2019-10-08 - Stockstill, Ray - Reasonable engineering practicesFrom:
Amy Yu
Sent:
Tuesday, October 8, 2019 1:55 PM
To:
Ray Stockstill
Cc:
AJ Ortega
Subject:
FW: reasonable engineering practices
Ray,
Have you seen the precise grading plan for your lot?
CALIFORNIA
Amy Yu I Associate Engineer
Design and Development
City of La Quinta
78495 Calle Tampico - La
Ph. 760.777.7047
www.laauintaca.aov
www.playinlaquinta.com
From: Ray Stockstill <scnbeach@earthlink.net>
Sent: Monday, October 07, 2019 11:48 AM
To: Amy Yu <Ayu@laquintaca.gov>
Cc: AJ Ortega <Aortega@laquintaca.gov>
Subject: reasonable engineering practices
Amy,
Quinta, CA 92253
Figure 1 below is what my foundation looked like before my home was built on it. The soil area that is 18' by
19' in the middle of the home is being redesigned. In Figure 2 you can see that the roofs drain into this area.
Based on the total area feeding into the courtyard for drainage divided by the area of the opening above the
courtyard, rainwater will be entering the courtyard at more than 8 times a 100 year storm during a 100 year
storm. There are no codes for the drainage in the courtyard so my engineer says that he needs to rely on the
appropriate standards found in the precise grading plan checklist, the engineering bulletins and the storm drain
checklist. My engineer said that it is a sump condition, which is mentioned in the plumbing codes in chapter 11
and sump also is mentioned on a check list. He said that using reasonable engineering practices that the
drainage design criteria should include a primary drain at the low stop in the center of the courtyard, a back-up
overflow drain away from the primary drain that is at a higher elevation in case the primary gets blocked plus a
minimum of a one foot freeboard. The principle debate between my engineer and the builder is the need for the
freeboard. My builder thinks that since there are no codes at all that having the pavers placed within 5-inches
of the pad is fine. My engineer feels that rainwater entering the courtyard on top of these pavers at 8 times the
rate of a 100 year storm will pose above ordinary risk of property damage. He said that the courtyard has its
own surface water elevation that is separate and distinct from the one for the front yard. He feels that the one
foot of freeboard should be included in his design criteria for the courtyard drainage because in his opinion, it is
a reasonable engineering practice given the potential for property damage if things go wrong in a 100 year
storm with the two drainage systems. I understand both arguments. My question is do you agree with my
engineer that including freeboard is reasonable engineering practice even though the stepdown will be slightly
less attractive or is it unnecessary and beyond a reasonable engineering practice? I'm trying to think like an
insurance company would if there was property damage during a 100 year storm that resulted from the
courtyard's drainage design.
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