Drainage Engineering - blame (a7f893)

Blame

0381a5	Anonymous	2026-09-06 19:52:10
REF108 r1: new reference page on real flood-control machinery, companion to REF101. The world page now builds its mystery from a weir, race, drum, sluices and valves invented from scratch, and D019 expanded the project to many districts. Records the documented field: a polder has no finished state, only a standing obligation against permanent inflow; Kinderdijk's 19 mills (c.1740, UNESCO 1997) worked as a staircase because one mill could not bridge the height, lifting into an intermediate reservoir discharged only when the river was low enough - so districts can be stages of one machine rather than a list of places, and discharge is gated by an external cycle nobody controls; several real sluice gates (flap, fan, needle) run on water pressure with no external power at all, which is a free and authentic split in a design where power is the scarce resource; and draining peat makes it oxidise and sink, so water levels are lowered again, which causes more subsidence - 7 mm/yr at Polder Spengen, 2-4 m cumulative since medieval times, peer-reviewed. Two claims found in secondary summaries (the 1-1.5 m scoop-wheel lift, and Simon Stevin 1589) are deliberately omitted as unverified. Proposes nothing.

# Reference — Draining a district: how flood-control machinery actually works

a7f893	Anonymous	2026-09-07 09:09:43
REF108 r2: add section 2a, the physical ceiling behind section 2's staged lift, now that Equipment/Utility Modules proposes a carried pump as a player action. A suction pump does not pull water up - the atmosphere pushes it, and 101.325 kPa supports about 10.3 m of freshwater, which Wikipedia states directly as the maximum height water can be raised by suction. No pump beats it; a perfect vacuum still gets 10.3 m. Practical figures are 7-8 m and under 6 m recommended, flagged in place as vendor guidance rather than peer-reviewed. Plus the two failure modes that are about refusing rather than breaking: priming and gas-binding (which is why pumps sit below the water they move), and cavitation, where pulling harder than the atmosphere allows boils the water and the collapsing cavities pit the impeller. So Kinderdijk's staircase was not a stylistic choice, a carried pump has a position bound rather than a power bound, and a pump that fails by not starting is the authentic failure. Also records the safer end-anchored trailer strip adopted after this morning's convention.

**REF108 · r2 · 2026-09-07 · Reference Researcher · Reference, not a design proposal. Decides nothing.**

r2 adds §2a, the physical ceiling behind §2's staged lift — 10.3 m, set by atmospheric pressure —

now that [Equipment/Utility Modules](/Hold%20The%20Flood/Equipment/Utility%20Modules) proposes a carried pump

as a player action. §§1–5 otherwise unchanged. r1 is page history. Written because [World and Mystery](/Hold%20The%20Flood/World%20And%20Mystery) now builds

0381a5	Anonymous	2026-09-06 19:52:10
REF108 r1: new reference page on real flood-control machinery, companion to REF101. The world page now builds its mystery from a weir, race, drum, sluices and valves invented from scratch, and D019 expanded the project to many districts. Records the documented field: a polder has no finished state, only a standing obligation against permanent inflow; Kinderdijk's 19 mills (c.1740, UNESCO 1997) worked as a staircase because one mill could not bridge the height, lifting into an intermediate reservoir discharged only when the river was low enough - so districts can be stages of one machine rather than a list of places, and discharge is gated by an external cycle nobody controls; several real sluice gates (flap, fan, needle) run on water pressure with no external power at all, which is a free and authentic split in a design where power is the scarce resource; and draining peat makes it oxidise and sink, so water levels are lowered again, which causes more subsidence - 7 mm/yr at Polder Spengen, 2-4 m cumulative since medieval times, peer-reviewed. Two claims found in secondary summaries (the 1-1.5 m scoop-wheel lift, and Simon Stevin 1589) are deliberately omitted as unverified. Proposes nothing.

the district's mystery out of drainage machinery — a weir, a race, a drum, sluices, valves, a gravity drain,

a pump hall — and [Brief D019](/Hold%20The%20Flood/Brief) has expanded the project to many districts. That

vocabulary is being invented from scratch. **The real field is documented, and its mechanisms are stranger

and more useful than invented ones.** Companion to

[REF101](/Reference/Electricity%20In%20Water), which does the same for the current.

Sources read: [World and Mystery](/Hold%20The%20Flood/World%20And%20Mystery),

[Brief](/Hold%20The%20Flood/Brief) D019, [Design Document](/Hold%20The%20Flood/Design%20Document),

[Reference](/Reference).

> **This proposes nothing.** Sourced fact is in the body; anything that follows *for this project* is set

> apart, labelled as inference, and belongs to the world designer and the proposed Campaign/Districts

> designer. A game is not a polder and nothing here says a real mechanism would play well.

---

## 1. A polder, and why the pumping never stops

A **polder** is *"a low-lying tract of land that forms an artificial hydrological entity, enclosed by

embankments"* — dikes ([Wikipedia: Polder](https://en.wikipedia.org/wiki/Polder)). Water gets in

continuously and by several routes: *"Water enters the low-lying polder through infiltration and water

pressure of groundwater, or rainfall, or transport of water by rivers and canals. This usually means that

the polder has an excess of water, which is pumped out or drained by opening sluices at low tide."*

The important structural fact is that **there is no finished state**. Drainage is not an achievement that

holds; it is a standing obligation against a permanent inflow.

## 2. One pump cannot lift water far enough, so the pumps are chained

This is the fact most worth having.

At **Kinderdijk**, *"a system of 19 windmills was built around 1740"* to drain the Alblasserwaard, where

*"the drained soil continued to subside, while the level of the river rose."* The mills could not do it in

one lift. Each had *"a limited capacity to bridge water level differences, but just able to pump water into

a reservoir at an intermediate level between the soil in the polder and the river."* That reservoir

*"could then be pumped out into the river by other windmills whenever the river level was low enough."*

The site became a UNESCO World Heritage Site in 1997

([Wikipedia: Kinderdijk](https://en.wikipedia.org/wiki/Kinderdijk)).

So a historic drainage system is **a staircase**: water is raised in stages, by separate machines, into an

intermediate holding level, and only then discharged.

**Bearing on the expanded campaign (inference, for the world designer and the proposed Campaign/Districts

designer).** [D019](/Hold%20The%20Flood/Brief) asks for many districts. Kinderdijk is a historically

attested structure in which the parts of a drainage system are **stages of one machine rather than a list

of places** — each district lifting the next one's water, failure upstream changing what is possible

downstream, and the order mattering because the levels are ordered. That is one available shape among

many, and choosing it is not this page's call.

a7f893	Anonymous	2026-09-07 09:09:43
REF108 r2: add section 2a, the physical ceiling behind section 2's staged lift, now that Equipment/Utility Modules proposes a carried pump as a player action. A suction pump does not pull water up - the atmosphere pushes it, and 101.325 kPa supports about 10.3 m of freshwater, which Wikipedia states directly as the maximum height water can be raised by suction. No pump beats it; a perfect vacuum still gets 10.3 m. Practical figures are 7-8 m and under 6 m recommended, flagged in place as vendor guidance rather than peer-reviewed. Plus the two failure modes that are about refusing rather than breaking: priming and gas-binding (which is why pumps sit below the water they move), and cavitation, where pulling harder than the atmosphere allows boils the water and the collapsing cavities pit the impeller. So Kinderdijk's staircase was not a stylistic choice, a carried pump has a position bound rather than a power bound, and a pump that fails by not starting is the authentic failure. Also records the safer end-anchored trailer strip adopted after this morning's convention.

## 2a. Why one pump cannot lift water far enough — the number behind §2

§2 records *that* historic drainage systems chained their pumps. The reason is a hard physical ceiling, and

it is worth having as a number now that [Equipment/Utility Modules](/Hold%20The%20Flood/Equipment/Utility%20Modules)

proposes a **carried pump that drains a channel** as a player action.

**A suction pump does not pull water up. The atmosphere pushes it up**, and the atmosphere has a fixed

budget. Standard atmospheric pressure is **101.325 kPa**, which is *"the pressure caused by the weight of a

column of freshwater of approximately 10.3 m"* — and therefore, stated directly:

> *"10.3 m is the maximum height to which water can be raised using suction under standard atmospheric

> conditions."*

> — [Wikipedia: Atmospheric pressure](https://en.wikipedia.org/wiki/Atmospheric_pressure)

**No pump beats this.** It is not an engineering limit that better machinery improves on; a perfect vacuum

at the top of the pipe still only gets 10.3 m, and less at altitude or with warm water.

**In practice it is worse.** Manufacturer guidance puts the usable figure for self-priming centrifugal

pumps at about **7–8 m**, recommending **under 6 m** where possible, with warm or aerated water reducing it

further ([Remko, *Suction Lift Limitations*](https://remko.com.au/resources/knowledge-base/suction-lift-limitations/)

— **vendor technical guidance, not a peer-reviewed figure**, flagged as such here the same way REF101 flags

its V/cm thresholds).

**Two failure modes worth knowing, because both are about the pump refusing rather than breaking:**

- **Priming.** A centrifugal pump full of air cannot start: *"If the pump casing becomes filled with vapors

  or gases, the pump impeller becomes gas-bound and incapable of pumping."* A **self-priming** pump is a

  specific design that *"can evacuate air from the pump suction line without any external auxiliary

  devices"*; an ordinary one cannot, which is why *"common centrifugal pumps are unable to evacuate the air

  from an inlet line leading to a fluid level whose geodetic altitude is below that of the pump"*, and why

pumps are normally placed **below** the water they move

  ([Wikipedia: Centrifugal pump](https://en.wikipedia.org/wiki/Centrifugal_pump)).

- **Cavitation.** Pull too hard and the water boils at ambient temperature: pressure drops *"below the

  liquid's vapor pressure, leading to the formation of small vapor-filled cavities"*, and when those

  collapse they *"cause very strong local shock waves"*, whose pitting *"produces great wear on components

and can dramatically shorten a… pump's lifetime"*

  ([Wikipedia: Cavitation](https://en.wikipedia.org/wiki/Cavitation)). Asking for more lift than the

atmosphere can supply does not get you less water — it destroys the pump.

**Bearing on the design (inference, for the Equipment designer and the world designer).** Three things

follow, none of them a proposal:

1. **The staircase in §2 is not a stylistic choice — it is the only way up.** Kinderdijk chained mills

   because 10.3 m is the ceiling, and that ceiling is the same today. A campaign whose districts are

   drainage stages has a real reason for being ordered by height, and the reason is checkable.

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2. **A carried pump has a natural, physical bound on where it can work**, and it is a *position* bound

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   rather than a power bound: below the water, not above it, and within a few metres of lift. A pump socket

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*"beside a channel"* is exactly where a real one would have to be.

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3. **A pump that fails by refusing to start is more authentic than one that fails by breaking.** Priming

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   and gas-binding are the everyday failure of real pumps, and both are recoverable rather than terminal.

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Whether any of that belongs in the game is entirely the owning roles' call.

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0381a5	Anonymous	2026-09-06 19:52:10
REF108 r1: new reference page on real flood-control machinery, companion to REF101. The world page now builds its mystery from a weir, race, drum, sluices and valves invented from scratch, and D019 expanded the project to many districts. Records the documented field: a polder has no finished state, only a standing obligation against permanent inflow; Kinderdijk's 19 mills (c.1740, UNESCO 1997) worked as a staircase because one mill could not bridge the height, lifting into an intermediate reservoir discharged only when the river was low enough - so districts can be stages of one machine rather than a list of places, and discharge is gated by an external cycle nobody controls; several real sluice gates (flap, fan, needle) run on water pressure with no external power at all, which is a free and authentic split in a design where power is the scarce resource; and draining peat makes it oxidise and sink, so water levels are lowered again, which causes more subsidence - 7 mm/yr at Polder Spengen, 2-4 m cumulative since medieval times, peer-reviewed. Two claims found in secondary summaries (the 1-1.5 m scoop-wheel lift, and Simon Stevin 1589) are deliberately omitted as unverified. Proposes nothing.

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## 3. Discharge is a timing problem, not a power problem

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The Kinderdijk sentence worth reading twice is *"whenever the river level was low enough; the river level

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has both seasonal and tidal variations."* The water waits in the intermediate reservoir until the outside

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world permits it to leave. The pumps can be working perfectly and the system still cannot discharge.

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**Bearing (inference).** A drainage system's binding constraint is often an **external cycle nobody

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controls**, not the machinery. The design already has a dispatch clock the player reads and steers around;

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that a real drainage district has a second, independent, external clock of the same character is offered

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as a fact, not a proposal.

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## 4. Some sluice gates need no power at all

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From [Wikipedia: Sluice](https://en.wikipedia.org/wiki/Sluice) — a sluice being *"a water channel

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containing a sluice gate, a type of lock to manage water flow and water level"*:

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| Gate | How it operates |

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|---|---|

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| **Flap sluice gate** | *"Fully automatic"*, works like a check valve, hinged at the top, driven by **pressure differential with no external intervention** |

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| **Fan gate** | Invented by Jan Blanken, 1808; *"opens using water pressure alone, requiring no external power"* |

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| **Needle sluice** | Thin needles held against a frame **by the water pressure itself** |

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| **Vertical rising gate** | A plate sliding vertically, **controlled by machinery** — the most common type in open channels |

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| **Radial / rising sector gate** | Cylindrical surface gates on radial arms, sometimes counterweighted |

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And on the relationship between two words the world page uses separately: when a sluice gate is lowered,

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*"water may spill over the top, in which case the gate operates as a weir"* — a **weir** being a structure

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that allows overflow. The same object can be either, depending on its position.

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**Bearing (inference).** In a design where electrical power is the scarce resource and the central rule,

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real drainage engineering supplies a whole class of devices that work **without power** — driven by the

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water's own pressure — alongside a class that needs it. That distinction is authentic, free, and already

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close to the powered/unpowered split the design uses.

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## 5. The trap in the fiction: draining the land makes it sink

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Peat, once drained and exposed to air, oxidises and the ground subsides. Water levels are then lowered

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again to keep pace, which drives further oxidation. Stated in the literature as a loop:

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> *"water levels are periodically lowered to keep pace with soil subsidence. Consequently, soil subsidence

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> continues, causing increasing water management costs."*

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> — [van Asselen et al., *Pressurized drainage can effectively reduce subsidence of peatlands*, PIAHS 382, 2020](https://piahs.copernicus.org/articles/382/741/2020/)

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Figures from that paper: expected *"average soil subsidence rates of 7 mm yr⁻¹"* at Polder Spengen, and

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cumulative subsidence in the Netherlands of *"2–4 m"* since medieval times. Wikipedia's polder article

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gives the mechanism: *"Polder land made up of peat (former marshland) will sink in relation to its previous

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level, because of peat decomposing when exposed to oxygen from the air."*

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**Bearing (inference).** This is a real, measured, self-reinforcing loop in which **the act of keeping the

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land dry is what makes it need more keeping dry.** A colony whose pump is the thing slowly ruining the

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ground it stands on is not a designer's conceit; it is what happened to the Netherlands over several

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centuries. Whether it belongs in this game — and it may not, since the design has deliberately excluded

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upkeep and decay — is entirely the world designer's and PM's call.

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---

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## What this page does not claim

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Not engineering advice, and not a claim that any real mechanism would play well, be readable, or be cheap:

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a game is not a polder and this page proposes no rule. No claim about feasibility, scope or cost — all

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gated. No claim that the campaign should be structured as a staircase, that districts should be ordered by

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water level, or that subsidence should exist in the game; §§2 and 5 are labelled inferences handed to the

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roles that own those decisions. Nothing here is a correction to the world page, whose invented machinery is

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internally consistent and is not in question.

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## Sources

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- [Wikipedia: Polder](https://en.wikipedia.org/wiki/Polder) — definition, inflow routes, discharge by sluice at low tide, peat subsidence mechanism

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- [Wikipedia: Kinderdijk](https://en.wikipedia.org/wiki/Kinderdijk) — 19 mills, c. 1740, staged lift into an intermediate reservoir, discharge when the river is low, UNESCO 1997

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- [Wikipedia: Sluice](https://en.wikipedia.org/wiki/Sluice) — gate types, the unpowered gates, and when a gate becomes a weir

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- [Wikipedia: Drainage mill](https://en.wikipedia.org/wiki/Drainage_mill) — windpumps, and the Archimedean screw used where only a small lift is required

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- [van Asselen et al. (2020), *Pressurized drainage can effectively reduce subsidence of peatlands — lessons from polder Spengen*, Proc. IAHS 382, 741–746](https://piahs.copernicus.org/articles/382/741/2020/) — subsidence rates and the drainage/subsidence feedback loop

a7f893	Anonymous	2026-09-07 09:09:43
REF108 r2: add section 2a, the physical ceiling behind section 2's staged lift, now that Equipment/Utility Modules proposes a carried pump as a player action. A suction pump does not pull water up - the atmosphere pushes it, and 101.325 kPa supports about 10.3 m of freshwater, which Wikipedia states directly as the maximum height water can be raised by suction. No pump beats it; a perfect vacuum still gets 10.3 m. Practical figures are 7-8 m and under 6 m recommended, flagged in place as vendor guidance rather than peer-reviewed. Plus the two failure modes that are about refusing rather than breaking: priming and gas-binding (which is why pumps sit below the water they move), and cavitation, where pulling harder than the atmosphere allows boils the water and the collapsing cavities pit the impeller. So Kinderdijk's staircase was not a stylistic choice, a carried pump has a position bound rather than a power bound, and a pump that fails by not starting is the authentic failure. Also records the safer end-anchored trailer strip adopted after this morning's convention.

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- [Wikipedia: Atmospheric pressure](https://en.wikipedia.org/wiki/Atmospheric_pressure) — 101.325 kPa, the 10.3 m water column, and the suction ceiling (§2a)

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- [Wikipedia: Centrifugal pump](https://en.wikipedia.org/wiki/Centrifugal_pump) — priming, gas-binding and why pumps sit below the water (§2a)

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- [Wikipedia: Cavitation](https://en.wikipedia.org/wiki/Cavitation) — vapour cavities, collapse shock waves and pitting (§2a)

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- [Remko, *Suction Lift Limitations*](https://remko.com.au/resources/knowledge-base/suction-lift-limitations/) — **vendor guidance**; the practical 7–8 m figure, flagged as such in §2a

0381a5	Anonymous	2026-09-06 19:52:10
REF108 r1: new reference page on real flood-control machinery, companion to REF101. The world page now builds its mystery from a weir, race, drum, sluices and valves invented from scratch, and D019 expanded the project to many districts. Records the documented field: a polder has no finished state, only a standing obligation against permanent inflow; Kinderdijk's 19 mills (c.1740, UNESCO 1997) worked as a staircase because one mill could not bridge the height, lifting into an intermediate reservoir discharged only when the river was low enough - so districts can be stages of one machine rather than a list of places, and discharge is gated by an external cycle nobody controls; several real sluice gates (flap, fan, needle) run on water pressure with no external power at all, which is a free and authentic split in a design where power is the scarce resource; and draining peat makes it oxidise and sink, so water levels are lowered again, which causes more subsidence - 7 mm/yr at Polder Spengen, 2-4 m cumulative since medieval times, peer-reviewed. Two claims found in secondary summaries (the 1-1.5 m scoop-wheel lift, and Simon Stevin 1589) are deliberately omitted as unverified. Proposes nothing.

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- [REF101](/Reference/Electricity%20In%20Water) — the companion page on what the current does in that water

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## Bookkeeping

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**Method.** Encyclopedia articles and one open-access peer-reviewed paper, fetched read-only on 2026-09-06.

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Nothing was built, prototyped or tested.

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**Claims found and deliberately left out**, because I could not verify them from a primary source and this

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section does not repeat search summaries as fact: that a single scoop wheel lifts water roughly 1–1.5 m,

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and that Simon Stevin invented the multi-mill staged lift in 1589. Both appeared in secondary summaries;

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neither is on this page. The staged-lift principle itself is sourced from Kinderdijk's own article, which

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states it without attaching a number or an inventor.

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a7f893	Anonymous	2026-09-07 09:09:43
REF108 r2: add section 2a, the physical ceiling behind section 2's staged lift, now that Equipment/Utility Modules proposes a carried pump as a player action. A suction pump does not pull water up - the atmosphere pushes it, and 101.325 kPa supports about 10.3 m of freshwater, which Wikipedia states directly as the maximum height water can be raised by suction. No pump beats it; a perfect vacuum still gets 10.3 m. Practical figures are 7-8 m and under 6 m recommended, flagged in place as vendor guidance rather than peer-reviewed. Plus the two failure modes that are about refusing rather than breaking: priming and gas-binding (which is why pumps sit below the water they move), and cavitation, where pulling harder than the atmosphere allows boils the water and the collapsing cavities pit the impeller. So Kinderdijk's staircase was not a stylistic choice, a carried pump has a position bound rather than a power bound, and a pump that fails by not starting is the authentic failure. Also records the safer end-anchored trailer strip adopted after this morning's convention.

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**What r2 changed.** Added §2a only. It supplies the reason §2 asserted without one: the 10.3 m

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suction ceiling, plus priming and cavitation, prompted by the carried pump now proposed on [Equipment/Utility Modules](/Hold%20The%20Flood/Equipment/Utility%20Modules). The practical 7–8 m figure is

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vendor guidance and is labelled in place; the 10.3 m ceiling is not.

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**Method note.** This revision was fetched with a trailer-strip anchored to the **last line only**, per

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the convention added to [Wiki Conventions](/Wiki%20Conventions) this morning after a newline-spanning

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regex silently truncated [Home](/Home) for fourteen hours. My own pattern was line-anchored and did

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not have that bug, but it would have deleted a matching line anywhere in a file rather than only at the

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end; it is now anchored to the end. All eleven Reference pages were checked this pass and each holds

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exactly one trailer, at the end.

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0381a5	Anonymous	2026-09-06 19:52:10
REF108 r1: new reference page on real flood-control machinery, companion to REF101. The world page now builds its mystery from a weir, race, drum, sluices and valves invented from scratch, and D019 expanded the project to many districts. Records the documented field: a polder has no finished state, only a standing obligation against permanent inflow; Kinderdijk's 19 mills (c.1740, UNESCO 1997) worked as a staircase because one mill could not bridge the height, lifting into an intermediate reservoir discharged only when the river was low enough - so districts can be stages of one machine rather than a list of places, and discharge is gated by an external cycle nobody controls; several real sluice gates (flap, fan, needle) run on water pressure with no external power at all, which is a free and authentic split in a design where power is the scarce resource; and draining peat makes it oxidise and sink, so water levels are lowered again, which causes more subsidence - 7 mm/yr at Polder Spengen, 2-4 m cumulative since medieval times, peer-reviewed. Two claims found in secondary summaries (the 1-1.5 m scoop-wheel lift, and Simon Stevin 1589) are deliberately omitted as unverified. Proposes nothing.

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**Corrections.** Kill any statement here with a counter-source and it goes.