The city of Frankfurt stops taking water from the overheated rivers and streams.
The reason is the rising water temperature with a lack of precipitation.
Frankfurt – As of Wednesday, it will probably also be forbidden in Frankfurt to take water from rivers or streams for private or commercial use.
This was announced by the climate and environment department head Rosemarie Heilig (Greens).
In addition, paddling and canoeing on the Nidda are initially prohibited until the end of July, according to the Darmstadt Regional Council (RP).
The reason is the warming of the rivers.
For the Main, the Hessian State Agency for Nature Conservation, Environment and Geology (HLNUG) measured a water temperature of more than 25 degrees this week;
next week even more than 26 degrees are expected for the Main with increasing summer heat.
The background to the warming is the lack of precipitation: the less water the rivers and streams carry, the warmer the remaining water becomes.
Discharges from commercial operations, such as cooling water, also contribute to this.
This explains why the Main is warmer than the Nidda according to the HLNUG figures, although it carries significantly more water, as fr.de reports.
Water in Frankfurt is becoming scarce: the biological degradation of nutrients is accelerating
"The streams are dry, the groundwater levels are falling dramatically again," says Heilig.
She has just led a film team through the city forest and was - as so often recently - shocked by the state of the local nature.
The dying of trees and the heating of the watercourses are an expression of one and the same problem: climate change is making the summers hotter and, above all, drier.
The rain is missing everywhere.
A water temperature of 25 degrees is considered the tipping point for life in the river.
Main and Nidda can then no longer take in enough oxygen, and the concentration drops below a critical mark.
At the same time, the biological degradation of nutrients in water is accelerated, which also consumes oxygen.
This damages animals and plants in the river - and of course also applies to standing water, i.e. ponds and lakes.
Not enough water in Frankfurt: preventive measures are important
What to do?
The paddling and canoeing ban also helps to avoid additional stress for the animals on and in the water.
In principle, turbines in hydroelectric power plants are suitable for introducing oxygen into water, explains the Frankfurt environmental department.
Such systems are extremely rare here.
Preventive measures can therefore help: reduce cooling water withdrawal and discharge;
Process water withdrawal only for the essentials;
avoid construction work in water;
Reduce nutrient input (fertilizers, sewage treatment plants);
Increased discharge via weirs - then the so-called weir overflow means that more oxygen gets into the water, at least in places.
However, Heilig emphasizes that much of this is not within the city's sphere of influence.
The RP is responsible for bans and permits - that's where the request to stop water withdrawal went.
Water in Frankfurt: Environment Department calls for water-sensitive behavior
The state government determined that industrial plants and power plants on the Main increase the temperature by a maximum of 1.5 degrees (as of 2008).
At that time, the companies up to the western city limits (17 percent) and the energy producers Staudinger (about 40%) and Mainova (about 30%) had the largest share.
When the critical temperature is reached, the RP orders the companies to shut down their systems.
And the consumers?
The environmental department warns of “water-sensitive behavior”: don’t leave the tap running unnecessarily, water sparingly in the garden, use rainwater – if it should rain.
And always live CO2-sparingly to counteract climate change.
The environmental protection organization WWF appealed this week: "Give the floodplains back to the rivers!" Rosemarie Heilig also expects a positive long-term effect through the renaturation of Nidda and Main sections - where it is possible.
It is no longer possible to pump out water in Frankfurt: the landscape will change
The Main, which was considered “largely biologically dead” until the 1970s due to water pollution, is again an important part of Frankfurt’s species protection concept: many fish have settled again even in the city area;
the renaturation at the Fechenheimer Mainbogen offers animal species retreats, such as the rare kingfisher.
He needs fish to survive.
The fish need oxygen in the water.
This shows how everything is connected in nature.
"We have to understand: it's all an ecosystem," says the head of department, adding: "It's the beginning of July" to make it clear: midsummer is yet to come.
The landscape, she believes, will change.
"We're getting Milanese conditions." How far the changes go depends on the people.
In an interview, the Frankfurt climate officer Rosemarie Heilig talks about hot days, rocky deserts and the risk of forest fires.
And emphasizes: "We are much too slow".