Before Rehabilitate large alluvial gullies like this: After the key to significant water quality improvements Take a picture to view our research page Damon Telfer RESULTS One down, 200 to go! v The effectiveness of large-scale alluvial gully Crocodile Station Strathalbyn Station rehabilitation in addressing Great Barrier Reef water quality Andrew Brooks1, 2, John Spencer1, Nic Doriean1, 2, Robin Thwaites1, Tim Pietsch1, James Daley1, Will Higham3, Mike Goddard4, Damon Telfer5, Lynise Wearne6 & Sunny Bezahdnia6 Erosion Deposition INTRO Sum Elevation Sum Elevation Change (m) Area Vol (m3) Change (m) Area Vol (m3)Net Gully erosion is the source of 40-50% of the sediment ‐4821.6 80.0 ‐12.05 9676 155.8 24.19 12.14 pollution entering the Great Barrier Reef lagoon. Hence to Percentage SSC reduction compared to control achieve GBR water quality improvement targets requires the rehabilitation of extensive areas of eroding gullies. This study tests the effectiveness of treating alluvial gullies using wholesale re-shaping, and various capping treatments at experimental sites on Crocodile Station in the Normanby River catchment and Strathalbyn Station on the lower Burdekin River, Queensland. < 2 METHODS 1. Gully treatments were undertaken using a Before- After Control-Impact (BACI) or semi-BACI design. 1. Treatment effectiveness > 80% Courtesy Greening Australia 2. “Before” erosion rates taken from a combination of for the < 20 µm sediment fraction historical airphotos and repeat airborne LiDAR. has been achieved within 2 years of 18 treatment 29 3. “After” treatment effectiveness was measured using a 104 13 15 967 combination of terrestrial LiDAR, high-resolution 2. Each site represents about 0.5% of 17 the WQ target for each catchment 5 airborne LiDAR and water-quality monitoring at 3094 3. Hence treatment of around 200 treatment and control sites. sites of similar magnitude will Sediment eroded (t) - 10cm LiDAR DoD (2018/19) 1Griffith Centre for Coastal Management, Griffith University, Australia, 2 School of Environment and Science, Griffith University. achieve the WQ targets in each 3Sugar Research Australia, Greenvale, Qld, Australia. 4Cape York Natural Resource Management Group, Atherton, Qld, Australia. 5Fruition Environmental, Townsville, Qld, Australia, 6Greening Australia, Brisbane, Qld, Australia. catchment.