Mill Network at Kinderdijk-Elshout

Since 1997 • Cultural

The outstanding contribution made by the people of the Netherlands to the technology of handling water is admirably demonstrated by the installations in the Kinderdijk-Elshout area. Construction of hydraulic works for the drainage of land for agriculture and settlement began in the Middle Ages and have continued uninterruptedly to the present day. The site illustrates all the typical features associated with this technology – dykes, reservoirs, pumping stations, administrative buildings and a series of beautifully preserved windmills.

The Kinderdijk-Elshout mill network is an outstanding man-made landscape that bears powerful testimony to human ingenuity and fortitude over a millennium in draining and protecting an area by the development and application of hydraulic technology.

It is located in the north-western comer of the Alblasserwaard. It drained the internal drainage districts of De Overwaard and De Nederwaard until 1950, when the mills were closed. The 19 mills that form this group of monuments are all in operating condition. The Alblasserwaard is bounded by the rivers Lek to the north, Merwede to the south, and Noord to the south. The properties consist of discharge sluices, Water Board Assembly Houses, pumping stations, and brick and wooden mills. Owing to changed technical requirements, the discharge sluices were reduced to two and reconstructed in the mid-1980s.

The Water Board Assembly Houses of De Overwaard and De Nederwaard survive intact. The former was built in 1581 and purchased by the Water Board in 1595 to house the Elshout lockmaster. It was used for several other purposes until 1648, when it became the headquarters of the Water Board. It is a two-storeyed brick structure on a rectangular floor plan with a hipped roof. When it became the Water Board Assembly House the modifications included provision of a meeting room, addition of a stone door-arch decorated with coats of arms of the reeve and board members, new windows, and bedrooms in the attic for members. It underwent drastic alterations in 1918 when the dyke there was raised and widened: 3 m was removed from the front of the house and a new facade built. It was restored in 1981-83. The assembly house of De Nederwaard is a plain rectangular two-storeyed building of the 18th century with a hipped roof.

The Wisbom pumping station was originally an auxiliary steam-driven pumping station for De Overwaard, built in 1868 with four scoop water-wheels on the exterior of the engine house. It was converted to electricity in 1924. At this time some modifications were carried out to the plain gabled brick structure. The Van Haaften pumping station, built for De Nederwaard, also dates from 1868. It was converted to diesel operation in 1927 and the scoop wheels were replaced by Archimedean screws. It was partly demolished in 1971-72 when the J.U. Smit pumping station was built.

The most characteristic features of this landscape are the windmills, used to pump water from the polders using internal or external scoops into reservoirs, on two levels. At one time there were more than 150 in the Alblasserwaard and Vijfheerenlanden area; this had dropped to 78 in the 1870s but today the total is only 28, of which 16 are in the Kinderdijk area. The eight mills that survive on De Nederwaard were all built in 1738. They are bonnet mills (in which only the top section revolves with the wind), built from brick and with large sails that come within 30 cm of the ground, hence their name, 'ground sailers'. Eight mills are also in place on De Overwaard. All date from 1740 (although one was reconstructed in the 1980s). They are bonnet mills and ground sailers but, unlike those on De Nederwaard, they are octagonal in plan and built from wood on brick substructures. The internal iron scoop wheels are slightly larger than those on De Nederwaard, as are the spans of the sails. In addition to the mills on De Nederwaard and De Overwaard; the World Heritage site contains two mills from the Nieuw-Lekkerland polder and one from the Alblasserdam polder. Both of the former are of the same type as on De Overwaard, but De Hoge Molen (The High Mill) has an internal steel Archimedean screw for raising water, rather than a scoop wheel. The De Blokker mill on the Alblasserdam polder is the only example in this area of the earlier form of mill, the hollow post mill, in which the upper part of the structure that revolves with the wind is considerably larger than that of the bonnet mill. The date of its original construction is unknown, but records show that there has been a mill here since the late 15th century.

Although they went out of use in the late 1940s, all 19 mills are still maintained in operating condition, because they function as fall-back mills in case of failure of the modern equipment. So far as the landscape is concerned, the other most striking feature is the evidence that still survives in two areas of the medieval land-tenure system, based on long thin strip fields. This is a landscape that has not changed significantly for centuries.

Historical context

The formation of the peat region of the Provinces of Holland and Utrecht began around 4000 BC and continued up to the beginning of the present era. Changes in the drainage of the region consequent upon cultivation resulted in a situation where farmlands lay below the level of the streams that had drained the peat. It therefore became necessary to construct dikes to prevent flooding of the land.

There has been human settlement in the HollandUtrecht peat region since the 11th century AD, on higher land, on the embankments, and along the rivers and watercourses. The medieval developments were mostly subdivided into long strips averaging 14m wide by 1250-l300m long, with farms at their ends.

Reclamation of the Alblasserwaard ( -waard = "land in or along the water"), part of which is the subject of this nomination, began on the northern, western, and southern sides in the 11th century, and later extended to the watercourses that traverse it. A low-level ring dike enclosed all except the western part as early as the 12th century, and this had been extended to include the whole area by 1320. The Alblasserwaard was crossed by two streams, the Alblas and the Giessen, the basins of which developed into De Nederwaard and De Overwaard respectively; the Alblas was extended by a man-made watercourse, the Graafstroom, around 1264.

In 1277 Count Floris V of Holland set up a central body to be responsible for the maintenance of the dikes in the Alblasserwaard, known as the Hoogheemsraadschap van den Alblasserwaard (District Water Board for the Alblasserwaard). It consisted of a dike reeve and 13 board members.

Prince Albrecht van Beieren (Bavaria) authorized the digging of a canal for draining De Overwaard from the Giessen to the river Lek at Elshout in 1365. Known as the Grote or Achter W aterschap (Large or Rear Internal Drainage District), it was 17km in length, with 12km of connecting watercourses. Four years later work began on another drainage canal, known as the Nieuw Waterschap, from the Alblas to the Lek. Both systems are still fimctioning today.

In 1612 the internal drainage district of De Nederwaard was granted a permit for the compulsory purchase of 70ha of polder-land to the west of the Nieuw Waterschap in order to increase the capacity of the reservoirs by creating a new elevated reservoir. This also involved raising the water-level in the reservoirs and, as a result, the levels of the roads and low-level inner dukes in the area all had to be raised.

Serious flooding in 1726 led to the decision being taken by the Nederwaard and Overwaard management boards each to build a series of eight "head" drainage mills to deal with the endless battle against water and transfer the water produced at that time by 43 polder mills from the lower to the elevated reservoirs. In 1740 a second sluice was installed at the elevated reservoir to handle the water flow, and in 1766 the elevated reservoir itself had to be enlarged.

However, this form of drainage using windmills proved to be inadequate, since the water-levels in the rivers were often too high, making it difficult to discharge water into them through the sluices from the lower reservoir. By 1860 the 25 mills in De Nederwaard could no longer cope, and so a steamdriven pumping station was installed in 1868, to raise water from the lower to the upper reservoir (successively replaced by modem equipment). A similar decision was taken on De Overwaard.

As a result of this process of modernization, the redundant wind-driven scoop mills were gradually demolished. The Kinderdijk mills came back into use during World War ll, when there was no fuel for the diesel-fuelled pumping station, but closed down again after 1945. Today eight polder mills survive in both De Overwaard and De Nederwaard

Justification for being a World Heritage Site

The Committee decided to inscribe this site on the basis of criteria (i), (ii) and (iv) considering that the Kinderdijk-Elshout mill network is an outstanding man-made landscape that bears powerful testimony to human ingenuity and fortitude over nearly a millennium in draining and protecting an area by the development and application of hydraulic technology.

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