Passive Rainwater Harvesting Systems
If your goal is to grow mostly drought hardy perennial trees, shrubs, and flowers perhaps what you need is a rain garden. Rain gardens are intentionally created shallow depressions in the landscape that collect water when it rains. Further rainwater can be directed to the rain gardens from roofs, patios, or walkways. Depending on the water needs of the plants they are planted according to their water needs with more water loving plants in bottom of the basins and plants that like thing a little drier on the edges and next to the depressions.
Rain gardens are easy and require hardly any energy once they are established. You do not have to think about watering as the rainwater has already been designed to go to your plants. These tend to be much cheaper per gallon than active systems as the storage mechanism is the soil itself and can handle many more gallons than would be typically feasible in a tank or cistern. Eden on Earth are experts in designing rainwater harvesting earthworks into any situation.
