Plumbing

[ Home ] [ Up ] [ Patio ] [ Electrical ] [ Plumbing ] [ Techniques ] [ Depot ]

North Pacific Coast Garden Railroad

Plumbing Infrastructure

The plumbing infrastructure for this project is made up of two projects.

	Installing a drip irrigation system to water the plantings on the garden railroad. Installing water lines to maintain the level of the large lower pond and the holding pond for the water feature at the top of the layout.
	Running a water line from the house to the pond so the pond (which leaks slowly) can be topped off when needed. A valve part way down the line will also be available to top off the top water feature.

Watering the Railroad

This railroad covers a significant area and will contain a significant number of plants. During hot summer months in Wisconsin, watering is necessary to keep them healthy. Options range from hose lines and sprinklers to automatic irrigation systems. I have way too much lawn to water my lawn. I would be worried about the life of the pump feeding water from my well. Even using traditional watering methods to spray the non-lawn portion of the layout would require significant water usage.

That's why drip irrigation appeals to me. You apply water to the roots of plants you want to water slowly and gradually. Because you are watering individual plants rather than 'the yard' you lose less water due to evaporation, avoid the negative effects sun and water can have on foliage, and maybe most importantly, you don't water weeds.

Drip irrigation systems can be as simple as simple lines hooked to hoses, with or without automatic controls. And they can be as sophisticated in their automation and controls as expensive home irrigation systems. Here's a good tutorial.

http://www.dripirrigation.com/drip_tutorial.php

And here's another by Jeff Stryker, a noted authority on irrigation and drip irrigation systems.

http://www.irrigationtutorials.com/dripguide.htm

I travel a fair amount. Here is a place I decided to splurge a bit. But automatic drip irrigation systems aren't as expensive as you may think if you shop around and are willing to do the work yourself.

Drip Irrigation System Components

Backflow Prevention

Maybe the single most important decision in installing an automatic drip irrigation system is how you will protect your house plumbing system from contamination resulting from back siphoning water (backflow) from your yard back into your drinking water supply. There are a number of options. If you are considering a drip irrigation system, I urge you to read this page.

http://www.irrigationtutorials.com/dripguide4.htm

You are likely to be covered by a municipal, county, or state code governing the kinds of backflow prevention devices they allow. Call and find out.

In my case, the City of Madison follows State of Wisconsin Code which allows you choose between Atmospheric Pressure Breakers, Pressure Vacuum Breakers and Reduced Pressure Backflow Preventers. They become increasingly expensive as you walk through the list in the previous sentence. But one Atmospheric Pressure Breaker must be installed for each valve (irrigation zone) on your system. On the other hand, you only need to install one Pressure Vacuum Breakers or Reduced Pressure Backflow Preventers. So if you have lots of irrigation zones in theory, the Atmospheric Pressure Breakers could become more expensive.

However, what tipped the scale for me is that Pressure Vacuum Breakers or Reduced Pressure Backflow Preventers in Wisconsin must be installed by a licensed plumber and they must be tested annually ($125-150). They need to be installed at least six inches above the highest emitter on your line. Not a problem for me because my water line will come out of the house at the very top of the hill!

Pressure Reduction

Drip irrigation systems are low pressure systems - 30 pounds per square inch or less. You can pick up a gauge at your home supply store to check your water pressure. It is likely to be 50-60 psi or more.

So a pressure reduction device is needed or you'll blow out all that nice irrigation line and those emitters.

Filtering

Drip irrigation lines have very small holes. It doesn't take much to clog them. So a filter in each irrigation district will help keep those lines free.

The grey device in this photo is an anti-siphon automatic control valve. It has an integrated atmospheric pressure breaker - Irritol 2711APR - $15.

The backflush filter is a Rainbird RBY075MPTX - $12

The pressure regulator is a Rainbird PSI-L30X-075 - $12

The valve is one of the most popular in the industry.

The later two items are designed specifically for drip irrigation.

Electrical Controls

An automated system requires a control unit that allows you to program your irrigation schedule and the time and length of day each irrigation system will operate. I'm still exploring this option and will post details later.

Lines and Emitters

I haven't fully explored all of these options as I don't expect to hook up my new system until spring of 2008. I'll fill you in once I've further researched these options.

Construction

This project will be implemented over time and will be completed in phases.

Phase 1 - Rough Plumbing

I don't plan to have the drip irrigation system operational until spring of 2008. However, so that the ditches along side the walkway can be filled, I plan to have the rough plumbing completed in the fall of 2007. This timetable forced me to make the decision on backflow prevention, valves, filters, pressure regulators and water lines as they are part of rough plumbing. Control system, irrigation line, and emitter decisions can be made over the winter for spring installation.

Components Chosen

Here is a listing of the components chosen and why.

	Anti-Siphon Control Valve - I chose the Irritol 2711APR based on a product review at Jeff Stryker's Web site. It meets city requirements for backflow protection and I can install it myself. If one breaks (frozen water) it is simple and inexpensive to replace.
	Backflush Filter - I chose the Rainbird 2711APR. There are cheaper filters. But this one clears itself every time the water is turned off through a backflush mechanism. For another $6 it thought this feature was a good investment. This device is designed specifically for drip irrigation.
	Pressure Regulator - I chose the Rainbird PSI-L30X-075. This device is designed specifically for drip irrigation. I just felt better staying with the rainbird line.
	Main Water Lines - I decided to go with Code 40 3/4 inch PVC. I have experience with this stuff and know nothing about the flexible alternatives.

Initially, I plan to run four irrigation districts. So I bought four valves, filters, and pressure regulators.

Note that devices like these are assembled into manifolds. In an automobile a manifold takes exhaust from individual cylinders and merges the gasses into a single exhaust pipe. A manifold in an irrigation system performs in just the opposite manner. It takes a single incoming water line and and distributes the water to the valves controlling the irrigation districts. I'll be constructing a manifold out of PCV and will post a photo when it is complete.

The four zones are as follows:

	Zone 1 - Herb bed and the upper part of the layout.
	Zone 2 - The bottom half of the hill.
	Zone 3 - The right half of the line circling the pond.
	Zone 4 - The left half of the line circling the pond.

The PVC lines for Zones 2-4 and the water line for filling the pond will be laid in the same trench as the electrical conduit.

The photo shows the proposed location of the manifold, to the left of the electrical line feeding the railroad. The PVC lines for Zones 2-4 and the water line for filling the pond will be laid in the same trench as the electrical conduit.

The PVC line for Zone 1 will run across the base of the deck and will be hidden in the gravel at the front of the patio.

This photo shows five 3/4" Code 40 PVC lines. The top line feeds Zone 1. Zones 2, 3, and 4 are fed by the three lower lines passing behind the conduit. The line coming into the left of the conduit is a water line that will be used to top off the pond when the water level gets low.

This is a photo of the completed manifold that will feed the four drip irrigation districts. Its proposed mounting location is shown two photos back. Zone 1-4 lines in the previous photo will be connected to the connectors coming out the bottom of the four pressure regulators.

In this photo, the water line to the pond and the lines for zones 2-4 emerge from underneath the lower tunnel.

The line for Zone 2 is pointing up in this photo. The elbow, vertical pipe and cap are pushed on keeping the end of the pipe clean and allowing the pipe to be located in the spring of 2008 when the system is scheduled to be hooked up.

Lines for Zones 3-4 and for the water line feeding the pond accompany the electrical conduit down the walkway. In 2008, the water feed will be extended to the pond. The Zone 3 line will provide irrigation to the right half of the pond. The Zone 4 line will provide irrigation to the left half of the pond.

With the exception of extending the lines an additional ten feet and capping the ends, both plumbing projects are complete at this end for 2007.