Northlake 635(7)-CS000407Pacheco Koch
April 7, 2000
PK No.: 1568-99.371
Mr. Kent Collins, P.E.
CITY OF COPPELL
Engineering Department
255 Parkway Boulevard
Coppell, Texas 75019
Re: PSlNet Addition
Northlake 635 Business Park, Lot 1, Block A
Coppell, Texas
Dear Mr. Collins:
As requested, this letter is being provided to explain the design parameter used in sizing
the storm water treatment system for rainfall within the equipment yard. The system
was sized to collect and treat all the water from the initial surge of storm water from a
typical rain event. The rainfall intensity selected for treatment was that of a 2 inch/hour
storm event. This water will be collected and treated in an oil/water separator with
adequate capacity. 'The additional storm water run off generated from rain events with
a higher intensity will overflow to the sites normal drainage systems.
If you have any questions or need any additional information please contact me at your
earliest convenience.
Sincerely,
Steve A. Markussen
SAM/emf
1568-39
enc.
cc: Tim Motsch-Alpha Corporation