THE POLDER BOARDRIJNWAARD · EST. 1533
PEILBESLUIT−2.40 m NAP

Water ledger № 491Summer order · 10 July

Keep the land dry.

For nearly five centuries, Rijnwaard has lived by one measured promise: the water may rise, but the fields remain.

Take the storm watch
OUTER TIDE+0.62 m
POLDER FLOOR−3.18 m
INNER PEIL−2.42 m
WATCH STATEORDERLY
Living cross-section of the Rijnwaard polderThe North Sea stands above farmland. Windmills drive Archimedean screws to lift water through stepped channels to a tide-controlled sluice. NOORDZEEBuitenwater · tidal WESTDIJK · 6.12 m NAP RIJNWAARD1,842 ha arable clay lage boezemhoge boezem DE WACHTER · 1741 DE AREND · 1828 0.00 m NAPLAND: −3.18 m BELOW SEA LEVEL
TIDE
EBBING
TRAVERSE 12—C · BRASS SOUNDING PIN

Drag the pin across the section. Read every height against Amsterdam.

LIFT I · DE WACHTER−1.18 m NAPwater pocket ascending
SECTION B—B · LIFT CHAIN

Water climbs here.

The screws do not push the polder away. They carry it upward—pocket by pocket—until gravity can finish the journey to sea.

Magnified view of the two Archimedean screw liftsTwo diagonal rotating screws carry visible drops from the low channel to the high channel. LOWER BOEZEM · −2.42LIFT I · 1.24 mLIFT II · 0.96 mTO WESTSLUIS
SCREW DELIVERY0.0m³/sWAITING FOR WIND
KEEPER’S DRILL 06/7

The tide is orderly. Start both mills before calling the storm watch.

HOLD THE LINE100%
31 cm reserve

01

Schouwboek · daily condition

Folio 218b

The water writes first

This morning’s
measured promise.

“No field is dry by accident. It is dry because every keeper upstream remembered the keeper below.”— Chairwoman Lotte van Ee, opening the July schouw
Canal reserve
31cm
below order
Discharge, 24h
4.8million
m³ lifted
Salinity at W-4
0.31g/L
fresh
Rain debt
−7mm
to target

The invisible horizon

Everything begins at zero.

Normaal Amsterdams Peil is the quiet line against which the Netherlands is read. Our pasture lies 3.18 metres beneath it; our summer canal order sits at −2.40. The difference, seventy-eight centimetres, is our working room.

Why Amsterdam?

In 1684, eight marble stones fixed the city’s average summer flood level. One survives in the Stopera. Modern NAP is carried by some 35,000 benchmarks, making every sluice and survey speak the same vertical language.

+6+4+20 NAP−2−4
WESTDIJK CREST+6.12
MEAN HIGH WATER+0.82
AMSTERDAM ORDNANCE DATUM0.00
SUMMER CANAL ORDER−2.40
RIJNWAARD FIELD FLOOR−3.18
BELOW THE SEA
YET NOT BENEATH IT
02

Molenboek · engine roster

Six stations

The old machines still answer

Six keepers.
One falling waterline.

Wooden sails and electric auxiliaries work a single chain from ditch to sea. Each station signs its output into the ledger at noon.

M–01

De Wachter

Lower boezem · 1741

Lift
1.24 m
Keeper
J. Vermeer
TURNING
M–02

De Arend

Upper boezem · 1828

Lift
0.96 m
Keeper
S. Blom
TURNING
P–03

Gemaal Van Ee

Diesel-electric · 1956/2019

Flow
18 m³/s
Keeper
A. Drost
RESERVE
S–04

Westsluis

Three brass-racked leaves

Sill
−1.62 m
Keeper
M. Roos
AUTO
PB
HOOGHEEMRAADSCHAP RIJNWAARDMinutes of the 491st Summer AssemblyConvened at the Dijkhuis, Thursday 26 June 2026 · 09:00
APPROVED

Resolved beneath the
painted rafters.

  1. 09:08

    The rye fields at Kavel 17

    Keeper Blom reports seepage at the northern toe. A clay blanket of 140 metres is authorised before first harvest. Vote: seven in favour, one abstention.

    R.491.1
  2. 09:41

    Night turning during eel passage

    De Wachter shall reduce to twelve turns per minute between 23:00 and 03:00 from 18 August. Screens to be inspected each dawn by the lower keeper.

    R.491.2
  3. 10:17

    The brass teeth of Westsluis

    Found sound after 38,410 cycles. The board records its thanks to smith Noor van Keulen, whose replacement pin differs from the 1896 drawing by less than a hair.

    R.491.3
For the chair,Lotte van EeKeeper of the seal,Hendrik Vos
15332026

So long as the gauge is read,
the gate is kept, and the screw still turns,

Rijnwaard remains.