During the 1st phase, the stormwater sewerage systems will be provided for the drainage areas No. 3, 4 and 7, in order to receive the run-off from the runway, the taxiway with exit ways, the existing and the designed terminals with aprons and roads as well as the de-icing pad.

The drainage area No. 3 encompasses the area F = 119.71 ha.

The calculated run-off from this area to the sewage system amounts to Q = 3,286.1 dm3/s. The sewage system will be provided with:

• a tank for biodegradation of products used for de-icing and contained in sewage drained from the de-icing pad and in stormwater flowing in the winter season from this station – the capacity of the tank V = 599.4 m3,
• a retention reservoir located before the outlet of the capacity V = 4,274.1 m3, including a separated tank for biodegradation of the capacity V = 1,906.8 m3,
• equipment for the treatment of stormwater: a decanter to stop the mineral suspension and a separator to remove oil hydrocarbons.
  The run-off to the B ditch in the catchment area of the Potok Strzelniczki, owing to the retention, will amount to:
  q = 239.1 dm3/s.

The drainage area No. 5 of the area F = 55.4 ha.

The volume of stormwater flowing to the drainage has been calculated as Q = 2,519.6 dm3/s. The sewage system will be provided with:

• a tank for biodegradation of the capacity V = 977.4 m3,
• a retention of the capacity V = 162.9 m3, and
• equipment for the treatment of stormwater: a decanter and a separator to remove oil hydrocarbons.
  The run-off to the B ditch in the catchment area of the Potok Strzelniczki, owing to the retention, will amount to:
  q = 239.1 dm3/s.

The run-off to the B ditch in the catchment area of the Potok Strzelniczki with the intensity of q = 101.7 dm3/s.

The drainage area No. 7 (concerning the road system, the new terminal and the car parks) has the area of 6.7 ha.

The volume of water flowing to the drainage system amounts to Q = 1,195.1 + 824.6 = 20197.7 dm3/s. The sewage system will be provided with:
- part 7a of the retention reservoir of the capacity V = 1,173.4 m3, preceded with a decanter and a separator of oil hydrocarbons, and part 7b of the retention reservoir of the capacity V = 711.4 m3, proceeded with a decanter and a separator of oil hydrocarbons.
The run-off to the reservoir with the intensity q = 104.7 dm3/s.