Moving rain water to storage tank.

[JJJessee]

I'm looking to fill a 3000 gallon tank with rainwater captured from downspouts on half of a 15,000 sf building.
The water is for crop irrigation. We typically receive 2-3+ inches of rainfall per month and my usage between average rainfalls would likely not be more than 1500 gal. so available volume is plentiful and timely.
I want to put the tank on top of a hill above my growing areas and use gravity to pressurize drip irrigation.
At the bottom of the hill, I'll use about a 150 gallon collection tank to feed the pump.
My question is, what type of economical pump should I buy to move this water up a 1/2" poly-pipe with 150' of head-lift -a typical electric well pump or would some other type be more appropriate? Any brand recommendations and sources would be helpful too.

Thanks for any advice,
JJ

 

[bimr]

A Diaphragm High Pressure low flow Pump should work. See the link:

http://www.sunshineworks.com/shurflo-8002-pumps.htm

 

[cvg]

depending on the precipitation rates during your frequent rainfalls, you may need higher flow and larger pipe if you intend to capture a substantial percentate of the 2 - 3 inches of rainfall each month

you are looking at 14,000 gallons of rainfall per month, captured in just a 150 gallon tank. At 2 gallons per minute, you can only capture 120 gallons of water in a 1-hour rainfall. The rest of the water will be lost. You either need a much larger receiving tank or a pond or a relatively high capacity pump, otherwise you will be unable to capture all the water

Until you can come up with a desired flow rate, you can't select the pump

 

[Artisi]

Is the tank on top of the hill (lets call it the day-tank), 150ft vertically different from the 3000 gal. collection tank feed from the roof and what is the length of the pipe-run between tanks?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[urgross]

You might have better luck going to the Civil/Environmental board. What you are intending is a typical Best Management Practice for Low Impact Design. Once you have your flow rate set, sizing the pump and sump should be straightforward.

At location I'm at we use the 95 percentile rain event, taken from NOAA data; turns out to be fairly close to the 2-year storm. More typical numbers may be readily available for the 90% rain event or 2-year storm due to NPDES permitting and EISA 438 requirements. A site or civil engineer could probably give better guidance.

 

[Artisi]

Well it seems that sizing the pump for the OP is not all that straight forward, hence his post in the pump forum.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[psv1990]

Use the big tank at the bottom of the hill to capture the rain water and the small tank on the top of the hill to feed your irrigation.

 

[cvg]

install a 5,000 gallon septic tank. this will allow solids to fall out and clear water to be pumped. install a small submersible pump with a filter and pump to the field. Not sure you need a second tank or gravity feed at all.