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March 24, 2008
City of College Station
Public Works Department
1101 Texas Avenue
College Station, Texas 77842
Attn: Carol Cotter, Graduate Civil Engineer
Re: Rock Prairie Heights Sanitary Sewer Capacity
Dear Ms. Cotter:
This letter shall serve as our revised report on the available sanitary sewer capacity of the
existing sanitary sewer serving the referenced proposed development.
The proposed development, which is 17 .221 acres, is located at the southeast intersection
of Rock Prairie Road and Old Rock Prairie Road approximately 1, 600 feet east of State
Highway 6 in College Station, Texas. The type of development shall be an apartment
complex with approximately 20 units per acre.
The existing sanitary sewer that is available to serve the proposed development is
approximately 1, 170 feet from the development. Currently, there is no known flow in
the existing sanitary sewer since the church it was serving has been abandoned.
According to available record drawings, the sewer is an 8" diameter PVC pipe with a
slope of 0.40%. Using "Mannings" equation and a coefficient of roughness (n) of 0.013
for PVC, the capacity of the existing sanitary sewer is 478,100 gallons per day at a
velocity of2.12 feet per second.
In order to develop the site, approximately 1,096 feet of 8" sanitary sewer, along with a
lift station and force main will be constructed by the developer. The location of the
proposed 8" sanitary sewer is show on the enclosed sketch. Utilizing a slope of .40%, the
capacity of the proposed sanitary sewer is 478,100 gallons per day at a velocity of2.12
feet per second.
Based on 20 units per acre, 267 gallons per day per unit, the apartment development will
generate a flow of 92,115 gallons per day. This is only 19% of the capacity of the
proposed 8" sanitary sewer, leaving 385,985 gallons per day available capacity for future
development.
If you have any questions regarding the information provided, please contact us.
Sincerely,
ENGINEERS • SURVEYORS • GIS
7600 W. Tidwell, Suite 400, Houston, Texas 77040
Phone: 713.462.0993 • Fax: 713.462.2732 • Toll Free 800.694.8241 • www.clri.com
CLR
March 25, 2008
City of College Station
Public Works Department
1101 Texas Avenue
College Station, Texas 77842
Attn: Carol Cotter, Graduate Civil Engineer
Re: Rock Prairie Heights Sanitary Sewer -City Standards
Dear Ms. Cotter:
This is to acknowledge that the City of College Station Standards have been followed for
the design of the referenced project.
F.H. (Rick) R
Senior Project
ENGINEERS • SURVEYORS • GIS
7600 W. Tidwell, Suite 400, Houston, Texas 77040
Phone: 713.462.0993 • Fax: 713.462.2732 • Toll Free 800.694.8241 • www.clri.com