Jo, it would be hard to make the type of system I have work in your lawn. My lawn slopes also, I doubt that it slopes as much as yours and I have mine set up in zones and each tube is controlled by a ball valve. There is a lot more flow in a PVC system than some of the others. there is no regulating device on my system other than the ball valve for each tube or area. Water has a natural pressure of .433 lbs per foot of rise, which means all the lower holes till flower more water.

Another thing to concider is keeping the lines from freezing in the winter. I use the slope of the land to drain my lines by a ball valve each year. At this point I remove my tubes above grade to make sure no water is trapped inside of them. ( the lines in the ground are the ones I drain)

Water will expand approx. 10% when it freezes, so you will have to design for that fact by draining the lines, having an expandable material, or some type if insulation, which could be mulch.

If I were looking at a project like your I think I would try to learn more about pressure compensating emmiters and to break the area into several zones.

Larry

Jo,

I use a drip irrigation system and put it away before freezing temperatures arrive. Parts of it...like the t-tape can be left outdoors but it drastically shortens its life.

My garden slopes much more than yours, so I have my drip irrigation set up in zones with ball valves, so I can shut off some sections while irrigating others. Since water tends to flow downhill pretty well, even underground, my higher beds dry out faster than lower ones and need to be watered more often. Also, because they are on the higher south and west ends of the garden, they are more exposed to summer's south winds. Most of the time,, since water does flow underground from our neighbor's higher ground to our south, the lower beds at the north end of the garden have good deep moisture under them for a much longer period of time and often I don't have to irrigate those beds at all until mid-summer or later. To make drip irrigation work in our big,sloping garden, setting up zones has worked better than anything else I've tried.

Our lowest temps at our house this winter have been 9, 10 and 11 degrees on several different nights, so I was glad we didn't have any drip lines out exposed to those temperatures.

The people who leave their drip irrgation lines in the garden all winter often unhook the lines and situate them so any water left in them can run out. Then they use an air compressor to blow air through them to insure they are dry, and then hook them back together in place to they are ready for spring. I am not certain what they do with the rest of the system, but I imagine that even if they leave the lines themselves in the ground, they take the pressure regulator, filter and other parts and dry them out and store them indoors where they won't freeze and crack.

Drip irrigation might not meet your needs if you don't want to put it up every winter, but it might work okay. You can learn more about drip irrigation at the website of Dripworks, which I'll link below. They even have designers who will help you design your drip system if you want them to, free of charge. If you go that route, be sure you tell them about the change in the grade in your garden so they can take that into account.

Also, there is an irrigation forum here at GW and I bet the irrigation specialists there would be happy to answer your questions.

I agree with Larry that a pressure compensating system likely would work for you.

Dawn

Here is a link that might be useful: Dripworks