Long term anthropogenic changes and ecosystem service consequences in the northern part of the complex Rhine-Meuse estuarine system

Abstract

Around 0 AD, the Rhine-Meuse estuary in the southwest of the Netherlands was a typical coastal plain estuary. Drainage of peatland and land subsidence behind the dunes later caused the sea to penetrate into the land. Most of the peat was eroded, and by 1000 AD the so-called Delta area had turned into a landscape of large estuaries and intertidal zones. Rotterdam developed from a small fishing village on the banks of the tidal river "Nieuwe Maas" from the 14th century onwards into the largest seaport of Europe in 2013. The Rotterdam harbour area situated in the northern part of the Delta area includes the former Europoort harbour, and is nowadays known as Rijnmond. The hydrology of the area is controlled by the drainage regime of the sluices in the Haringvliet barrier that was constructed as part of the "Delta Works" project to protect the southwest of the Netherlands against storm surges. The sluices are opened at slack tide to discharge river water to the sea and are always closed at flood tide. As a baseline study for environmental and ecological reconstruction and development, we describe in detail the loss of intertidal soft sediment ecotopes due to land reclamation, harbour development and river training works (straightening of the navigational channel) in the tidal rivers, and the expansion of hard substrate ecotopes (quay walls, groynes, training walls, riprap, concrete, stones etc.) in the Rijnmond area in the 19th and 20th centuries. Within 135 years, more than 99% of the original 4775 ha of characteristic pristine soft sediment estuarine ecotopes have disappeared. In the same period, 338 ha of hard intertidal substrate zone was constructed. Such trends can also be observed in harbour areas elsewhere, and have ecological and environmental consequences for estuarine areas in particular. Restoration of soft substrate estuarine ecotopes can be achieved by opening the Haringvliet Sluices at both ebb and flood tide, which would restore large-scale estuarine dynamics to the northern part of the Rhine-Meuse estuarine system. This will have a highly favourable effect on many ecosystem services. The Dutch division of the Word Wild Life Fund has launched a new proposal for a safer and more attractive South-West Delta area. It comprises the reopening of the sea inlets such as the Haringvliet by removing the barriers, and building climateproof dikes in combination with natural wetlands. In case of storm surges, the hinterland could be protected with a new generation of barriers that do not hamper the free transport of sediment, tides and animals. Based on 30 ecosystem services or subservices, it was calculated that opening the Haringvliet inlet would lead to an increase in Total Economic Value (TEV) of at least 500 million Euro per year. The costs of removing old barriers and the construction of new ones was not included in the calculations.

Socio-hydrological modelling: a review asking "why, what and how?"

“…It is important to note that, while this study focuses on modelling, system understanding cannot be brought about solely through modelling, and other, more qualitative studies are of value, particularly in the case of historical investigations (e.g. Paalvast and van der Velde, 2014).…”

Studying the historical evolution of ecosystem services to inform management policies for developed shorelines

“…It must be remembered that aside from the aforesaid changes in ES, additional losses were produced in the marine area into which the port expanded as a consequence of imperviousness. The reduction in ES caused by the artificialization of intertidal softbottom ecotopes has been precisely defined (Paalvast and Van der Velde, 2014).…”

Management options for restoring estuarine dynamics and implications for ecosystems: A quantitative approach for the Southwest Delta in the Netherlands

“…The Haringvliet and Hollands Diep are fresh water basins closed off from the North Sea by the Haringvlietdam ( Fig. 1) (Paalvast and van der Velde, 2014). The water distribution is nowadays largely regulated by the Haringvlietdam sluice, which is operated in such a way that the Nieuwe Waterweg can discharge 1500 m 3 /s for as long as possible to minimize salt intrusion.…”

“…As the new ecosystems developed, the estuarine landscape with natural transitions between tidal fresh, brackish and saline waters was replaced by more stagnant and disengaged fresh water, brackish water or salt water lakes (e.g. Saeijs and Stortelder, 1982;Wijnhoven et al, 2010;Paalvast and van der Velde, 2014). Each water basin has specific environmental problems (Table 1) (van Wesenbeeck et al, 2014).…”

“…Paalvast and van der Velde, 2014). However, so far no quantification of the consequences of various management options for development of estuarine nature and dynamics in the Southwest Delta as a whole has been made.…”