chch.live the made ground, engineered fill

The made ground

Christchurch sits on a swamp it kept filling, 8,885 parcels the property files describe as made or characterised ground, about 3,268 hectares. Some of it is engineered fill an engineer signed off; some is sawdust, ash or mixed fill with rubbish nobody certified; some is the natural silt and peat the files simply kept a note of.

Parcels on record
8,885
Made ground
3,268 ha
Certified work
4,380
engineer-signed or NZ4431
Unvouched fill
391
rubbish, sawdust, uncompacted

The made ground, drawn

AddingtonAidanfieldAkaroaAranuiAvondaleAvonheadAvonsideBeckenhamBelfastBexleyBishopdaleBottle LakeBromleyBrooklandsBroomfieldBryndwrBurnsideBurwoodCasebrookCashmereCass BayChristchurch AirportChristchurch Central CityCliftonCorsair BayCoutts IslandCracroftDallingtonDiamond HarbourDuvauchelleEdgewareFendaltonFerrymeadGovernors BayHalswellHarewoodHeathcote ValleyHei HeiHillmortonHillsboroughHoon HayHornbyHornby SouthHuntsburyIlamIslingtonKaingaKennedys BushLe Bons BayLinwoodLittle RiverLytteltonMairehauMarshlandMcLeans IslandMerivaleMiddletonMoncks BayMount PleasantNew BrightonNorth New BrightonNorthcoteNorthwoodOkains BayOpawaOuruhiaPAPANUIParklandsPhillipstownPigeon BayPort LevyPrebbletonRedcliffsRedwoodRiccartonRichmondRichmond HillRollestonRussleySaint AlbansSaint MartinsScarboroughShirleySockburnSomerfieldSouth New BrightonSouthshoreSpencervilleSpreydonStrowanSumnerSydenhamTai Tapute-onepoto-taylors-mistakeTempletonUpper RiccartonWaimairi BeachWainoniWainuiWalthamWestmorlandWigramWoolstonYaldhurstEngineered Fill, certified or engineeredSawdust, fill the file can’t vouch forMixed Fill with Rubbish, fill the file can’t vouch forUnrecorded material, natural ground on the fileMixed Fill, fill the file can’t vouch forBuried Topsoil, natural ground on the fileUnrecorded material, certified or engineeredSilt, certified or engineeredSand, certified or engineeredTopsoil, certified or engineeredCompacted Hardfill, certified or engineeredClay, certified or engineeredPitrun, certified or engineeredLoess, certified or engineeredBuried Topsoil, certified or engineeredOrganic Material, fill the file can’t vouch forGravel, certified or engineeredPeat, certified or engineeredSilt, natural ground on the fileSand, natural ground on the fileTopsoil, natural ground on the filePeat, natural ground on the fileClay, natural ground on the fileMixed Fill with Demolition Material, fill the file can’t vouch forFibrous Plasterboard, fill the file can’t vouch for

Every parcel over the suburb outlines: green is certified work, red is the fill the file can’t vouch for, blue is the natural ground the file recorded. Hover for the material.

By what was laid

Unrecorded material natural ground on the file · 1481 certified 4,972
Silt certified or engineered · 920 certified 1,066
Engineered Fill certified or engineered · 809 certified 813
Sand certified or engineered · 482 certified 629
Topsoil certified or engineered · 112 certified 281
Mixed Fill with Rubbish fill the file can’t vouch for · 1 certified 212
Gravel certified or engineered · 105 certified 198
Peat certified or engineered · 82 certified 172
Compacted Hardfill certified or engineered · 85 certified 121
Loess certified or engineered · 65 certified 86
Pitrun certified or engineered · 58 certified 70
Buried Topsoil natural ground on the file · 28 certified 61
Mixed Fill with Demolition Material fill the file can’t vouch for · 3 certified 53
Mixed Fill fill the file can’t vouch for · 24 certified 45
Organic Material fill the file can’t vouch for · 9 certified 40
Clay certified or engineered · 8 certified 25
Sawdust fill the file can’t vouch for 17
Uncompacted Hardfill fill the file can’t vouch for 17
Fibrous Plasterboard fill the file can’t vouch for 3
Ash fill the file can’t vouch for 3
Charcoal fill the file can’t vouch for 1

The made ground, by suburb

By the count of parcels the property files describe as made or characterised ground.

Each fill parcel files under the suburb its exterior’s middle sits in, the count of parcels, their hectares, how many carry unvouched fill, and the top materials. A record is the file’s word on what was laid, not a fresh survey.

Questions, answered briefly

What is the made ground?

The ground the city *put there*. Christchurch’s fill layer holds 8,885 parcels the property files describe as filled or made, about 3,268 hectares. Some of it is engineered fill an engineer signed off; some is sawdust, ash or mixed fill with rubbish that nobody certified; some is the natural silt and peat the files simply recorded.

Does a fill record mean the ground is a problem?

Not by itself, the layer records what the file says was laid, not how it behaves now. Engineered fill with an engineer’s sign-off is the ground the city trusts; the unvouched fill, sawdust, demolition rubble, uncompacted hardfill, is what the record flags without condemning. 4,380 parcels carry the certified mark; 391 carry fill the file can’t vouch for.

Why is there sawdust under Christchurch?

The timber and tannery trades tipped their waste where they worked, sawdust fill is the city’s own signature on the old industrial ground, alongside ash, charcoal and the odd load of plasterboard. The files kept the note because filled ground behaves differently in a shake and under a foundation.

How is this different from the buried city?

/landfills is the *tips*, sites kept as dumps, open to the city or to a tradesperson’s truck. This layer is the *parcels*, ground the property file says was made, whether by a certified engineer or by whoever tipped the sawdust. A site can be both. A point’s own answer is at /before.

The record behind this

Christchurch City Council’s open land layers, the Fill layer of OpenData/LandCharacteristic, kept from the property and hazard files. A record is the file’s own description of what was laid, not a fresh survey, and "certified" means the file carries the engineer’s mark, not that anyone checked it since. Ask a point’s own record at /before; the tips are /landfills; the dangerous work is /hazards.

This page as markdown: /fill.md · the record as data: /fill.json · /fill.geojson · /suburb-fill.json · on the live map: /map?layer=fill.