Landscaping - Irrigation on a slope

I have a pretty large slope (2:1 and around 12 feet high at the top) in my backyard that I need to set up some sprinklers for. Currently, the whole slope is covered with ice plant and has a couple of recently planted trees on it, but I plan to plant a lot more plants all over it. What's the best way to irrigate such a slope? Do I put sprinklers at the top and set them up to just spray over the entire slope? Sprinklers + drip system for individual trees/shrubs? I want to set it up now so that I don't have to change it too much over time as things grow in.

Thanks for you help!

You can do 1 of 2 things for ease of installation.

1. Go to the top of slope as you said and "throw down" over the entire hill. This way you make sure and cover the top which is often harder to hit from the bottom. You can choose either rotary heads which turn back and forth, or spray heads which do not turn at all.

If this is going to be its own zone then sprays would be ideal. However, if you are trying it off of another zone you have to make sure that you have enough water to do this with. It is not a good idea to mix sprays and rotors as the two water too differently and it only leads to problems.


2. Use rotary heads on the bottom of the hill and bury them crooked on purpose. Make them tilted so that they spray higher up, facing the hill. A normal head will not go up the 45* hill you describe but if they are tilted/crooked, it should be just fine.


The biggest problem you will have is if your plants start getting too tall and start blocking the water from your heads from reaching. I would rather see you water from the top of the hill downwards, but without a total picture of the area in question, this might not be best. That, and I don't have to install them, either. But you only want to do this one time so spend the extra time and do it once the right way.

The plants getting tall and blocking the spray is definitely a concern. Should I consider putting smaller heads over the entire slope in a grid similar to what would be done for a lawn? The slope is about 75' wide and probably close to 20' from base to top measured along the ground.

A couple of other questions...

1) Assuming the slope has to be broken into multiple zones, should I run a single supply line up to the top and place the valves up there with all of the lines running downhill after that? I'm not sure if that would serve any purpose, but it seems easier than having to run multiple lines up the slope. Plus, once the valves turned off, the water wouldn't flow downhill back to the valves, it would go downhill to the heads.

2) Might it work to simply run one line along the top of the slope with heads throwing down and another line at the bottom with heads throwing up?

Thanks a lot for your input!

do you have an existing irrigation system now that you are hoping to expand, or are you just starting out with one and wondering how to set this up? Just trying to learn where you are coming from this so I can help you out better.

A few things I need to know first are:

1. what is your water source? be sure to include any booster pump size if you have one.

2. is this going to be a new zone or are you tying into an existing one?

3. Do you already have the materials or are you getting them later? Also, is there a budget in mind?

I think you can do this all in one zone. If you have a clear idea of where you want your trees then you can easily place your sprinkler heads in places that will not interfere with future growth. Ill try and post a pic here to give a ballpark explanation.

If you went up one side and came down the other, you should be able to cover everything, give or take.

http://img204.imageshack.us/img204/8717/roughdrawing.th.jpg (http://img204.imageshack.us/i/roughdrawing.jpg/)

I am not an artist, but this may better demonstrate what I mean.

What can help you out would be to put buckets or markers in this area where you would like your tall trees. Then, walk around the whole area and imagine that if you stood in certain locations, what part of this landscape could you hit with water if you were a sprinkler. This may help you to plan out where to place them.

Once I know more about your sprinkler system we can talk about drainage--it sounds like a concern and it should be if you live in an area where things will freeze.

I really appreciate you taking the time to help me on this. Here's some more info...

Currently, there is no irrigation system at all so I will be starting from scratch. The slope is just the first area we need to tackle. The water supply comes in from the city and there's a hose bib in the back yard where a previous sprinkler system used to be T'd off from (there's a valve there) and where I was thinking I would hook up the new one. I get about 70 psi from the hose bib, but am not sure about the GPM. There is no booster pump.

I'm in Southern California so freezing is not an issue. At the base of the slope, I plan to build a 30" seating wall and will run drains behind that and divert water to the sides of the property where they will tie into drains running to the street.

I have not purchased any materials as of yet and have no particular budget in mind. I'd rather spend more now and do it right. I will definitely need to add more zones so I need to account for expanding the system. I think probably 3 or 4 additional zones will be needed to cover the rest of the back yard.

Your drawing makes perfect sense and I was already thinking of placing some stakes in the ground where I think all the shrubs and trees will go to help plot out the placement of the heads.

Here's a photo of the slope (about 3/4 of it anyway) to give you an idea of what I'm working with. I've placed graphics of trees on it to indicate the type of placement I'm planing for the trees and shrubs. I'll be choosing stuff that all has similar watering needs to the camphor and jappanese privet trees we've already planted (not shown in photo).

http://www.espcustoms.com/house/exterior/slope.jpg

First off, I love those tree pictures you put in. nice touch.


Due to how you are placing the trees and all, I think that since you are already digging a trench at the bottom to lay in your tile, you might as well through in a 1" poly line for your irrigation as well. If you form a giant letter "u", you can throw from all 4 corners of the slope and be able to water it and not worry about missing sections due to large trees.

When you dig a trench for tiling, half the work will be done already. You will only have to make 2 runs up to the top of the hill, one at each side.



Another possibility would be to use dripline irrigation. All you would need is several hundred feet of the stuff and a bunch of stakes to hold it down. You can make loops around all of the trees to provide extra water. Its easy to install and you can bury it with your mulch later when you add that.


In order to stay legal, you will have to connect any of this to a garden hose which provides about 5-10 gallons per minute, maximum. You would probably be better off installing a vacuum breaker and the whole nine yards if you want to water anything but this, but I cannot possibly walk you through all that. It would be like telling you how to build a house--just too much to explain.

[QUOTE=glorystomper;1610934]The water supply comes in from the city and there's a hose bib in the back yard where a previous sprinkler system used to be T'd off from (there's a valve there) and where I was thinking I would hook up the new one. I get about 70 psi from the hose bib, but am not sure about the GPM. There is no booster pump.


I do not know the laws in California, but I imagine they are water-concious, too. If you are going to use the water for irrigation or if it will go underground at all, it must have a vacuum breaker, sometimes called a backflow prevention device. They cost around $100 plus extra for the fittings and all that.

If you only wanted to water this area to get it established and then not worry about it, a garden hose and a garden hose timer would make the most sense. That would set you back less than $50 for the timer and hose, give or take.

Ok, that all sounds pretty straight forward. Just to be sure, I put together some drawings to make sure I understand you correctly (I'm a graphic designer by trade so I can't help myself!). Do any of these look right? The first one is how I understand your description. However, I think there could be a couple of spots along the top of the slope that won't be hit with this configuration depending on how out of scale my drawing is. I tried a couple of other configs trying to avoid putting too much demand on the system since each head will have to cover about a 18' radius and I'm assuming that will require a lot of water and pressure. What do yo think?

http://www.espcustoms.com/house/exterior/MainSlopeZone.jpg

http://www.espcustoms.com/house/exterior/MainSlopeZone2.jpg

http://www.espcustoms.com/house/exterior/MainSlopeZone3.jpg

http://www.espcustoms.com/house/exterior/MainSlopeZone4.jpg

Also, would I need a vacuum breaker for each zone or just one for the entire system? I realize now my drawings show it in a way that would require one for every zone, but now I wonder if I could just put one between all of the valves and the main supply.

Thanks!!!!

Your drawing on the bottom I like the best but I was trying to minimize the digging you will have to do. You don't want to overkill the area with water or you could risk drowning your plants--unless you have really good drainage.

A normal rotary head will throw around 30-40 feet or so, depening on pressure and available water, etc. A mini rotor can do from about 15'-25', again this is all varying on pressure and volume and assuming you have large enough pipes carrying this water through your system.

Ill try and draw a picture of what you will need to have a setup like--mine will not look as good as yours. ;)

http://img217.imageshack.us/img217/5033/sprinklersetup.th.jpg (http://img217.imageshack.us/i/sprinklersetup.jpg/)



Here I found a picture of something important. A vacuum breaker does have to be 12" above the highest head on your system. If this is not possible, then you have to use a double-check vacuum breaker. The cost difference between the 2 varies but an average vacuum breaker that is any good will cost around $90+ and a double check is around $200+. That does not include any fittings, copper, etc. Anyhow, here is a helpful picture:

http://www.wjordan.com/Images/PublicWorks/sprinklers_(PVB).jpg


Here is another example of what it can look like outside:

http://lancaster.ne.gov/city/pworks/water/crossconn/images/pvba1lg.jpg

Please note this are just pictures I found, I in no way endorse where they came from, but they all appear to be setups that particular cities require people to use. You will probably find similar guidelines in your own city so what I say may not neccessarily be what you need. But having your water shut off and possibly fined is not something to mess around with.

Excellent. Thanks so much!! I think I'm just about ready to get started.

Since the slope is covered with iceplant, I'm wondering if I can just run the poly line above ground and thread it under the iceplant. I know it shouldn't be exposed to the sun, but would there be any other concerns with doing it this way?

Also, is there an advantage to the poly tubing versus regular PVC pipe?

pvc pipe exposed to the sun gets brittle and cracks. At the end of the day, PVC ends up a little less expensive, but harder to work with, harder to repair and more fragile.


You can also get a quote from a sprinkler company, usually for free, and you can see what things might cost if you went that route, too.

I got a quote from one guy already who wanted a small fortune. I've done a small system myself once before and didn't have any trouble so I figured this would be a good one to tackle myself and save a lot of money - so long as I get good and educated first.

Thanks again for all of your advice. I'm sure I'll be back with more questions, but I think I'm armed with enough info to get started. Time to start digging!

yep. you can always power it with a garden hose in the meantime. it will not be anywhere near as powerful as using water straight from the water source in your house, but its better than nothing.