Pumping River Water

One of the experiments we are working on at Rally Creek is trying to cool our tiny shed cabins via a passive cooling system. One of the reasons we invested in this property is the fact that there is a spring-fed brook that runs through the edge of the property. The idea for cooling is that we may be able to pump up the cool water from the river through metal tubing in the ceiling and letting natural convection do the work.

The idea is simple, pump the water up the 50′ rise over 500′ distance through the pipes in the rafters, then let it run out freely from the back side. We will guide the water through a simple culvert where we will direct the water back down the hill to the brook close to where the drew the water out. The impact on the brook level and temp should be minimal; Likely far less ecological impact than running a room air conditioner powered by who-knows-what on the other end of the 30 amp electrical line.

Pump Research

To lift water to a 50′ vertical the general recommendation is for a 1 horsepower pump. Given the run of 500′, which adds friction, and our rise measurement may not be precise, we will look at 1HP and 2HP pumps. We also need a pump rated for “dirty water”; Though the brook runs cold and clean, technically it is not filtered water and is thus “dirty”. It will also pick up plenty of sediment and debris during the once/month deluge of rain that comes along all spring and summer in this area.

The lift of 50′ is only on part of the equation, what is needed is “Total Dynamic Head” (TDH) which accounts for loss due to friction. This happens from the size of the outflow pipe, the type of material it is made of, and the length that it runs. This chart will help: https://www.engineeringtoolbox.com/pressure-loss-plastic-pipes-d_404.html

At 20GPM with a 1 1/4″ standard HDPE pipe, you ned to add what would be the equivalent of 5.6′ of lift to account for friction. At 500′ and about 6′ per 100′ we have 30′ of extra “lift” required, so we need to make sure we can clear 80′ … let’s make it 100′ to get water to flow out to the cabin.

Pump-to-ground: 10′ (closer to 6′)
Transport distance: 500′
Ground-to-outlet: 50′

TDH: 10 + (500/10) + 50 = 10 + 50 + 50 = 110′ ~ 33.5m

A/C Powered Pump Candidates

The first one that came up on search is this listing from Amazon:

XtremepowerUS CLean/Dirty Water Submersible Pump : not a candidate

A generic “sump pump”, which means it only operates when “the hole fills with water above 4.7 inches”, which our brook should be at nearly constantly during the low run during the winter.

Listed as 1.5HP
$70 at Amazon (July 2023)
3700 GPH (may be more than the flow of the brook)
Corded electric at 115 V.
Float switch, requires 4.7″ or water – turns on/off automatically in low water.
Passes up to 1/2″ solids (we will put it in a filter box to keep anything near that size out of the pump.

Max Lift rating: 16′ — well that’s not going to work!

Next up…

Vevor 1.5-HP Submersible Well Pump

$210 at Lowes (July 2023)
Power: 1.5HP / 1.1KW ; 115V
Flow Rate: 37GPM
Max Head: 276′ (that is more than enough)
Diameter: 4-inches, discharge via 1 1/4″ NPT
33′ Electric Cord
IP68 waterproof rating
Stainless steel frame.
Check valve to prevent back flow.
Life: 8-10 years

Vevor 0.5-HP Submersible Well Pump

$105 at Lowes (July 2023)
Power: 0.5 HP / 0.37KW ; 100V
Flow Rate: 25.5 GPM
Max Head: 164′ (that is more than enough)
Diameter: 4-inches, discharge via 1 1/4″ NPT

Ram Pumps

1 1/4″ Hyrdaulic Ram Pump by Land To House

Requires 8GPM to operate and 2′ lift.

1:7 compression ratio, 2′ drop = 14′ lift.

That is not going to work. We have a maximum drop of 6′ of water across the entire property (1,000ft) which would yield a maximum lift of 42′ after a lot of work.

Solar Pumps

☀️ ECO-Worth 3.2GPM Solar Well Pump Kit

$450 from Amazon (July 2023)
Max Head: 230′
Max GPM: 3.2

1 x 100W monoc panel , max output 5.5A up to 18v
1 x 12V solar pump, max consumption 10A, outlet 1’2″ barbed with 10′ cable
1 x 20A solar controller
1 set 16′ solar cable

at TDH: 110′ (33.5m) output is approximately 140 GAL/h ~ 2.3 GPM — this is very doable for our application.

RPS Solar Well Pump Kit

$1800 direct from RPS (July 2023)
Max Head: 125′
GPM: 3.3 @ 75′

2 x 100W monocrystalline panels
brushless pump
pump controller
1″ hose barb and clamps
low water sensor w/ 100′ wire
tank shut off sensor w/ 100′ wire
solar panel cable connectors

Related Resources

Ultimate Guide to Pumping Water From A River, Lake, or Creek

Clemson : Water Withdrawal Regulation in SC (2022)

In SC , permit required to draw > 3MG in a month (25.5 GPM = 36,720 per day = 1.1MG each month). You can do hydroelectric generation without permits in SC as the water is not removed but passed through turbines.