Long term landscape planning for the type of floods which have afflicted Australia could involve designing the landscape in the manner of a regional waffle. Much of the problem seems to have been caused by flows of water on an almost continental scale. The principles, as for Sustainable Urban Drainage Schemes, (SUDS) should be to detain, infiltrate and evapo-transpire flood waters. This process would be assisted by raising embankments where possible: field boundaries, roads, garden boundaries etc should all become dykes. In some cases the dykes would protect against floods but the main objective would be to stop the flood water cascading from zone to zone. Also, the dykes would serve as wild-life corridors and sanctuaries. My guess is that waffle-type measures would be cheaper and more effective than building large dams. The next stage would be to move from flood landscape planning to flood landscape architecture, by finding other uses for the dykes and by making them beautiful as well as useful. Individual properties would gain some similarities to motte-and-bailey Norman castles. Another advantage of waffle landscape planning is that when the rains come there will be more time for water to infiltrate into the ground and re-charge aquifers – in preparation for the next long period of drought. Does anyone know if waffle landscape planning has been considered, and if the engineering calculations have been done?
Image courtesy mhaithaca
The big question for what happens next for the city of Brisbane and for many cities worldwide is the role of climate change in flood events.
The previous big flood event in the city was in 1974. Since then a dam has been built as flood mitigation and in 2011 it has protected the city from more severe flooding.
However, with climate change, the expected frequency and severity of flooding could be expected to increase. So yes, a competition too – looking at the bigger picture – to design floodable spaces and places for cities would be a great contribution to urban flood defences and urban design.
…And all creatures great and small.
Having recently experienced the flooding of my city I am keen to help some of the less visible victims as well. Having spotted a dead echidna by a tree next to a usually busy road in a flood affected inner city suburb, and realizing that he was most probably washed there in the flood waters from Toowoomba, I am keen to start an online charity to assist wildlife.
I am proposing an Ark Appeal for Wildlife. Would gardenvisit be happy to sponsor a charity and gardenvisit readers happy to contribute to it?
A terrible thing happened to Pakistan, reminding us of the Sumerian Flood Tablets and the flood of the Old Testament (which may refer the same flood). The ancient floods were seen as a call to humans to change their ways – and so should the great Indus Flood of 2010, the great Australian flood of 2011, the great Brazilian flood of 2011 and the great Sri Lankan flood of 2011 . As the aerial photograph shows, Pakistan is largely desert. Would it have been possible to divert the flood waters onto barren land? If so, it might have done a lot of good and might have let us enjoy the great potential beauty of flooded landscapes. The issues involved have much greater significance than the geographic extent of Pakistan: they concern us all. We need to learn, perhaps from the baolis and hauz of India and Pakistan, how to store flood waters and use them over extended periods of time. Every human-used landscape should have plans for floods with return periods of 1-year, 5-years, 25-years, 100-years, 1000-years etc. See diagram for a modest suggestion on how to plan the management of flood landscapes.
What can urban designers do to design for flood resistance? They can exercise their imagination in flood design competitions and contribute to flood charities. Professional people should so some work for money and some work for love. We need floodable buildings, floodable gardens and floodable parks. The photograph below shows part of London (Strand on the Green) where regular flooding is expected, planned-for and enjoyed.
Top image courtesy Richard