Article 3, St. Anselm’s Response to a Drought: A Success Story


California has always been and will probably always be a water-short area. Water-conservation measures aid in preserving this increasingly scarce commodity.

St. Anselm’s has six large gardens.  Our water use during past two irrigation seasons has averaged about 1,500 gallons per day (gpd), except during August/September 2012[1], when usage spiked to 3,500 gpd, see Figure 1. The spike was probably due to an unattended hose left running.  Our base flow[2], which is fairly constant throughout the year and supports cooking, cleaning, and preschool and bathroom activities, consumes 200-300 gpd. The remainder is consumed by irrigation.

In response to the drought of 2014, we have cut our warm-weather water use to the range 400 to 800 gpd, see the red dashed line, Figure 1.

Final Water Chart
This reduction has been largely accomplished by trying to understand our gardens’ minimum irrigation needs and then throttling back water delivery to match those needs and by using our programmable flow controllers (timers) more effectively than we have in the past.  A stop watch and EBMUD’s water meter are used to assess flow volumes and flow rates to individual garden areas. 

Table 1 shows how radically our irrigation rates have changed.

Article 3, Table 1


While base flow has and will remain constant, irrigation rates havedropped precipitously.  Flows to the columbarium lawn, the major individual irrigation-water consumer, have been reduced by 1/3.  Flows to all other plants are now 28% of what they were previously.

Has this project succeeded?  Yes, it has.  We have maintained the health and appearance of our landscaping while reducing our water use and water bills    Table 2 shows just how much we have reduced them.  Water use has been more than halved.  Our water bills have been reduced by about 40%.

Article 3, Table 2

[1] Data are presented in two-month intervals because that’s how often EBMUD reports water usage.

[2] Base flows correspond to the troughs on Figure 1, cold-weather periods when there is no irrigation.

Doug Merrill

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