Water quality

This program area will determine the effectiveness of conditions related to water quality. The program will do this by establishing an evidence base on how the riparian exclusion zones, riparian ground protection zones, road and track protocols and soil conditions adequately maintain water quality in Coastal IFOA state forests.

Monitoring waterway and wetland health

The program will determine if the Coastal IFOA conditions and protocols are effective in minimising the potential impacts of harvesting, roads, tracks and crossings on waterway and wetland health. It is important to understand the current state of knowledge in this area - including monitoring and research approaches - to ensure the program prioritises research and monitoring effort to address knowledge gaps and uncertainty.

Project WQ1: Review of the current state of knowledge for the monitoring of forestry impacts on waterway health in NSW coastal forests

Alluvium has delivered a peer-reviewed literature review on forestry impacts to waterway health and water quality in Coastal IFOA state forests. The review included research on practices and conditions in the Coastal IFOA. For example, temporary log crossings, class 1 stream riparian exclusion zones and soil and water protection in intensive harvest operations and exclusion zones for Coastal State Environmental Planning Policy wetlands.

The review found the management practices in the Coastal IFOA related to soil and water controls are consistent with best practice and standards. When major runoff events occur, the impact on water quality is typically short-term and transitory.

However, the frequency of intense rainfall and bushfires are likely to increase into the future due to predicted climate change. These predicted changes have the potential to increase the risk of impacts of timber harvesting on water quality in the future. As such, it is important that the objectives for this monitoring program reflect predicted changes in climate and monitoring is designed to investigate implication for the IFOA conditions and protocols.

Based on this review, the program will refine the objectives of the water quality monitoring plan to provide a stronger link between what is being monitored, and its relevance for values that are being managed for now and into the future. It will also adopt a risk based approach to monitoring. This approach will link timber harvesting, and the forest road network more broadly, to hydrologic and ecological impacts on waterways and wetlands. The approach will also measure catchment response in areas where harvesting and wildfire intersect. This will build a better understanding of how current forest management can be adapted to address emerging risk associated with new catchment disturbance regimes.

Project WQ2: Post-fire erosion mapping in southern NSW

Following severe wildfires – such as the 2019-20 wildfires - soils in eucalypt forests are at greater risk of erosion under high intensity rainfall conditions due to the removal of vegetation cover. This erosion can lead to increased sedimentation of waterways which may have significant consequences for aquatic habitat.

However, the location and the volume of sediment that is transferred into waterways is not well understood. Further research about these features can provide options for improved forest management to protect waterway health.

The Coastal IFOA monitoring program has partnered with Jacobs who will work collaboratively with Forestry Corporation of NSW and University of Melbourne. The project will develop a method that can readily map post-fire erosion. This will improve our understanding of how future wildfires impact water quality and provide options to reduce those impacts. This is particularly important given the predicted increase in the frequency of intense rainfall and bushfires due to climate change.

This project will use aerial imagery collected pre- and post-fire in the catchment of the Tumut River and Blowering Dam Reservoir in the south coast of NSW.

Monitoring landscape-scale trends

The Forest Monitoring Steering Committee commissioned the University of Melbourne to deliver baselines, drivers and trends for water quality and quantity in NSW forest catchments. The researchers have now delivered a final report. READ MORE...