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 habib May 25, 2013 03:23  |
The idea to improve city drainage to cope with large floods is laudable but engineering solution as one proposed here are seldom practical. Enhancement of existing drainage systems in built urban environments is too costly even if we know all below ground services. It is usually the cost of reloaction of these services and mangement of services above ground that add to the cost of drainage enhanements. e.g. in a city like New York the cost of just managing the traffic during a major drainage upgrade would run into tens of millions of dollars.
I am currently working on a project in a built up area of Sydney and a preliminary cost estimate for the provision of a 2km large drain through a built up area to improve flooding is approx $100 million. The benefits of this option are very local and bascially solves the flooding problem for s single suburb upto a 100 yr flood. The cost to undertake any substantial city wide program would cost tens of billions of dollars, in particulr if a higher level of protection (catastrophic flooding) is required.
So, in my view, the solution does not lie in providing additional drainage but rather in the city planning. Any flood affected area should be assessed for flod risk and then appropriate planning measures can be adoptedt o ensure that the damage to life and property is minimised through such planning. If required, temporary relief can be provided through drainage improvement measures.
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 2013urbanadaptationjudges 2013urbanadaptationjudges Jun 30, 2013 05:00  |
This is an interesting concept of storing flood/rain water to reduce potential damage and reusing it. A similar idea is being tried in Singapore. The proposed engineering solution has been thought out, but the costs of implementing this suggestion could be very high – this should be revisited in the next proposal iteration. This very good idea may be extremely difficult to implement practically and financially. Key to determining advancement in the proposal process is the feasibility of a project. The concept does not adequately factor in existing drainage systems that have been put in place, generally at great costs, but is proposing an alternate system, which seems like an additional system to existing one, making it a little difficult to justify. Adaptation is not necessarily about building new infrastructure, it can also be about suitably modifying existing systems. Also, no climate scenarios are mentioned e.g. for coastline cities that the proposal mentions, would the system be effective or relevant in a 1m SLR scenario? Can this be addressed? Instead of suggesting only an engineering based solution, the proposal could also benefit by suggesting a basket of solutions e.g. wetlands / water bodies and areas around them have the capacity to absorb flood waters – these need to be protected (this is a low cost high benefit option); proper maintenance of existing drainage systems.
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2013urbanadaptationjudges 2013urbanadaptationjudges Jul 29, 2013 04:58 |
Despite revisions, the proposal still needs more specificity and detail.
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