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Request for Proposal -- SFTF Irrigation system components

I am in the process of expanding and need a reasonable way to water a zillion or so trees. Caveats:

1. I have run no debt so far in creating the farm. I intend to continue working this way. I don't have a lot of money. This may mean some parts don't get implemented this year. It may mean that something gets done cheap and sleazy now knowing that I'll redo it in a few years.

2. Plans are subject to change. I've rearranged the pot yard three times in 5 years. And it looks like I need to do part of it yet again. All designs have to be flexible. E.g. I don't bury my pipes, but instead run them flush with the surface of the sod. Moving a line isn't a big deal. Fixing a line is also easy.

3. Lambastings from my peers on the Strawbale construction mailing list, along with some research have convinced me that PVC is right up there with car batteries as a pollutant. While I recognize that I can't avoid PVC entirely, I wish to minimize it's use. There will be no general PVC plumbing here.

4. I need convincing reason to not use standard black poly pipe for my distribution lines. My oldest chunks of it have been in use for 6 years now, and the only problems I've had have been the occasional fitting breaking.

5. I'm looking for a long term business relationship. I'm not looking for the cheapest solution today. I'm looking at the best solution long term. And while inexpensive is good, it isn't the goal. Because of item 1, it may mean postponing, or doing short term compromises.

Story Time:

A while ago I went into an unamed irrigation dealer in Edmonton. I think that they sold primarily to contractors installing home watering systems. They had a rep as a company who did great jobs on golf courses. Perhaps a different division.

I diagrammed my problem out. We concluded that one part of my system needed 45 gallons per minute to run as a single zone. The counter person then tried to persuade me that pushing 45 gpm through a 1/2 inch black poly line would not be a problem.

When somoone tells me something that I know is wrong, it casts doubt on everything they say. When they do so in earshot of two other people in the store, I start wondering about the general competence of the entire firm.

I've asked questions like, "What's the head loss over this fertilizer injector" or "If I have a thousand feet of 1.5" line full of water moving at 8 feet per second, what happens when that valve closes?" I get blank looks. More than once I've ended up with a drawing pad and spent an hour or so teaching them stuff I picked up off of Jeff Stryker's site www.irrigationtutorials.com

I bought a venturi fertilizer injector. It was rated at 1 gpm. I figured that I could put it in a side loop, ease the main line branch of the side loop to partially shut, and use it for my 5 gpm flow. I explained this to the guy I bought it from. He said it would work great that way.

Well, not with my system. Seems that the unit required about 15 psi presure drop over it. Closing the main line enough to get 15 psi over the injector left me about 10-15 psi to run my sprinkler. Needless to say, I've not gone back to him for further needs.

I expect the company I deal with to know more than I do about most things concerning moving water to the place I want it. I expect them to politely tell me that I'm wrong, and explain why. The words "I don't know" are a great answer. I don't mind hearing it. As long as it's followed by a "I'll see if I can find out."

Current Setup:

Geography and Geometry

The main pot yard is about 1200 feet from the house, and about 30 feet higher. At present I have a 1.5" black poly line that taps into the well to the house. This minimizes friction head loss. I get just under 5 gpm at the pot yard from a hose bib. This gives me sufficient water to run one oscillating sprinkler well, or run two of them badly.

The field trees are about the same distance from the house.

The shade house and the nursery area are both close to the house.

There is no power at the pot yard. Power is a long extension cord to both the nursery and the shade house.

Water Supply

I have one and a half sources of water. I have a well that provides 6-7 gpm from an open hose bib. At this delivery rate, the well pump does not shut off. I've inquired about replacing the pump with a larger capacity one. My local pump guy said that I shouldn't. Most of the wells here draw from a sandstone formation. Drawing water faster than 5 gpm may result in sand and silt in the sandstone formation moving, and packing the area around the well bore to the point that the well can only produce a gallon a minute.

Up to now I've used this supply to water my trees. This takes some 23 sprinkler moves to to all my trees. Inefficient. Tedious.

The second source of water is a pond. The pond holds about 800 cubic meters -- roughly the amount of water I used last year. My thought is that I can pump from the pond to water the trees, and use the well pump to top up the pond.

My preliminary research in automated control systems shows that there is very litle price difference between turning a small amount of water on and off, and turning a large amount of water on and off.

If I want to eventually automate my watering, I should try to do so in as few zones as possible.

I have on order a gas operated fire pump that will supply 50 gpm at 100 psi. This pump is somewhat overkill. 1.5" water line at 7 feet per second (highest recommended velocity) corresponds to about 35 gpm. With a gas engine I can adjust engine speed to a lower value.

Eventually I will replace the current 1.5" line with 2" line.

The gas operated pump will allow me to run a bunch of sprinklers at the same time, or will allow one of the other ideas mentioned below.

Components sought:

Floating Intake to get the clearest water from the top of the pond. (Pond is aerated) (Can probably get locally at Peavey Mart or equivalent.

Water filter to that duckweed from the pond doesn't end up in the plumbing, AND one fine enough so that I can use drippers in the field. At present I have a netafim disk filter (1" connections) which I think will be too small for the proposed pump below. However I can repurpose that watering the areas around the house.

Fertilizer injector Most of my reading indicates that young trees do well with 10-50 ppm total N in their water supply rather than having larger amounts of fertilizer at longer intervals. Since the system will run at varying rates depending on how many sprinklers are currently running (or how many zones are open) I want a system that responds well to different flows. My reading shows that venturi based systems are not constant in their dilution.

Remember that there is no power at the pot yard, so an injector that is water powered, or one that runs off of 12 volts is needed. (I'm willing to move a battery back and forth on occasion)

Pressure Reducer Gotta stop that pump from blowing apart my fittings. It may be that PR's have to be distributed.

Water Hammer release Some form of poppit valve so that when that lumbering slug of water traveling down the pipe has a valve close that it won't start taking apart the plumbing.

Water Quality

I've had the water tested, and the only thing even slightly marginal is 400 ppm carbonate, and 90 ppm sodium. I haven't had the pond water tested yet. Need to wait for the ice to come off it.

Working areas

The Nursery

The Nursery is about 100 feet from the house, and will run from the household water supply.

When seedlings come in they are initially planted in Beaver Plastic styroblocks. At present most stay in these blocks from their arrival in spring until dormancy sets in in the fall. At that time they are potted up into #1 or #2 trade pots, and the blocks stored until next spring.

These are watered with an oscillationg sprinkler. I've had some problems with overwatering the overlap area between sprinkler moves.

The blocks are set in strips 4 feet (2 blocks) wide so that weeding is easy. This could be increased to 6'. The last two years I've had about 240 blocks (3600 seedlings) this way. This year I have 4500 seedlings coming in, but some will go directly into trade pots.

Drip irrigation is unreasonable for these. I'd like to put a line of posts in, and run inverted sprinklers over these beds. So far I've been unable to find a supplier of inverted sprinklers that will cover a 4' strip with reasonable uniformity.

Components needed:

Pipe clips (Saw these on a page on vineyard irrigation) to attach poly pipe to wire.

1/4" drop line To get water from the pipe to the sprinkler, and to allow the sprinkler to hang vertically.

Micro Sprinklers These need to be able to run inverted, on the end of 1/4" poly line. I need good uniformity, with around 80% of the water in a 4 to 6 foot wide strip. I'd like to be able to cover a 4 x 80 foot strip with a flow of under 6 gallons/minute.

4 zone controller (Probably postponed.) I will probably initially do this with cheap mechanical timers, but eventually I'll put in a programmable controller. Another two years should tell me to what extent I'll be zoning the nursery.

What else?

Pot Pens

When a tree moves from a styroblock into a pot, it initially goes to a pot pen. These are rows of bales, 3 feet apart, 200 feet long with rows of 6 pots each, packed tightly.
So a pen will typically hold 2400 pots.

This width can be increased to 5 feet if necessary to conform to the right technology.

I have two possible ways to deal with these, but I don't have the experience to know which is best.

• Treat it like the nursery yard, and run suspended sprinklers overhead. This will require moving my main line so that it crosses the pens near the middle, instead of at the south ends as it does now. OR it means running 3/4" line for the sprinklers. Either way works.

The downside: The pot yard is exposed to a lot of wind. Which means I would need to schedule sprinkler operations for night or dawn.

What I would like to do is put in an 8' post every 50 feet, run a strand of high tensile strength fence wire along the tops of the posts, then hang a water line from the wire. The water line would have a barbed connector connecting to 1/4" line, with a micro sprinkler on the end of it. The length of the line would be sufficient to put a loop in it. By adjusting the loop the sprinkler head can be raised or lowered.

Because of the wind, the residual curl in 1/4" poly line, and the force of the sprinkler spray, some form of stabilization is necessary. I think a square block of 2x4 with a 3/8" hole drilled through it, with the 1/4" line passing through the block may be sufficient for this. However, sprinklers would need to be symetric in their operation. E.g. ones that progressively direct a stream around a circle won't work.

• Run a 3/4" line down one row of bales. Every 6" attach a 3" chunk of 1/4" soaker line, or 1/4" line with an emitter every 6" This line then is secured to the pot at the side furthest from the supply line with a geotextile stable. This requires a mile of 1/4" drip/soaker line per pen.

A third possibility, that of running a sprinkler stake or dripper into each pot has been suggested. Note that this would require 12 connections to the main line per linear foot of pen. I want this to be simple, and easy to set up. I don't want to have to spend hours untangling lines when trees are sold, or are moved to other pots. Generally these pots need to be weeded twice a year. Having a lot of pipe will interfere with this. This requires 4 miles of line per pen.

Components needed:

Sprinklers Initially I thought that these could be the same as the ones in the Nursery, but they may not be. Ideally I'd like to run a pen as a single zone. 3/4" line however has a maximum flow around 10 gpm I think. A 200 foot pen with sprinklers every 10 feet is 20 sprinklers which means only 1/2 gpm per sprinkler. Is this possible?

What else?

Pot in Pot

I have 600 trees in a pot in pot system. Currently they use "poor man's drip line." It's just 1/2" black poly with a needle hole for each tree. This method is not ideal for several reasons.

• The uniformity is terrible. Even using the same needle, held in a vice grip, poked to the same depth each time, there is a factor of 2 difference in uniformity.

• The holes clog, or stop running in a month or so. I've been unable to determine if this is due to blocking caused by sand or grit, to lime depositing out from the water, or from "plastic creep" the slow flow of plastic that was pushed aside by the needle.

• The holes move. At present I have the pipe stretched tightly by double stakes at both ends. This works to keep most of the holes centred over their pots. I have to unhook one end in fall to keep the pipe contraction in the cold from pulling out the stakes.

• The pipe, in running just over the tops of the pots, gets in the way of mowing and trimming arround the pots.

I think I'd like to do this in a way similar to what I've proposed for the pot pens: Put a post every 50 feet, run a wire, run a poly pipe. Each tree has a supply line and a dripper. This is attached to the trunk a few inches above the pot with velcro plant ties (or duct tape...).

This allows me to walk by and SEE that the dripper is dripping.

Components needed:

Much stuff similar to the above, and

Drippers I want drippers that don't need cleaning. Eventually I'll have several thousand of these. Taking them apart to get the lime out is not a good use of my time.

Field trees.

These don't exist yet, but people want bigger trees than I can easily grow in a pot.

For these, it would be a magnified version of what I'd use for the PnP. A hung water line, with one, perhaps two drippers per tree.

Not clear to me what the optimum layout for the field trees is. At present I'm looking at 7 foot in row, with alternating 7 foot and 12 foot aisles.

What I need to know: Rules of thumb for planning distribution networks. E.g. What's the best way to break a 1.5" line down into feeder lines? Ultimately is it cheaper to run 3/4" feeder lines or half inch. (Longer rows with 3/4", fewer connections.) Is there less grief with runninglines down the center of an area, and feed off both directions, or run it on the side, and keep the main line out of the way.

Components needed

I think it is just mroe of the same above.

Shade house.

This area will be near the house, and served by a hose bib run off the domestic water system. I have a DIG 510.100P timer on order to act as a mist timer for this work. The house is sized for approximately 70 styro blocks. At this point I'm not planning any changes, but may put in a solar powered bed heating system.

(Simple experiments with a manually operated mister, and plants in partial shade in the open were successful enough to encourage me to take it a step further.)

Components needed:

Mist timer On order.

Shade Cloth

Mist nozzles that run well at 60psi (Current ones are from Lee Valley. I'm satisfied with their performance. The mist is heavy enough that it doesn't run away at the slightest breeze.

Long run

Eventually I'll have to automate the pot yard and field tree watering. Almost all the systems I've looked at have used two wires running from the controller to each valve. And they required 110 volts at the controller. Yikes. Thats a LOT of wire.

So far I've found that watering doesn't fit a regular schedule. It depends on how warm it is, and how much the wind blows, and the humidity. So generally I do a morning tour, and poke my finger in a pot hear and there, and from that decide what I need to water that day.

The ideal watering timer for me (no one makes them, I've looked) would be a simple mechanical timer with two dials. First one: How many hours to wait before opening. Second one: How many hours to run before closing. That's it. That's all I want a timer to do. If it's more clever than taht, it's icing on the cake. E.g. If it had a clock so I could say instead of how many hours to delay, I could say instead, "start at 2:00 p.m."

But it has to be fast. It can't take more than 10-20 seconds to set it.

A remote watering system has the minimum amount of wire. I've read of sytems that have a 'signal bus' system. There is a pair of wires that run near each valve controller. Coded signals tell the valve when to open and close. Much cleverer.

The ideal system is one that uses no wires. In theory this is possible using latching solenoids on the valves, and sending signals using sound waves in the pipes themselves. It would require special pipe fittings. (mroe gradual corners) but the lack of wireing should make this sytem much cheaper. In practice, I've not seen it in use.