Thank you, JD, for the link to the article on Moroccan khettaras. However the system described (and the similar qanats in the Middle East) cannot be easily related to Australia.

The Atlas Mountains, which stretch the whole length of Morocco and make up about a quarter of the country, are high, up to 4000m, and although the climate is dry, they direct rainfall and snow melt to surface streams and ponds and more importantly groundwater to the lower alluvial slopes. The khettaras harvest this shallow groundwater through earth canals to small-scale fields.

The article describes 300km of channels supplying 9000ha, through a dense networks of channels. So there isn't a single 300km channel; the local groundwater is tapped in many places through many small channels, most just a few kilometres.

We already do this sort of distribution on a much larger scale. Just Southern Riverina Irrigators alone supplies water through 3,000km of earthen channels to an area of 748,000ha. This is the Deniliquin-Moulamein-Wakool area, to the east of Balranald. https://southernriverinairrigators.com.au /. But this water is extracted from the Murray, and depends on rainfall upstream, on Australia's piddling mountains. Southern Riverina Irrigation has to compete with all the other water users along the river. There is no local source of groundwater to be tapped.

Distributary channels for irrigation water are one thing, but the real problem is sourcing enough water, whether from a large river with many competing interests, or by finding and piping enough water over long distance which is very costly, before you can distribute through local channels, whatever length these add up to.

Apologies, JF Aus!

No worry Cossomby. I will get back to you later tonight or tomorrow.

Yes individual, windmills are great. My neighbour has one down by the river.

It lifts water from 45 metres down his bore, & pumps it 300 metres across & up 30 metres to a tank at his house. It gives him 4400 litres a day at that height, or 6400 litres a day at the mill.

Another neighbour has 5 windmills putting out about 5000 gallons a day each. This goes into his dam, from which he uses an electric pump to irrigate his small turf farm. It takes 26000 gallons of water to put one inch on one acre of land. His 5 windmills allow him to irrigate one acre a day.

I have seen some supply a little water at 200 metres height, a few litres not gallons. Can you imagine how many windmills, power generating or water pumping, it would take to move a meaningful amount of water 130 kilometres from the coast & up 800 metres to the top of the tablelands. The practically is not too good.

Can you imagine the scream that would go up if you start taking water from coastal irrigators & cities to supply inland. In my 26 years here irrigators have been on water restrictions in at least 12. We are often reduced to 4 hours pumping 3 or 4 days a week. Some years our river is dry for more than 5 months in late winter/spring. Thus serious irrigators have to build their own storage, & harvest water during floods.

The only time excess water is available is during floods. As I said in an earlier post, you would need huge pumps & power supply to move much in the few days that coastal floods last. It would be nice, but we have to be practical. Pumping water up over the coastal ranges is just not viable to produce feed for millions of cattle.

Continued

Continued.

Perhaps the best idea is a channel from the Bight to Lake Eyre to flood the place completely. Evaporation should produce some rain, & make the area much more humid, so should help, but supplying irrigation water to graziers is just not viable.

Local aborigines claim exclusive rights to the lake. They prevented sailors racing on it. May be a good fight flooding it too.

PM Malcolm Turnbull, if you can give over 400 million to Great Barrier Reef cronies you can give a billion or more to drought impacted Australian farmers.

It's worse than we are being told.

http://amp.abc.net.au/article/10074216?__twitter_impression=true