Cause of contaminated ditch water identified

In the Zoeterhage industrial area and Van Tuyllpark, sewage has entered ditches and ponds. As a result, the water has become contaminated, and contact with the water is not recommended. The municipality of Zoetermeer and the Schieland and Krimpenerwaard Water Board (HHSK) have been working closely together over the past two weeks to determine the cause of the contamination, prevent its spread, and clean up the contaminated water. The cause of the contamination has now been identified.

Temporary detour put extra strain on the sewer system

Due to renovation work on the Rokkeveen sewage pumping station, wastewater from the Oosterheem neighborhood was temporarily diverted via a different route. This placed additional strain on parts of the sewer system. Part of the sewer system was constructed in the 1970s. At that time, the sewer network had not yet been fully mapped. As a result, two overflow outlets on Edisonstraat and Franklinstraat were not known. Due to the increased pressure, these overflow outlets began to discharge, causing contaminated sewage to enter the ditches and ponds. One overflow has since been closed off; the second overflow is currently being closed off to prevent contaminated water from entering the ditch water.

Repair work

The contaminated stormwater system is currently being flushed. This may temporarily cause additional odor nuisance in the surrounding area. Although this may be bothersome, the odor poses no risk to public health. Water quality and water levels are being monitored at multiple locations in and around the contaminated area. These measurements will continue until the water returns to normal conditions.

Advice for residents

As long as the water quality in the ditches within the contaminated area remains inadequate, the current recommendation remains in effect:

  • Avoid contact with water
  • Do not let dogs swim in the water
  • Do not let children play in or near the water
  • Do not use the water to irrigate sports fields

There are no risks to the drinking water supply.

Follow-up

The temporary diversion of the sewer line will be discontinued in the coming period. The overflows have already been closed or will be permanently sealed in the coming days. Because the overflow is located beneath the road surface of Franklinstraat, the asphalt will need to be broken up in certain areas.

Cleaning of the stormwater system and ditches will continue over the coming week. In addition, an investigation is underway into the impact of the contamination on water quality and the surrounding environment. As soon as water quality returns to normal, the informational signs in the area will be removed, and updates will be posted on the HHSK and Zoetermeer municipal websites, where the current situation is being shared: Avoid contact with ditch water in Zoeterhage and Van Tuyllpark.