“Without
water nothing lives”. Not to profound a statement; in fact, kind of a no
brainer.
“Too much
water and nothing lives” Well, yea….
OK….. I can see that too, only lily pads live in a pond.
Yet these two swinging ends of the
Hydro-pendulum account for most of the deaths to our botanical acquaintances.
We have Hostas rotting away because
the Begonias in front of them need more waterings than once a month. Yews are
getting pale and yellow because watering the grass patch to their right is
putting them directly in the line of fire. But then, giving your yucca the
environment it needs causes its neighboring Siberian Iris to wither away in the
hot sun.
Automatic sprinkling is wonderful
convenience, but, if it is done cheaply or with no thought to what is planted
within its circles of influence, you will end up with plants that only like the
settings your irrigation system is set for.
Sprinkling is not just about
spraying water all over the place. Yes, coverage is important, but the “how’s,
what’s, and when’s” of this coverage are the important parts of a good
irrigation system.
To begin this odyssey into man-made
rain making, certain preliminary things need to be found out and established
before one piece of pipe or one hose clamp is purchased. As I researched for
this article I received a wealth of information from Rick the plumbing and
sprinkling guru at Gemmen’s; you too would be wise to pick this man’s brain
before you start this project.
For those who have city water you will need to know the size of the
water meter; newer construction is quite often 3/4”; older homes are typically
5/8”.
The size of the main line that runs
throughout your house is number two; which is typically ¾” or 1”.
And lastly, the water pressure you
have. This can vary depending on how close you are to the water tower, and your
elevation. Gemmen’s, and I’m sure, other good hardware stores, rent water
pressure measuring devises, and are simple to use. Knowing this will give you a
gallons-per-minute total.
Armed with these three bits of
information, let’s say the water meter is ¾”; the main line running throughout
the house is 1” and your water pressure is 50 psi. Rick’s handy little Gallons
per Minute Flow chart says you are generating 15 gallons per minute. By knowing
this you can determine how many and what kind of heads you can put on a zone.
Zone? What is a zone? If your whole
yard could be sprinkled by one sprinkler you wouldn’t need underground
irrigation, but since it takes multiple sprinkling heads to adequately water
your lawn and landscaping you will need to divide this number of heads into
zones so as to not run out of water volume and water pressure. A typical system
is around 5 to 8 zones.
People with wells will get their “PSI” number by watching their
line mounted psi gauge. This gauge will show them their maximum (pump stops)
and minimum (pump starts up again) water pressure.
Your minimum and maximum numbers
are not the numbers you will be using; you want to know what pressure your well
pump will hold at, the needle going neither up or down when a certain number of
faucets are running.
This psi “holding pressure” number
is found out by first turning on all outdoor faucets, then, one by one, turning
on some of the indoor faucets. Let’s say with just the outside faucets are on,
your well pump still shuts off because it comes up to maximum pressure. It
still comes up to max pressure and shuts off with the two bathtubs running. But
when you turn on the kitchen sink your gauge stays right at, let’s say, 40 psi;
it doesn’t go up or down. But when you turn on one more sink faucet the 40 psi
gradually drops, the pump can’t keep up. 40 psi, in this scenario, is your
constant pressure number.
I must add here that both city and
well folk’s psi gets chewed into a bit because of the irrigation piping you
will be using. The water friction, or restriction, within any size water supply
pipe is a 9th grade physics class fact. But as you will see, as the pipe gets
larger, the friction gets less; which in turn means a smaller bite into the
gallons per minute equation you will be figuring out below.
These supply pipe friction loss
findings are on a sheet that Rick supplies at Gemmen’s, but to show you an
example of this, here is a typical scenario off that sheet for a 14 gpm system.
For every 100 feet of ¾” pipe used,
you lose 15.46 psi, so you don’t
want to pipe your whole system with this; you do use this pipe when you
split off to your heads a short distance away from your bigger main line. For
every 100 of 1” pipe you lose 5.08
psi; quite a drop from ¾”. If you use 1 ¼” it drops to a 1.34 psi loss, now we getting into main trunk type piping. At 1 ½” you will loose .63 psi for every 100 feet; and at 2”, .19 psi. So keep in mind the length your pipes and their diameter
sizes; this must be subtracted from your total psi house water number before
you plug that number into Rick’s Gallons per Minute Flow chart.
In order for well people to get
their “Gallons per Minute” they must continue to keep the above mentioned
faucets running and go to each one with a gallon container and time how long it
takes to fill it up. Let’s say the south side outdoor faucet took 20 seconds to
fill. That means 3 gallons per minute (60 seconds divided by 20 = 3 gpm). The
north side faucet took 28 seconds (little farther away from the well’s pressure
tank); this one measures 2.14 gpm. The downstairs tub took 15 seconds, that
make 4 gpm. The upstairs took 21 seconds, that’s 2.85. And the kitchen faucet
took 35 seconds, which translates into 1.7 gpm. Add all these up and you get
your wells gpm capacity, 13.7 gpm at 40 psi. But after you figure up all the
pipe you are using throughout your yard, 20 feet of ¾”, 150 of 1 ¼”, and 50’ of
1 ½” you must subtract 3.09 psi for the ¾” (100 / 20 = 5 / 15.46 = 3.09), 2.01
psi for the 150’ of 1 ¼ , and .315 for the 50’ of 1 ½”. That totals up to 5.415
psi that needs to be subtracted. That leaves you with around 13.7 gpm at 35
psi. for the well people and 13 gpm at 45 psi for the above mentioned city
folk.
Underground sprinkling must be
divided up into two separate areas; your grass and your shrubs; these two areas
are as different as night and day. Grass can, for the most part, handle water
on a daily basis, shrubs, trees, and perennials cannot.
If you are dealing with new
construction you will want to know exactly where the grass, landscape and
flower beds will be; an established homestead has all this clearly
grandfathered in.
A side note here about new
construction, the best order of outside events is to work out from the house; this way nobody is walking on
the other guys finished product. First is the spreading of the top soil, second
is the establishing of the Landscape Beds and Trees; third is the irrigation,
with hydro-seed or sod finishing the project.
A map to scale of your property
will save you gobs of time. Use a 1 inch equal 10’ or 1/10th scale
as you draw your property lines. Then, to the same scale, draw in your house as
it sets on your property. Add the landscaping, sidewalks, and driveway all to
scale. As well as decks, swing sets, plantings and gardens that set away from
the house.
Gathering all this information
should keep you busy this week. Next week we will get into the nuts and bolts
(or pipe, wire, and clamps) of installing your irrigation system.
I trust everybody did their
homework and found out what their Water pressure and gallons per minute are, if
not, you must go back, and read last week’s article. It is so important to get
these two bits of info, without them your watering system will not work right.
Let’s start with lawn watering.
Coverage here is important, you don’t want dry areas; but then big wet overlapping
areas don’t make any sense either. With the many different sizes and styles of
sprinkler head available you will be able to dial this in with a great deal of
precision.
The “big gun heads” will cover big
areas and should be used in your big areas, but not as the sole source of your
watering. You are dealing with circles, radiuses, diameters. These geometric
shapes are not the best for even coverage. Either you will have large dry areas
with a smaller water bill, or large wet areas with a large water bill, which
then, because of the cash draining away from your wallet, turns into a smaller
water bill again, but with a big huge dry area.
Heads are expensive, and yes the
more heads you have, the more it will cost you now; but, a well laid out
sprinkling plan, one that makes every drop count, will pay for those extra
heads quickly; especially for you folks hooked up to city water.
Heads come in all kinds of sizes
and types, their performance changes under different pressures though. Let’s
say you are installing Nelson 6000 series heads. The #4 nozzle at 50 psi will
shoot a 34 foot radius at a rate of 1.7 gallons per minute. This same head at
35 psi will shoot 31 feet at 1.4 gallons per minute, at 20 psi, 30 feet at 1
gallon per minute..
The 1.7 gallons per minute this #4
head will throw lets you know that you can easily put 8 of these heads (1.55 x
8 =12.4 gpm total) on a zone without compromising the 45 psi water pressure, or
the 13 gpm it is generating. See how important knowing your water pressure is.
It lets you know how far to place the heads
But, if you went with the #11
nozzle, your radius will be an impressive 47 feet at 45 psi, but your water
consumption will rise to a hoggish to 7.25 gallons per minute, making it
impossible to put two of these overachievers (7.25 x 2 =14.5gpm total) on a zone.
Better then to drop down to the #10 nozzle which still gives you a 46 foot
radius but only spits out 6.1 gpm; totaling your GPM, for two heads, to 12.2
gpm; well under the 13 gpm you have to spare. You will not only find all this
information on the heads themselves, but where you purchase them generally has
a sheet with all the heads, and their capabilities, printed out for you.
Now, armed with your “heads of
choice” information sheet, you can start cutting out sprinkling radius circles
to scale, to fit the areas that need watering on your property drawing.
Overlapping is necessary to achieve good coverage, but excessive overlapping is
a waste of water. Keep in mind that many heads come with a modifiable ability,
be it streams distance, or the ability to travel a complete 360 degrees or down
to 5 degrees only.
Take the time this “fitting of
sprinkling radiuses” needs; you will again save yourself gobs of time.
Landscape irrigation will be our
next area focus.
I am not a big fan of heads in the
shrubs and perennials. They would do the job if they were on three to six foot
extenders, but this has not been my experience. They are generally installed as
if the landscape plants were not going to grow any taller than the lawn grass.
The heads are typically rendered ineffective behind shrubs or taller than
expected perennials; which in turn kills the plant by either drowning it or
blowing the leaves off it.
The best irrigation method is by
way of a Dripper or Emitter line system. A determined length of ¾” black pipe is place centrally throughout
the landscaping, with little hoses secured into the left or right sides of this
¾” pipe. On the ends of each little hose is either a valve that can be adjusted
or shut off, or a set of prongs that allow different amounts of water flow, as
well as being able to stop the flow of water all together. Like I said in the
beginning different plants have different water needs; this method gives you
the best control in this area.
Another way is the use of weeper
hoses and how they are placed.
A weeper hose is a hose that allows
water to “weep” through the hose walls. This method is a little more water
wasting but can be installed quickly and with less cost.
Adjusting the water amounts to each
plant kind of goes as follows. For instance plants that like a lot of water,
Red Twig Dogwood, Siberian Iris ect., loop the weeper hose around them twice.
Plants like Yews and most evergreens
like the hose to run next to them but no looping. Water storing plants such
as Sedums, Yuccas, Daylilies and bulb type plants like to left out completely,
our average rain fall takes care of them nicely. Most everything else likes a
loop or half a loop of hose.
Either method can be hooked up to a
zone of its own.
I know I have spent a lot of time
talking about things that haven’t put drop one of water on your grass, but the
things mentioned so far are the most important part of your sprinkling system,
trust me.
Now let’s talk about the nuts and
bolts of installing your irrigation system.
First on your list is to call Miss
Dig at 1-800-482-7171 especially if you will be using a pipe puller; Miss Dig
requires three day notice. If you don’t call and you rupture a gas line or cut
a phone cable or electric line you will pay for its repair. If you run the
puller over a flagged area and damage one of these lines you will pay for its
repair. If you damage a line in an area that is not flagged due to a mistake by
Miss Dig you will not be held liable. If you did some damage hand digging you
will not be liable for you took the necessary precautions when burying your
pipe in a flagged area; but be careful, just because it’s flagged it doesn’t
mean you can shovel around like a mad man.
Next, buy all the things your scaled
drawing has specified, pipe, heads, clamps, wire, valves, reduced-pressure backflow
preventer, ball valve, and controller.
With parts purchased and laid out
in your yard, start placing the heads according to your drawing out in your
yard. Now your 1 ½” main lines can
follow a path through them, allowing you to use as little pipe as possible.
“Hand trench” or “pipe pull” with a machine, this 1 ½” pipe into the ground
about 12 inches; leaving enough pipe to attach to the Pressure Vacuum Breaker which
will be mounted typically on the house twelve inches above the highest head in
your system.
This Pressure Vacuum Breaker keeps
the potential of contaminated water from siphoning back into your drinking
water. It is important to tap this into your house’s main cold water line. It
is even more important to make sure this Preventer is mounted 12 inches above
your entire system.
A Reduced Pressure Backflow
Preventer may be used in areas where a Pressure Vacuum Breaker becomes
unsightly due to the 12” height requirement. It must be installed in an area
not subject to flooding, and accessible for inspection or repair. It must also
be protected from freezing, which will result in internal damage.
With the main in place, trench in,
or machine pull, the 1 ¼” lines that go to the zone valve boxes throughout the
yard. Color coded wires follow along this pipe but will most likely start from
the garage area or some other location different from the Reduced-Pressure Backflow
Preventer.
These different colored wires are
hooked up to a control box that turns on the different zones you have
established. Every wire color is a different zone with a single white wire
being the “common” neutral wire that completes the circuit from zone to zone;
you don’t have to run separate white wires to each valve zone. Most likely you
will have to trench from this controller box location, making a beeline to the
first zone valve location; from there you will follow the main zone pipes to
the different zone valves boxes, leaving a continually connected white wire and
a different colored power wire at each valve box along the way.
From there trench or pull more 1 ¼”
water lines from each zone valve location to that zones series of heads. From
this zone main hand dig out to each individual head’s location using ¾” pipe.
Cut the pipes to the right lengths
and hose clamp them to all heads and valves, and attach wires to the valves.
Fill in the trenches, pressing the soil into place, especially around the
heads. Lastly hook up the wires to your controller box.
There are some tips that that can
take some of the potential frustration out of the mix. One is to clean out the
lines before you install the heads. This can be messy but it does add years to
the heads. Let the water run for a few minutes, this will flush any dirt out.
The other tip is to install your system (if possible) so it all drains to one
lowest point. This makes it easier to
winterize the system. You may need a transit for this, and it will take
some extra time if your yard has very little elevation drop, but it is worth
it, for most systems need to be blown out with compressed air professionally.
Maybe after
reading this it just sounds too overwhelming, there are many reputable
irrigation companies out there that will do a fine job. At least in reading
this you have become just a little wiser when it comes to irrigation.
