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Plaza Watering


I have a Delphi Question regarding the new Tree Plaza at the Mesa Lab.
There is almost always a puddle or damp stain on the concrete surface due
north of the apex of the highest grass terrace. It appears to be seepage
under the concrete bench. Is it just a drainage problem from the
sprinklers, or has a possible leak in the underground plumbing after the
control valve opens to the sprinkler heads been considered? It is rather
persistent in spite of the hot weather we have been experiencing.

Also, in view of the reasons given for the use of grass in a June Delphi
column (,
it appears that the sprinklers are either insufficient or not properly
adjusted. Areas of brown are beginning to appear on some of the terraces.
Seems odd to go through all of the expense and have some obvious problems
remain. Thanks.

Answered on July 02, 2001


As should be expected with a large flat surface like the Tree Plaza, water
may sometimes pond. The new drains installed during the renovation
alleviated most of these ponding areas. You are correct, however: water is
ponding north of the highest grass terrace. After running the sprinklers,
the water is percolating through the soil and seeping under the north
bench, rather than running west as was designed.

This problem was noted during construction. Unfortunately, the remedies
have been only marginally successful. The underground plumbing is not leaking.

During the recent 90-degree heat wave, the sprinkling schedules were
adjusted to minimize the browning areas. Even with the challenges of
managing the grass and the irrigation system, I hope you can agree that the
Tree Plaza looks much better than before the renovation.

-Tina Bogott, Project manager, Mesa Lab refurbishment