solar pump - sourced from river: advice for 20m head

Hi everyone,

This is my first post in the forum! I have a piece of land that sits next to a small river in Portugal. My idea is to put a tank in the top of the property and I am thinking about using a solar pump to get the water there. I have no experience in any of these so would appreciate a lot of knowledge from permies out there!

Some considerations:
- Water tank (thinking about 1000 L)
- Water head: 20m
- Distance from pump to tank: 60m (measured in google, so I assume this is the ground distance and not horizontal distance)
- Water usage: shower (100L/ day max), irrigation (200 L/day max)
- Will use gravity drip irrigation - but that's for another post
- The project is not really a farm, this will be more of a campsite for friends with some kind of low maintenance food forest that will only truly need water until all plants established
- Plenty of sun, facing south, latitude 41º
- "Small river" means something like 50cm depth in summer, way more in the winter (2m?)
- A good location for the solar panels would be some 25m away from the river, thus avoiding shading from river bank trees
- My idea is to put the solar panel on top of a shack where i will store tools and would store the solar panel when away (risk of theft)
- The idea is to allow use the solar panels for some kind of powerbank for minor stuff like charging cellphone when not pumping
- Filling the tank quickly is not a must (thus 1000L tank...)


I have been researching some solar kits, and have asked for a quotation here: 1800 EURO for a 650W 24V panel, pump (portuguese brand Joval EOS BS3 1.5/16 submersible) with a flow of 1.3m^3/h for 20m head and a controller. That's too expensive for me, i would just rather ask for someone rent a gasoline pump once every two weeks. Also the solution allows for a head of 50m so perhaps oversized. So I am trying to get the cheapest solution out there.

My questions:
- What considerations am I missing?
- Submersible or surface pump? I've done quite a bit of research and found contradictory answers;
- Are brands important in this? If yes: for the pump, the controller, the panels?
- Solar kit or design my own system?
- I have no clue of how to fix the pump in the convenient place...
- Alibaba prices look amazing. Am I missing something?

Thanks a bunch!
fernando

I would recommend using a Hydraulic ram pump.
It is powered by water flow.
Here is one description
pumping water
Page 62 details what I am talking about.
You can make your own.

Build your own hydraulic water pump

Hi John,

Thanks for the link. I am familiar with hydraulic ram pumps. I could do a little extra research to measure the head, but i think it's not enough for implementing a ram pump

Fernando, remember a Hydraulic ram will pump anywhere. All its needs is a long pipe laid upstream
from the Ram unit.
I guess if you only have access to a short length of stream it maybe an issue. But neighbours may help you.

Here is a calculator
Hydraulic Ram calculator

Hi again John,

I though that with such a small head it would be impossible, but if i can run a long pipe and make a 1m fall, apparently i would fetch something like 1000 L in a day! I will try to do this and if it fails I will go to the solar pump. Many thanks for your input, again

A manufactuer Blake rams pricing etc

They do cost a lot and parts are available should you need any.
I will look for alternatives

The 1M fall may require a long piece of pipe, check the diameter required to get flow.
It may be expensive if you need to go 3-400M.
But its still better than anything else because the Ram is almost maintence free.

Hi again John,

I actually found there is a small spring 200m away from my site.
First calculations are promising! Using your source https://life4water2.webs.com/documents/L4W%20Guide%20to%20Designing%20and%20Sizing%20Hydraulic%20Ram%20Pump%20System.pdf

Q 60 quantity supplied at source (L/min)
F 1 fall or height of the source above the ram (m)
E 0.33 efficiency (66% commercial, 33% home)
L 30 lift height above the ram (m)

D_minute 0.66 delivery of water (L/min)
D_day 950.4 delivery of water per 24 hours (L)


My questions now are now related to the quantity supplied at source. I should size my pump and pipes according to the summer, because in winter water is not an issue around here. So I should start making a small pump with small diameter and see how it goes. If needed in the summer, i can build a bigger pump.
My idea is to run the delivery pipe first down to the river and then up to my tank. I assume this is not an issue.


Again, thank you for opening my eyes to the ram pump! Hope I'll be able to make it. I will keep you updated. Perhaps before the summer this won't be doable doing to the pandemic.

Fernando

Where are you doing this work out of interest?
Always plan for the lowest water flow.

My idea is to run the delivery pipe first down to the river and then up to my tank.

This is confusing.
Will you install the delivery pipe from the pump to the tank area and then up to the tank?

The drive pipe lies in or near to the water supply.
200M is a reasonable distance, put the biggest pipe in that's affordable for the scheme.
Why not
- build pump
- install drive and delivery pipe
- finish project?

John,

This is in Portugal.
OK I will estimate the water flow in the summer. I think it is quite difficult to estimate. But a fun project anyway and will size a second pump later if the first is not appropriate.

My explanation was poor. Now with an attached pic I hope it is easier:
- First in the original post I was just thinking about pumping from the river to the storage using a solar DC pump
- Now the idea is to take advantage from the spring which is not on the border of my parcel
- The fact that the ram pump is far from the storage will make a long delivery pipe. There are three options: (A) run it up from the pump via the road. Bad idea. (B) The neighbour land is a no-go. (C) To go down to the river and then up to my parcel. Do you see any problem with this third choice?

Using the photo where are the following areas?
- boundary with neighbour
- where is your parcel compared with the 'storage' and ' river' pins?
- Does your parcel have direct access to the river?

Also is that square shape between the river and the road your shack?
How would you install an underground pipe downstream of the spring?

To calculate water flow in the river, draw a profile of the river and determine its shape and rough area in sq M.[A]
The throw a leave in the stream and measure the time taken to flow say, 20M.
if its 6 seconds [ T] we calculate the flow in Litres / minute [V] as follows;
T divided into 1 minute [60 seconds] is equal to 10.
10 times 20 Metres is the distance travelled for 1 minute, 200M.
Speed of the water is 200 x 60 minutes = 12 Km per hour.
Area of stream profile [A] is 2 sqM.

12KPH is probally too fast and would cause erosion, it needs to be generally less than 10 KPh to avoid erosion.

Times 200M gives us a volume of 400 cubic metres in 1 minute
River flow is  400,000 L per minute at 12KPH.

Hi again John,

Neighbour parcel is in the new pic inside the red line and the square shape is a storage space of the neighbour. My parcel is inside the yellow line, which has access to the river.
I don't need to install underground pipe, the pin I put there with "underground" is an already existing underground pipe (new pic, green), which links the pond (new pic, pink) to the river.

Again: is it a problem if the delivery pipe from the ram goes down to the river instead of going up again? Probably this decreases efficiency because if it goes down 3m in vertical, this counts as increased head, right?

I understood your calculations for measuring the flow (area x velocity)! Can barely wait to mount my first ram pump B)

Cheers,
Fernando

How about something like this "12V Solar Submersible DC Water Deep Well Pump + 100W PV Panel + 20A Controller"?

I'll keep that in mind, Sebastian. Thanks!