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
Environmental issues in the Niger Delta Niger Delta. Vegetation in the Niger River Delta consists of extensive mangrove forests, brackish swamp forests, and rainforests. The large expanses of mangrove forests are estimated to cover approximately 5,000 to 8,580 km² of land. Mangroves remain very important to the indigenous people of Nigeria as well as to the various organisms that inhabit these ecosystems. Human impact from poor land management upstream coupled with the constant pollution of petroleum has caused five to ten percent of these mangrove forests to disappear. The volatile, quickly penetrating, and viscous properties of petroleum have wiped out large areas of vegetation. When spills