Im in the south of Portugal - Algarve, I guess zone 9?
On my land there is what i recently found to be old spring that has dried up.
I noticed in winter (when it rains) that it starts trickling again and there are some moisture loving plants that seasonally grow here.
Further down it fills up the well which stays with water until the end of June.
At the moment there are some very old stone oaks still planted but the rest of the little valley is completely dry and exposed. And Im guessing and hoping this is why the spring has disappeared.
Last winter before I realised it used to be a spring I started planting the trees I had in pots around (the spring source)
A little further down I noticed that even as little as 10 cm beneath the top soil was super wet.
My question is which trees do I plant to replant the spring ?
So far I have put in the vicinity:
Monchique oak (Quercus Canarienses)
Wild strawberry (Medronho)
Are any of these a bad tree to plant i.e. will it deplete the water instead of plant it?
Also about 40 meters higher is the old ruin that Ill be reconstructing from its original Taipa (mud)
Ill be pulling down the outhouses that were built from old bricks etc and as the slope is quite steep in front of the house and as I want to have minimum waste, Im planning on using the rubble to extend the area in front of the house using the rubble and dirt instead of removing it with a skip.
Do we think this will affect the (currently dry) spring further down (around 40metres) in a negative way or by planting more trees would it raise the water table somehow through the covered rubble?
Good questions. I wonder if you have any species of maple around, or if it's too hot. In your position, I would look for a tree that acts like a Sugar Maple, carrying out a process called hydraulic lift, where it basically pumps water up from the water table for use by itself and the plants and other trees around it. I had thought that some type of fig, or something else with a really long taproot, was tapped for this purpose in a few of the regreening the desert projects.
I think perhaps looking into the pioneer species available locally would be a good idea. If you had pioneer plants, weeds, essentially, and pasture plants that live for an extended period without rain, it would be good to get them in the ground before the rains come. They will cover any minimally covered ground, providing shade, reducing evaporation, and increasing water infiltration and groundwater recharge when it does rain, basically refilling your spring's underground reservoir.
I would then look at what comes closest to treed savanah in your area, and what the makeup of the grasses are. I would look at this at very least like a transitional aid, an ecosystem of nursery plants to care for the soil, which will then support your new trees.
You might also consider looking into Air well (condenser) construction. These structures literally condense moisture out of warm air, and can be as simple as a pile of rocks.
The same principle can be used with a deep layer of rock mulch laid with enough airflow to permit the same process, and it provides the same benefit as organic mulch, in that it shades the soil, and soil life, from the baking sun.
Pictures would be greatly appreciated. Otherwise, keep us posted, and good luck.
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First of all, don't use any heavy machinery around the spring, or you can seal it for ages.
Try to check if the spring is silted. One way to do that is to look at trees on the UPPER side/slope of the spring. If their roots are appeearing clearly outside the soil, like skipped veins, then there's a good chance of silting.
Check also the under slope of the spring, looking for cattails. Cattails are one of nature's way to avoid nutrients from silt being lost to the sea. Some cattails are just ok, but a lot of them means they are thriving on the nutrients being washed away from the upper soil.
If the spring is silted , measure the flow of the spring. Use your hands to clean any leaves on the spot. To measure the flow use a small spout, a bottle or bucket and a chronometer. Check how much water flows in one minute. Write down the flow and the hour you made that.
If the spring is silted, try to desilt it using hand tools. Dig carefully right on the spot of the spring. If the flow of water increases fast, stop digging.
Go there the next day and measure the flow again at the same hour. Springs can change their flow according to the hour of the day.
Compare both flows. If the flow increased related to the first day, then it is silted for sure. Dig a little more, leaving the spring water runs freely.
You can dig half a meter around the spring. More than that and you could "hurt" the spring.
If it is too silted, there's not much you can do.
If there's cattle roaming there, fence the spring using barbed wire. The fenceshould be at least 5 meters radius from the spring. The long, the better. 50 meters would be great. Don't put the lowest barbed wire too low. It should allow small wild life access the spring.
The problem is, not enough rain water is soaking down to the water table. So how can we fix that.
1) Swales/Berms on contour
2) Aerate/Decompact the soil with Daikon Radish and other such roots
3) Increase the amount of bio-available mineral per cup of soil water so the plants demand less (legumes, rockdust, biochar)
4) Woodchip/etc to cut down on soil evaporation
5) Crovercrop/ground cover to increase overnight condensation, dew on grass leaf in the morning.
This is best done not just along the 'riverside' but for 1000 acres around it, but ever little counts.