Fourteen-lot subdivision with a stormwater pipe through Lot 7
A 14-lot medium-density subdivision is proposed on a 0.62 ha site in a town centre edge zone. Lots range from 420 to 480 square metres, with 6 m frontages. A 300 mm stormwater pipe, 3 m deep, crosses proposed Lot 7 from the road to a council reserve at the rear. An existing 3 m wide easement is shown on an old CSD, but its position does not match the pipe as built. The district plan requires a 20% permeable surface, a 3 m setback from the rear boundary, and an outlook space of 6 m by 4 m for each dwelling. Council has granted resource consent with a condition that all lots have legal access and that the stormwater pipe is protected by an easement in favour of council. The developer wants Lot 7 filled and built on, and asks whether the pipe can be relocated or covered. You need to decide the survey and legal layout, the easement position, and what urban design evidence the consent planner will need.
1. Determine how the stormwater pipe should be legally protected and how the cadastral layout should respond. Consider easement, reserve, relocation and building platform.
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The pipe must be protected by an easement in favour of council, because that is the consent condition and because the pipe serves more than Lot 7. The old CSD easement cannot be relied on if the as-built pipe is elsewhere. I would survey the actual pipe alignment and depth, then define an easement of sufficient width around it, usually matching council’s standard width and access requirements. The easement should be shown on the CSD and in the easement instrument. Relocating the pipe is possible only if the engineering design, grades and council approval support it; it is not a survey decision made to free up Lot 7. Covering the pipe with fill or a building may be acceptable only if the easement remains and the building platform is outside the easement and any required clearance. The Lot 7 building platform should be shifted rather than pretending the pipe is not there. If relocation is approved, a new as-built survey and a new easement are required before the lot is sold.
2. Outline the survey setout and CSD checks needed to show compliance with the consent conditions, including access, easements and boundary dimensions.
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I would set out the lot boundaries from an adjusted control network tied to the cadastral network, then check every lot for legal access to a formed road or legal accessway. The CSD must show boundary dimensions, the easement and its relationship to the pipe, and any restrictions that affect the building platform. I would survey the as-built pipe and compare it with the easement diagram, not simply copy the old CSD. I would check that no lot depends on a boundary that crosses an easement without legal access, and that the easement is in favour of the correct authority. The CSD checks should include closure, boundary point accuracy, easement widths and the consistency of the lot areas with the approved plan. I would also provide the planner with spatial evidence for the 20% permeable surface, the 3 m rear setback and the 6 m by 4 m outlook space, using the surveyed boundaries and building platforms as the base.
3. What urban design matters should the planner assess, and what is the surveyor’s role in that assessment?
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The planner should assess frontage and street interface, outlook and daylight, privacy between lots, the usability of the 6 m by 4 m outlook space, rear setback, permeable surface and the relationship of buildings to the stormwater easement. The planner should also consider whether Lot 7 can achieve a practical building platform without compromising the pipe or the amenity of neighbouring lots. The surveyor’s role is to provide accurate boundaries, levels, easement geometry and building-platform information, not to make the urban design judgement. I would supply a clear plan showing the legal boundaries, the easement, the surveyed pipe and the available building area, and I would identify any constraint that the planner needs to assess. If the design depends on a boundary dimension or an easement offset, that information must be surveyed rather than scaled from an old plan. The surveyor supports the assessment with reliable spatial evidence; the planner decides whether the urban design outcome meets the district plan and consent conditions.