LINZ Tenders for Post-quake Surveyors in Canterbury

Bolstered by an $850,000 Government top-up, Land Information New Zealand (LINZ) issued a Request for Proposal (RFP) this week for surveying firms to tackle urgent work in Canterbury following the 4 September earthquake.

"Government's decision this week to fund LINZ's re-surveying in Canterbury means that critical work can now get underway. The timing is ideal – we’ve been advised that aftershock land movements are minimal, and so we’re in a position to move forward," says LINZ Chief Executive Colin MacDonald.

LINZ has already re-prioritised $250,000 of its own funding to complete this work.

"At the moment, re-building infrastructure in the region is delayed by the lack of accurate data following the quake – the earth isn't where it was, and that means that surveyors need to document Canterbury’s new topography, and re-establish the geodetic control network," says Colin.

Geodesy is an area of land management that deals with measuring and documenting the location the land’s physical features, for example height, depth, and distance between points. The Geodetic control network is the sum of all these accurate measurements.

Urgent survey work required by Canterbury local authorities includes the re-establishment of height networks. Accurate information on the height of land is critical for infrastructure that depends on gravity to ensure the appropriate direction and speed of water flow, for example sewerage and storm drain systems, as well as hazard monitors for flooding.

Canterbury's flat landscape makes this information even more important.

"Quite simply, sewerage pipes are laid at an angle so that waste water runs downhill," says LINZ's Chief Geodesist, Graeme Blick.

"Where the earth has shifted considerably, we need updated and accurate survey data so that when that infrastructure is rebuilt, the effluence isn’t suddenly trying to flow uphill and thus creating significant problems and health hazards."

Another top priority for LINZ is the restoration of the horizontal control system – a network of coordinate markers vital to hazard monitoring, mapping property boundaries, and rebuilding infrastructure like telecommunications cables and water reticulation systems.

First on the agenda will be providing heights in Christchurch City. This work is expected to be completed by the end of February. The remaining work will cover most of the Canterbury Plains and is expected to be completed by June 2011.

The closing date for tenders is Thursday 9 December. For more information visit the GETS website.