Gravity fed drip irrigaiton - advice needed.

hello to all who might have recommendations, ideas, or who might want to learn from this discussion.

Earlier this spring we hand-dug a 10m deep well at the highest elevation of the site to have easy water access for future projects on a sandy farmland on the southern, sunny part of germany, in a hope that we can transform this land to our little paradise.
soon after the well was done and tested, we have planted 15 fruit/nut trees staked, mulched, and more to come.

Right now we are about to set up an expandable drip irrigation system, and thats where advice comes in really handy.
first round to water the trees ASAP, as for now we are watering them by hand, second circuit for a vegetable garden next year.

the trees are scattered on the "edible hedge zone" of our land, that is about 100 meters long.
we could lift a 1000l water tank (that needs to be refilled with a small electric pump periodically) about 2 meters from ground level, use a 100 m 1/2 inch distribution tubing with 1/4 inch branches and reducer tees, and multiple adjustable emitters (these ones: https://www.amazon.com/dp/B07173Y5KD/ref=sspa_dk_detail_3?psc=1&pd_rd_i=B07173Y5KD&pd_rd_wg=82AT2&pd_rd_r=KZKTVE7BE2RBZAS2X8T8&pd_rd_w=3MKNk ) for each tree.

im about to build this system described, then adjust each emitter so they emit the same amount of water in a given time (open more the ones that are further away from the tank, taking less pressure), then every time fill up the tank with the amount of water needed, and let it flow down in the system, no matter how long it takes. so far more like build, test, and then see the GPH, instead of knowing what flow rate I need and design accordingly.

this setup means very little water pressure, still without experience on the field I think its possible. what do you think?

I basically need advice here from people of experience in low pressure, gravity fed drip irrigation, to understand if this idea makes sense at all, if this setup is in fact would be able to bring the water so far from the source, If it could provide sufficient water for the trees, and for future veggie garden areas.
I know with more elevation comes more pressure, yet not only our resources are limited, we also face local law restirictions - we can not lift the container higher.
thanks for all ideas, recommendations and advice.

My thoughts are that 2 meters off the ground may give you enough pressure to feed the system. We have a 1000L water tote only about 45cm off the ground that I started experimenting with this year. I don't have the system set up yet, but have been playing with what we have just to get a better feel for the system. I attached a 50 foot hose to the water tote (too long but that is all I had), which feeds the water only about 30 feet to the garden. The regular hose is attached to a soaker hose in the garden. I wasn't expecting much to come out of the soaker hose since the tote is not high off the ground, and the garden hose is so long and twisty. I was surprised, however, by just how much water was being pushed through the soaker hose. If I got that going with such a low pressure system, I imagine that you would have enough pressure with the tote being 2 meters off the ground. I think it is certainly worth a try, especially with the adjustable emitters. And if it does not work, perhaps install another pump to the tote.
Please let us know the final outcome of whatever your decisions - I would be very interested to hear about it (as, I think, would others thinking about a gravity fed system).

If you could lift that tank to 3m off the ground level you would be better off since the pressure will drop as the tank empties.
At 2m height you could find the lines don't empty all the water from the tank.

I use 270 gal. Totes that are set 2m off the ground and fed by our gutters, these feed water down hill to gardens that are lower so the head ends up measuring 3m-4m, the drip lines will run for about 3 hours on a full tote.

Redhawk

That doesn't seem like much pressure at all.  I would be worried that over time the extremeties would not get adequate irrigation.  Have you looked into something called a Ram Pump?  It is this completely hydraulic pump made out of pvc and two brass checker valves.  Basically, it pushes water through the pump, and shoots it uphill.  This could allow you to pump water up to a higher tank, which then could feed the drip irrigation with a bit more gravity force on the water.  

Here is an article about building a hydraulic ram pump https://www.motherearthnews.com/diy/hydraulic-ram-pump-zmaz79mjzraw

William Wallace wrote:That doesn't seem like much pressure at all.  I would be worried that over time the extremeties would not get adequate irrigation.  Have you looked into something called a Ram Pump?  It is this completely hydraulic pump made out of pvc and two brass checker valves.  Basically, it pushes water through the pump, and shoots it uphill.  This could allow you to pump water up to a higher tank, which then could feed the drip irrigation with a bit more gravity force on the water.  

Here is an article about building a hydraulic ram pump https://www.motherearthnews.com/diy/hydraulic-ram-pump-zmaz79mjzraw

The ram pump needs a pre-existing water flow. It won't be applicable in this situation (lifting water from a well) unless I am missing something?

I know with more elevation comes more pressure, yet not only our resources are limited, we also face local law restirictions - we can not lift the container higher.
thanks for all ideas, recommendations and advice.

I'd be looking for ways to bend that legal restriction somewhat.

For example, you might consider some "landscaping" earthworks in the area to raise the soil level slightly. Maybe digging a pond and using the soil to make a wide and shallow platform? Then when you raise your tank 2m you might actually be getting 2.5m or 3m. It doesn't sound like a lot, but that extra height will make a big difference to flow rates. You might also consider simply hiding it with trees and bushes around it. A dense perennial screen of vegetation does a lot to avoid problems. I'm thinking of something like holly bushes, planted around the location where your tank platform will eventually go.

Hi there again, thanks for all of your effort understanding the situation and contributing to the project. With my first post i might appear new here but i come to the permies community since many years for inspiration, design ideas and solutions. I´m glad for all of your answers!

Dear Annie! Thanks for sharing your setup, im happy if it does good service to you. I think our elevation might be higher than yours, but the area we would like to cover is way bigger in relation to that elevation. As far as I understand a dripping hose will loose much pressure over the lenght, delivering less water at the end. Partly thats why I choose these adjustable emitters, to have a closed system where I can regulate and equalize water delivery. However, on the product page I linked earlier they say "working pressure 1-3 kg". Could somebody please try to explain me what does that mean? To my understanding, kilogramm is not a valid unit here (not because its metric ).

We understand that for now we must use a pump to fill the tank, but we would like to use it as less as possible. Thats why gravity feeding, and thats why drip irrigation. Isn`t it the most energy and water saving solution? I know, now its stinky and noisy as we run it from a generator, but we would also like to exchange this setup to a solar pump that could fill our tank slow, but steady. And you can make sure I will let you knowhat is our solution.

RedHawk! It´s a honor to read your comment here. I understand that might be the case.
"At 2m height you could find the lines don't empty all the water from the tank." - Is this an estimate in relation to the length of my main pipe laid down, or is a guess based on your intuition and experience on the subject?

Dear Wil! Thanks for your comment, yes I did! As far as I understand the principles of the Ram pump it gives a lower flow rate, where I need the opposite. I find it a good and interesting option for many scenarios, but here I agree with Michael unless there is something we dont see.

Michael Cox: Thanks for your comment, I like the idea of raising soil levels slightly. However, what I did not mention so far is that the land we are developing is in the flood area of the Rhine river, where an annual flooding is predictable on 2/3 of the land. Therefore, countless (german...) restrictions apply to what and how, especially about housing, or permanent structures. we are in the process of learning the legal grounds. Drilling a well not a legal activity. We are thinking of the flooding factor often, and we are going to experiment with what happens to a swale or mound, poles or small manmade structures this winter. However, we need to get the watering system done in the next weeks. And yes, we are about to hide whatever is going to take place on the land, by growing more edible hedges all around. Is there somebody who would like to engage deeper in designing them with me? If anybody is interested, I can give more details

Comments, ideas all welcome! Thanks you all!

RedHawk! It´s a honor to read your comment here. I understand that might be the case.
"At 2m height you could find the lines don't empty all the water from the tank." - Is this an estimate in relation to the length of my main pipe laid down, or is a guess based on your intuition and experience on the subject?

That is what happened to me on my first try at gravity irrigation lines, the main line was only 50 feet long, the emitters slowed the water enough that the tank stalled with about 8 inches of water left in it.
Once I raised the tank to 3m it emptied nicely, no stall out.

If your tank behaves similarly, you might try using a secondary tank fed by the large one, that way you could have more head space perhaps (by raising the small tank so the tops are at the same level).

Redhawk

Michael Cox wrote:

William Wallace wrote:That doesn't seem like much pressure at all.  I would be worried that over time the extremeties would not get adequate irrigation.  Have you looked into something called a Ram Pump?  It is this completely hydraulic pump made out of pvc and two brass checker valves.  Basically, it pushes water through the pump, and shoots it uphill.  This could allow you to pump water up to a higher tank, which then could feed the drip irrigation with a bit more gravity force on the water.  

Here is an article about building a hydraulic ram pump https://www.motherearthnews.com/diy/hydraulic-ram-pump-zmaz79mjzraw

The ram pump needs a pre-existing water flow. It won't be applicable in this situation (lifting water from a well) unless I am missing something?

You can't run a gravity fed drip irrigation from a well, so he's obviously pulling the water to a tank of some sort.  As Bryant pointed out, you need a 3m or 2m height to be effective.  What the ram pump is for, is to gain additional height, so that you have more pressure to get to extremities.  Let's say he pulls water from the well, and into a tank that's 2m high.  Then you use a ram pump to send the water from 2m up to like 30m, so that you have better pressure.  As for flow rate, you're not irrigating with the ram pump.  You'd be using the ram pump to continuously fill another vessel, and then you can irrigate at whatever speed you want from that vessel.   I don't think you'd be irrigating 24/7, whereas you can leave the ram pump running 24/7 so that you're continuously building up your available water pressure by sending your water to a higher reservoir.  The output on your highest reservoir can be much larger than the input flow from the rampump, because you'll only be using it a fraction of the time.  What I liked about the ram pump is that it's basically free.  I have plans to buy some IBC containers (you know those big squarish plastic containers with the metal cage), in order to use for irrigation on my land.  I will then have them set up in a series to get to higher and higher elevation.  As for the water flow of a ram pump, I am surprised at how much it pushes with no electricity.  They have different sized ones, and of course bigger pushes more water, but it also depends on how well they are built (quality check valves and such)

But if he is already pumping from a well to a tank at 2m high, then he already has a pump that can potentially pump much higher. I don't see what the ram pump is adding to the system?