Prepare your Watering System​

​Before trees are planted, shape the earth for passive water harvesting and install any piping, tanks, pumps or other equipment needed to implement your water resources strategy. ​

​Use passive water harvesting structures to capture runoff from direct rainfall, adjacent land areas, roofs, driveways and other impermeable surfaces. Make sure basins will infiltrate water quickly to avoid mosquito breeding. Construct overflow routes for large basins and swales that intercept water from slopes to direct excess rainwater safely to lower elevation depressions. Avoid digging into and around the roots of existing trees. Trees planted inside basins should be placed on a small mound or terrace to keep water and mulch away from the tree trunk.​

​You can size passive water harvesting depressions for the eventual mature size of trees or begin with a basin that is sized for the smaller trees you plant. Keep in mind the drip line of trees—the outer perimeter of the tree canopy where raindrops “drip” down from the leaves. The roots of trees generally extend horizontally to a distance wider than the tree’s drip line. Think ahead about how you will supply water at or beyond the drip line when trees reach their mature sizes. As you expand basins outward, be careful not to disturb tree roots. You may need to add a raised berm at the mature drip line to harvest more water rather than digging a basin deeper. ​

​Before planting, install any pipelines needed to distribute graywater and AC condensate to trees. If you will be using a rainwater tank, install the tank, piping, hose bibs, and distribution lines. Be sure the tank has an overflow pipe to route surplus water away, and fine-mesh screens on inlets and outlets to keep out mosquitos and other critters. Gravity-fed delivery is simple and saves energy. Rainwater tanks with pumps can deliver rainwater through drip irrigation systems and to higher elevation trees. ​