Maybe you, like many of us, have wondered why the sprinklers are going when it is raining. We put the question to Cathy Brown-Wertz after we observed some sprinklers on a rainy Wednesday, April 22, 2020, and she sent the following informative response.

While we don’t have underground devices that automatically control the irrigation, we do monitor the system, consider weather conditions (recent past, present and near future) and adjust accordingly. Our “central control system” allows us to communicate with many individual controllers located on Campus from one access point. While at times, Wednesday’s rain was more than a drizzle, overall we felt it wasn’t enough precipitation to warrant shutting it off because of the lengthy dry spell we had gone through and it was running at a 50% rate.

Due to the unseasonably dry warm weather this April, some of the irrigation system was turned on a little earlier than usual. These zones went on at 50% of their normal rate. During this time, with everything coming out of dormancy, plants need some moisture. Many plants on campus are located under eaves and large overhangs, next to larger plants or within the drip line of trees. For plants and grass in these locations, they are especially vulnerable to drying out due to the overhead protection from rain and competition from tree roots. Consequently, it is easy to dry out in these places, and if this happens it can be difficult to make up for the lost moisture. Both ornamental plants and turf can be at risk for damage. While established plants can withstand some drought, new spring growth and young plantings are particularly vulnerable to injury (including death).

Our system was installed and modified over many years of acquiring lots, reconfiguring yards and accommodating plant growth. As a result, there are irrigation zones that water “open” and “protected” areas at the same time. Occasionally, in order to water dry areas, other areas may get extra water or vice-versa. In an effort to accommodate our ever changing landscape, and the zones that become impacted, we continually modify our water output by adjusting nozzles/sizes and head/emitter style where we can and reconfigure zones when we can. Unfortunately, we cannot just simply “add a new zone” because more water volume would be needed and the water meters that feed our mainlines are already being used to their maximum capability. Additionally, we have a variety of “programs” on the controllers we use that adjust water percentages and schedules to accommodate various conditions including weather, exposure, soil, and plant requirements. Some of these specific programs address wet or dry areas, plants vs. turf (especially important for mowing), shade vs. sun, new plantings, and annual beds.

The other item we consider is the city restriction on watering with the “odd/even schedule and skipping Fridays all together” rule. Sometimes this requires us to water (or give extra water) ahead of time to compensate for upcoming weather or events as we may not be able to water on a given day. During our watering season with the amount of acreage we irrigate, the volume of water available, and the time it takes to cycle the zones, it requires two full days of programs running from 4 p.m. on one day until 8 a.m. the following morning to complete the campus. We water during these hours to help conserve water by losing less to evaporation, and residents are less likely to be using their yards during these hours as well.

While we monitor the forecast and real time weather very closely, decisions to turn the system off can be tricky. Mostly the decision to shut down is made by 4 p.m. because that’s when the programs begin and we are leaving campus for the day. While the system can be controlled remotely, it’s a hard call to make when not on site unless a storm is blanketing the entire region. As you know so many of our weather systems are spotty at best with periods of sunshine in between and forecasts can prove unreliable on many occasions. If we shut down and the rain doesn’t come, the opportunity to water is missed and we might not have another again for several days due to the logistics of the system.

Thank you, Cathy. We appreciate the hard work of you and your team. The campus is beautiful.

A shortened version of this article appears in the July 2020 Panorama News.