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 by planted vegetation or revetments. Although the new plan brought along additional cost, it was received favourably. The re-considerations of the Delta Project indicated the growing importance of integrate environmental impact assessments in policy-making. The Delta Project of which the Delta Works are part of was originally designed in a period of time in what environmental awareness and ecological effects of engineering projects were barely taken into consideration. Although the level of awareness for the environment grew throughout the years, the Delta Project has caused numerous irreversible effects on the environment in the past. Blocking the estuary mouths did reduce