English

Tiengemeten, the plan

(source: brochure of the project organisation Tiengemeten, R. Posthoorn/Karin Anema)

TIENGEMETEN
ISLAND OF WILDERNESS, WEALTH AND WISTFULNESS

The last surviving island in the southwest part of the Netherlands is to become a unique nature reserve. Tiengemeten Island, together with the Ventjagerplaten and Spuimonding, will make up an area of more than 4000 hectares of protected countryside. The island is a real gain for eco-visitors. Peaceful, spacious and unspoiled and close to a major urban area. This brochure explains the plans, with the possibilities and the constraints. It describes the future of an island that was once owned by corporations with very ambitious construction plans, but is now the property of the Society for the Preservation of Nature (Natuurmonumenten) in the Netherlands, where nature can take its course and people can find peace and quiet.

As long ago as 1990 Tiengemeten was recognized by the Ministry of Agriculture, Nature Management and Fisheries as an important new nature reserve. The island - at present mainly used as arable land - was incorporated in the Ecological Main Structure (EHS), the network of existing and new nature reserves in the Netherlands. In 1994 the Province of South Holland designated the island as a nature development area. The Society for the Preservation of Nature in the Netherlands has owned the island since 1997. At the same time all the plans of project developers to use the island as a recreation park or for the storage of polluted dredging spoil were rejected once and for all.

Nature island

Tiengemeten's future landscape is made up of three spheres. Nature dominates the largest of these - the wilderness. The central and easily accessible part demonstrates the richness of the ecology particularly well - the wealth. A small section will be restored to its original state, to the landscape of wistfulness.

People will not desert the island completely and similarly nature will not take over exclusively. The Tiengemeten Nature Development Steering Committee has drawn up a development plan that is based on a number of premises and constraints. This will result, particularly at the outset, in a more structured development.

The Steering Committee has formulated the following premises:
* Tiengemeten is part of the Haringvliet/Hollandsch Diep water system.
* Nature development enhances the existing ecology.
* The layout is sufficiently robust that there are sufficient opportunities to retain and restore important ecological values in regard to both the current and future water level management of the Haringvliet sluices.
* The unique characteristics of Tiengemeten (island character, isolation and quiet) have priority.
* After the layout has been completed, characteristic traces of the human use of Tiengemeten will remain.
* Tiengemeten will remain accessible after the layout has been completed.
* Set safety levels of rings of dikes in the vicinity of Tiengemeten will not be negatively affected.
* The plans address the safety of residents and visitors and access for emergency services under normal and extreme circumstances.

What does Tiengemeten look like now?

Tiengemeten appeared in the 17th century as an insignificant sandbar in the then untamed Haringvliet. The area of this sandbar was 10 "gemeten" (approximately 5 hectares) and it explains the origins of the island's name. It was not until between 1750 and 1860 that the island was impoldered for agricultural purposes. The island now covers an area of approximately 1000 hectares. Currently 700 hectares are used for arable farming. The landscape is wide open and the layout is practical and utilitarian. The Blanke Slikken (300 hectares) are outside the dikes and have never been reclaimed. The landscape is rough and natural.
There are three small settlements in the polder. Many of the former workers'cottages became weekend cottages a long time ago. Some of them are now empty. Most of the farmhouses are also empty. The development vision gives a broadbrush description of which houses and farmhouses will be given a new function.

Study of the island

Tiengemeten has been studied from three different perspectives: nature, cultural history and recreational use.

Nature

Will Tiengemeten be an island without dikes?
Nature is nature, or so it would seem. Nevertheless the Steering Committee is confronted by important questions. What sort of natural ecology can exist and what is the best choice?
Tidal habitats in the Netherlands are very rare. There are good opportunities on Tiengemeten for freshwater tidal habitat. By removing the dikes the waters of the Haringvliet are free to flow over the island and to create the landscape. This is therefore preferred.
The study of the flora and fauna that can be expected in this situation yielded a number of interesting discoveries. Tiengemeten is above the average water level. The island would therefore generally be dry even without dikes. Assume that nature is left to its own devices in this relatively dry situation. It would soon result in large areas of tangled growth with little variation in flora and fauna.
There are several reasons for making the island somewhat wetter. The soil of Tiengemeten is made up of layers of clay and sand. This structure means, for example, that rainwater is barely able to soak away into the soil. A high ridge, the residual of a high mudflat created during the second impoldering phase, runs across the middle of the island. The Benedenpolder, the Middenpolder and the Brienenswaard therefore act as basins on the island. If the pumping is stopped, these are the places where the water mainly accumulates and a swamp is created.
Excavation is another way to obtain more water on the island. Dikes and the ridge on the island can be used to retain the water. By lowering the dike, after a flood the water remains on the island. The result is a wet area that is very sought after by rare species of birds. A section of the dikes can therefore play an important (but reversed) role on the future island nature reserve.

RELATION BETWEEN HARINGVLIET SLUICES AND TIENGEMETEN

In 1970 the Haringvliet estuary was closed of from the sea by a huge complex of sluices. In the Haringvliet the restoration of the natural estuary is dawning, with a gradual transition from the freshwater of the river to the salt water of the sea and a significant effect of the tide. It was decided in the spring of 2000 to keep the Haringvliet sluices ajar starting in 2005. Migratory fish can then pas through the sluices without hindrance and reach Tiengemeten, for example, as an attractive spawning area. Leaving the sluices ajar produces no additional tidal effect, but the policy goal is aimed at opening the sluices more in the future in accordance with the "Tamed Tide"option. Under this alternative the average tidal difference around Tiengemeten increases to about 70cm. However, the salt water will not reach the island.

Landscape and cultural history

The aim is to retain, to restore and to accentuate the main structure and the history of the development of Tiengemeten. Originally the island was made up of several polders. The dikes that encompassed these polders disappeared after the disastrous floods in 1953. They can be restored in order to show the historical development of Tiengemeten. The most important elements of the cultural history and the landscape include the three built-up areas, the former duck trap, the former refuge terp and the reed mounds on the Blanke Slikken. The settlements and the buildings determine the face of Tiengemeten and the quality of its cultural history. Most of the farm buildings are empty. A new farm was found for these farmers on the mainland. Many weekend cottages have also been abandoned. Most of the remaining residents have moved to the central residential core. Demolition, deterioration and renovation are options depending on the location and possible new functions for the empty buildings.

The southern dike of Tiengemeten alongside the Mariapolder appears to be the best candidate for lowering the dike level from a scenic point of view. It is immediately adjacent to the Haringvliet and over the last hundred years it has been breached a number of times. The main breach was here in 1953. Removal or lowering of this dike will make it possible to see the Haringvliet and the Ventjagersplaten. The dike also has to be lowered at the Blanke Slikken in order, among other things, to emphasize the wideness of the landscape.
As the new swamp develops, the rows of poplars along Grevesweg, which dominate the landscape, will disappear.

Recreational use

Tiengemeten offers scope for recreation whereby enjoyment of the ecology is at the core. The island is only 7000 m by 1500 m. Walking therefore has priority. The quality of the habitat and the quality of the pleasure are at the top of the agenda.
Visitors will get a real island feel of freedom and openness, peace and quiet, unspoilt countryside and they can enjoy looking at the flora and fauna. This is what makes Tiengemeten special. It has to become an island for a wide cross-section of people who enjoy nature and the countryside.

Enjoyment of nature and the countryside is the primary reason for visiting the island. A way therefore needs to be found to let as many people as possible get to know the island without disrupting the ecology. Part of the island will be readily accessible to visitors, part will be reasonably accessible and part will be inaccessible. This will be achieved through the density and the nature of the paths and tracks.
The classification into zones provides options for responding to the growth in the number of visitors. If the number of visitors grows above 40,000 per year, an evaluation will have to answer questions, for example is further growth possible without damaging the qualities or does the zoning have to be adjusted?

In 1999 all the proposals about nature, cultural history, the countryside and recreation were discussed in a group made up of a broad range of experts. They made the following recommendations:
* Retain the eastern extremity of the island (Oude Polder) and enhance it as an area with cultural history value, together with Griendweipolder.
* Keep the dike on the northern side. It can serve as the most important new access route.
* Restore the former refuge terp and have it serve (again) as a safe haven from flooding and as a viewing point.
* Cut through the dikes thereby allowing the ecology to develop under the influence of the dynamics of the tide.
* Restraint with regard to the tendency to "create" nature. However, basic conditions should be created.
* Retain the remnants of civilization and habitation.

A review is currently being made of the extent to which trees, avenues and dikes fit into the desired landscape, where the ferry should drop and pick up passengers (east or middle) and whether bird sanctuaries with observation facilities should be set up. Further study is needed in regard to buildings, recreation and the possible removal of asphalt roads that will end up under water.

NUMBER OF VISITORS

Research shows that between 30,000 and 40,000 visitors a year can be expected. The more than one million people who live in the Rotterdam region can reach the island in less than an hour, for instance. Tiengemeten is expected to become progressively more attractive as a result of the future structure and new flora and fauna. The number of visitors will vary greatly throughout the year. Currently a few hundred people come to the island during a weekend with fine weather. There may be only 20 visitors on a weekday during the winter. During the first few years after the new layout has been completed it is assumed that there will be more than 30,000 visitors a year. However, additional attention needs to be given to providing enough space for parking on the mainland.

Wich options have been devised?

Studies resulted in six development options, which have considerable overlap. Three of these were therefore selected for further analysis.

OPTION 1

The whole island is exposed to the direct influence of the Haringvliet. The possibilities for recreation are limited. A virtually natural tidal landscape will be created. As a consequence of the island¡¦s elevation, this will result primarily in reeds and brush. Mud flats and shallow open water will only develop in places where the soil is excavated. Tides and waves will be unrestrained after the water defences have been removed. Openings in the dike are also necessary between the Blanke Slikken and the Brienenswaard. The western settlement will be abandoned and the buildings will deteriorate into ruins. Recreational access is limited and there are no paths around the island.

OPTION 2

In addition to tidal flow, a great deal of attention was paid to retaining water that is needed for the development of swampy areas. There is much more variation here than in option 1. There is greater emphasis on wet types of land, shallow open water and mud flats that are dry from time to time. This option follows the important cultural history lines most closely. The ridge between Middenpolder and Benedenpolder and the Brienenswaard/Mariapolder connects to the dike around the Griendweipolder. The drainage of surface water in the Middenpolder and Benedenpolder stagnates because of this ridge. A large freshwater marsh will be created. The water levels in the rest of the island are determined by the Haringvliet.
The access is better than in the preceding option. There are walking routes around the island with an overall length of 11 km.

OPTION 3

In this option the dynamic tidal area is in the Middenpolder and Benedenpolder. Here drainage stagnates in the Brienenswaard as a result of a connection between the ridge and the Mariapolder, whose southern dike has been broken through in two places. The low sections of the Middenpolder are connected to the Haringvliet by streams. The low parts of the Brienenswaard have to be lowered even more in order to produce a substantial area of open water. The dike remains. This option provides the greatest scope for walking. Unlike option 2, there is a less clear zoning for recreational use. However, few really quiet spots remain. The western settlement can be retained.

Option 2 complies best with the premises that were specified through:

* More diversified nature development.
* The historical identity of the island, such as the phases of the impoldering, are expressed with natural accents.
* Mariapolder, adjoining the Haringvliet, is the best place to amplify the dynamic and to make the landscape open.
* The ridge between Middenpolder and Mariapolder obstructs the drainage of water and is a walking route at the same time.
* The Benedenpolder/Middenpolder is a permanent wet area. Attractive to water birds.
* Other functions are concentrated primarily along the northern dike and at the eastern extremity.
* The western and southern parts can remain as peaceful and quiet as possible.

Vision: what will it look like?

The introduction referred to wilderness, wealth and wistfulness. Tiengemeten is an island with three types of nature. This image is a consequence of the vision that has been formulated after a thorough planning process. The Steering Committee was thorough in its work. The island of Tiengemeten was examined from all perspectives. A very wide range of experts have taken or are still taking part. Tiengemeten deserves to be the subject of the most careful planning. The task is by no means simple. The goal is to ¡¥convert¡¦ a primarily agricultural island into a landscape where nature can take its course.

On this occasion WWW does not stand for World Wide Web, but for three different yet closely interlinked forms of nature and landscape. Wilderness, Wealth and Wistfulness. We start our journey through the future types of nature and landscape on Tiengemeten on the eastern side of the island, where the island originally appeared. Here we find the landscape of Wistfulness. First and foremost is the memory of what the landscape and the flora and fauna used to be. The wistful nature covers only a small area but it contains much. Human use remains visible, for example in small fields with natural flora. The intensive experience of the ecology here has the character of a longer stay. Nature study and accommodation for a few nights are possible.

The nature of Wealth holds the promise of great diversity in both plant and animal species. A landscape with grassland, reed and swamp vegetation, brush, occasionally dry mud flats and shallow water. The impact of people is barely visible. The lightest possible touch on the tiller to direct natural processes. Aimed primarily at maintaining the different types of nature. Everything is tailored to a short stay on the island and a good supply of information.

Wilderness is the third type of nature on Tiengemeten. Natural processes, such as the tides of the Haringvliet, dominate here. A dynamic landscape containing ecological communities of mud flats, pioneer vegetation, reed and rush fields, swamp vegetation, brush and tidal woods. The former impact of people can still be seen because the "tidal streams" are made up of former ditches and roads. This landscape, which unlike the other areas will not be managed, will be experienced as wild, exciting and spacious. There are few amenities, but there are narrow natural tracks, viewing points etc. This is habitat intended for nature roamers, nature explorers and searchers after peace and quiet. Part of the area remains naturally inaccessible to visitors because of tangled vegetation and the effect of tides.

The new island of wilderness, wealth and wistfulness is attractive. Visitors who are into nature will be completely in their element here. Walking has priority. There will be between 10 and 15 kilometres of roads, paths and tracks as well as viewing points, hides and observation posts. The nature of Wealth will have a few readily accessible and easily observed spots that have been designed as ¡¥ideal¡¦ locations for water and marsh birds. The basic amenities on Tiengemeten will be an information centre with basic catering services and an undeveloped campsite tailored to stays of a few days. The information centre will be in the Margueritahoeve, close to the ferry, which needless to say will remain in service. A suitable use is also being considered for the Idahoeve, among other places, for example as studios for landscape art.

Over and above the basic amenities there can also be special facilities, which obviously will not be allowed to detract from the nature function. The buildings in Midden will remain is use as (holiday) accommodation.

Everything has been thought of. Although nature has absolute priority, the attractiveness to visitors plays an important part. This is why safety, for example, is an area of attention. Emergency services like the fire service must have access to the island

Obviously the plans will be implemented in phases. A detailed layout will first of all be made on the basis of the development vision. The layout can be implemented when agricultural activities on the island have stopped and the necessary permits have been obtained. The work may take several years.

It is interesting right now. Natuurmonumenten in the Netherlands is pleased to be host on the island where there is already an open landscape and there are peace and quiet to be enjoyed. The special atmosphere can be enjoyed while walking along the present roads and paths. The sounds of the waders in the Schutskooipolder are a foretaste of what will soon fill the fields. The impressive tangle of reeds in the Blanke Slikken, intersected by meandering tidal streams. But above all the expectation of what the future holds in store.