Terminal to city
The Dunwich ferry terminal is being rebuilt now. It still does not say where the cars go. The chain ends in a city under the sand.
Dunwich (Goompi), the terminal and the bay · Copernicus Sentinel-2 · sources
Happening now
$41 million is committed to the Dunwich (Gumpi) ferry terminal at Junner Street: $10 million federal, $30 million Queensland, $1 million local. It is staged across the build, not money sitting in an account today. One of 29 South East Queensland City Deal commitments. Consultation ran 28 May to 21 June 2026. No construction start date has been published.
The upgrade does not say where vehicles wait. Parking has been tight for decades.
About 375,000 visited in 2018. No newer count has reached the project. About 2,200 live here. That is 170 visitors for every resident, and it does not arrive evenly: in peak weeks the island's population triples. The civic pack files it under what angers beach users: carparks full by eight.
Where do cars wait when the island is full?
Sandworm Subterranean Systems, start.html.
The site now
Every design brief from the terminal lab reads the site the same way: blank, overgrown, old sand-mining ground.
The chain
committed money committed, staged over yearsproposed put forward, not decideddesigned in the repositories, not built
| Link | State | What it is |
|---|---|---|
| Terminal upgrade | committed | $41 million, staged. Junner Street. It still does not say where the cars go. |
| Tunnel park-and-ride loop | proposed | Cars stay up top in a car park. The tunnel carries people and freight down to the ferry, not vehicles. More stops later if it earns them. |
| Main routes under the roads | proposed | Two tunnels so traffic runs both ways at once, town to town and out to the busy spots. Fewer animals hit on the surface roads. Whether any of it gets built comes down to cost, speed and whether people want it. |
| Autonomous shuttles | proposed | Buy them, do not build them. Cybercab and the Chinese fleets are already coming off the line cheap. The island limit is 80, so whatever gets bought has to sit on 80. |
| All three towns, and the camps | proposed | One corridor: Dunwich, Amity Point, Point Lookout, the smaller settlements and the camps. Terminal at one end, the sand-sports and cinema ground at the other. |
| Digging wet sand | designed | Wet sand falls back in as fast as you dig it. Freezing the face, shielding it and using water sprays looks like a better bet than the bentonite mud the textbooks reach for. The machine gets built for this sand, not bought secondhand for someone else's ground. |
| The dug sand gets used | designed | Nothing gets carted off the island. The sand that comes out of the hole is the sand that builds the reef. |
| Erosion, living shorelines | designed | Plants, mangroves and a gentler slope instead of a concrete wall. |
| Artificial reef | designed | New reef built from the sand dug out, outside the reserves, and only where the sea Country custodians say yes. |
| Oyster and shellfish beds | designed | Oysters clean the water, give young fish somewhere to hide, and take the punch out of the waves before they reach the beach. |
| Shaped banks for the surf | designed | Shape a point break on screen first. Try it a hundred times before anyone touches the water. |
| Wave power, no blades | designed | Ten kinds of machine, one rule: nothing spins, nothing snaps shut, nothing that could hurt a whale, a turtle, a dugong or a kid on a bodyboard. |
| Tidal, no blades | designed | Works from two knots, which is about what the water does around Amity and through the bay channels. No blades in it either. |
| The tunnels as the battery | designed | Pumped hydro, underground. Water gets pumped up to a pond when power is cheap, then runs back down the sealed tunnels through a generator when it is needed. Same idea as Snowy 2.0, except the machine that digs the city digs the battery on the way through. |
| The subterranean eco-city | designed | Forty-three buildings, all still on paper. What one throws out, the next one uses. None of them may break into the fresh water sitting in the sand. |
The objective, corrected
The second build opens its ground physics file with a correction, dated 19 August 2026.
Speed of tunnelling doesnt matter to me. the tunnelling is arbitrary.
What counts is lining the wall and the power it takes to hold the sand still. Widen the hole and the wall you have to line grows with it, but the sand you dig grows faster: double the width and you get four times the sand. So the width of the hole decides how much tunnel a given budget buys. The freeze energy falls out of the physics: the heat it takes to freeze water, the heat water and ice and quartz each hold, and how much a cubic metre of quartz weighs. Run it and a cubic metre of wet sand costs about 55 units of power to freeze. That is 550 kettle boils, or three days of an ordinary house. It buys the ice once. Holding it is not costed anywhere, and the file says so.
The number that decides the method
The water sits 42 metres higher in the middle than at the coast, five and a half kilometres away. That is less than a centimetre of fall for every metre you walk, flatter than a wheelchair ramp. Through very fine sand the water creeps two centimetres a day. Through gravel, over two metres. The ground file puts the freeze limit near a metre a day.
Nobody has measured it here. A real value would flip the method.
Portals and shallow loops
A sealed empty tunnel in wet sand wants to float, the way a bottle does when you hold it under. At 1.5 metres wide it takes 370 millimetres of sand on top to hold it down. The float never changes with depth but the sand on top does, so this only bites where the tunnel runs shallow or comes up to the surface. The park-and-ride loop is exactly that kind of job.
That 370 millimetres assumes a concrete lining and a weight for wet sand that the file itself calls a figure to argue with rather than anything measured here. Change the sand and the number changes with it.
The numbers
Each number sits in a file.
| Quantity | Value | What it decides |
|---|---|---|
| Tunnel bore | hole width 1.5 metres by default, about two doorways; 0.6 to 5 metres across the range, 1.5 to 3 for people, 5 for big machines | How much tunnel a casting budget buys. |
| Advance rate | 25 to 1,250 m a week; the calculator opens at 300 | Sets the calendar. Dunwich to Amity Point is 38 weeks at 300 m a week and 9 at the 1,250 ceiling. A kilometre a week is marked in the source as the aspiration near the high end. |
| Forming factor | 1.15, applied once | Sand packed in the ground takes up fifteen per cent more room once you dig it out. Use it for reef and dune volumes. Never for weight: the mass does not change. |
| Sand bulk density | 1.6 tonnes a cubic metre, heavier than a small car | A kilometre of 1.5 metre hole lifts about 1,770 cubic metres out of the ground, near enough 2,800 tonnes. Dunwich to Amity Point is about 32,500 tonnes, some 2,300 tipper loads. Weigh the in-ground volume, not the loose one. |
| The freshwater lens | stands about 42 metres above sea level under the middle of the island, dropping to sea level at the coast | Heat sink, water supply and shielding at once. The two builds disagree on Blue Lake. One takes the shore at 72 m from an ASTER satellite reading marked low confidence, and calibrates the lens on it. The other tops the water table at 42. A window lake is the water table showing itself, so it cannot sit thirty metres above it. The same data file warns that ASTER reads high over vegetation and should be treated as canopy, not ground. |
| Mainland aquifer take | about 20 megalitres a day since 1996, 7,300 megalitres a year; the island uses 1.6 megalitres a day | Eight Olympic pools a day, one every three hours, round the clock. Twelve and a half times what the island uses. One file puts the take at 40 per cent of Redlands supply, another at 60. Nobody has printed the total those shares come out of. |
| Wave resource | 15 kilowatts for every metre of swell front, day and night; 500 metres gives about 180,000 units a day, six times what the island uses. A unit is what your power bill counts, about ten kettle boils | Whether the reef pays for the city. The 15 was never checked against a measurement taken here, and the whole 180,000 rides on it. Four devices do carry ratings: the wave column at 110 kilowatts nameplate and 15 on average, the tidal vortex at 25 and 6. |
| Bladeless tidal | works from two knots | Ties the animal-safe rule to a real current. The twin runs a tide system. |
| Island demand and rooftops | about 30,000 units a day for 2,200 people, near enough 1,700 homes; 19,000 units a day off 21,000 square metres of roof, about eighty tennis courts, all of it roof that is already there | Every load under the sand is compared with this. |
| The city's own load | 2,478 kilowatts connected for tiers one to three, 5,438 across all four; 23,792 units a day at forty per cent use; 54 kilowatts of generation in the pack | The sums do not add up. Day against day it is 18 times short. Set the printed ratings side by side and it is 9.5 times: 2,478 kilowatts of load against 262 kilowatts of gear. The pack printed that rather than a nicer number. |
| Conveyance trunk | two metre bore; 260 kg a minute a belt lane, four solid lanes; 700 kg a minute a pipe run, six fluid lanes; plus a walkway and a services duct | Everything the city moves fits down one hole. The fluid side shifts about 6,000 tonnes a day, four times the solid side. Argue with the lane count first. |
| Heat rejection | 120,000 cubic metres of sand, a footy oval dug six and a half metres down; the ground loop shifts 26 kilowatts for every degree it warms, the seawater loop 44; output starts dropping at 8 degrees over, the corridor is unusable past 12; the sand sits at 20.5 degrees down there | Underground, heat has nowhere to go. The processes throw off 2,094 kilowatts of waste heat and want 709 back. The rest lands in ground that shifts 70 kilowatts for every degree it warms, so it settles about 20 degrees above where it started. The same row says the corridor is unusable above 12. |
| The three panel numbers | connected load against generation, orphan stream total, residual to landfill | If all three worsen, the city is not working. |
The law