We're MAD For Irrigation

MAD. It’s all the rage.

But, what is MAD? I’m glad you asked.

MAD is an acronym for Management Allowable Depletion, the best and most recommended way to schedule your irrigation. But what is it?

To explain, let me use an analogy. Imagine your soil is a sponge, and imagine that sponge is as full of water as possible. As the grass or plants absorbs water from the sponge, or as it evaporates into the air, the amount of water in the sponge becomes less.

With an older style of irrigation, water would be added to the sponge on a fixed, regular schedule, regardless of how much water has been removed. For example, the sponge would have water added every three days for 30 minutes each day. This could result in over-watering, because the sponge is already full, or under-watering, because the sponge became completely dry before a fill up.

With MAD, the goal is to add water to the sponge when it reaches a certain amount of dryness, but before it is completely dry. This has a few key benefits:

• It encourages plants to develop deeper root structures, which creates stronger, healthier plants that are more resistant to drought.
• It requires less frequent waterings, because each watering is for a longer period of time with the goal of deeper watering. The overall effect is less water used.
• It allows less water to be lost to evaporation, because the water is deeper into the ground.

It is called Management Allowable Depletion because this irrigation schedule allows the amount of water to deplete to a fixed level before refill.

Compared to a fixed schedule, MAD would fill up the sponge only when required, which could be every two days, or five days, or even longer!

There are two key factors that need to be calculated for MAD style of irrigation: how big the sponge is, and how much water is in the sponge at any one time. To get to those two elements, there are quite a few data points that go into this:

• The type of plant
• The type of soil
• The amount of precipitation
• The amount of water the plant absorbs
• The amount of water that evaporates

The challenge in calculating MAD is ensuring that the inputs are correct, particularly because they are ongoing inputs. However, once you have these inputs, you can create an irrigation schedule that is tailor made for your soil and plants, while saving a large amount of water.

Whenever you install or update your irrigation system, this is a great opportunity to make sure that you know what type of soil you have, and what types of plants are in each zone. This will allow you to be as accurate as possible when creating your watering schedule.

If you’d like to know how Rachio incorporates MAD, please check out our support articles on Flex Schedules.