If you still have a job, get everything in order, and quit. Do it as soon as you can, because we’ve never had a more important work to do. -Kyle Chamberlin
"I awoke, only to see the rest of the World was still asleep" - Leonardo Da Vinci
It's just my 2 cents,
Paka no hida
It would appear that you joined the PRI Forum well after I submitted that post. However, next time I'm up your way, I'll certainly do my best to drop in.
Cheerio, and good luck to you, too.
around here we Banana Bender Aussies call them "pondages". A swale was a term used in my youth for the dune behind a beach for-dune. There are plenty in Qld especially west and North west of Rockhampton on a very large scale. Some 5-10 km long, holding back moisture for kilometres. They are also used to direct water into storages in heavy rainfall events. My late Father built some around the Dulacca area in the 1940's with horses and mouldboard ploughs and dam scoops. He grew sorghums and millets in summer in the resultant pondage. I know of plenty that have been functional for over 30 years in grazing areas where there is a marked summer/autumn wet and winter/spring dry season on gently sloping country. Plenty of Keyline drained farms here as well. One of my surveyor brothers was involved on a large scale in western Queensland in the early '70's. I still use my modified yeoman's on an annual basis. I have a 3 tine and a 5 tine that I hire out also. The main problem is that pondages only work if you have rain. After many years of drought the vegetation dies off them and when it does rain, and then heavily they can easily be eroded. They cost money to build and maintain.
Are you sure that what you saw were not good old fashioned 1 degree fall contour banks, designed to slow the flow of water off slopes and direct the water to grassed waterways to minimise soil erosion? These contour banks have been used for over 50 years by farmers all over Australia. They came about after the second world war when heavy earth moving machinery became widely available, but were largely done in the 60's and 70's with the aid of tax deductability of soil conservation measures and relatively cheaper fuel prices.