low yield well with storage tank

[rickd]

Hello everyone.  I'm setting up an irrigation system for a 0.5-acre lot with conventional landscaping (lawn, etc.) as well as a large vegetable garden and about 50 grape vines.  The lot has an irrigation well that produces only 5 gpm and I want to add a 1500-3000 gal cistern with a booster pump for extra storage.  I plan to run the submersible well pump at night to fill the cistern and a booster pump during the day to irrigate.  The cistern will be located about 100' away from the well and 4-6' higher in elevation.  The booster pump will be located at the well.  The system will only be used for 6 months/year, during the dry season in California.

I'm putting the trenches in now but won't be installing the cistern until next winter.  I'd appreciate any advice on the design.  For instance, what type of wire should I put in the trench now for float valves and other controls at the cistern?  Is 18 or 22 gauge sprinkler control type wire adequate? How would I calculate the smallest size pressure tank for use with the booster pump? The pumps will be running off a 240V circuit that I'm bringing from the house to the well, a 50' run.

Thanks.

[Cary Austin]

No matter how large a cistern you put in, you only have as much water as the well will produce.  5 GPM is not bad.  That is actually 7,200 gallons per day.  You can store 3,000 gallons in a cistern so you can use it all in 100 minutes at 30 GPM.  Or you can use 5 GPM for 10 hours, and do the same amount of irrigation.

Either way a Cycle Stop Valve will help you out.  The CSV will deliver exactly 5 GPM from the well at a constant pressure so you can water directly from the well.

Or you can use a CSV on the booster pump, so it will vary the flow to match varied irrigation zones, so you can be through in a couple of hours.