I'm trying to do some restorative work at a friend's place in Northeast Arizona and he has quite a few natural springs and some wells that have gone dry in the last 10-20 years. He thinks that the Russian olive trees (Elaeagnus angustifolia) are to be blamed. They have really taken hold and can be found growing anywhere that there is water, has been water, or where there is sometimes water. My suspicion is that this is more to do with a larger issue of things drying out around here in a big way but I was wondering if there might be any merit to the theory that Russian olives are soaking up the spring water for themselves.
It doesnt strike me as thirsty. It is a nitrogen fixer with deep roots so it has potential benefits in providing a bit of shade and improving soil. It seems to do fine in poor dry conditions, it stays green in the hottest driest weather.
In my experience russian olive (e angustifolia) is very drought tolerant, even as a seedling in a pot, and its fuzzy leaves suggest it doesn't loose a lot of water. It grows slowly enough, so if it is using a lot of water, where does it go?
We had Olive trees at Arcosanti they were not overly thirsty for being a fruit tree.
I would say your theory of there being other issues is probably right. I would heavily doubt the olive trees as being responsible.
"Where will you drive your own picket stake? Where will you choose to make your stand? Give me a threshold, a specific point at which you will finally stop running, at which you will finally fight back." (Derrick Jensen)
In all seriousness, though, I feel deeply for anyone who has lost wells and springs. This speaks to a broad change in the larger landscape, rainfall patterns, seasonal flows. For those on the land, it changes everything.
I think the water levels are going down not because of native/invasive plants but due to humans emptying the aquifers and ground waters at alarming rate.
If the invasive lowered it by 10, humans lowered it by 1,000