chch.live the moving ground

The ground that moves

The district plan’s slope-hazard management areas, 631 mapped patches where the hills are watched for rockfall, cliff collapse and mass movement, drawn from the Port Hills geotechnical review after the earthquakes. The named bands guard the edges and runouts; one broad overlay keeps the rest of the hill country on watch.

Hazard areas
631
In named bands
1,499
hectares: rockfall, cliff, movement
Blanket overlay
92,260
hectares of remaining-instability watch
Drawn from
Port Hills
post-quake geotech review

Where the hills are watched

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Management Area 3Cliff Collapse Management Area 2Cliff Collapse Management Area 2Cliff Collapse Management Area 2Cliff Collapse Management Area 2Cliff Collapse Management Area 2Cliff Collapse Management Area 2Cliff Collapse Management Area 2Cliff Collapse Management Area 1Cliff Collapse Management Area 2Cliff Collapse Management Area 1Cliff Collapse Management Area 2Cliff Collapse Management Area 1Cliff Collapse Management Area 1Cliff Collapse Management Area 2Cliff Collapse Management Area 2Cliff Collapse Management Area 2Cliff Collapse Management Area 2Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 1Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 2Rockfall Management Area 1Rockfall Management Area 1Rockfall Management Area 1AddingtonAidanfieldAkaroaAranuiAvondaleAvonheadAvonsideBeckenhamBelfastBexleyBishopdaleBottle 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 BeachWainoniWainuiWalthamWestmorlandWigramWoolstonYaldhurst

The named bands in deep earth tones: burnt sienna for rockfall, umber for cliff collapse, amber for mass movement, over the pale "remaining instability" wash that blankets the Peninsula. Hover any patch for its category. The suburbs carrying the named bands are below; a point’s own answer is at /before, and the rocks that already came down are at /boulders.

The bands the plan draws

Eight categories in three hazard families, the numbered bands tighten the rules as they near the hazard; the remaining-instability overlay is the broad background watch.

Cliff Collapse Management Area 1 4 areas · 12 ha
Cliff Collapse Management Area 2 51 areas · 34 ha
Mass Movement Management Area 1 9 areas · 14 ha
Mass Movement Management Area 2 19 areas · 34 ha
Mass Movement Management Area 3 12 areas · 7 ha
Rockfall Management Area 1 171 areas · 1,168 ha
Rockfall Management Area 2 348 areas · 231 ha
Remaining Slope Instability Management Area 17 areas · 92,260 ha

The suburbs on the watch

By share of outline under the named bands, read from a sampled join, so a sliver still counts. The Port Hills suburbs carry the rockfall and cliff bands; the flat city doesn’t.

Questions, answered briefly

What is this map?

The district plan’s slope-hazard management areas, 631 mapped areas covering 93,759 hectares where the plan watches for rockfall, cliff collapse and mass movement. The mapping comes from the Port Hills geotechnical review after the Canterbury earthquakes, the ground that already moved, and the ground that still could.

What do the numbered bands mean?

The plan draws most hazards in two bands. Area 1 is the band nearest the hazard, the face a cliff could shed from, the ground a boulder crosses first (171 rockfall areas). Area 2 is the runout, ground the hazard could still reach. The rules tighten with the band.

What is the "remaining slope instability" overlay?

One broad overlay blankets the Peninsula hill country, most of the mapped hectares on this page. It is the plan’s background watch: land outside the named bands that still carries slope risk. Sitting inside it alone means fewer constraints than a numbered band, not none.

Is ground outside the map safe?

Not certified. The map is a management overlay for consent rules, drawn from post-quake geotech work, it is honest about where the risk was mapped, not a promise about where it ends. New information can redraw the line.

The record behind this

Christchurch City Council’s open data, the DistrictPlanB service’s DPSlopeHazard layer, the operative plan’s slope-hazard management areas, drawn from the Port Hills geotechnical review after the Canterbury earthquakes. A management overlay for consent rules, not a prediction: ground outside the line is not certified stable, and ground inside is not condemned. The boulders that already fell are mapped at /boulders, the sea’s reach at /tsunami, the rivers' flooding at /floods, and the liquefied flat ground at /liquefaction.

This page as markdown: /slope.md · the record as data: /slope.json · /slope.geojson.