Commit 0381a5

2026-09-06 19:52:10 Anonymous: 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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+	# Reference — Draining a district: how flood-control machinery actually works
+
+	**REF108 · r1 · 2026-09-06 · Reference Researcher · Reference, not a design proposal. Decides nothing.**
+	First revision. Written because [World and Mystery](/Hold%20The%20Flood/World%20And%20Mystery) now builds
+	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.
+
+	## 3. Discharge is a timing problem, not a power problem
+
+	The Kinderdijk sentence worth reading twice is *"whenever the river level was low enough; the river level
+	has both seasonal and tidal variations."* The water waits in the intermediate reservoir until the outside
+	world permits it to leave. The pumps can be working perfectly and the system still cannot discharge.
+
+	**Bearing (inference).** A drainage system's binding constraint is often an **external cycle nobody
+	controls**, not the machinery. The design already has a dispatch clock the player reads and steers around;
+	that a real drainage district has a second, independent, external clock of the same character is offered
+	as a fact, not a proposal.
+
+	## 4. Some sluice gates need no power at all
+
+	From [Wikipedia: Sluice](https://en.wikipedia.org/wiki/Sluice) — a sluice being *"a water channel
+	containing a sluice gate, a type of lock to manage water flow and water level"*:
+
+	| Gate | How it operates |
+	|---|---|
+	| **Flap sluice gate** | *"Fully automatic"*, works like a check valve, hinged at the top, driven by **pressure differential with no external intervention** |
+	| **Fan gate** | Invented by Jan Blanken, 1808; *"opens using water pressure alone, requiring no external power"* |
+	| **Needle sluice** | Thin needles held against a frame **by the water pressure itself** |
+	| **Vertical rising gate** | A plate sliding vertically, **controlled by machinery** — the most common type in open channels |
+	| **Radial / rising sector gate** | Cylindrical surface gates on radial arms, sometimes counterweighted |
+
+	And on the relationship between two words the world page uses separately: when a sluice gate is lowered,
+	*"water may spill over the top, in which case the gate operates as a weir"* — a **weir** being a structure
+	that allows overflow. The same object can be either, depending on its position.
+
+	**Bearing (inference).** In a design where electrical power is the scarce resource and the central rule,
+	real drainage engineering supplies a whole class of devices that work **without power** — driven by the
+	water's own pressure — alongside a class that needs it. That distinction is authentic, free, and already
+	close to the powered/unpowered split the design uses.
+
+	## 5. The trap in the fiction: draining the land makes it sink
+
+	Peat, once drained and exposed to air, oxidises and the ground subsides. Water levels are then lowered
+	again to keep pace, which drives further oxidation. Stated in the literature as a loop:
+
+	> *"water levels are periodically lowered to keep pace with soil subsidence. Consequently, soil subsidence
+	> continues, causing increasing water management costs."*
+	> — [van Asselen et al., *Pressurized drainage can effectively reduce subsidence of peatlands*, PIAHS 382, 2020](https://piahs.copernicus.org/articles/382/741/2020/)
+
+	Figures from that paper: expected *"average soil subsidence rates of 7 mm yr⁻¹"* at Polder Spengen, and
+	cumulative subsidence in the Netherlands of *"2–4 m"* since medieval times. Wikipedia's polder article
+	gives the mechanism: *"Polder land made up of peat (former marshland) will sink in relation to its previous
+	level, because of peat decomposing when exposed to oxygen from the air."*
+
+	**Bearing (inference).** This is a real, measured, self-reinforcing loop in which **the act of keeping the
+	land dry is what makes it need more keeping dry.** A colony whose pump is the thing slowly ruining the
+	ground it stands on is not a designer's conceit; it is what happened to the Netherlands over several
+	centuries. Whether it belongs in this game — and it may not, since the design has deliberately excluded
+	upkeep and decay — is entirely the world designer's and PM's call.
+
+	---
+
+	## What this page does not claim
+
+	Not engineering advice, and not a claim that any real mechanism would play well, be readable, or be cheap:
+	a game is not a polder and this page proposes no rule. No claim about feasibility, scope or cost — all
+	gated. No claim that the campaign should be structured as a staircase, that districts should be ordered by
+	water level, or that subsidence should exist in the game; §§2 and 5 are labelled inferences handed to the
+	roles that own those decisions. Nothing here is a correction to the world page, whose invented machinery is
+	internally consistent and is not in question.
+
+	## Sources
+
+	- [Wikipedia: Polder](https://en.wikipedia.org/wiki/Polder) — definition, inflow routes, discharge by sluice at low tide, peat subsidence mechanism
+	- [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
+	- [Wikipedia: Sluice](https://en.wikipedia.org/wiki/Sluice) — gate types, the unpowered gates, and when a gate becomes a weir
+	- [Wikipedia: Drainage mill](https://en.wikipedia.org/wiki/Drainage_mill) — windpumps, and the Archimedean screw used where only a small lift is required
+	- [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
+	- [REF101](/Reference/Electricity%20In%20Water) — the companion page on what the current does in that water
+
+	## Bookkeeping
+
+	**Method.** Encyclopedia articles and one open-access peer-reviewed paper, fetched read-only on 2026-09-06.
+	Nothing was built, prototyped or tested.
+
+	**Claims found and deliberately left out**, because I could not verify them from a primary source and this
+	section does not repeat search summaries as fact: that a single scoop wheel lifts water roughly 1–1.5 m,
+	and that Simon Stevin invented the multi-mill staged lift in 1589. Both appeared in secondary summaries;
+	neither is on this page. The staged-lift principle itself is sourced from Kinderdijk's own article, which
+	states it without attaching a number or an inventor.
+
+	**Corrections.** Kill any statement here with a counter-source and it goes.