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
Indus River Delta-Arabian Sea mangroves time it reaches the delta, the flow of freshwater is down by more than 90% compared to historic levels. Active flow only lasts for about two months, and the sediment load is similarly diminished. Saline water intrudes upstream for about and this affects both the mangroves growing in the area and the agricultural land. Loss of sediment causes increased coastal erosion, and this is exacerbated by land subsidence and rising sea levels. Other factors affecting the mangrove areas are pollution from sewage and industrial effluent, and parts of the mangrove area have been lost to agriculture and urban development. The