HomeMy WebLinkAboutWastewater Design Report July 25, 2011
Mr. Stephen Maldonado Jr.
City of College Station Water Services Department
1101 Texas Avenue
College Station, TX 77842
Re: Wastewater Design Report
Proposed Stepping Stone School
205 Rock Prairie Road
College Station, Texas
Gessner Engineering Job No.: 11 -0152
Dear Mr. Maldonado:
The peak wastewater flow was calculated in accordance with the fixture count
determination method. A total fixture unit count of 72 was determined for this
building. This calculation was determined based on the fixture unit Toad factor
given in Table I of the Sanitary Sewer Chapter of the Bryan /College Station
Unified Design Guidelines. The values are shown below in Table One.
Fixture Number Load Total
Factor Value
Lavatory 11 2 22
Dishwasher 1 2 2
Washer (Clothes) 1 4 4
Shower 1 3 3
Water Closet,Tank 8 4 32
Operated
Commercial Sink 3 3 9
(Service) Gessner
Total 72
Table One: Fixture Units Engineering
The peak wastewater flow based on the fixture units is 125 gallons per 2501 Ashford Drive
minute for less than 500 fixture units. Using the Manning equation with Suite 102
an n value of 0.013, the velocity in all sections of the proposed sewer
line were calculated as shown in Table Two below. College station, Texas 77840
P.O. Box 10763, 77842
Pipe Section Pipe Size Pipe Slope Pipe Velocity (ft/s)
(in) (io) 979.680.8840
BLDG - TIE -IN 4 2.00 3.43
Table Two: Pipe Size, Slope and Velocity fax 979.680.8841
All pipe slopes are within the required range of minimum /maximum
pipe slopes for sanitary sewer from the Bryan /College Station Unified 2204 S. Chappell Hill Street
Design Guidelines.
Brenham, Texas 77833
979.836.6855
fax 979.836.6847
Please contact us if you have any questions or if we can be of further assistance.
Sincerely,
GESSNER ENGINEERING, F -7451 ''.c.,9 ��A��1`
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Melissa P. Thomas, P.E. : ....... M
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