Embellished groundwater model may jeopardise stability of planned opencast mining lakes

Cottbus, 30.01.2023. In a comprehensive statement, the environmental network GRÜNE LIGA has criticised the plans of the opencast mine operator LEAG to continue pumping out groundwater in the Jänschwalde opencast mine until 2044. The GRÜNE LIGA sees the stability of the planned opencast mining lakes at risk because LEAG's application ignores the increasing water shortage in Lusatia.
"The consequences of open-cast mining are being made up with fictitious amounts of water. LEAG's plan only works if there are no droughts and no increasing evaporation until 2100. Relying on this could cost the region dearly: If the planned water levels of the opencast lakes are not reached, the stability of the banks at Heinersbrück, Jänschwalde and Taubendorf will be in danger," explains René Schuster from the Green League's Federal Lignite Contact Point, who prepared the statement.
The GRÜNE LIGA also sees LEAG's request for permission under water law as contradictory to the official justification for groundwater extraction. Schuster comments:
"LEAG wants to pump out significantly more than is necessary for the safety of the mine, apparently in order to evaporate more water in the cooling towers of the Jänschwalde power plant. The aim is to burn as much coal as possible from the Welzow, Nochten and Reichwalde opencast mines at the expense of groundwater resources."

 In its statement, the GRÜNE LIGA demands, among other things:

• Limit groundwater extraction to what is demonstrably necessary from a geotechnical point of view and not to extract any additional water, for example as cooling water for power plants,
• The banks of future open-cast lakes should also be made stable for significantly lower water levels. It must be examined whether additional areas can be backfilled,
• A transparent overall concept for a climate-resilient post-mining landscape instead of the slice-by-slice publication of groundwater extraction, recultivation concept (final operating plan) and creation of the opencast lakes.
• Compensation and replacement for areas damaged by groundwater lowering or by the future threat of clogging.

Background:
LEAG plans to end coal production in the Jänschwalde opencast mine by the end of 2023, but to continue operating the neighbouring Jänschwalde power plant with coal from other opencast mines until 2028. Between 2023 and 2044, the company plans to pump out another almost 1.4 billion cubic metres of groundwater from the Jänschwalde opencast mine. This is to ensure the stability of the mine during the construction of the lakeshores and until the flooding of the planned three opencast lakes is completed. The public participation period ends on 31 January.

It is not clear in the application how the requested water withdrawal volume was determined; it was already specified by LEAG in all the expert reports submitted. In addition, 10 % more water is being requested than was examined in the environmental assessment. This difference alone, 122 million cubic metres, is more than three times the volume of the Müggelsee.

The application and the environmental impact study are based on a groundwater model that ignores climate change. An average groundwater recharge for the years 1980 to 2010 is used to model the period 2020 to 2100, although the application itself refers several times to declining groundwater inflow. The scenario used is too improbable to be the basis for planning the subsequent landscape or for the environmental assessment.
With lower groundwater recharge, fixed extraction quantities lead to a spreading of the drawdown funnel around the opencast mine. The impact on water-dependent areas in the surrounding area is thus greater and lasts longer than previously admitted. In the case of Lake Pinnow, the lowering of the groundwater level caused by the project can also be expected to have a considerable impact on the water body. The less groundwater is newly created, the less groundwater withdrawals may be permitted.

In the years 2017 to 2022, groundwater extraction from the Jänschwalde opencast mine already significantly exceeded the amount permitted under water law. Deutsche Umwelthilfe and GRÜNE LIGA took legal action against this, and in May 2022 the Higher Administrative Court of Berlin-Brandenburg refused to stop the opencast mining operation in summary proceedings. Whether it is being operated illegally must be clarified in the lengthy main proceedings.

(Photo: "geotechnical event" at the Cottbus opencast mining lake near Schlichow, spring 2022, ideengruen Markus Pichlmaier)

Links:

Detailed statement of the GRÜNE LIGA (with 2 pages of prefaced summary).
Public display of the application documents on the internet