Local Government Magazine
Technical Briefings

Developments in survey technology and its application to freshwater environments

This paper, ‘Developments in survey technology and its application to freshwater environments’, was presented at the Water New Zealand Annual Conference. Discovery Marine’s Declan Stubbing, Jimmy Van Der Pauw (both senior surveyors) and Kevin Smith (business manager).

ABSTRACT
The latest survey sensors capable of capturing high resolution data, combined with survey expertise, processing and visualisation software, are now being used to map freshwater environments. High density point cloud data acquired through simultaneous and seamless data collection techniques is now possible above and below the waterline.
The Rotorua Te Arawa Lakes Programme is working to protect and restore the water quality in 12 Rotorua lakes. Since 2014 the University of Waikato and Discovery Marine have been using a high resolution Multibeam Echo Sounder (MBES) to accurately survey a number of the lakes. A practical and flexible approach was adopted to enable effective use of commercial resources to produce 3D bathymetric surfaces of the lake beds.
High resolution mapping of Watercare’s fresh water reservoirs using MBES and laser scanners has enabled the production of 3D fly throughs revealing remarkable detail of the flooded terrain. It has provided Watercare with a baseline data set from which to better understand their assets and the impact of the environment.
Our full paper provides an overview of the technology, processes and deliverables for these two projects demonstrating the wider applicability of the technology to support regulatory compliance, asset management and environmental planning.
INTRODUCTION

Watercare’s Lower Huia Dam.
Watercare’s Lower Huia Dam.

It wasn’t that long ago that hydrographic surveying of freshwater bodies was limited to single beam echosounders, sidescan sonars, or in a lot of cases, a chainman equipped with a prism pole doing their best not to get washed away in a river current.
Our full paper aims to:

  • present an overview of current technology within the hydrographic surveying and mobile mapping industries;
  • highlight the level of processing required to manage large multipoint data sets; and
  • provide local examples of new types of products which aim to support regulatory compliance, asset management and environmental planning.

Technological advancements in survey equipment, acquisition software and smaller on-water survey platforms have allowed for more data to be gathered to a high degree of accuracy. Hydrographic surveyors are now able to collect high-resolution bathymetric data sets in areas that were previously difficult to access with traditionally bulky survey equipment and large vessels.
The improvements in field data acquisition have gone hand in hand with the ability of software applications to process and manage large data sets with a high degree of agility on smaller computing platforms. It is now possible to load and manage very large point cloud data sets, within PC-based 3D visualisation tools similar to high end gaming technologies and GIS software packages.
Our full paper describes the marriage of several of these emerging technologies to map, visualise and create accurate easy to use baseline datasets of freshwater bodies, surrounding topography and any associated infrastructure. By creating more detailed and easy to use baseline datasets engineers, scientists and managers are able to make informed decisions on environmental impacts and asset management.


This article was first published in the February 2017 issue of NZ Local Government Magazine.

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