Experts consider the plan to build additional dams as a means of combating drought to be technocratically one-sided, which should help solve only the consequences, not the cause. They agree that the fight against drought can only be won through changes in the landscape and the construction of dams can only be supported if there is a real shortage of drinking water. Which, apart from about three areas in the Rakovnicko and Zlín regions, does not threaten the Czech Republic yet.
In a broader context, two camps are currently being defined across the professional and political spectrum, but they share a common goal. This is to increase the ability to retain as much water as possible in the Czech Republic. The reason is clear. We need to prepare more for the drier period, which, according to climatologists, will come more and more often. Especially in the past five years, when the whole of Europe was experiencing an unusual heat wave, especially in 2018, we have witnessed such extremes that were approaching the national crisis. We should clearly consider these as a warning.
In addition, this year's mild winter does not bode well for the coming summer. The reason is that much warmer winters - with less snow cover - are less able to fill winter moisture reserves. This is because snow can better replenish the moisture in the soil profile and the groundwater supply. This deficit is then very noticeable in early spring, which makes the vegetation more vulnerable to drought than in previous years.
According to the server Intersucho.cz, which intensively maps and predicts the Czech "water situation", despite the fact that rainfall in May was slightly above average, we will most likely have to prepare for the spread of drought in the upper layers of the soil in the longer term. "The worse situation will remain mainly at depths of 40-100 cm," reads their website.
At present, there are two expert opinions on how to prevent this in the future. On the one hand, they are to help build new retention reservoirs and dams in selected more than 30 places in the Czech Republic, on the other hand, it is proposed that the right path leads through water retention in the soil in forest, agricultural or residential landscapes.
Is there an alternative where the ideal combination of both proposals could be expected?
Prof. Jakub Hruška from the Institute of Global Change Research of the Academy of Sciences of the Czech Republic last month told Aktuálně.cz that the key is above all to be able to distinguish between the fight against drought and the effort to provide drinking water. I contacted the professor and asked for an idea. "The Ministry of Agriculture considers this issue mainly as the provision of drinking water for the population. They argue that dams need drinking water, or irrigation for agriculture or some other utility water. But the joke is that if we want to face the drought, we have to keep the water where it fell. You don't need it to a certain extent in a dam, you need it in a field, in a forest, "says Hruška.
Everyone must immediately think that agriculture has a great influence on the dynamics of water in the landscape. This is not only a feeling due to intensive farming, but also because agricultural land, which, when in good "condition", is much more effective in retaining water than most forest soils (which, on the other hand, can release water quickly into deeper layers and thus supplement the level of underground reserves). From this it practically follows that the discussion about the construction of other dams in connection with the drying up of the landscape must always (or should) naturally expand towards working with the landscape as a complex whole, of which agriculture is an important active part.
According to a professional publication, they have the infamous credit for "drying up our republic" Agricultural drought in the Czech Republic (published under the auspices of the Agrarian Chamber of the Czech Republic and written by a team of leading experts led by professors Zdeněk Žalud and Miroslav Trnka) reclamation activities (construction of drainages and leveling of river flows, etc.) carried out between 1935 and 1940, later in 1965–1985. However, it should be noted that the drainage of the landscape occupies its justified place for improving fertility, especially in the colder climate that prevailed in the Czech Republic until the end of the 1980s. Given that at that time drainage systems were planned mainly on the basis of the then historical climatic data, it can be said that our ancestors cannot be so angry with this. At that time, it was difficult to predict that the average temperature would increase by about 1.6 ° C over the next 40 years.
At present, about 26 % from the agricultural land fund are ameliorated. "If we have 1.1 million hectares of land undermined by land reclamation, which drains the water efficiently away, the fight against drought should begin there. By piping it to the nearest stream and then to the dam, for example, you will never keep the water in the landscape where it should be and where it is missing, ”says Hruška about the direct relationship between agricultural areas and the surrounding landscape. In addition, irrigation systems can be found in the Czech Republic only in South Moravia.
But what can be read to our ancestors is the dramatic change in the fragmentation of agricultural land. In the above-mentioned publication, it can be calculated from the historical film Kyjovska in the Hodonín district from the 1950s with relatively decent accuracy that the average area of one square was around 1 ha (just to give you an idea: the average football field size for an international match is 0.7 ha). In the picture from the last years of the same area, the "hectare" fields merged into areas with an area of about 40 ha and more. This current situation is mainly attributed to post-war nationalization, which led to the merging of fields. You can see an interesting comparison of different fragmentation in our country and in Austria if you "zoom in" on an aerial image, for example, along the entire length of the border with Lower Austria (Niederösterreich). At first glance, the differences are more than obvious.
Among other things, such a dramatic transformation of soil blocks, which is one of the largest in the EU, is the cause of intensive degradation of agricultural land. It loses its retention capacity, it is more prone to erosion, where according to the above-mentioned publication, many soils in our country are so disturbed that they have completely lost their ability to retain water. In addition, Hruška adds that the current trend of increasing areas is also accelerated by better, larger and more efficient agricultural machinery. "I would see such an ecological limit somewhere on 15, 20 hectares, because you will still use the technique there. One of the bizarre arguments that is being made today is that the fields do not have to be small when they have such large machines, "he says, adding that such fragmented fields should be divided by some terrain barrier preventing water runoff, in the form borders, draws or grass areas. Just for completeness: from next year, the maximum size of the soil block of one crop will be 30 ha.
However, the whole issue is even more complicated, because other factors also enter into it, such as the types of cultivated crops and their rotation, the rate of use of pesticides and artificial fertilizers, excessive compaction of the soil mass and others. However, let's stay by the water. According to the landscape ecologist prof. Josef Fanta, our situation is defined from the ground up by the specific position of the Czech Republic, which has become, or should become, a principle on which it is necessary to build further strategies to address the situation in the country. In other words, Professor Fanta emphasizes the geographical location of our republic, which is not for nothing called the "roof of Europe". The reason for this is that water that would serve as supplies does not come to us from anywhere. The Czechia is thus explicitly dependent only on precipitation.
The good news is that the current annual precipitation is fluctuating, but stagnant - that is, unchanged. What is increasing, however, is the evaporation of water from the landscape, which results in the occurrence of so-called dry episodes, and in warm summers, such as in 2018, when several meteorological warnings applied throughout the territory, we may get more and more in the future. trouble. Experts thus agree that the fight against drought requires a comprehensive approach with specific steps for individual parts of the territory, because each bears its own characteristics. Hruška adds that, for the same reasons, there is practically no ideal recipe between building dams and transforming the landscape in the fight against drought.
In other words, experts in various fields agree that the Ministry of Agriculture's intention to build over 30 new dams in the next decade is technocratically one-sided, where they somehow show that they probably have no idea how to work with the landscape. "The only recipe they have for both drought and floods is simply 'we'll build more dams.' They are not mentally able to work with the landscape as such, "says Hruška. And it describes a specific example, often presented by him, of the almost built Nová Heřmínova dam in northern Moravia, which, according to the Ministry of Agriculture, is to help against drought. "However, the original planning of this dam was due to floods. The Nová Heřmínova dam was planned after the catastrophic floods in northern Moravia in 1997, "he adds.
Logically, it can be considered that if water does not accumulate to a greater extent mainly in the surrounding landscape, mere precipitation is very unlikely to ensure that the newly proposed water works will be filled in the coming years. In August 2018, ie during the incriminated extremely hot summer, a leading expert on ecology and forester, prof. Josef Fanta told DVTV that "it is necessary to move to a completely new way of thinking as soon as possible." And then he describes his own negative experience that politicians are very poor at handling already available research information, which they are more or less not interested in. "He constantly adheres to the economic principle where the market solves everything."
"Everyone must immediately think that agriculture has a great influence on the dynamics of water in the landscape"
"The good news is that the current annual precipitation is fluctuating, but stagnant"