Relaxing tranquility, brutal strength: we are drawn to the beauty of the rivers and streams. At the same time, the power of water is as fascinating as it is terrifying.
The droughts of the last few years and the floods of 2021 have made us see in a drastic way that we humans have made drastic mistakes in expanding streams and rivers for decades. Whether we experience drought or heavy rain – the state of the rivers determines how devastating the consequences are for cities, villages and fields.
How much man has destroyed, why floods caused less damage centuries ago and why climate change is just an excuse here, explains the natural scientist, ecologist and bestselling author Josef H. Reichholf in BILD.
“Floods are man-made”
Reichholf just got the book “River nature. A fascinating living space in transition “ released. The book clearly shows why rivers, in addition to all their beauty, are also so prone to conflict.
“Floods are man-made in their severity. They will also come back, regardless of whether something is done about global climate change or not – this is what the earlier times with their often much larger and more devastating floods teach us. Politicians and those responsible are shirking their responsibility by resorting to ‘climate change’! This is criminally misused as an ideal excuse, ”says Josef H. Reichholf to BILD.
▶ ︎ For the renowned scientist, one thing is clear: drought and floods arise because alluvial forests have been cleared, wetlands drained, rivers straightened and areas sealed. All of this has overloaded the water balance.
“Alluvial forests were destroyed”
BILD: What were and are the greatest sins that we have done to rivers? River expert Reichholf:
1. Straightening (“drainage improvement”) with the destruction of up to 90 percent of the floodplains and floodplain areas, so that floodwater is no longer held back, but even discharged in an accelerated manner (“elsewhere”).
2. Use by agriculture right up to the banks, which favors runoff and drains the wetlands (destruction of the floodplains).
3. Large-scale maize cultivation even on slopes, which turns clear water that falls as rain into toxic brown floods and even medium floods cause severe damage. The reservoirs so combated by nature conservation are, however, far less problematic. Quite rightly, many were even placed under nature protection because they have become so rich in species and so indispensable for river life.
“Vineyards reinforce the floods”
How can a river give us more security in the future? What may and must be allowed to be flooded?
Reichholf: “The floods of summer 2021 made it very clear that the main damage was caused by the way the river valleys were managed and built. The rainwater is channeled far too quickly into the rivers, which rise correspondingly rapidly. Vineyards on the slopes, whose rows of vines are arranged in the fall line from top to bottom and not parallel to the slope, intensify the floods, as do corn fields with open ground on slopes until July. For good reasons and centuries of experience, river valleys used to be built practically only at heights that were safe from flooding. The fact that building land was designated in the natural floodplain is now taking its toll. In addition, flood retention basins were built too hesitantly and in far too few numbers. “
What are your demands on politicians and decision-makers? What needs to be done?
Reichholf: “The people affected should not be fobbed off with the measures against climate change promised by politicians. These will only become effective in the distant future, if at all, because the climate is a global issue and cannot be influenced significantly through local or regional measures. But since floods have always existed and will continue to occur, local and regional countermeasures and precautionary measures are sorely needed. These must start with land use. “
“Precipitation does not belong in the sewer system”
“In addition, the following is required: Wherever new building areas are designated by the municipalities, these should be equipped with appropriately large retention basins for water that are adapted to the local precipitation conditions. The sewer system is just a special form of rapid drainage of rainwater. Water has to be stored, especially for expected longer dry seasons, as the years 2018 to 2020 have shown. Rainwater does not belong in the sewage system and sewage treatment plants, but in ponds and small lakes that hold it back and allow it to be reused. “
Josef H. Reichholf taught aquatic ecology and nature conservation at the Technical University of Munich. The multiple award-winning scientist and author is one of the 40 most prominent natural scientists in Germany.
How is our rivers currently doing?
Reichholf: “According to the official classification, the water quality is quite good; Most of them have quality class II. But structurally not good, because almost all of them are straightened over the vast majority of their route, “drainage-capable”, without accompanying riparian forests and too heavily burdened with agricultural washings from the meadows. “
Which river is the most polluted? Which body of water is still doing well?
Reichholf: “The creeks and small rivers in the agricultural landscape are hardest hit because they lack the necessary buffer zones. The conditions on large rivers such as the Rhine and Elbe have improved. Things are looking pretty good with the renatured Isar south of Munich, which was allowed to become a wild river again for almost 50 kilometers. “
Are there any examples of how we can breathe life back into rivers? As with the Emscher in North Rhine-Westphalia?
Reichholf: “Yes, of course, wastewater treatment in efficient sewage treatment plants has generally brought about major improvements. But these are nowhere near as effective as they should be with the high wastewater charges that we pay, because around three times the amount of domestic wastewater in the form of manure from animal husbandry, untreated, floods the land, rivers and groundwater (heavily) burdened. “
Do you have a favorite river?
Reichholf: “This is the Inn, because I grew up there and did by far the most extensive of my own research on river ecology.”