LETTER: Flood ‘patch jobs’ will create more problems
The issue of potential flooding of the Base Hospital in Coffs Harbour requires a broader debate and explanation. I wish to express my personal opinion.
A primary objective of urban planning is to locate major hospital facilities in a safe location which is not subject to flooding.
Unfortunately, the Base Hospital, including the extension of the hospital currently under construction and Special Medical Centre, have been located in a flood prone area. During major flood events these facilities will be without an access road. Obviously, major hospitals should be operational during critical natural disasters.
These structures will also cause back-flow and increase flood levels upstream of the above facilities.
The explanation of the spokesman of Coffs Harbour City Council that: "We have planning for new residential areas and development in general and North Boambee Valley residential area has been on the cards for a long time" indicates an inappropriate process of planning and a lack of coordination with engineering inputs.
If an appropriate process of planning had been adopted, the current situation could have been avoided.
Further, the proposed detention basin is a patching job which should never happen.
Detention basins are good in theory but never good in practical application.
To work properly, a detention basin should be empty before the rain starts and this requires proper management to empty them. But if the basin is, for example, half full when the next rain comes the flood may be bigger, as was the last flood in Brisbane.
The experience and recommendations from the last flood in Brisbane should have been considered and taken into account into the Coffs situation. Detention basins are risky solutions.
It is necessary also to mention that due the climatic change the intensity of rainfall is getting greater, so all subsequent floods will also be greater.
In addition, it is obvious that the existing bridges at Newport Creek and Coffs Creek have not been designed for the existing and proposed development. So, the consideration should be given to increase length of these bridges to accommodate future flows. It appears that this option should be investigated.
In conclusion, detention basins are not good and safe practical solutions. A detention basin may, or may not save the hospital from flooding, and North Boambee Valley development should be abandoned or more options should be investigated to protect the base hospital from future flooding.