@njhaley I agree that getting accurate water usage from single-point emitter systems is cumbersome. You can back calculate an ‘Area’ value to plug into your zone that will be fairly accurate, but when you add more plants you’ll need to update that value. I agree it would be easier to just add a number of emitters for that. If you want to back calculate an area to give you a better reflection of your water usage for that drip zone, here’s what I did.
By the way, you may face other challenges with your current irrigation setup if I understand it correctly. Do you have cacti, shrubs, ground cover and trees all on the same zone ? The different emitter rates are nice for throttling the amount of water delivered per watering, but that range of vegetation also has a vastly different set of needs for frequency. For example, the cacti would be much better off with less frequent watering. They may eventually have problems if they are watered as frequently as your shrubs and/or ground cover.