Trinity Shores-CS011226T H i= C I T Y 0 F
A 8 . ~
December 26, 2001
Houshang Jahvani
Jahvani Engineering Associates
2125 N Josey Lane, Suite 202-B
Carrollton, TX 75006
Trinity Shores
Construction Plan Review Comments
Dear Mr. Jahvani:
The City of Coppell has reviewed the revised plans and has the following comments to offer:
Final Plat-
1. The minimum finished floor elevation should be 1 foot above the ultimate flood plain
elevation or 2 feet above the existing flood plain elevation. In this case, Lots 1-5 and Lots
15-19, Block A should have a minimum finished floor of 447' and Lots 6-14, Block A should
have a minimum finished floor of 446.5'.
Sheet 3 -
1. The grading plans should show both existing and proposed contours on the property.
2. The letter of permission provided for the property to the east and north of Lots 13-19, Block
A shows the property owner as Bryine M. Graham. Our records show the property owner is
Fred Harrington. If the property owner is Bryine Graham, then the letter of permission
should be notarized. Also, if Bryine Graham is the owner of the property, the final plat
should be changed as it still shows Fred Lee Harrington as the owner of the property.
3. A letter of permission is also needed for the property to the south, which your plat shows is
owned by Golf Enterprises.
4. The elevations shown on this sheet for Lots 14 and 15 are different than those shown on
Sheet 4. The finished floor elevation of 448.75' for Lots 14 and 15 is probably too low
considering they are located at a low point. With driveways off of Trinity Court, you could
get flooding in the street during a heavy rain. If the inlets were malfunctioning, the
driveways of Lots 14 and 15 could allow water to enter, potentially flooding the garage area.
5. On this sheet and on numerous sheets throughout the plans, there is a scale of 1"--40' in the
title block and a scale of 1"=50' adjacent to the North arrow on the plan. Please revise and
be consistent.
255 PARKWAY ~r PO.BOX 478 dr COPPF'LL TX 75019 ~' TEL 972/462 0022 dr FAX 972/304 3673
Sheet 4 -
1. In general paving note//3, please be advised that lime shall be applied at a minimum rate of
30 lbs. per square yard.
2. The minimum grade around the cul-de-sac is 0.5%. Please provide additional spot elevations
to insure that has been met.
3. These construction plans cannot be approved until such time as we have received, reviewed
and approved the revised Sandy Lake Road plans from Sverdrup that show a relocated inlet
and a relocated transition area that do not conflict with your proposed street location.
Sheet 5 -
1. Once again, you are showing pipe sizes for line ST1 in the plan view that are different than
what is shown in the profile view on Sheet 7. As previously stated, the City of Coppell is not
here to provide quality control on your plan design. Please provide consistent pipe sizes
throughout the plans.
2. Line ST1 should be centered in the proposed 20' drainage easement or an additional drainage
easement should be provided from the property to the north so that there is a minimum 10'
on each side of the storm drain pipe.
3. Your inlet data shows a grate inlet for drainage area 2A. However, in the plan view you
show a wye inlet. Which is it?
4. Your inlet data shows drainage areas 2A, 2B, and 2C to have two grate inlets. Your
information shows those inlets to be 4' x 4'. Please be advised that our Standard Details
show those inlets to be 1'5 %" x 5'2 ¼ ". Please be consistent with our details.
5. Our construction plans show that the lots in Riverview Estates that back up to Lots 3, 4, 5, 6,
& 7 installed onsite drainage systems at the rear of those lots. If they did, you should show
that information on your plans. The location of those inlets, and the grading on the back of
the lots in Riverview Estates, could impact your ability to have that drainage flow to your
proposed inlet systems.
Sheet 6 -
1. You should provide the angle for all bends in the storm drain system. Also, all bends should
be factory.
2. The wye inlet at station 7+30 on line ST1 and the wye inlet at 2+13 of line ST1 will not
function during a 100-year storm. Please be advised that the entrance to these wye inlets
should be above the 100-year water surface of 443'
Sheet 7 -
I. As previously stated in comments for Sheet 6, the ~vye inlets should be above the 100-year
water surface. Your previous design showed the wye inlets to be at an elevation of 444'.
Please advise why they were lowered with this design.
2. Your plans show the wye inlet at station 2+13 to be at an elevation of 449'; however, the
plans call it to be 443'. Please revise. As previously stated, the pipe sizing on ST1 is
inconsistent with the plan view.
3. What is the outfall velocity on line STI?
4. Our experience with headwalls, in locations such as the one you are showing for ST1, is that
over a short period of time they tend to erode, settle and break the pipe. The City of Coppell
is then expected to access those systems, repair the pipe and stabilize the headwall. We
accomplish that by, at times, providing piers for the headwall to help carry the weight.
Please design your headwall with piers so that it does not settle and break the pipe in the
future.
Sheet 8 -
1. You are showing a 12" plug on an 8" water line at your east property line along Sandy Lake
Road. Please be consistent. Also, there should be some type of blow off or fire hydrant
provided at the end of the water line.
Sheet 12A-
l. These details show walls around parking lots, streets, entry features, walls that have metal
hand rails, etc. Please provide information on where these various details apply to your
construction plans.
Sheet 12B -
1. Once again, the details provided for these retaining walls do not appear to be applicable to
what you're proposing with your development. As a reminder, you are proposing to slope
your ground away from the retaining wall and to have a fence on top of the retaining wall.
Please be advised you should submit retaining wall plans for your development, not just
generic designs.
There are various other minor comments throughout the plans that also need to be addressed.
Once all comments have been addressed, please re-submit these marked-up plans and two sets
of revised plans to the City for an additional review. If you have any questions, please contact
this office at your convenience.
Sincerely,
Kenneth M. Griffin, P.E.
Director of Engineering & Public Works