted out the ins and outs of the incident. The focus of the problem is the superior agency responsible for this river basin, the Vltava River Water Resources Management Bureau.

The story begins in August 2002. At that time, two low pressure areas moved from northern Italy to Central Europe, bringing heavy rains to the Krabava River for several consecutive days. The 227mm precipitation caused the river water to rush out of the river channel, and the water level of the reservoir rose at a rate of 23 cm per hour, almost exceeding the carrying capacity of the reservoir. Obviously, in the context of global climate change, the old infrastructure has been overwhelmed, and the project of river management has been put on the agenda. The Krabava River is under the jurisdiction of the Vltava River Water Resources Management Bureau, so the Rokycany Municipal Government along the river commissioned the management bureau to plan a management plan to widen the river channel and build a 1-meter-high concrete wall along the river.

But the plan designed by the administration failed to be implemented. Not only is it quite ugly, but it only protects the city center and transfers the pressure of floods to the upstream and downstream. When the flood comes, other urban areas downstream may face greater damage; and if there is a once-in-a-century flood, the accumulated water that has overflowed the concrete wall will have nowhere to go. In short, this is a plan that "treats the symptoms but not the root cause", which has been opposed by a large number of citizens and environmental organizations. More importantly, some of the rivers involved in the plan are privately owned, and the plan cannot be implemented without the consent of these people.

Time dragged on until 2018. That year, the city government, unable to bear it any longer, started a new plan and hired an external professional designer to plan a new governance plan. This plan was obviously more scientific, abandoning the concrete wall in favor of a more complex levee system. It also took into account the needs of citizens for daily travel and entertainment, adding stairs, sidewalks and bicycle lanes, and also included a complex governance project for the upstream and downstream riverbeds.

Unexpectedly, this new plan was rejected by the Vltava River Water Resources Management Bureau. Nominally, this was due to disagreements on the scope of the project. The new plan required a wider scope of governance than the old plan, and the management bureau insisted on its own analysis of the old plan and refused to approve the excess. Whether this actually involves years of grievances between the bureaucratic agencies of both sides, probably only the parties involved can tell. In any case, the new plan has come to a deadlock. As of the time the paper was written in 2019, the author Marie still had some hope for the negotiations - but judging by the lack of subsequent reports, the progress of the negotiations is probably quite limited.

The good news is that the treatment of another section of the river nearby was completed without delay. The length of this half-kilometer river includes re-laying the river and building a flood discharge area. The cost is 17.245 million Czech crowns, equivalent to about 5 million RMB - for reference, the cost of the aforementioned 9 million RMB dam can be used.

The beaver-dammed Padrťské Lake, located not far upstream from Rokyčany, may be part of the comprehensive Klabava River management project, or it may be related to other projects, but in any case it is under the jurisdiction of the Vltava River Management Bureau. This part of the management is likely to be caught up in the same bureaucratic wrangling. According to the CT24 TV report, "The management bureau was negotiating the scope of the project and the ownership of the land, but the beavers overtook it." How this negotiation was negotiated can only be left to the reader's imagination.

This incident, which may have happened a year ago, has suddenly made the news. Perhaps it is the result of the negotiating parties finally losing their patience. It is worth noting that neither the Czech news of CT24 nor the English news of Czech Radio interviewed relevant personnel from the Vltava River Administration.

From this point of view, the offer of 9 million RMB is more likely to be a way for the party concerned to vent his anger . In fact, referring to the other project just mentioned, the offer of 9 million RMB should include the overall management of the regional river section, not just limited to building a small dam.

Copyright images in the gallery. Reprinting and using them may lead to copyright disputes.

In any case, the beavers at least completed one of the tasks of the project, which was to raise the water level and create new wetlands. In the Czech Radio report, the zoologist praised the beavers, saying that "no one could have chosen a better site." (This may be the source of the statement in the Chinese report that "the site is consistent with the planned location of the reserve")

In fact, in this specific case, it is not difficult for the beaver to choose a suitable location. Because the location of its dam was originally a water diversion canal dug by humans. Water diversion projects dug by humans are generally contrary to the natural distribution of local hydrology (otherwise there would be no need for humans to dig). On the other hand, blocking the canal dug by humans can achieve twice the result with half the effort for the beaver. To put it more bluntly, the beaver is a genius engineer, but its genius serves itself, not humans or the overall ecological environment.

Therefore, beavers often cause trouble for humans. Beavers in the Czech Republic have flooded fields and railways before. In other areas where beavers are distributed, conflicts between humans and animals are also common. In Argentina and Chile, beavers are even regarded as invasive species. A famous conflict case occurred in 1948: After World War II, a large number of residents in Idaho, USA, moved to the countryside and soon clashed with the original beavers in the area. More and more people complained that beavers gnawed trees, built dams and destroyed property. However, the number of beavers in Idaho has fallen to a low point after years of hunting. The authorities are reluctant to kill beavers easily, so they captured 76 beavers and dropped them into nearby mountains by plane and parachute, leaving video records.

Ultimately, as long as they are not invasive species, beavers can make a huge positive contribution to the ecosystem , but their interests are not always consistent with human interests. So in areas where beavers are naturally distributed, we should applaud and welcome them to build dams - just don't expect them to be the ones to do human projects.

Planning and production

Author: Fang Gang, popular science creator

Review丨Huang Chengming, Professor of Hainan University

Planning丨Xu Lai

Editor: Yang Yaping

Proofread by Xu Lailinlin

The cover image of this article comes from the copyright library. Reprinting and using it may cause copyright disputes