Editing Delta Works (section)

=== Alterations to the plan during the execution of the Works ===
[[File:Schaalmodel Maeslantkering.jpg|thumb|Scale model of the [[Maeslantkering]]]]
During the execution of the works, changes were made in response to public pressure. In the Nieuwe Waterweg, the heightening and the associated widening of the dikes proved very difficult because of public opposition to the planned destruction of important historic buildings to achieve this. The plan was changed to the construction of a storm surge barrier (the [[Maeslantkering]]) and dikes were only partly built up.

==== The storm-surge barrier ====
The Delta Plan originally intended to create a large freshwater lake, the ''{{lang|nl|Zeeuwse Meer}}'' (Zeeland Lake).<ref name="ley196110">{{cite magazine |last=Ley |first=Willy |date=October 1961 |title=The Home-Made Land |department=For Your Information |url=https://archive.org/stream/Galaxy_v19n06_1961-08#page/n65/mode/1up |magazine=Galaxy Science Fiction |pages=92–106 }}</ref> This would have caused major environmental destruction in Oosterschelde, with the total loss of the saltwater ecosystem and, consequently, the harvesting of oysters. Environmentalists and fishermen combined their efforts to prevent the closure; they persuaded parliament to amend the original plan. Instead of completely damming the estuary, the government agreed to build a storm surge barrier. This essentially is a long collection of very large valves that can be closed against storm surges.

The storm surge barrier closes only when the sea-level is expected to rise 3 metres above mean sea level. Under normal conditions, the estuary's mouth is open, and salt water flows in and out with the tide. As a result of the change, the weak dikes along the Oosterschelde needed to be strengthened. Over 200&nbsp;km of the dike needed new revetments. The connections between the Eastern Scheldt and the neighboring [[Haringvliet]] had to be dammed to limit the effect of the salt water. Extra dams and locks were needed at the east part of the Oosterschelde to create a shipping route between the ports of Rotterdam and Antwerp. Since operating the barrier has an effect on the environment, fisheries and the water management system, decisions made on opening or closing the gate are carefully considered. Also the safety of the surrounding dykes are affected by barrier operations.

====Environmental policy implementations====
In an attempt to restore and preserve the natural system surrounded by the dykes and storm-surge barrier, the concept 'building with nature' was introduced in revised Delta Program updates after 2008. The new integrated water management plan not only takes into account protection against flooding, but also covers water quality, [[leisure industry]], economic activities, shipping, environment and nature. Whenever possible, existing engineering constructions would be replaced by more 'nature friendly' options in an attempt to restore natural estuary and tides, while still protecting against flooding.<ref>{{cite journal|last1=Kabat|first1=Pavel|last2=Fresco|first2=Louise|last3=Stive|first3=Marcel J.F.|last4=Veerman|first4=Cees P.|last5=van Alphen|first5=Jos S.L.J.|last6=Parmet|first6=Bart W. A. H.|last7=Hazeleger|first7=Wilco|last8=Katsman|first8=Caroline A.|title=Dutch coasts in transition|journal=Nature Geoscience|date=July 2009|volume=2|issue=7|pages=450–451|doi=10.1038/ngeo572|bibcode=2009NatGe...2..450K}}</ref> In addition, building components of the reinforcements are designed in a way that they support formation of entire ecosystems.<ref>{{cite journal|last1=Deltares|title=Bouwen met de natuur in de praktijk|journal=Delta Life|date=2014|volume=1|pages=14–15}}</ref> As part of the revision, the [[Room for the River (Netherlands)|Room for the River]] projects, enabled nature to occupy space by lowering or widening the river bed.<ref>{{cite journal|last1=Van Buuren|first1=A|last2=Ellen|first2=G.J.|last3=Warner|first3=J.F.|title=Path-dependency and policy learning in the Dutch delta: toward more resilient flood risk management in the Netherlands?|journal=Ecology and Society|date=2016|volume=21|issue=4|doi=10.5751/es-08765-210443|doi-access=free}}</ref> In order to establish this, agricultural flood plains are turned into natural parks, excavated farmland is used for wild vegetation and newly excavated lakes and bypasses create habitats for fish and birds.<ref>{{cite journal|last1=Rijcken|first1=Ties|title=A critical approach to some new ideas about the Dutch flood risk system|journal=Research in Urbanism Series|date=2015|volume=3|issue=1}}</ref> Along the coast, natural sand is added each year to allow sand to blow freely through the dunes instead of having the dunes held in place by planted vegetation or revetments.<ref>{{cite web|last1=DGW|title=Nationaal Waterplan|website=rijksoverheid.nl|url=https://www.rijksoverheid.nl/documenten/rapporten/2009/12/01/nationaal-waterplan-2009-2015|archive-url=https://web.archive.org/web/20150926204410/https://www.rijksoverheid.nl/documenten/rapporten/2009/12/01/nationaal-waterplan-2009-2015|url-status=dead|archive-date=September 26, 2015|publisher=Ministerie van Infrastructuur en Milieu}}</ref> Although the new plan brought along additional cost, it was received favourably.{{citation needed|date=November 2018}} The re-considerations of the Delta Project indicated the growing importance of integrate environmental impact assessments in policy-making.