This summer the city of Sacramento moved to conserve water with new rules that extended a watering ban earlier in the morning on watering days.
The heart of the water-use ordinance, which uses an odd/even day schedule, is a ban on watering lawns and gardens from 10 a.m. to 6 p.m. That's two hours longer than the previous limit of noon to 6 p.m.
But a look at what's behind the extended hours found that water conservation, even during the third consecutive year of drought, was just one of the ordinance's goals – and not the most important, ranking behind things like saving on electricity it takes to pump water.
The review also found that the new watering hours do not conserve as much water as possible considering the city's weather conditions.
That's because the ordinance's ban includes hours when the evaporation rate during watering is actually lower than during some of the hours Sacramentans are now allowed to irrigate.
An analysis by The Bee found that the city could conserve more water, especially during summer, if it would instead ban watering between 6 and 8 p.m. when temperatures and the Delta breeze are still robust.
Calculations show that during the summer – June, July and August – an evening watering ban from 6 to 8 p.m. would conserve 3.9 percent to 5.3 percent more water than the existing morning ban of 10 a.m. to noon.
That's a savings of as much as 16 gallons for a typical system that runs 20 minutes once a week over 1,000 square feet of lawn.
Should it really take research by the Bee to point these things out, or should we expect water managers to factor these things into the equation without the expert assistance of journalists?
The Bee also pointed out the easiest, and best, way to make sure your landscape irrigation accounts for both evaporation and transpiration:
Now if only I knew where to get one of these smart controllers...
Some of the newer "smart" watering controllers can sense weather conditions such as temperature and if it's raining, and adjust the amount of water used.
"If it's raining, it won't water. And if it cools down, it will water less," Ingels said. "You set your program, and it will take over."