Mobil Sta MacA-CS 890816Page Two
Mr. Doyle
Job No. 8804704
August 16, 1989
The 8-inch connection at manhole station 0+00 was constructed by the Mobile station
contractor 1.14 feet higher than designed and the invert elevation of manhole
station 0+25.79 was constructed the Mobile station contractor 1.28 feet higher than
designed. The Dallas County 10' x 6' RCBC was constructed approximately 0.13 feet
lower than designed. An 8-inch sewer line that extends from existing 0+25.79
manhole and clearly passes under 10' x 6' RCBC must lie on a ±0.11%.
Construction Alternates
(Based on limited knowledge of available sewer service and flow characteristics of
properties east of Valley Ranch Center)
Reconnect 8-inch to existing manhole 0+00 at invert flowline 431.90 and
reconstruct manhole 0+25.79 to invert flowline to 431.98. Install remainder of
Line "SA" per approved construction plans resulting in a ±0.05 pipe separation
at 10' x 6' RCBC crossing.
Construct line "SA" from Station 0+25.79 to Station 6+01.90 at a minimum 0.33%
from the existing manhole 0+25.79 to service Valley Ranch Center only. Trinity
River Authority, City of Coppell, or Dallas County install sewer service
across Belt Line Road from eastern property's northwest corner to existing
33-inch on north side of Belt Line Road.
o Install siphon under 10' x 6' RCBC.
o Punch 8-inch sanitary sewer through 10' x 6' RCBC.
Due to a critical construction schedule, please respond to this issue as quickly as
possible. Thank You.
Sincerely,
SKL/rel
cc: Scott Morway
Rick Walker
Howard Pafford
Steve Gorham
~Larry Davis
Mike Robertson