Water harvesting and management is one of the first things (along with solar orientation) to consider when designing a yard.
Water can be directed in various ways, beginning with gutters, drains, chains, downspouts, etc.; moving across the land via swales, berms, and diversion ditches; and finally being stored in either containers or earthen depressions, ideally serving trees or other plants.
I’ve enjoyed as much as 4,400-gallon capacity storage at my rural home in Cochise County, Arizona. The smaller, flat-roofed building behind the house in the photo is filled 2/3 with the huge tanks which accepted water from the roofs of both buildings. The water (thermal mass) kept the building (a bathhouse) at a constant comfortable temperature year-round! (Enclosing them also protected them from solar damage, as well as damage from errant hunters.)
Today, I store not quite 300 gallons in a single storage tank (in the process of being artfully covered in this post), and I collect more at other places around the yard in a variety of containers. One tank is for bathing, another for birds, another for watering the most outlying vegetation. I also keep numerous other small watering dishes or ponds filled for lizards, birds, and other wildlife.
Almost all the water from my rooftop drains to one corner – not a good design (done in 1924), but not changeable now. Therefore, a storm could result in a huge pool of water right outside the kitchen door.
My solution: a swale (shallow depression) that drops slightly lower than contour westward from the house, alongside planting areas, then eastward, again slightly lower than contour, all the way across the yard, again alongside planting areas. The result: all the water is moved to where it can be used, and none of it flows off the property, and none of it pools where it is a problem! Yeah!
Here’s a 1-minute video of the flow of the water off the roof, overflowing the tank, around the new patio, and tracing the swale.
Since there are many forms of swales (wandering on or slightly off-contour, fish-scale, net-and-pan, etc., almost every property can be lightly amended in its topography to accomplish this same benefit.
When we added the patio, I designed it to contribute even more water into the swale:
Water harvesting techniques similar to these can be used on a larger scale to solve erosion and other problems.
Swales have even been used across the contour lines of parking lots (and filled with gravel to accept water while being driven on) to provide water to desert trees, providing shade for vehicles!
As I said, whatever your design, if you live in the desert, plan in your earliest considerations to harvest water! I can help you do that on small properties, or refer you to a specialist for large properties.