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“Discharge into river cheapest option”

by on July 8, 2013

In one of the many newsletters that find their way into my Inbox, I saw this headline last week and had to read on.

The full article which can be read here describes the Shannon wastewater upgrade project in New Zealand that is comparing several options for discharge of treated human effluent and wastewater. Using all the water to irrigate an 85 hectare farm (already purchased at NZ$4.1m) did not prove cost effective due to the technicalities and high risks. So, a combination of partial irrigation and discharging into the local river, Manawatu River, are now open for public feedback.

It got me thinking that we see similar outcomes with stormwater, whereby what appears as a common sense approach cannot be taken because the costs don’t add up. How can that be so?

In this case it appears as if more checks and balances have to be put in place to prevent a spill of untreated wastewater onto farmland than into our rivers. Do we really value the farmland more than the natural ecosystem that is a river? We talk a lot about multi-benefit approaches and multi-use space. Surely our natural environment is the best example of this. A river provides not only an ecosystem but also amenity value, a resource, a drainage feature and more.

Can it really be more expensive to re-use treated wastewater for irrigation and potable water cleaned to the high drinking water standards in many countries? I am guessing that this is the alternative irrigation option although I don’t know for sure. If not in this particular project we certainly see it in others.

In many cases “green” d15rainage solutions such as WSUD, LID and SuDS are being overlooked because the costs do not add up. When you consider the additional values these solutions provide on an environmental scale, an amenity scale, potential for saving potable water and so on it doesn’t make sense.

So how to move forward? An increase in the cost of potable water? Placing a real value on environmental improvements? And a cost on any negative impacts? Perhaps only then will we see common sense solutions become cost effective. We’d love to hear your thoughts below.


From → Future Design

One Comment
  1. it’s the same discussion with Sydney Councils. It’s always about the maintenance! Some Council’s would rather concrete a medium strip than have to maintain it! Surey, this is the wrong way to think about it!

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