PDA

View Full Version : irrigation using a cistern as supply


RyanD
11-28-2006, 02:15 PM
Hey guys. Haven't done much in the way of irrigation before but I just bought this house with a 2 acre lawn. I was thinking of irrigating it and using the cistern to supply the water (ithe water is caught from the gutters on the house). I am guessing the cistern is approximately 5000 gallons. Would this work? And what should I be looking at spending for parts / supplies (ballpark)? I am sure there is lots of info I didn't provide. Let me know. Thanks.

Dirty Water
11-28-2006, 02:19 PM
I've worked on a couple systems like this.

Ideally you would want a submersible pump inside the cistern. I've maintained a system that uses a standard centrifugal pump about 30 feet from the cistern and its been problematic.

5,000 gallons would take a while to deplete, but I wonder how fast it would refill in the summer?

Hank Reardon
11-28-2006, 02:49 PM
Check local codes. If it is hooked up to the house, you may (should) be required to have a backflow device installed. For instance, besides a double check valve assembly, our local code will not allow tapping into an existing underground cistern being used for potable. We have to install a new one, above ground.

Two acres is a lot of property to irrigate. Like DW brought up, the recharge could be an issue.

RyanD
11-28-2006, 03:30 PM
Ideally you would want a submersible pump inside the cistern. I've maintained a system that uses a standard centrifugal pump about 30 feet from the cistern and its been problematic.

That is what I was thinking too (submersible).


Check local codes. If it is hooked up to the house, you may (should) be required to have a backflow device installed. For instance, besides a double check valve assembly, our local code will not allow tapping into an existing underground cistern being used for potable. We have to install a new one, above ground.

It is not hooked up to the plumbing inside any longer.


Two acres is a lot of property to irrigate. Like DW brought up, the recharge could be an issue.

I'm not really looking to irrigate it as much as most people would. Just supplement when precipitation is lower. Replenishing the supply could be a problem, depending on how long we go between rains.

jerryrwm
11-28-2006, 03:39 PM
You can also use a centrifugal pump at the cistern if it is an elevated cistern or an above ground unit. It will have a flooded suction so any pressure you make with the pump is not lost on suction lift. As close to the cistern as possible to locate the pump.

Hank is spot on if the cistern is used for domestic water. Check the codes.

Jon is correct. 5000 gals will last a while. It takes 27154 gals to put an inch of water on an acre so your water requirements for two acres will be somewhere around 54000 gals for 1" of water. The cistern will have to refill about 10 times to get you all the water you need. If it is refilling due to rain that often chances are you won't need an irrigation system anyway.

You might consider using the cistern and pump set up to water a garden or flower beds etc. Use it for a smaller requirement system.

paolaken
11-28-2006, 06:46 PM
you know how the summers have been around these parts the last few years. very dry. just had 1" of rain last night, the most we've had in months and months.

RyanD
11-28-2006, 10:12 PM
It takes 27154 gals to put an inch of water on an acre

Holy Crap;) I think I will just water the garden:o

So... do people with 2 acres ever irrigate? I would have a water bill in the 1,000's! (By the way, I checked the math. You are right on. I never would have thought it was that much).

Hank Reardon
11-28-2006, 10:22 PM
Holy Crap;) I think I will just water the garden:o

So... do people with 2 acres ever irrigate? I would have a water bill in the 1,000's! (By the way, I checked the math. You are right on. I never would have thought it was that much).

My largest residential client irrigates 5 acres (over two are turf).

PurpHaze
11-29-2006, 08:28 AM
Holy Crap;) I think I will just water the garden:o

So... do people with 2 acres ever irrigate? I would have a water bill in the 1,000's! (By the way, I checked the math. You are right on. I never would have thought it was that much).

And to think that unless your cistern is regularly recharged and/or you have a lot of rain during the growing season you'll pull all of it in a fairly short time.:)

Ira
11-29-2006, 02:19 PM
I just had my part of my three acre yard partially sodded with 2400 sqyds of Palisades Zoysia (a little less than 1/2 acre of the yard). The area that was sodded is covered by an irrigation system with water provided by a submersible well. Each zone puts out about 28 gallons per minute at about 50 psi. I calculated that if I were to try to put down 1" of water per week on the sod, I would have to run the irrigation system for a total of eight hours per week, assuming relatively equal precipitation from each zone. Good thing we usually get a lot of rain.

Ira

justgeorge
11-29-2006, 04:38 PM
I did a new construction install this year on only about a 3/4 acre lot. He chose to put down sod right in early/middle August during a heat wave (in the 90s) and no rain for 3 weeks. I had the system running about 18 hours per day to save the sod, which was about 10,000 gallons PER DAY. Ouch on the water bill. But it was a 1.2 million dollar house on the market and the builder wanted instant green.

BTW, new sod and that kind of heat will show any areas getting missed REAL quick!

George

Pro-Scapes
11-29-2006, 10:35 PM
Holy Crap;) I think I will just water the garden:o

So... do people with 2 acres ever irrigate? I would have a water bill in the 1,000's! (By the way, I checked the math. You are right on. I never would have thought it was that much).


We have a client who waters 3 acres of turf. Cheapest way was to drill a well for them. 5k gallons wont do much against 2 acres but it would be alot better than nothing in a dry dry spell thats for sure