Wasserrechtliche Erlaubnis für Grundwasserabsenkungen

In the case of construction measures, temporary groundwater lowering may be necessary to keep the excavation pit dry and/or to avoid a hydraulic ground fault. For these groundwater lowerings, you must apply for a permit from the water authority before starting the measure.

According to § 8 and § 9 of the Water Resources Act, the lowering of groundwater is a water use requiring a permit. The water law procedure serves to check whether harmful groundwater changes are to be expected with the use of the water and whether other requirements under public law are met.

• Information required when applying for a permit to lower groundwater levels

  The application should contain at least the following information:

  • Applicant (name, address, telephone number)
  • Property concerned (address)
  • Site plan with entry of the drawdown area, the extraction and discharge point and the marking of the building plot
  • Floor profiles at the tapping points with specifications of the GW level in relation to NN
  • Hydrological calculation of the system (flow rate, lowering area, lowering depth in relation to sea level)
  • Sectional drawings
  • Indication of the planned discharge (sewer/surface water or re-injection into groundwater)
  • Reduction period
  • Nature of the lowering procedure

  Lowering of groundwater in small quantities for a temporary purpose, where no adverse effects on the water balance, ecology or third parties are to be expected, may be exempted from the permit requirement in consultation with the water authority (Article 46 (1)

  Sentence 1 Water Resources Act).

  The prerequisite for a permit-free use in the course of a construction measure is that there is no groundwater contamination, contaminated sites or settlement sensitive development in the area of influence of the groundwater lowering and that the groundwater is not discharged into a surface water body. It is recommended to notify these projects to the water authority for examination in good time before the start of the measure, stating the local situation and the time frame.

  Detailed information on groundwater abstractions is summarised in the information sheet on groundwater lowering. The leaflet is available for download under the heading "further information, where can I find out more".

To apply for a groundwater lowering permit, an application form is available for download under "further information".

It is recommended to use the prepared application form. However, submitting an informal application with the required documents is also possible.

The application should contain at least the following information:

• Applicant (name, address, telephone number)
• Affected property (address)
• Site plan with entry of the subsidence area, the withdrawal and discharge point as well as the marking of the building plot
• Soil profiles at the extraction points with details of the GW level relative to NN
• Hydrological calculation of the system (flow rate, drawdown area, drawdown depth in relation to sea level)
• Sectional drawings
• Indication of the planned discharge (canal/surface water or re-injection into groundwater)
• drawdown period
• Type of drawdown method

Groundwater drawdowns in small quantities for a temporary purpose, where no adverse effects on the water balance, ecology or third parties are to be expected, may be exempted from the permit requirement in consultation with the water authority (Section 46 para. 1

sentence 1 of the Water Resources Act).

The prerequisite for a permit-free use in the course of a construction measure is that there is no groundwater contamination, contaminated sites or settlement-sensitive development in the area of influence of the groundwater lowering and that the groundwater is not discharged into a surface water. It is recommended that these projects be reported to the water authority for examination in good time before the start of the measure, stating the local situation and the time period.

Detailed information on groundwater withdrawals is summarized in the fact sheet on groundwater drawdown. The leaflet is available for download under the heading "further information , where can I find out more".

The granting of permission for the lowering of groundwater in areas with groves on private, as well as public land, can only be considered without restrictions in the period from October 1 to February 29 with regard to vegetation. In the period from March 1 to September 30 (vegetation period), the affected woody vegetation must be protected by irrigation measures.

Under the heading "where can I find out more" you will find further information on the subject of groundwater lowering.

You will find sample templates for the preparation of an irrigation plan and for the documentation of the irrigation.