Conserve Water is the 4th of 7 Bay Friendly practices. Even with the wonderful winter rains, water is and will always be a scarce and valuable resource in California. Of all urban water use, landscapes consume 1/3 and most residential properties are over-watered by 30-40%. By 2020, the state will require all residents to reduce water consumption by 20%.
Water-wise landscaping includes more than water recycling and conservation. We also need to improve the water retention capacity of the soil, in addition to installing the latest irrigation technology.
To begin, follow procedures below for nurturing the soil - the 3rd Bay Friendly principle. Then continue to build on these principles to create a thriving, living soil with enough organic content to hold water and increase permeability.
Soil: first, know your soil texture – clay, silt, sandy.
o Incorporate 2-4” compost into top 6-12” of soil to reach a soil organic matter of 3.5% under turf and 5% in planting beds.
o In spring and fall, top-dress with compost around shrubs and trees and on turf/lawn;
o Regularly apply mulch as needed to all exposed surfaces to reduce evaporation.
Plants: install drought-tolerant California natives, Mediterranean plants and succulents:
o Not all native plants are drought-tolerant so be wary and match plant requirements with your soil type and microclimate;
o Select plants from Mediterranean climates; these are Chile, South Africa, Australia & New Zealand and of course Mediterranean countries that share our long dry summer seasons;
o Minimize high water use plants.
o Plant in fall to take advantage of winter rains that help roots become established;
o When planting, remember to leave enough space to allow plants to grow to their natural size… and adjust the irrigation as plants mature.
Minimize the Lawn:
During the long dry summer season, lawns require frequent watering, cutting with machinery, pesticides to remove weeds, etc. So where lawn is desirable for kids or pets, minimize its size and/or plant low ground-covers…
o Replace lawns with water conserving native groundcovers or perennial ornamental grasses;
o Avoid turf in areas less than 8 ft. wide to accommodate efficient irrigation;
o Avoid planting turf on slopes greater than 10% or in irregular shapes.
Hydrozone your Plants - Group Plants by Water Needs:
Basically this means grouping plants by their low, medium or high water requirements and sun/shade needs;
o Locate thirsty plants in smaller, more visible areas and where possible, in spots that naturally collect water;
o Plant drought tolerant species in larger planting beds;
o Discontinue irrigation for California natives once they’re established, and be sure to continue irrigating those that need ongoing water;
o Use separate irrigation valves and circuits for each hydrozone; lawn should have its own valve.
Harvest Rainwater, Recycle Water & Graywater:
Harvesting: redirect rainwater from your downspouts and gutters into a storage barrel to use for irrigation.
Recycling: refers to water treated at a regional facility that can be used for irrigation – but not for consumption.
Graywater (not suitable for drinking): wastewater from sinks, showers, bathtubs and washing machines can be reused for subsurface irrigation of roots of trees and shrubs (as it’s not contaminated by human waste).
The simplest way to get started is to harvest rainwater from your roof. For other means, check your local building codes.
Install High-Efficiency Irrigation System:
Irrigation systems are becoming more efficient and sophisticated. Weather-based self-adjusting controllers now have soil moisture and rain sensor shutoffs. For all your irrigation needs and materials, an excellent resource is
http://www.urbanfarmerstore.com/. If you plan to install the system yourself, bring them your planting plan and they can design it for you. Otherwise, to optimize water conservation, best to have a professional to it.
Once your system is up and running, be sure to maintain it properly; have a landscape professional check it once a year for leaks, broken tubes, blocked sprinkler heads, etc. For mature systems, check whether your local water district or utility company will provide a free irrigation audit.