I have a 60' (long) x 30' (top to bottom) hill I am landscaping with perennials, a Japanese maple and some shrubs. I can't seem to find suggestions (on the internet) about how to account for the slope in my irrigation design. Are there concerns with pressure changes going up and down the hill? I was planning on using tubing and emitters where needed rather than predrilled drip tubing. I am considering using all the same emitters and adding more than one for larger plants. The farthest plants on the top of the hill from the spigot(source of water) is approximately 75-80 feet. I am brand new at this. Any suggestions would be appreciated
I hope the day finds you well :)
You do have it right, slopes can cause emitters at the bottom of the slope (and thus under more pressure) to emit more water than those at higher elevation. I think you're on the right track in planning to use button drippers rather than pre-installed emitter line -- this is because you can use pressure compensating drippers. Pressure compensating drippers can compensate for higher pressure caused by gravity, at least within a range. Many operate at 10-45 PSI, give or take depending on the brand. This means that within that range, they'll put out pretty close to the same volume of water.
As a quick example, let's say there's 10' of elevation drop between the top emitter and the bottom emitter and the starting pressure is 25 PSI. This means the top emitter will be operating at 25 PSI and the bottom emitter at 29.33 PSI (1' of elevation change causes a gain or loss of 0.433 PSI), but with a pressure compensating dripper, the one at the bottom will still be putting out approximately the same as the top (there is some variation, but it's very minimal with a pressure compensating emitter).
I hope this helps!
The Rain Bird Xeri-bug emitters have a check valve pressure compensating emitter that is design for use on hillsides.The XBCV emitter prevents drainage by holding back 10
feet (3 m) of water.
On a hillside emitters are only needed upslope from the plant and a small trough dug above the plant where the emitter is located helps to hold water back and give it time to sink into the soil.