The northern industrial and residential area of South Park experiences chronic flooding for three reasons:

  • The main drainage pipe to the Lower Duwamish Waterway is underwater during high tide..
    When it rains during high tides, the main pipe in 7th Ave S that flows to the Duwamish Waterway cannot drain out to the river, and water backs up in the drainage system. Rain falling in the lower areas of the basin cannot flow out, and water in the main pipe can sometimes flow back out of inlets and catch basins, flooding the neighborhood. A pump station will allow the main pipe to drain during high tides and relieve flooding in areas that have a drainage system in place.
  • Not all streets in the area have a drainage collection system..
    Additional conveyance improvements will not be fully effective until the pump station is installed so that the pipes can drain at high tide. When additional roadway drainage is built, it will connect to the main pipe in 7th Ave S and the pump station will allow the system to drain when the tides are high.
  • Many private properties in the basin do not have drainage pipes connected to the public drainage system..
    Some properties are lower than the street or are located along streets where there is no existing collection system. In these areas, individual property owners may want to make site improvements to connect to a public drainage system in the street once one is available.