Shonga, water is a state responsibility, not a federal one. And the turkey who vetoed the Wolfdene Dam site (where it actually rains) was Wayne Goss and the turkey who passed the Wild Rivers (outlawing dams) Act was Beattie.

This brings to mind the Urban myth that the toilets at Oxford University have little signs reading "Flush generously, London needs your water".

It is realy good the see constructive proposals, and annoying to see the same old same old political jibes intruding.

Yes technology may be feasible, but to what extent are the high cost final squeeky clean steps at the end needed, and as Perseus notes is this best use of investment. Low tech can be good too.

Let us applaud the overall direction, but also listen to reasoned criticisms which may help a better final strategy emerge.

Toowoomba is a large,growing city in a region with declining rainfall and inadequate dams. It can't desalinate seawater and one can't return to the past expecting all households to meet their total use from tanks (remember, the rainfall problem). Purification of wastewater must happen. Far from being patted onm the back Toowoomba Council needs a kick up the rear for not acting years ago. Brisbane must follow suit yesterday. Tell me, when are Queenslanders going to start stockpiling bottled water and are there plans by the State to prevent profiteering by retailers? Brisbane City and the State should fully (100%) refund all proven purchases of tanks and consumption limiters for both domestic and private use.

Rainwater is a reliable source of water for Toowoomba. For the 12 months to March, 2006, 601mm of rainfall occurred in Toowoomba. This rainfall was sufficient to supply 50% of an average household’s indoor water needs for the entire year. An average house collecting rainwater from the roof and using it for all purposes would have derived at least 75 000 litres of water (assumes 175 sq.m roof area; 75% yield/25% losses; annual water use indoors 150kl) from a 4 500 litre rainwater tank. Rainwater must be collected from the whole roof area and used immediately it is received to maximise the rate of tank draw down.

It is both practical and economic to collect water from all downpipes of a house by using “skinny tanks” which are up to 1m wide, 1m high and can be 1m – 3m in length thereby having capacity of 1000 litres – 3000 litres each. The tanks easily fit under the eaves of a house. They are linked and draw down is controlled to provide uninterrupted supply whilst water is available. Continuity of supply is guaranteed by seamless, automatic transfer to mains water supply when tanks are empty and back again immediately rainwater becomes available. It is not necessary for rainfall to be even during the year. The only influence of extreme rainfall events is when tank capacity is insufficient to contain the water produced. This loss has been included in the above yield calculation for Toowoomba over the last 12 months.

When used like this, rainwater tanks will permanently secure household drinking water supply by providing about one-half of annual indoor water requirements in Toowoomba.

When all buildings replace mains water with rainwater (building owners can be providers of drinking water to the general public provided the quality is certified drinking quality which can be achieved to ADWG standards by ultra-violet treatment; or they can simply supply rainwater for non-drinking purposes) this will secure Toowoomba’s drinking water supply.

In addition, when greywater that initially was rainwater is recycled on-site for non-drinking water supply, the yield increases further.

Greg Cameron
www.urbanrainwater.com

A very good point, GC.

I need to correct the numbers provided in my above post on farmers loaning their irrigation water to Toowoomba for use and return to the farmer when he needs it. I got the population figures wrong. I said,

"The 130,000 residents(actually 91,000), in 50,000 (actually 35,000)households will use 12,500 (actually 8,750) MgL a year. This would reduce to 9,000 (actually 6,560) MgL if all houses captured their shower water for flushing toilets.

Irrigators in the area are likely to use 4-6 MgL per hectare on their crops or pastures so the entire water needs of the city could be delivered from only 1,500 to 2,000 (actually 1,090 to 1,650) hectares of irrigated land. The city itself is in the order of 5,000 hectares and is bigger than the irrigated area needed to loan the water.

So if the city of Toowoomba was meeting it's obligation to take all reasonable steps to help itself, like adequate water tanks, before putting it's hand out for public money, nearly all of it's current water allocation could be re-allocated to nearby farms. They could then loan it back to the city for drinking, washing, flushing purposes before returning it with value added nutrients, to the nearby farmers when they need it.

This would boost local agricultural production by $2 to $5 million a year, have flow-on effects of another $5 to $10 million a year and produce 150 to 300 extra local jobs. In contrast, the interest on the $40 million (?) recycling plant will see $2.5 million going out of the community each year at a cost of 50 local jobs.

The recycling sewerage option is a typical bureaucratic solution that is long on image value and very short on real public benefit.

It is also not widely understood that, unless Toowoomba's population makes a sudden jump to take the entire output from the recycling plant, this new water will be more than double the reported cost.

Put simply, the costings of projects such as this one are usually based on the assumption that the plant works at full capacity. But if the city already has an allocation of water then the project will only be replacing existing water not creating new supply. So while the whole city will get to drink their neighbour's urine, their existing water allocation will either evaporate from the Dam or be released back into the river. And this will remain the case until the population increases enough to use both lots of water.

So forget all these calculations that show the recycled sewerage to be a similar cost to the existing water. If the actual demand for extra water is only another 1,000 MgL a year then the whole interest cost of $2.5 million, and likely operating costs of at least another $5 million should be spread over that 1,000 MgL. And that would mean the real cost of this water is about $7.50 per thousand litres or seven times the current price.

If anyone has more detailed costings I would appreciate your sharing them with us here.