How To Install A Large Scale Watering System Using 1/2" Flexible Pipe
For these instructions we are going to use a simple, actual example: This
system was installed in a 35' x 135' plot of unimproved earth. The altitude
of the rectangular plot remained stable along its 135' length. The 35' width
however had one side about 8 feet higher than the other, all the way from
one end to the other. There was one 3/4" hose spigot available, with good
70+ PSI. The property is in Marina, a small seaside community on the
Monterey Bay. The site is about one mile from the ocean, with sandy soil. We
had just planted 16 Monterey Pine saplings, which are native to the area,
and are being replanted in increasing numbers to replace the many that have
perished due to a beetle infestation.
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| Plot of Monterey Pines in Marina, California |
(1) Figure out how much 1/2" pipeline you will need: On this site there
were two rows of eight trees per row, one going along the high side of the
rectangular area, one going along the low side. Each row was about 100 feet
long from the first tree to the last. The rows of trees were about 20 feet
apart. The hose spigot was at a far end of the site, so all in all, about
300 feet of pipeline was required.
(2) Straighten out the pipeline from the roll: Getting the pipe unrolled
and straightened will make actually laying the pipe in place much easier. If
you try to unroll it onto where you want it to go you risk kinking it over
and over, as well as ending up with a few twists in the middle of the line
after you've finished getting it in place. Two people make this job easier,
one to unroll the pipe roll, the other to pull the other end of the pipe
further and further from the roll. The twists in the role (this is
important!) can be eliminated by the puller if they continuously untwist the
pipe as they pull it away from the roll.
(3) Place the first pipeline along the trees: Generally the first length of
pipeline should go from the hose spigot to the furthest tree. Try to get the
pipeline to pass as many trees as possible in between the spigot and the
furthest tree, but avoid curving around too much, since you can always fork
onto this main pipe secondary pipes that will cover your grove section by
section. At Marina the spigot was on the low side of the property at the far
end, so the first pipe went from the spigot along the trees at the low end,
and once at the furthest section the pipe was curved up hill to get a few of
the trees in the row at the top. This way the second pipe wouldn't have to
cross a path that ran through the upper mid-section.
(4) Connect your pipeline to the water source: It's a good idea to get
water into the line to flush out any dust or pebbles that might later block
an emitter. As you add lines it's good to turn on the water and flush out
each new line. To connect the pipe to the hose spigot, first screw onto the
spigot a 15 PSI Flow Restrictor. Onto the end of the Flow Restrictor, then
screw on a 3/4" Hose to 1/2" Pipe Connector. Make sure both of these
adaptors are on hand-tight and have new washers for a tight seal. Now you
can press the end of your 1/2" pipe into the concave opening of the
Connector. Be sure to push the pipe in at least 3/4 of an inch. Your
system is now powered up! Run some water through for a while to clean the
inside of the pipe.
(5) Add the rest of your 1/2" pipe to your main 1/2" pipeline to reach all
the trees in your grove: In the Marina grove, there only was the remaining
row of trees along half the upper length of the rectangular site, so the
main line was tapped about 10' from the spigot, and a 1/2" line was run up
the hillside and laid alongside the row all the way to the last one before
the pathway. To tap into the line, cut the line with a sharp knife (a
pocket knife or a steak knife will do) where you want the connector to go.
Then get a 1/2" "T" Connector and push the line you've just cut into the two
ends of the connector. Then simply push the new pipeline into the remaining
opening on the connector. Again be sure to push the pipe at least 3/4 of an
inch into the connector.
(6) Flush out the system and prepare to install the emitters: Here you
will need to make sure you get the right type of emitter, since you have a
choice between three standard flow rates: 2 GPH, 1 GPH and 1/2 GPH.
Generally trees that are in very dense soil such as clay should have a very
slow emitter, 1/2 gallon per hour in most cases, so that the water will be
coming out slow enough to seep into the soil by the tree. Large systems may
in total be able to release more water than your spigot can supply, which
will cause your system to lack sufficient pressure to deliver water to the
uphill or far ends of the system. Make sure to add up how many gallons per
hour your whole system will use, then divide by 60 to get the gallons per
minute requirement from your spigot. You can measure your supply's gallons
per minute output by filling and refilling a 4 gallon paint bucket (or
whatever) for a minute.
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Awl and Blunter
Punch |
(7) Install the emitters: Our soil in Marina was very porous sand, so to
be sure they would get enough water we installed two 1 gallon emitters per
tree. The best way to install an emitter is using a hole-punch. Hold the
1/2" pipe in one hand and poke the awl gently into the pipe, taking care to
penetrate the pipe but not going all the way through both sides of the pipe.
Wiggle the awl around in the pipe, pushing it (at an angle so as not to
damage the other side of the pipe) in far enough to enlarge the hole to
about 2 millimeters wide. Remove the awl and select an emitter. Take the
pointed side of the emitter and poke it swiftly and firmly into the hole you
made. If you do it right the emitter will snap right in. To be sure,
rotate the emitter a bit and try gently to pull it out. It shouldn't budge.
Installing emitters can be a real headache, particularly if you use the tool
that is sold for that purpose, instead of a sharp awl. One variant on the
above instructions that is effective is to use the awl to make the initial
hole in the pipe, then use the blunter punch to enlarge the hole before
putting in the emitter. That can be quite time-efficient.
(8) Flush out the system and cap the ends: Once all the emitters are in
place, you need to turn the water on full blast and get all the dirt out of
the pipes. On large systems this should be done after every new fork in the
system is added. Then cap the ends of the 1/2" pipes using the Hose End
Clamps, where you push the end of the pipe through one eye of the clamp,
then bend it over and push it back through the other eye. Be sure to cap
the ends at the lowest elevations first, then at the upper elevations.
(9) Run and test the system: Turn on the water and make sure that all the
emitters are running. With your 15 PSI flow restrictor, note that it may
not function properly if your entire system is not releasing at least 10
gallons per minute. Check to see that the emitters at the higher altitudes
and at the far extremities of your system still show acceptable flow rates.
Sometimes it's necessary to put extra emitters at the higher spots to make
up for lower pressure. Be sure you flush air pockets and sediment out of
your system at least once per month. Even people with purified water will
get sediment in their system, and sediment will clog your drippers,
especially at the lower elevations. Check every emitter on your system once
per month during the dry season, or more often if the trees are young or
there's a heat wave; make sure they are all getting adequate water to your
trees.
HAVE FUN!
