Fort, vesting en -onderdelen, Betonnen werken tussen 't Werk by Maarsseveen/Fort Tienhoven Maarssen (Stichtse Vecht 26)

English translation

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Description

Cluster 22. Schotbalk Sluice/Check Sluice.

NEW HOLLANDIC WATERLINE

Introduction

SCHOTBALK SLUICE / CHECK SLUICE as a combined civil and military hydraulic engineering component of the inundation works of the New Hollandic Waterline and located at the beginning of the drainage of the Bethune Polder. The defence system of the New Hollandic Waterline was in the first place based on the controlled flooding of (large) terrain areas. Controlled inundation required an ingenious system of waterworks, such as sluices, weirs and canals, by means of which the necessary water level could be rapidly set and maintained within tight limits. Many different types of sluices were applied, depending on the place where they functioned in the system. Sometimes already existing navigation, drainage or check sluices were used, but many new ones were also built or existing ones were (substantially) adapted. Sometimes local water-level differences between individual polder units had to be bridged by incorporating or using check sluices in existing quays or dykes. For this purpose schotbalk barriers in waterways or even in cuts in quays were often applied, but also so-called locks with wooden or iron lifting gates or culverts with sluice gates were used for this purpose. The schotbalk sluice / check sluice was built in the culvert on the outlet side of the Bethune Polder Pumping Station and forms a water barrier / inundation barrier of the water catchment area of Amsterdam.

Description

SCHOTBALK SLUICE / CHECK SLUICE built as a double culvert on the outlet side of the Bethune Polder Pumping Station. Two adjacent culverts, opening into two brick outlet structures / wings built in the shape of the letter W, with in both outlets double schotbalk grooves, set in natural stone blocks. The schotbalk sluice / check sluice from 1929 served as an inundation barrier. On top of the sluice a balustrade of iron tubes and on the middle wing a blue water level gauge.

Valuation

SCHOTBALK SLUICE / CHECK SLUICE on the outlet side of the Bethune Polder Pumping Station is of general importance because of

* Cultural-historical values as part of the New Hollandic Waterline as designed by C.R.T. Kraijenhoff and initially from 1815 realised by him, Jan Blanken and major-engineer Willem Offerhaus and subsequently by others over approximately 125 years strengthened and improved.

* Architectural-historical values, in particular as an expression of combined military-strategic and civil engineering, which is based on the system of inundation and access defence (20th century).

This concerns a water engineering component built for use within the New Hollandic Waterline, related to military-strategic engineering, namely a schotbalk barrier in service of military inundation.

* Ensemble value and situational values as part of the New Hollandic Waterline in general and because of the functional and physical coherence with the other components of the complex.

* The component is representative because it emphasises and illustrates the application of sluice and barrier works in the functioning of the New Hollandic Waterline and is fairly rare because it is a water barrier in conjunction with a pumping station.

* The component is fairly well preserved because the main form, constructional detailing and various components have remained recognisable and functional.