Compared to surface irrigation which is 60% effecient and sprinklers at 75% effeciency, drip irrigation boasts a 90% effeciency rating. If that doesn’t get you excited consider that drip irrigation is also the slowest method to apply irrigation and in heavy clay soils like we have around here that means the deepest penetration of moisture into the soil, not to be wasted to evaporation into the atmosphere. Setting up a drip irrigation system in Terlingua is 100% the best way to water!
Drip irrigation systems can seem complex to the uninitiated but they really are not if you know a few design details ahead of time but let’s get one BIG issue out of the way first:
We humans have lived our whole lives training our subconsious to derive satisfaction from watching droplets of water fly through the air and onto plant’s leaves, the soil, the mulch, and sometimes the sidewalk. Ah, the smell of rain or the sprinkle from a hose is so lovely and cooling that the plant must love it too! But the truth is the plant can’t smell, it only wants to drink, and all that water flying through the air is for human enjoyment only. When you drip irrigate, you cannot SEE the water. Your subconscious will fight you and tell you that it is not working, that your plants are not getting the water they need!!! You have to fight your subconscious back and watch the behaviour of your plants to know if your watering schedule is correct. This is hands down, the hardest part of drip irrigation, trusting the process.
Now onto the important design considerations to start with:
- Water source must be clean, first time use water, not greywater. (Check out Working with Greywater Sources for more info)
- Drip Irrigation requires backflow prevention. If you click on that link I promise you will learn everything needed to know about backflow prevention. You can skip learning and just read on about what to buy, but you must promise me that you will use backflow prevention.
- Pressurized water is the easiest to implement although gravity fed systems will work too with some differing considerations. The two sections below address differences in pressurized vs. gravity fed systems.
- Thirsty desert critters will try and sometimes succeed to get to the water in your lines so it is important to protect and occasionally check your lines and it’s also nice to put out a shallow drinking dish for the critters too.
Basics of an irrigation system:
A hard piped irrigation system that uses a hardwired multi-zone controller, 24v solenoid valves, underground piping, laterals, risers, and heads is a yard disturbing and expensive system to install and is most often used for lawn sprinklers. They can also run drip irrigation but the cost is complete overkill for the benefits, plus no one should have a lawn out here anyway. These systems are ultimately wasteful of resources and it really doesn’t fit into context in Terlingua. There are only a few of these systems in existence in South County, most of them in Lajitas (makes since right?)
Most households will be interested in the cheaper and easier to install irrigation system that starts with an outdoor hose bibb. All of the remaining information assumes we are building the system off of an outdoor hose bibb. No hose bibbs? Contact your local plumber Josh Keenan and he will hook some up for you.
Building the system: Pressurized Systems
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Let’s jump right in with parts buying at DripDepot.com I buy my main supplies from them, they are consistant, quick to ship and send you candy. (plus they sell kits) In addition, there are informative how-to videos and tutorials on their site if you need to learn more.
If you would rather shop in an actual store, Rain Bird parts can be purchased at True Value Garden Center in Alpine. Most pieces are essentially the same but I don’t like the Rain Bird connectors as much because they can be almost impossible to reuse. I have certainly stabbed myself in the hand trying to cut a tube piece out of a $1 connector, not worth it! However, an actual store is especially convenient when you need to grab a few pieces quickly.
For the main connection to the hose bibb you will need these parts in order, clicking the links will take you to the exact part.
- Vacuum breaker
- Hose splitter (optional) if you want to also have a hose on this bibb
- Timer (optional) $ manual timer, $$ automatic timer, (many different options in this category), $$$ smart wi-fi connected timer
- Pressure regulator only recommended if you are on Study Butte or Lajitas water
- Tubing adapter, straight or elbow
- Mainline tubing
- Flush valve
Any discussion needed on these parts? Why of course, yes! let’s start with timers.
The cheapest solution of all, the manual timer, based on the mechanics of the dial and spring, they run about $10. I’m happy to report that they work as intended until the plastic eventually breaks down in the sun but at least failure should not lead to catastrophic water or plant losses. You do have to turn the dial to make it come on but the good news is that you don’t have to remember to turn it off, it ticks along until the spring turns back to 0 and the door closes and the water shuts off. There is still room for error from freezing or general breakdown but if you have to walk over and turn the thing on, then you are likely to walk around and admire your plants and then more likely to check your emitters too which needs to happen occasionally and then you are just as likely to notice a total breakdown in your $10 timer as well. So this is my most recommended timer, the cheap yet reliable one. This recommendation only applies if you are living at your house full time. If you leave for the summer, you need to pick a different option.
The next level of timers are automatic timers that run from $20 to $70 depending on options. There are a plethora of different brands but most are based on the same type of actuator. Some have a solar panel for recharging the battery, which I like a lot. Most have an LCD display for setting your watering time and frequency and are pretty easy to set up and use. I have used many, many different types because every one of them has broken or malfunctioned and then I switch to a new brand to see if maybe this one will last longer. So far, I cannot recommend one over the other as I have never had one last for more than
2 edit: 3 years. In the worst case scenario, the electronic malfunction kept resetting the time so that the water never turned off! causing flooding across the road and a high water bill for the owner. (ok, I’ll say it, It was an ORBIT timer that did this!) What I can recommend is that if you use one of these “automatic” timers, consistantly check to make sure it is coming on and going off as it is supposed to. Wow, not so automatic then but it will do when you need to leave town for a vacation.
Powered by the sun, this wi-fi connected timer is insanely feature rich. I have been using these for my clients that have second homes (ie. they do not manage the lanscape, I do.) I now have 8 of them running and it is so far so good. I’m talking about the Netro Pixie, btw. Everything is controlled through the free app which means I can change watering schedules without setting foot on the property. Plus the settings are highly configurable, much more so than the not so smart timers. The watering schedules change based on the local weather so in many ways they are just set it and forget it timers, check in on the app occasionally and make sure everything is rolling well.
Speaking of checking in, the biggest problem I have had with these timers is a that low wi-fi signal knocks them offline and then they do not water if they cannot connect. Bummer, just be sure you can really get a strong wi-fi signal at your hose bibb before investing in one of these.
Moving along, WHY A pressure regulator only for Study Butte or Lajitas water? Because realistically, that water system is the only one capable of creating enough pressure to damage your water system and blow your fittings apart. If you are on a well or off grid, you are likely safe from this problem, but you can add a pressure regulator if it makes you feel better.
You should definitely use a screen filter before the water goes into the tube, and a flush valve at the end of the tube, even if you have a filter on your water already, this is extra protection for the emitters. There is no advantage in skipping these parts and letting the emitters clog up with gunk. The screen filter is cleanable and there is nothing more to buy later so just add it.
Tubes and emitters
I am going to tell you what I use and don’t use with a little bit of the why.
I use a 3/4 inch mainline and branch off to 1/2 inch drip line with 0.5 gph emitters built in at 24 inch spacing. This is a one size fits all solution that works in almost every situation. 3/4 line has a maximum run of 400 feet and 1/2 line has a maximum run of 200 feet so theoretically I can cover an area around 80,000 square feet off of one hose bibb with this combination. (number of emitters contingent of course) You could use only 1/2 inch but the reasons that I don’t are: A) 3/4 matches the size of the hose bibb connections and allows for a higher flow rate throughout the whole system. B) I use a barb takeoff connector to connect the 1/2 to the 3/4. The barb takeoff uses a large punch and easily snaps right into the larger mainline. I like this system for speed and ease of putting it together.
I rarely use any smaller line like 1/4 inch because it is much harder to work with all the tiny line and the tiny connetions AND the bunnies eat it.
24 inch spacing for emitters?? Yes, counterintuitive to what may be rational thinking that this is the desert and the spacing should be closer together, since we have such high clay soils, the water travels much further laterally than in sandy soil. 24 inch is just a general spacing though. Loose soil needs closer spaced emitters so if you have a raised garden bed with a lovely amended loam you might want to space emitters closer together. You can get the same pre-built drip line in other configurations such as 1.0 gph at 12 inch spacing.
Having the emitters built into the line is just another speed, versatility and convenience preference. I buy pressure compensating drip line so it can be used on flat or hilly ground and can also be buried. The individual emitters that you punch in the line should never be buried and hence are not as protected from the world.
Don’t forget the various elbows, tees, couplings and maybe more that you will need to put the pipes together. Perma-loc fittings are my go to for ease of use and reuse, but you can get cheaper ones. You can do what ever you like!
A lot of these choices come down to personal preference, experiment and find what works for you. Drip irrigation systems save so much water and time that the effort and money spent is completely worth it so just do it!
I buy my drip irrigation supplies from dripdepot.com I have been doing business with them since 2019.
Building the system: Gravity Feed Systems
Now most of the basics are the same but we have to take our shopping list and modify it slightly, clicking the links will take you to the exact part.
- Vacuum Breaker
- Hose splitter (optional) if you want to also have a hose on this bibb
- Timer (optional)
$ manual timer, $$ automatic timer, $$$ smart wi-fi connected timer, $$ zero pressure timer Pressure regulator Filter
- Tubing adapter, straight
- Mainline tubing
- Flush valve
Let us begin again with the discussion of timers. Err… the one timer that you can use.
You have very limited options and the reason for this is all in the type of valve. Most timers require at least 20 psi for the valve to operate properly and most peole have pressurized water so it is no big deal. It took a company to make a completely different valve mechanism to make gravity flow timers work. The Irritec Zero Pressure Timer uses a motorized ball valve that physically opens a hole to let water through. It works with zero pressure! Well it wouldn’t actually work with zero pressure but close enough.
After the timer, obviously don’t need the pressure regulator and we can eliminate the filter to preserve flow rate. But I already said the filter is needed to keep the emitters from clogging up! Don’t worry, we aren’t using the same emitters for gravity feed. Eliminate that elbow too, keep all the runs as straight and as short as possible to preserve flow rate.
Tubes and Emitters
3/4 mainline is the way to go here, the more water in the line the more pressure behind it. This is one of the few instances where I will use small tube. The best emitter for this system is an adjustable emitter which can help restrict the flow down to a drip. If it clogs you can unscrew the top and clear the line. You will need a small punch tool for attaching a barb and 1/4 inch tubing to the mainline. All other emitters create too much resistance and you won’t get any water out.
It will take some adjustments to get all of this right as gravity flow is sensitive to even tiny elevation changes. Just keep working on the details and adjusting to get exactly what you want. Don’t forget the goof plugs if you need to change a line’s location.
Drip Irrigation is a very effecient way of watering and can save a lot of water over the long run so it is worth the investment. There are several different ways to set up the systems so it is wise to draw out a diagram and make a parts list before you buy. If you just love to read and want to read some more about gravity feed irrigation click the following link and open up a wormhole into an even more extensive discussion of all things irrigation, starting with gravity feed systems. ***Irrigation Tutorials*** If you need additional help with outdoor plumbing call our local plumber Josh Keenan and he can help you. If you have any questions or want to talk more with Jenny about drip irrigation you can schedule a call.
Post featured image of drip irrigation and carrots by Matthew.kowal is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License