Filoli’s Drought Response
A view across the north field to the back of the House. Photo by Jerry Barrack.
With record low rainfall for the 2013–2014 season, Filoli is taking several measures to reduce its water use this spring, summer and fall. Typically our garden uses a great deal of water during the summer months, but our efforts should considerably reduce that quantity this year.
The source of Filoli’s water is partly from our three wells and partly domestic water from Crystal Springs Reservoir. In a wet year, most of our irrigation water comes from our wells, but with fifteen months of very low rainfall, our wells are not able to keep up with our demand. In fact, two of our wells are completely dry, and the third can only supply a tiny fraction of our needs. Although we can purchase all the water we need from the neighboring reservoir, we feel we need to play our part in conserving like everyone else. The other consideration is the impact purchasing additional water will have on our finances.
After the Bay Area’s last significant drought in the 1980s, Filoli installed an irrigation system in the garden. Prior to that, all our irrigation was done using hose–end sprinkler heads. Upwards of two full workdays each week were spent manually watering the garden during the summer. Such an inefficient system led to a great deal of waste (both water and time), hence the decision to move to an automated system.
We feel we already do quite a lot to prevent the over use of water at Filoli. Our irrigation schedules are based on CIMIS (California Irrigation Management Information System), which uses historic weather data to predict evapo–traspiration (a measure of plant water use), and plant requirements based on plant type (turf vs. annuals vs. woody plants). This is then fine–tuned for specific microclimates within the garden like slopes, turf adjacent to a hedge, compacted soil, etc. With a good irrigation system, we are able to keep our plants supplied with just enough water to thrive, without much waste.
The other key to having an effective and efficient irrigation system is continuous monitoring by trained horticulturists checking the system for any troubles. Filoli staff perform a complete check of all our irrigation systems each spring correcting for broken or misaligned sprinkler heads and inspect for any cracked and broken parts. Then, throughout the dry season, our irrigation systems are monitored. Historically dry areas are regularly probed to check the water content of the soil. An irrigation system is only as good as the horticulturists who maintain it. You cannot be on autopilot and expect the system to take care of itself.
In the face of this severe drought, our plan is to operate under a philosophy of allowing parts of the garden to thrive, while other parts will be irrigated just enough so that the plants are able to survive. All display beds and highly visible sections of the garden will receive our standard irrigation amounts. A few of our less visible lawns will be allowed to go mostly or completely dry. Woody plants can survive with 40% of normal irrigation, so many of our orchards and other woody plants will be irrigated significantly less this summer and fall.
Filoli’s Planned Water Conservation Measures
Turf Areas scheduled for significant water reduction and planned order of reduction:
Recommendations For Your Garden
Many of these practices apply to any year in California, but they are particularly applicable for 2014: