Friday, February 10, 2012

Residential Flood Irrigation for Citrus Cultivation


I ride by this all the time, but remembered how strange it looked the first few times I saw it


After the popular and tasty post about the pallets of grapefruit in my bike lane from a few days ago, it seemed relevant to also show a couple of pictures of the flood irrigation that makes those fruit possible here in this desert valley.

The Arizona Canal (with its great paths along the banks) carries water about 20 miles from the Granite Reef Dam on the Salt River, through the city, and then a system of neighborhood pipes, ditches, gates, and valves brings the water to our yards, every two weeks in the warmer months, and about once a month (or so) during the cooler months. The Bermuda grass and citrus trees do pretty well with this regime. I remembered how strange it seemed the first few times I noticed yards filled up with water when we first moved here, but in the flood irrigated areas, but the history of this particular instantiation of Salt River water diversion for this area goes back to 1883, which is 129 years. And these canals were built along many of the same alignments as those of the Hohakam who lived here and lived off diverted river water from AD 0 to 1500 or so. Salinity continues to be an issue, though, and more water is required as the salt level increases in order to push the salts below the root level. According to a chart in this article, citrus don't like TDS above 768 mg/l, which is in the ballpark of what the water has. Salt has been flowing into this valley in its rivers for millions of years. There's a salt mine in Glendale that pumps water through drill bores a few thousand feet underground to get the salt from a 15 cubic mile salt dome and brings brine back up to prove it. It's interesting to me how that all comes together, and what it means, it a front yard with citrus trees.



The white paint is like sunscreen for the trees. It's needed more when the trees are trimmed up pretty like this.
   

5 comments:

  1. I am impressed with the use of "instantiation" and the fact that you read that 309 page article on salinity.

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    1. Heh, it was only 17 pages, and I did read it. I will seek out further opportunities to use "instantiation" and derivative forms of it.

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    2. The long one, I was specifically looking for the TDS tolerance for grapefruit, so I admit I only skimmed it for that.

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  2. Hey, thanks. I had grapefruit this morning. It's nice to know how others come by it. (Just ask me anything about maple syrup production and I could regale you with those facts.)

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    Replies
    1. I saw a food show about maple syrup production behind a restaurant where most or all of the dishes included it. I'm getting hungry just thinking about it. I've been putting it on my oatmeal lately.

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