# The quiet lines

The district plan’s noise overlays, 21 mapped areas covering 44,250 hectares before overlaps. Where the other overlays answer what the ground looks like or what stands on it, these answer what the air over it sounds like, the airport’s contours, the engine-testing hum, Ruapuna’s boundaries, the precincts where loud is allowed, the insulation zones, and the bird-strike buffers.

## The standings

- 50 dB Ldn Air Noise Contour: 1 area, 7,797 ha
- 55 dB Ldn Air Noise Contour: 1 area, 4,211 ha
- Composite Ldn/Lae Air Noise Boundary: 1 area, 1,145 ha
- Engine testing 65+ dB Ldn: 1 area, 312 ha
- Engine testing 50–55 dB Ldn: 1 area, 923 ha
- Engine testing 60–65 dB Ldn: 1 area, 213 ha
- Engine testing 55–60 dB Ldn: 1 area, 402 ha
- Ruapuna Inner Noise Boundary: 1 area, 448 ha
- Ruapuna Outer Noise Boundary: 1 area, 479 ha
- Category 2, Lower Noise Level Entertainment and Hospitality Precincts: 4 areas, 39 ha
- Category 1, Higher Noise Level Entertainment and Hospitality Precincts: 3 areas, 19 ha
- Category 3, Lower Noise Level Area: 1 area, 581 ha
- Inner Noise Insulation, CMUA: 1 area, 7 ha
- Outer Noise Insulation, CMUA: 1 area, 63 ha
- 3 km bird-strike buffer: 1 area, 5,511 ha
- 8 km bird-strike buffer: 1 area, 22,100 ha

## The suburbs under the quiet lines

By share of outline inside any noise overlay, a sampled join, so a sliver still counts.

- Avonhead: 100% under noise overlays, 43% inside the airport’s contours
- Bishopdale: 100% under noise overlays
- Broomfield: 100% under noise overlays
- Bryndwr: 100% under noise overlays
- Burnside: 100% under noise overlays, 35% inside the airport’s contours
- Casebrook: 100% under noise overlays, 4% inside the airport’s contours
- Christchurch Airport: 100% under noise overlays, 100% inside the airport’s contours
- Fendalton: 100% under noise overlays, 1% inside the airport’s contours
- Harewood: 100% under noise overlays, 95% inside the airport’s contours
- Hei Hei: 100% under noise overlays
- Hornby: 100% under noise overlays
- Ilam: 100% under noise overlays, 44% inside the airport’s contours
- Islington: 100% under noise overlays, 50% inside the airport’s contours
- Merivale: 100% under noise overlays
- Middleton: 100% under noise overlays

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Christchurch City Council open data, the DistrictPlanB service’s noise overlays (the airport’s air-noise contours, aircraft engine-testing contours, Ruapuna’s motor-sport noise boundaries, the central-city entertainment precinct categories, the CMUA noise-insulation zones, and the bird-strike mitigation buffers). Modelled planning lines, where the rules bite, not a meter’s reading of tonight. A point’s own answer: https://www.chch.live/before · the ground’s other hearings: https://www.chch.live/zones · https://www.chch.live/matters. The files: https://www.chch.live/noise.json · https://www.chch.live/noise.geojson · by suburb: https://www.chch.live/suburb-noise.json