Plant Answers

Express-News Weekly Article
Saturday, May 6. 2006
By Calvin R. Finch, PhD,
SAWS Water Resources Director, and Horticulturist
“Watering Once Per Week”

The rains we had last week and a week before that have been welcome. Most of us were able to avoid irrigating our lawns during that period. Research completed in

San Antonio in the late 90’s as part of the Seasonal Irrigation Program (SIP) proved that most San Antonio lawns will stay healthy and green with watering once per week. They will not look as good, but most lawns will survive with irrigation every two weeks. It is no coincidence that the one week and two week watering schedule are the basis of the drought restrictions that San Antonio and most other communities in the area impose when the Aquifer level falls. Stage one is declared when the Aquifer level measured at the J-17 well falls to 650 feet. At 640 feet, Stage II is imposed. You can still irrigate once/week based on address, but the hours that watering is allowed are reduced. Stage III goes into effect when the Aquifer falls to 630 feet. Stage III is when we are limited to lawn watering every two weeks – enough to keep the lawn alive, but it will not necessarily look great unless you have deep soil and shade.

In the summer time one-half of our water use is on the lawn. Stage I of the restrictions is designed to reduce water use on the lawn by one-third. The second week restrictions are expected to reduce water use on the lawn by another third. Homeowners that have zoysia, buffalo or Bermuda grass can quit irrigating all together and let their lawn go dormant. The lawn grass perks up again when the rains start without any permanent damage. Over half of the people in San Antonio do not water their lawn at all, so those of us who do have special responsibility to water efficiently. Unless we receive some big time rains before then, it is expected that we will be in drought restrictions by about May 27, 2006.

Even when the Edwards Aquifer is relatively high and we are not in drought restrictions, there are several rules to follow that are designed to reduce water waste. Irrigation is only allowed between 8:00 p.m. – 10:00 a.m., because that is when evaporation and wind are at their lowest.

The second rule to consider is that your water must stay on the lawn. Water running down the road is wasted water. In San Antonio, and most communities in our area, violation of either rule is a misdemeanor offense punishable by a fine of $50 - $250 for the first violation. In most cases, however, SAWS’ Conservation Enforcement Officers do not give a citation on the first offense. Businesses and homeowners are notified that a water waste violation has been reported and the individual is asked to change the behavior so the violation will not occur again. In situations where the violation continues, the Conservation Enforcement Officers put the address on the Water Waster list. If the behavior is witnessed again by the Officer or another SAWS Conservation official, the ticket is written.

Other ways to save water on your landscape include:

· Use a sprinkler that sprays large drops of water on a horizontal plane rather than up into the air. Some sprinklers are only 50% efficient.

· Only water when your lawn is dry enough to see it change color slightly and then apply enough water to fill the soil reservoir (usually ¾ inch).

· Take advantage of the SIP recommendation. Visit SAWS website at saws.org and click to Conservation to sign up to receive a free personalized e-mail or phone message telling you how much water your lawn needs. The recommendation is based on your lawn grass type and shade conditions. You do not need to be a SAWS customer to participate.