Large woody debris and flooding

Debris such as large woody debris (or snags) can cause blockages to waterways, particularly around waterway crossings. This may have an effect on flood levels and flood behaviour.

However a channel needs to be substantially blocked (>10% of the cross sectional area of the channel) before there is any measurable affect on water levels.

Large woody debris in creeks and rivers is natural and is important for bank stabilisation and fish habitat. It can help protect the beds and banks of streams from erosion and in many cases can help to slow floodwaters and reduce the height of downstream flood peaks. Also when flood waters reach the top of the river bank and move onto the floodplain, the wood within the channel may have very little impact on the distribution of floodwaters. 

In general, City of Coffs Harbour will only act on large woody debris in urban areas not within private land, and only if there is serious risk of blockage and impacts on flood levels of behaviour.

Report Woody Debris in Waterways

Step 1.Report to Council 

If you have concerns about large woody debris causing flood issues, and it is within an Urban Area please contact council.

Step 2.What happens next?

Council will investigate the issue, and if there is a substantial blockage that may impact flood levels and/or behaviour, works will be undertaken to resolve the issue. 

Step 3.What if the debris is within a rural area or private land?

  It is advised that the Natural Resource Access Regulator (NRAR) be contacted.