Real canals: a calibration reference for great works
Purpose: ground the sim's canal model ([[t-great-works]], [[t-canal-site-scan]]) in real projects. It covers what canals were for, what they cost, who could build them, how long they took, which failed and what made them decay. Gathered 2026-10-03 at the author's request.
Figures are approximate. They come from the standard references (mostly each canal's Wikipedia article and the works it cites), recalled rather than re-checked line by line. Lengths are the navigable route; "dug" is the artificial part where a canal also uses lakes or rivers. Use them for orders of magnitude, not as data.
1. Pre-industrial (closest to High Fantasy technology)
| Canal | Built | Length | Summit / locks | Joins | Purpose | Builder, labour |
|---|---|---|---|---|---|---|
| Canal of the Pharaohs (Nile–Red Sea) | begun c. 600 BC (Necho II), finished c. 500 BC (Darius I) | ≈ 150–200 km | near sea level | Nile delta ↔ Red Sea | trade, prestige | Egyptian, then Persian state; Herodotus claims 120,000 dead under Necho |
| Xerxes Canal (Athos) | 483–480 BC | ≈ 2 km, ≈ 30 m wide | sea level | across the Athos peninsula | military: the fleet avoids the cape where a Persian fleet was wrecked in 492 BC | Persian army, ≈ 3 years |
| Diolkos (Corinth) — portage, not a canal | c. 600 BC, used to the 1st c. AD | ≈ 6–8.5 km paved haul road | over the isthmus | Gulf of Corinth ↔ Saronic Gulf | ships or cargo dragged across instead of sailing round the Peloponnese | city of Corinth; a cheap alternative used for centuries |
| Lingqu (Qin) | 214 BC | ≈ 36 km | contour canal over a watershed; flash locks later | Xiang (Yangtze basin) ↔ Li (Pearl basin) | military supply for the conquest of the south | Qin state |
| Grand Canal (China) | sections from 486 BC; Sui trunk 605–610; Yuan route to Beijing 1280s–1290s | ≈ 1,800 km | summit ≈ 40 m (Shandong) | Yellow River ↔ Yangtze ↔ Beijing | grain tribute to the capital, army supply, unity | Sui state; millions of conscripts (figures vary) |
| Fossa Carolina | 793 | ≈ 3 km dug, never finished | over the Rhine–Danube divide | Rezat (Rhine) ↔ Altmühl (Danube) | link two great river systems | Charlemagne; abandoned (rain, soft ground) — a failure |
| Stecknitz Canal | 1391–1398 | ≈ 95 km | summit canal, ≈ a dozen locks | Elbe ↔ Trave → Lübeck (Baltic) | salt trade (Lüneburg) | city of Lübeck; one of Europe's first summit canals |
| Briare Canal | 1604–1642 | ≈ 55 km | summit level, ≈ 40 locks | Loire ↔ Seine | inland trade to Paris | French crown (Sully, Henri IV), then a company |
| Canal du Midi | 1666–1681 | ≈ 240 km | summit ≈ 190 m, ≈ 60–100 locks (counts vary) | Garonne (Atlantic) ↔ Mediterranean | avoid the long, hostile route round Spain via Gibraltar | Riquet with Louis XIV's backing; ≈ 12,000 workers |
2. Early industrial (locks, steam; still fits a magic-assisted age)
| Canal | Built | Length | Summit / locks | Joins | Purpose | Notes |
|---|---|---|---|---|---|---|
| Bridgewater Canal | 1759–1761 | ≈ 65 km | level | coal mines ↔ Manchester | coal | halved coal prices in Manchester |
| Caledonian Canal | 1803–1822 | ≈ 97 km (≈ ⅓ dug; rest is lochs) | summit ≈ 32 m, 29 locks | North Sea ↔ Atlantic across Scotland | avoid the stormy Pentland Firth; naval use; work for the jobless | built for frigates; ships soon outgrew it, so it was a commercial disappointment |
| Göta Canal | 1810–1832 | ≈ 190 km (≈ 87 km dug) | summit ≈ 92 m, 58 locks | Baltic ↔ Kattegat via lakes Vättern and Vänern | avoid the Danish Sound tolls and route | ≈ 58,000 soldiers, ≈ 7 million man-days; obsolete as a trunk route soon after (railways) |
| Erie Canal | 1817–1825 | ≈ 580 km | rise ≈ 170 m, 83 locks | Hudson ↔ Great Lakes | open the interior to the sea | freight cost Buffalo–New York fell by ≈ 90 %; made New York the leading port |
| Welland Canal | 1829 (rebuilt 1932) | ≈ 43 km | ≈ 100 m, 8 locks (today) | Lake Ontario ↔ Lake Erie | bypass Niagara Falls | a lake-to-lake access canal |
3. Ship canals (sea-going ships)
| Canal | Built | Length | Summit / locks | Saves or opens | Notes |
|---|---|---|---|---|---|
| Suez | 1859–1869 | ≈ 164 km (now ≈ 193) | sea level, no locks | London–Bombay ≈ 7,000 km shorter (≈ 40 %) | company with state backing; forced labour early on; deaths in the tens of thousands (contested) |
| Corinth | 1881–1893 | ≈ 6.4 km | sea level, cut up to ≈ 90 m into rock | ≈ 400 km round the Peloponnese | tried by Periander and Nero (begun AD 67, abandoned); too narrow for big ships, so it never paid |
| Kiel | 1887–1895 | ≈ 98 km | sea level, locks at both ends | ≈ 460 km round Denmark | military first: the German fleet between the Baltic and the North Sea |
| Manchester Ship Canal | 1887–1894 | ≈ 58 km | 5 locks, ≈ 18 m | ocean ships reach an inland city | built to bypass Liverpool's port dues |
| Panama | French 1881–1894 (failed), US 1904–1914 | ≈ 80 km | summit lake ≈ 26 m, 3 lock flights | New York–San Francisco ≈ 13,000 km shorter (vs Cape Horn) | disease (yellow fever, malaria): ≈ 22,000 dead in the French attempt; a sea-level design failed, locks worked |
| Volga–Don | 1948–1952 (attempted 1697 by Peter I) | ≈ 101 km | ≈ 88 m, 13 locks | Caspian ↔ Black Sea river systems | Peter's attempt was abandoned |
| White Sea–Baltic | 1931–1933 | ≈ 227 km (≈ 48 km dug) | 19 locks | White Sea ↔ Baltic | forced (Gulag) labour, ≈ 12,000–25,000 dead; too shallow (≈ 3.5 m) for the ships it was meant for — a cautionary case |
| Rhine–Main–Danube | 1960–1992 (Ludwig Canal 1836–1846 before it) | ≈ 171 km | summit ≈ 406 m, 16 locks | North Sea ↔ Black Sea by inland water | finally achieved Charlemagne's link, 1,200 years later |
4. What this suggests for the sim
Why a polity digs — four kinds of gain, often mixed:
- Shorter route (Suez, Panama, Kiel, Corinth): gain ∝ traffic × distance saved.
- Access, where no water route existed (Erie, Welland, Manchester, Lingqu, the Grand Canal joining river systems): the largest gains. A whole hinterland or lake joins the sea economy; freight costs fall by up to ≈ 90 %.
- Avoiding a hazard or toll (Xerxes: a storm cape; Caledonian: the Pentland Firth; Göta: the Danish Sound dues; Manchester: Liverpool's dues).
- Military logistics or fleet movement (Lingqu, Sui Grand Canal, Kiel, Xerxes). States accept a poor commercial return for this.
Who can dig: centralised states that can command mass labour (Persia, Qin, Sui, Louis XIV's France, Sweden's army). Later, chartered companies with state backing (Suez, the second Panama). Cities in leagues manage smaller works (Lübeck's Stecknitz). A polity must hold, or control, both ends.
Scale of effort, as a rough guide:
- Big pre-industrial projects take 3–15 years of work by 10,000 to 100,000 people, or millions for the Grand Canal.
- Cost rises with length, with every lock (summits of 30–200 m are common; ≈ 400 m is the extreme), with rock (Corinth), and with disease and climate (Panama).
- Deaths can be large and are a story hook (the Pharaohs' canal, Panama, White Sea).
Failure is common:
- The Fossa Carolina and Nero's Corinth were abandoned; the first Panama attempt went bankrupt.
- The Caledonian and White Sea canals were finished too small to matter.
- Peter I's Volga–Don stalled.
So the sim should let works fail or come out undersized, not just succeed.
Cheaper alternatives: a portage road (Diolkos, used for centuries) gives part of the gain at a fraction of the cost. It is a natural first stage before a canal.
Decay: canals need upkeep. - The Pharaohs' canal was reopened and silted up several times (finally closed 767). - The Grand Canal declined when the state weakened and the Yellow River moved (1855). - A canal should decay or close when its polity collapses. That fits the decline from High into Low Fantasy.
Ship size matters: a canal that only fits barges (the Midi, the Göta) serves inland trade. One that fits sea ships (Suez, Kiel, and the Republic's neck cut onto a deep lake) joins two seas for the same fleet. The site scan should record depth and level on both sides so the sim can tell which kind of canal a site allows.
5. Mapping to the model sketch
- gain = traffic × days saved, plus an access bonus when no water route exists, plus a hazard/toll term, plus a military weight for strong expansionist polities.
- cost = length × (1 + climb / k_lock) × terrain (rock, marsh, disease) — labour-years. Labour-years / available labour gives the build time, and the polity must stay stable that long, or the work fails.
- options: a portage road (cheap, partial gain) → a barge canal → a ship canal.
- upkeep: a yearly cost; it decays without a strong owner.
Placeholder numbers only; tune against the cases above (e.g. the Erie access gain, the Suez distance gain, the Göta labour-years) when sub-project 2 is built.