Delta Works was completed by the Europoortkering which required the construction of the Maeslantkering in the Nieuwe Waterweg between Maassluis and Hoek van Holland and the Hartelkering in the Hartel Canal near Spijkenisse. The works were declared finished after almost forty years in 1997. In reality the works were finished on 24 August 2010 with the official opening of the last strengthened and raised retaining wall near the city of Harlingen, Netherlands. Due to climate change and relative sea-level rise, the dikes will eventually have to be made higher and wider. This is a long term uphill battle against the sea. The
Delta Works region. The commission initially set the acceptable risk for complete failure of every "dike ring" in the country at 1 in 125,000 years. But, it found that the cost of building to this level of protection could not be supported. It set "acceptable" risks by region as follows: River flooding causes less damage than salt water flooding, which causes long-term damage to agricultural lands. Areas at risk from river flooding were assigned a higher acceptable risk. River flooding also has a longer warning time, producing a lower estimated death toll per event. These acceptable risks were enshrined in the Delta