What are some of the impacts of artificially opening ICOLLs?
Artificial opening of ICOLLs results in a rapid lowering of the water level and the exposure of extensive areas of sediment and aquatic vegetation such as seagrass and algae. Exposure of sediments to the air and the death of aquatic vegetation can lead to the release of hydrogen sulphide (rotten egg gas) and other foul smelling gases which often lead to odour complaints by residents and visitors. Decomposition of exposed aquatic vegetation can also result in deoxygenation of the water column (low dissolved oxygen (DO), which can lead to the death of fish from suffocation (i.e. fish kills). Under natural conditions, closed ICOLLs break out over a relatively wide range of water levels which is termed the ‘natural breakout range’. An occasional artificial opening of the entrance within this range is not likely to have a significant environmental impact since it falls within the expected natural variation. However, over the longer term, numerous artificial openings especially at a low wate
