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Cornell specialist: Automatic systems no easy way out

BEVERLEA WALZ PHOTO | Dr. Tamson Yeh of Cornell Cooperative Extension reported to the Irrigation Committee Saturday March 1.

Dr. Tamson Yeh of Cornell Cooperative Extension reported to the Irrigation Committee Saturday March 1.

Set it and forget it? Fugetaboutit.

That’s the message about automatic irrigation systems that Dr. Tamson Yeh, turf management and pesticide specialist at Cornell Cooperative Extension, brought to Shelter Island Saturday, March 1. Dr. Yeh told the town’s Irrigation Committee and handful of residents that no matter how much you spend for the most sophisticated automatic irrigation system, there’s no easy way to effectively water your lawn.

Dr. Yeh’s report came on the heels of the Town Board passing a resolution the day before to hold a public hearing to extend the moratorium on automatic irrigation systems through December 31. Originally the ban was slated to take affect in September 2013, but after hearing some heated exchanges from the public at a meeting last August, the board put a moratorium in place until July 2014. Now, if passed by the board, the ban on the automatic systems will extend for all of 2014.

Dr. Yeh explained the complexities of not just the Island’s aquifer, but its many types of soils and the near impossibility of giving your lawn just enough water to nourish roots without over watering and destroying them.

Even quarter acre lots on the Island are likely to have more than one type of soil and each type has its own absorption qualities, she said.

Leave it to Mother Nature, Dr. Yeh advised, except for the occasional extremely hot and dry period when lawns might need just enough water to make up the evaporative process so grass doesn’t become irreparably damage. Lawns beginning to turn brown is nature’s way of protecting the grass and, if left alone, it will recover when it rains, she said.

“What happens to it when you don’t irrigate?” Dr. Yeh asked rhetorically. “Absolutely nothing.”

Defy Mother Nature and Dr. Yeh’s advice and if you’re going to effectively care for your lawn and you will have to become an expert on soil, various weather conditions, including wind, and make constant adjustments to assure proper watering. Being a mechanic is essential, since they system has to be monitored closely to ensure there are no leaks or malfunctioning sprinkler heads. In addition, you will have to understand the effects of evaporation, precipitation, infiltration, runoff, percolation, freezing, thawing and traffic across your lawn, Dr. Yeh said.

Employing an experienced lawn maintenance is not a solution either, the scientist said. The best companies have personnel who take courses and get certified. But there’s no requirement that such companies use properly trained and certified workers.

And how does all this affect the town’s shallow and fragile aquifer?

Dr. Yeh said she can’t make judgments about whether the approximately 100 known automatic irrigation systems or the others that aren’t registered but operating here are having any dramatic effect on the aquifer. She deferred to the Irrigation Committee’s consultant, John Benvegna, on that issue who has said he sees the effect as minor.

But Dr. Yeh cited statistics that show that homes with hose-based systems average 28 percent less water use than those with in-ground systems without timers. And properties with inground systems that have timers use 43 percent more water than those without timers.

Those figures vary from information the committee has received previously, claiming that less water is consumed by automatic irrigation systems than by someone watering with a hose.

In response to a question about the effect of all the snow the Island has had this winter in terms of replenishing the aquifer, Dr. Yeh said that given the drought that proceeded the snow, it’s unlikely the snow melt has sufficiently filled the loss.

That answer came more fully Monday morning from Ken Pysher of the Water Advisory Committee who offered the latest data from the United States Geological Survey on the monthly water levels in test wells (see previous post).

There needs to be a lot of replenishment of the aquifer this spring to avoid a call by the Water Advisory Committee for water use restrictions. The precipitation this winter is so far not resulting in raising water levels at five test sites, Mr. Pysher said.

That could change between now and May when the season of more heavy water usage typically begins on Shelter Island. But if it doesn’t, it’s entirely possible there may be a need for water use restrictions, according to WAC chairman and Irrigation Committee member John Hallman.

The Irrigation Committee will get a report on recent field tests of chloride levels in test wells at Thursday night’s meeting at 7 p.m. at Town Hall. The Town Board will take up the issue of extending the date by which the committee would issue its final report from mid-July to December 31 at its March 28 meeting. That meeting begins at 4:30 p.m. with the public hearing on extending the automatic irrigation moratorium scheduled for 4:50 p.m.