Delta Works needed level of flood protection and the resulting costs are a recurring subject of debate, and involve a complicated decision-making process. In 1995 it was agreed in the Delta Plan Large Rivers and Room for the River projects that about 500 kilometres of insufficient dyke revetments were reinforced and replaced along the Oosterschelde and Westerschelde between 1995 and 2015. After 2015, under the High Water Protection Program, additional upgrades are made. In September 2008, the Delta Commission presided by politician Cees Veerman advised in a report that the Netherlands would need a massive new building program to strengthen the country's
European land exploration of Australia discovered—the Darling, Macquarie, Murray and Murrumbidgee rivers—all of which flowed west, a theory was developed of a vast inland sea into which these rivers flowed. Another reason behind the idea of an inland sea was that Matthew Flinders, who had very carefully mapped much of Australia's coast had discovered no great river delta where these rivers should have emerged by had they reached the coast. The Murray-Darling basin actually drains into Lake Alexandrina. Matthew Flinders had noted this on his maps but viewed from the sea does not look like the outfall of a large watershed, but instead as a