Help with mixed use low pressure system

14 years ago

This is a drawing of my backyard. I hope to explain everything in enough detail so I can get some solid info.

Kennewick, WA

Weather data: http://www.idcide.com/weather/wa/kennewick.htm

88 psi (this year) from the irrigation main. Generally, it's right around 85 psi.

Under the 11" tall, 8 sq ft. raised beds is pea gravel (1/4" round rock), and under/around the trees is hemlock bark mulch. The valve box in the corner spits out two 1" PVC lines running along the property lines on three sides.

Along the bottom is what I call "The Island". It's surrounded by grass, house, patio, and path. I currently irrigate TI by turning on the hose bib. Out of the HB, the city water goes straight down (through a 25 psi reducer and a fancy union fitting) to buried 3/4" PVC lines that come back out of the dirt and feed flexible poly tubing, and finally to 1/4" drip line. They pop up in about eight locations. Based on the plants water needs, there is either an open 1/4" tube, a shrubbler, or a microsprayer. All plants are well irrigated, but we chose more drought resistance species. That section runs five minutes per day at most.

The raised beds all have drought resistance species and only shrubblers. Every two beds are fed from a threaded PVC saddle connected to the 1" main line, 25 psi pressure reducer, and poly pipe into 1/4" drip line. Most have three shrubblers. They are running at nearly no flow, and are set to run fifteen minutes, three times a day. Healthy plants in there.

The trees are also set to run fifteen minutes, three times a day. They each have their own saddle, 25 psi pressure reducer, and short poly pipe into 1/4" drip line. All six trees have "tree stakes" at the root system. 12-20" long PVC stakes that have 2gph shrubblers stuffed down to the bottom running wide open. Each tree also has a wide open shrubbler at the root base.

Finally, the questions!

What is a good way to start irrigating The Island using the irrigation water based on how the timer is currently set? I was thinking that anything in TI would need to be REALLY set to almost no flow, based on how it's irrigated now. Or do I add more lines to the trees and adjust the time down?

Switch to super low output microsprayers for TI?

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Comments (3)

lehua49
14 years ago
ft,

Some questions to achieve your stated goal.
1. What is TI?
2. Is the "Island" the lawn area?
3. What type of lawn grass are you going to use?
4. What is the square footage of the lawn or the dimensions?
5. You have vary strong pressure for sprinklers. What types of sprinklers heads would you prefer to use?
6. Is your house pressure the same as the irrigation mainlines?
7. Are you expecting to automate everything with a controller?
8. Where are the pressure regulators located?
9. Why are the valves so far from the house?
1. What knowledge do you have about how much water to apply to certain plants?
2. Are the trees newly planted?
3. Where is the source for the lawn located?
  Aloha
filetree
Original Author
14 years ago
1. What is TI?
The Island.

2. Is the "Island" the lawn area?
The Island is the section of annuals and perennials at the bottom of the graphic.

3. What type of lawn grass are you going to use?
Grass is established; Kentucky Bluegrass.

4. What is the square footage of the lawn or the dimensions?
About 60'x60', accounting for the cutout at upper left.

5. You have vary strong pressure for sprinklers. What types of sprinklers heads would you prefer to use?
The entire backyard is using Hunter PGP heads.

6. Is your house pressure the same as the irrigation mainlines?
House pressure is slightly higher; 92psi as measured with a Rain Bird gauge.

7. Are you expecting to automate everything with a controller?
Once irrigation (not house) water is going to The Island, it will be automated. The 1" lines on along the fence are part of the valve box that has two valves and a simple Hunter battery operated timer. I'm hoping to combine the water needs of newish trees and annuals/perennials on the same irrigation duration.

8. Where are the pressure regulators located?
There is a single pressure reducer (dropping to 25 psi) for The Island. Each of the trees has it's own 25 psi reducer. Every set of two raised beds has a 25 psi reducer.

9. Why are the valves so far from the house?
The valve box listed here is a secondary system. Added last year, and teed into the irrigation main buried by the irrigation water supplier. It only irrigates the items listed here. The lawn is irrigated by the same water, but from a separate timer and valve box.
1. What knowledge do you have about how much water to apply to certain plants?
  I generally plant drought tolerant stuff and apply as little water as I think it can handle, then pay close attention to soil dampness decreases, then increase the amount of water.
2. Are the trees newly planted?
  Planted Spring of 2011.
3. Where is the source for the lawn located?
  All lawn and property line plantings are supplied by irrigation water, not city water. The Island uses city water.
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lehua49
14 years ago
ft,

now we get serious. Sorry for the stupid questions. 0.25 hr x 3 time per day x 2 bubblers(wide open) x 2 gallons per hour that equals 3 gallons per day for year old trees. Unless you have very sandy soil that is way too much for one-yr old trees. Check that your 25 psi regulators are working properly. 95 psi to 25 psi reduction is extreme and the in-line regulators are not made to make such a drastic pressure reduction. It seems to me, by regulation shrubblers to almost no flow, your regulating a line that is not properly pressure regulated. Usually the reduction is done in stages. 95 psi will affect your irrigation system with water hammer and shorten the life of your system's fittings. Pressure for a house pipes should be around 50 psi so that your water appliance's water seals are not overly stressed as well. I think you have the basic concepts down correct for the flower bed but are dealing with a system that is out of the norm. Also soil type is a big factor to water movement when minimizing the use of irrigation. JMHO Aloha