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Tasmania Australia

Hi, just a curious question on watering with T-Tape or any drip tape really.
I have got mine all layed out and set up,
I am running 22 lines and each one is around 30 feet long
I have just hooked up a water flow meter to it just to see what flow rate i am getting at 15 psi.
I am getting around 800 ml ( .21 gallons think that is .845 quart ) per 30 foot run per minute.
That works out to be around 26 ml per dripper ( 1 inch of water per dripper per minute )

I am trying work out if this all sounds right, as i have heard that you only really need 1 inch of water per week.

I am sure i am missing something obvious here as it doesn't sound right to me, as from this, i only need the T-Tape on for 1 minute a week.
Or do i measure the water amount my seeing how long it takes the water to soak down 1 inch?

Sorry for the basic question, just trying to get my head around understanding the T-Tape or drippers in general and how much water i need.
Any information would be appreciated.
Cheers.

11/25/2018 9:05:20 PM

Grittyville, WA

You need about a hundred cubic inches at each dripper if you are going to apply the the equivalent of a one inch of rain at that spacing so multiply by a hundred. For hot dry weather... easily probably over an inch per weak depends on your soil well cultivated clay-loam would hold moisture best perhaps.

11/25/2018 11:23:07 PM

Massachusetts

I am guessing you have about 1000 sq.ft. to irrigate based on your drip tape layout. One acre is 43560 sq.ft. Your patch is 0.023 acres (1000 divided by 43560). One inch of water over one acre is 27100 gallons of water. Your target then is 623 gallons per week (27100 times .023).


Drip tape flow rates are on the box (or available online). Common Aquatraxx rates are 0.34 gallons per minute (low) or 0.67 gallons per minute (high) per 100 linear feet of tape. You have 660 linear feet of tape so your system will deliver 2.25 gallons per minute (low flow tape) or 4.5 gallons per minute (high flow tape).

So 623 gallons per week is the target. In the above example you run the low flow tape 277 minutes per week or the high flow tape 138 minutes per week. Divide those numbers by the number of days you intend to water to get the length of time to run the system per day.

The above is an example. YMMV. The tape is usually rated at 8PSI and you are higher than that. Check the flow for your particular brand of tape.

11/26/2018 10:48:35 AM

Tasmania Australia

Thanks for the reply and information, appreciated.
I had a look and the T-Tape that i have is Rivulis, and the numbers are 515-12-450 the flow rate is 0.450 GMP

My soil is clay base, with mushroom compost mixed in, I am running a tad high at 15 psi, still looking for a smaller pressure regulator.

So going from those figures, i must be running the high flow rate T-Tape at .450 GMP

So just for example and say that i am running at 8 psi as labeled on the box, works out roughly to be 138.4 minutes per week or 20 minutes per day.

I realize this is only a rough guide, but am i on the right track so far?

11/26/2018 5:52:20 PM

Massachusetts

Your system is delivering 0.45 gallons per minute per 100 linear feet. So 660 linear feet delivers roughly 3 gallons per minute. The target is 623 gallons per week. So 207 minutes per week or 30 minutes per day.

11/26/2018 10:07:24 PM

Morgantown, WV

some GREAT PUMPKIN TALK RIGHT HERE!! Been struggling with irrigation rates myself, this will help a lot. Thanks for a great breakdown Tom!

11/28/2018 8:27:52 AM

Sonora, CA

I have had the same questions—this has truly helped me. One other problem I have is the drip tape clogging up with calcium. Is there a better system besides drip tape?

12/28/2018 11:54:37 PM

Morgantown, WV

I'm 20 credits shy of my Bachelor's degree with a 3.85 GPA... my only math course is my only C on my transcript... so please bear with me and check the math here...

So I have tape with .33gph emitters @ 12" spacing over 2400 linear feet of drip tape for roughly 2600 sqft. That to me means 2400 emitters over the patch at .33 gallons per hour each.

2,600 divided by 43,560 is .0596 acres. 0.060 x 27,100 is 1626 gallons per week. 2400' x .33 gph is 792 gph, meaning I need approx. 2.05 hours ( 123 minutes) run time per week for 1" rainfall?

I feel I'm mis-reading Tom's post or my math is incorrect... my emitters are rated each rather than over 100 feet, but it may just end up being a decimal place?

Thanks to anyone who can verify :)

1/7/2019 9:46:09 PM

Corryton, TN

Your math is correct
or
we're both wrong.

1/8/2019 6:03:06 AM

Morgantown, WV

ok great, thank you.

Carla, a lot of people use a combination of drip tape for clean water irrigation, and then overhead whizzer type sprinklers with a transfer pump from fert tank for the actual feeding. This lowers the risk of stuff clogging your emitters. If your normal water is clogging them, you may have enough dissolved solids in your water to warrant filtering prior to use. I've used my tape for 3 years now with no clogs, so maybe look into what is in your water if it is an issue?

1/8/2019 7:21:00 AM