Northpoint Dr-CS020117Halff Associates
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8616 NORTHWEST PLAZA DRIVE
DALLAS, TEXAS 75225
(214) 346-6200
FAX (214) 739-0095
January l7,2002
Kenneth M. Griffin, P.E.
Director of Engineering & Public Works
255 Parkway
Coppell TX, 75019
RE: Amberpoint Business Park At Coppell, Northpoint Drive extension
Dear Mr. Griffin:
We have reviewed the comments dated December 19, 2001 regarding the above stated
plans. We have addressed the comments as follows
Sheet CPP01
1. We have reconfigured the proposed Northpoint Drive at the connection point with the
existing pavement. We have flared the pavement as requested. In addition, we have
revised the plat to reflect the changes to the right-of-way resulting from the flared
connection.
2. As requested, we ~,~ve widened the proposed access drive to the City of Coppell
elevated storage tank.
3. We have added a note to the general notes section that states that all construction shall
be in compliance with the City of Coppell Standard Details and subdivision Ordinance.
Sheet CPP02
1. The 54" storm sewer has been extended beyond the driveway as requested.
Sheet CPP03
1. We have shown the limits of grading as requested. The limits are shown on sheet
CGP01. We have added a wye inlet to pick up the low area shown on sheet CDA02.
This will insure that storm water does not pond adjacent to the proposed road.
Sheet CGP02
1. The proposed pilot channel was designed to help drainage in the pond during low
flows to reduce the possibility of standing water in the pond after a low flow event.
We feel that the pilot channel is large enough to serve this purpose. In, addition we
have added a toe wall to the design of the proposed pilot channel as requested.
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lll
-- Halff Associates
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Sheet CDA02
1. We have added a north arrow as requested. In addition, all drainage areas match
the drainage area designations in the plans for BLDG. 1
Sheet CDA03
1. All drainage areas are now consistent with those shown on the plans for BLDG.1.
Sheet CSD01
1. The rock riprap at the outfall of the 72" RCP will be grouted.
2. Prefab wyes are being used at the connection of the laterals as requested. In addition,
turning angles along the main storm line are now specified.
3. Concrete collars have been added at pipe size changes as requested.
4. We have increased the amount of cover over the 72" storm line between STA 1+50
and STA 2+50 to a minimum of 2 feet.
Sheet CSD02
1. A type B manhole has been added where the 54", 66", and 42" RCP's come together.
2. Dimensions from the back of curb to the storm sewer have been added.
3. We have fixed the typos on notes referencing lateral A2.
Sheet CSD03
1. We have revised lateral A-1 to provide a minimum of 2 feet between the top of pipe
and bottom of pavement.
2. We have removed all negative hydraulic jumps from the sheet.
3. We have added the use of ductile iron pipe for the 12" waterline where it crosses under
any proposed storm sewer.
Sheet CSD04
1. We have revised Lateral A-2 to provide a minimum of 2 feet between the top of pipe
and bottom of pavement. In addition, we have evaluated the effects that changes to
the drainage area map had on pipe sizing as requested. No increase in pipe size was
needed.
2. All hydraulic information for laterals A-2A and A-2b have been added.
3. Concrete collars have been added at pipe size changes as requested.
Il,
--- Halff Associates
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Sheet CSD05
1. The riprap at the outfall of line B will be grouted.
2. Concrete collars have been added at pipe size changes as requested.
Sheet CSD06
1. Slope-end sections have replaced the type B headwalls along the 18" RCP
under Northpoint Dr. at Sandy Lake road as requested.
2. We have revised the outfall of storm sewer line D to minimize conflicts with the
existing sanitary sewer manhole.
Sheet CWW01
1. The proposed 12" waterline has been extended to connect with the existing 12"
waterline within existing Northpoint Drive.
2. We have revised all 8" waterline stub outs to a minimum of 20 feet long.
3. Dimensions from the back of curb to the waterline have been added.
4. We have added a double detector check to the irrigation meter as requested.
Sheet CWW02
1. We have revised all 8" waterline stub outs to a minimum of 20 feet long.
Sheet CWW03
1. The proposed 12" waterline is now connecting to the existing 12" waterline in Sandy
Lake Road. As requested, we have verified the location of the waterline size change
from 12" to 10" along Sandy Lake Road. The size change is indicated on the plans.
Sheet CWW04
1. We have revised the proposed 8" sanitary sewer to reduce the depth of the pipe in
some areas. We feel it is necessary to keep the sanitary sewer line at the depth shown
in the plans in order to serve future buildings west of the proposed Northpoint Drive
and north of Building 1. In addition, we plan to serve future buildings east of the
proposed Northpoint Drive both north and south of the proposed sanitary sewer. Due
to the uncertainty of the layout of future buildings we feel that is in the best interest to
install the sanitary sewer at the depth shown in the plans to allow for the greatest
amount of flexibility in serving these buildings.
-- Halff Associates
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Sheet CWW05
1. We have moved the proposed 8" waterline within the limits of the 30' utility easement.
In addition, dimensions from the sanitary sewer line to the waterline have been added.
2. A blow off valve at the end of the proposed 8" waterline has been added.
3. We have moved the proposed 2" waterline and irrigation meter within the limits of the
30' utility easement.
Sheet CPMO1
1. Proposed signage has been added along the proposed Northpoint Drive.
We have also addressed other minor comments throughout the plans that are not
addressed in this letter. If you have any questions please do not hesitate to call me at
(214) 346-6324.
Sincerely,
Jaime R. Beard, E.I.T.
Cc: Jim Gaspard, Transwestem Commercial Services