Water Harvesting 101 introduces you to:

Passive Water Harvesting: This is the act of sculpting your land with basins, berms, and drainage swales. The goal? To channel rainwater toward plants and away from structures – like your house. Passive water-harvesting earthworks eliminate the need for landscape irrigation connected to municipal water systems. In arid regions, that spells substantial cost savings.

Active Water Harvesting: Want fresh garden produce when it's 105 degrees out? And it hasn't rained in six weeks? At my place, the 1,500-gallon rainwater harvesting cistern makes year 'round gardening possible. And, on wash day, I don't let the wastewater go down the drain. Instead, I use a greywater harvesting system that effortlessly diverts that wastewater from the laundry to my four fruit trees.