9ASM 2018 A comparison of methods for measuring water quality improvements from gully rehabilitation in Great Barrier Reef catchments (#79)
Recent advances in our understanding of the causes of declining water quality in the catchments draining to the Great Barrier Reef World Heritage Area (GBRWHA) have highlighted gully erosion as a key sediment source. Both the Australian and Queensland Governments now have major programmes focused on gully rehabilitation. With this focus, however, there is an increasing need to be able to quantify the water quality improvements associated with gully rehabilitation efforts, particularly as it appears likely that resource allocation will shift towards a model that funds quantifiable water quality outcomes through a Reef Credits market-based approach. Under such an approach, water quality improvements must be measurable, and hence the monitoring methods employed must be both scientifically rigorous, but also cost-effective. At present there is no standardized approach employed in monitoring gully rehabilitation success, but the success of an outcome-based funding model depends on the development of rigorous approaches with known margins of error and signal to noise ratios. In this paper we outline and compare a range of gully monitoring methods and discuss the pros- and cons of the various techniques. We compare various LiDAR methods, including standard resolution airborne LiDAR (typically 4-6 pts m-2), terrestrial LiDAR (up to 5000 pts m-2) and high resolution airborne LiDAR (up to 300 pts m-2). We also compare various water quality monitoring methods, including Sigma auto-samplers, low cost Rising Stage Samplers, and a new low cost integrated sampler know as a Pumped Active Suspended Sediment (PASS) sampler developed at Griffith University.
