Item 7A - Support InformationM
100 TO:
FROM:
DATE:
Tons M Matthews, Jr. • 1600 E Southluke Blvd. . Suite 110-.313 Southluke, Terns 76091
MEMO
KEN BAKER
TOM MATTHEWS FAX NO.: 817/481 -4074
TELE NO.: Of. - 817/329 -6996
Mo. -- 214/676 -3434
EMAIL: tmatthews @fourpeaksdev.com
MARCH 30, 2009
SUBJECT: GLOSSER ADDITION
Ken, per your request from our meeting last week, please find enclosed a letter and
backup material from Michael Boyd, P.E with Nathan D. Maier noting that a
development like we are proposing will actually be better for the flooding issue.
Please call me if you should have any thoughts, questions or comments
Thanks,
tan
i
NATHAN D. MAIER ple
CONSULTING ENGINEERS, INC. .A fa
1 pjan 61nc
March 27, 2009
Tom Matthews, Jr., Principal
Four .Peaks Development, Inc.
2600 E. Southlake Blvd.
Suite 120 -323
Southlake, Texas 76092
RE: Proposed Glosser Addition, Southlake, Texas
Dear Mr. Matthews:
I have provided a preliminary look at the potential project that we discussed yesterday.
The project involved platting four 1 -acre residential lots out of a larger 10 -acre tract that
is bounded by North Peytonville Avenue and Sleepy Hollow. Higgins Branch flows
south to north through this parcel, which will separate the easterly 4 single- family lots
from the westerly larger property.
AS we discussed, I ran a preliminary hydrology model on Higgins Branch watershed to
establish the impact of adding some impervious area to the Sleepy Hollow property
(adding 4 lots to this tract). Pre project (existing conditions) have a peak combined flow
of 3038 cfs with 98 cfs coming off of the design subarea. For post project (with the
proposed development) we have a peak combined flow of 3030 cfs with 132 cfs coming
off the design subarea. We are increasing the flow off of our area by 34 cfs but
decreasing the peak flow in the creek by 8 cfs,
The condition is created because the runoff response time is faster when we put streets in
to convey the runoff from the smaller area but the larger watershed response time remains
unchanged, When the storm hydrographs are combined we get a slightly decreased peak
discharge at our point in the watershed.
Attached are copies of the computer models and a copy of the watershed map. If you
have any questions concerning this analysis please call or email.
Thanks,
44
Michael Boyd, A.E.
Executive Vice President
Two Park Lane Place / 8080 Park Lane / Suite 600 / Dallas. Texas 75231 / (214) 759 -4741
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