ST9905-CS040429Suzan Taylor - RE: Bethel Road
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From: "Sam Meisner" <sam~freese.com>
To: <staylor~ci.coppell.tx.us>
Date: 4/29/2004 8:48 AM
Subject: RE: Bethel Road
CC: "Tricia Hatley" <thh~freese.com>
In the plans that we just submitted, the top of curb elevation over the culvert is 509.52 (at Sta 9+82) and the Iow
point just to the west is at 509.18 (Sta 9+00). Assuming that the full depth of the typical roadway section is
maintained over the culvert, the top of the culvert cannot be more than 507.68. When this culvert is resized to
allow for protection of the existing sewer line, the headwater needs to be within the freeboard limits established.
This would mean a maximum freeboard of 508.18 for ultimate flows or 507.18 for existing flows. The driveways
at Sta 9+48 and 10+71 are what control the road profile over the culvert. The current design shows both
driveways with a 2% rise from the gutter to the ROW and then a 4% and 6% drop to the existing driveway.
An option to raise the elevation of the road would be to increase the grade break at the driveways to a maximum
of 10%. This is traversable for most cars, but it is possible it could cause scraping problems with Iow ground
clearance vehicles. This change would allow the road to be raised 0.40 feet.
Another option to raise the road elevation would be to omit the rise in the driveway from the gutter to the ROW,
and instead maintain a 2% slope down before beginning a steeper slope (max 10%) at the ROW. A curb inlet
would be installed at Sta 11 +00 to capture all of the gutter flow upstream of the driveway at 10+71, and the
driveways could be graded to direct local runoff to the stream and away from the house. This change would
allow the road to be raised 1.30 feet. This change would create a sag point at Sta 7+75 and would require an
additional pair of inlets. It would also require reconstructing the driveway all the way up to the structure at Sta
9+48 (620 Loch Lane).
The current profile is the most desirable option and is the option we would recommend, but I know that there are
other constraints on the design of the culvert. If you have any questions please call me or Tricia.
Sam Meisner
?reese and Nichols, Inc.
p 214-217-2235
From: Suzan Taylor [mailto:staylor@ci.coppell.tx.us]
Sent: Wednesday, April 28, 2004 10:44 AN
To: Tricia Hatley
Subject: Bethel Road
Tricia:
file://C :~Documents%20and%20Settings\staylor\Local%20Settings\Temp\GW} 00001 .HTM 5/4/2004
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Have you had a chance to determine how much we can raise the road at the proposed culvert?
Thanks
file://C 5Documents%20and%20Settings\staylor~Local%20Settings\Temp\GW} 00001 .HTM 5/4/2004