Mitigation - carbon fixing in waterways

Waterways are important in cycling of carbon. Waterways cover about one twelfth of the Earth’s area yet contain approximately one third of the world’s terrestrial carbon. Clearing and drainage of waterways can lead to large losses of stored organic carbon to atmospheric carbon dioxide. As a result the importance of waterways in carbon sequestration and storage is significant. The Wimmera has the highest concentration of waterways in Victoria. This provides great opportunities to better protect waterways for carbon storing benefits as well as biodiversity and farm productivity through a broader range of funding opportunities. While there has been a significant amount of research into carbon and marine ecosystems the same cannot be said for terrestrial waterways. There is some uncertainty about the best waterways for carbon capture and storage and management techniques to maximise it. It is believed that rivers and streams do not have the same ability to store carbon as wetlands, however the vegetation both instream and in riparian areas has significant potential to store large volumes of carbon. In the interim, Wimmera CMA have developed a model based on a report produced by the Danone Fund for Nature (DFN) discussing potential carbon offsets through wetland ecosystems (Danone Fund for Nature, 2009). This model is discussed in NRMPCC Modelling – Waterways (Wimmera CMA, 2015).

Priorities actions include:

• Seek funding to research the carbon capture potential of the range of waterway types in the Wimmera.
• Promoting carbon benefits to landholders along with the other benefits of managing waterways.
• Implement actions from the Wimmera Waterway Strategy (2014)..
• Where appropriate, incorporate high carbon storage waterways into investment decision matrices for Wetland Management (see Map).

Adaptation

Substantial water savings and overall water security has occurred through the construction of the Wimmera Mallee Pipeline. This is one of the most significant adaptation actions the Wimmera has taken.

Previously climate change modelling has been used to assist in determining water availability and water planning in the Wimmera. This information has been used to determine environmental flow regimes under a range of scenarios. As new information becomes available, time passes and experience grows there may be opportunities to revise this modelling.

As with other assets, our waterway’s ability to deal with climate change will be aided by our ability to adapt our management to suit the situation. The Wimmera Waterway Strategy (2014) establishes an approach for this whereby actions are prioritised based on the risks and opportunities associated with a particular climatic situation. For example, if conditions are very dry efforts will be focused on protecting refuge pools rather than the whole river system. Storm events are predicted to become more common so actions will focus on repairing flood damage when this occurs.

The priority actions for adapting to climate change are outlined in the Wimmera Waterway Strategy (2014).

Other priority actions include:

• Support the review of the Bulk Entitlement using updated climate change scenarios.
• Focus waterway management actions in areas of highest vulnerability identified by mapping.