FIRST things first. With up to 300mm for the week in the catchments, nothing was going to stop the flooding of Victoria’s north-western river systems.
You just can’t handle that sort of rain in that sort of timeframe and not see water going in unusual places.
However, the real issue once the floodwaters abate will be how has the hand of man influenced these floods?
Up until now, the dominant school of thought has been to let the rivers run as close to naturally as possibly.
With parched terminal systems such as lakes Hindmarsh and Albacutya on the Wimmera River and the Kerang swamps on the Loddon, it is a noble objective to get as much water as possible into these fragile areas that have been ravaged by the drought.
But claiming that the best way is just to let nature take its course and let the rivers run free is a naïve approach.
With agriculture influencing the landscape for over 150 years in many parts of the catchments and the extensive channel systems in most of the catchments of the Wimmera, Avoca, Loddon and Campaspe Rivers, water does not flow the way it used to.
It is a great thing to have water flooding over natural floodplains that have not been built up, but when that area now contains, for better or worse, houses and development, attempts need to be made to minimise the impact.
In the Wimmera, Pine Lake has been used in this flood to try and take some of the mighty flow coming down the river, but it has not been enough to prevent major damage.
As we said, preventing all damage is impossible, but hopefully much has been learnt from the lessons of these massive floods and hydrologists and the CMAs have a better idea of where the water comes in and how it spreads and mitigating that impact in agricultural and urban areas.
Events such as the devastation at Charlton, or even the cutting of a major rural city of Horsham need to be prevented.
Issues such as the partial filling in of the open channel system in the Wimmera-Mallee and the removal of some culverts under roads has meant water has behaved in ways never seen before, and certainly not in the way it would have prior to white settlement.
Letting water dam up on roadsides and spill back into private property does no-one any good.
Now we have a better idea of what happens when it gets this wet, hopefully strategies can be created that ensure the water gets where it does the most good, that is our magnificent river systems and wetlands, along with water storages, and as little where it does harm, such as backing up stormwater drains through built up areas.
There is probably going to be a round of bashing of the relevant water authorities in light of the floods, and there is no doubt there are things that could have been done better, but let’s also realise that this is an unprecedented event. The real crime would be to not learn from what has taken place.
Is there scope for alterations to the river systems in terms of flood mitigation? Its not my area of expertise, but you’d have to suggest some more weir systems apart from the modest Yawong Weir along the Avoca would have been a good thing for Charlton.
For years, the focus on dams and reservoirs has been as water storages, forgetting about their vital role in flood mitigation.
I’m all for water getting into these previously parched river systems, but there has to be a balance and you could not possibly argue that the devastation of an entire town such as Charlton is worth it.
On the flipside, future development also has to be closely looked at. I realise this is an extreme event, but with climate change leading to these severe events become more common, then perhaps developers need to err on the side of caution with where they build. Having a nice river view is fantastic. Having the river track through your lounge room is less good.
Our immediate attentions now need to be on the clean-up process but following that, a lot of hard work and research needs to be done on finding the correct balances that allow both healthy rural communities and riverine systems.