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1008 Woodcreek Drive,Suite 103 •College Station,Texas 77845
(979)693-3838•Fax:(979)693-2554•Email:MeClureBrowne@Verizon.net
June 15, 2007
Carol Cotter
Graduate Engineer
City of College Station
P.O. Box 9960
College Station, Texas 77842
Re.: Drainage Letter
Adamson Lagoon Building
MBESI No. 10140005
Dear Carol:
This letter shall serve as our drainage analysis of the proposed improvements for the above
referenced project. This project consists of the replacement of the existing ±2,300 s.f. pool
building with a new 5,300 s.f. pool building. The following table summarizes the storm water
runoff for the existing conditions, proposed conditions and the difference between the two
conditions:
STORM WATER RUNOFF SUMMARY
Storm Event Existing Flow Proposed Flow Difference
(cfs) (cfs) (cfs)
2-Year 0.46 0.69
0.23
5-Year 0.56 0.84
0.28
10-Year 0.62 0.95
0.33
25-Year 0.71 1.08
0.37
50-Year 0.81 1.22
0.41
100-Year 0.84 1.27 0.43
Existing Flow Data: 2,600 s.f. impervious(C=0.9)and 2,700 pervious(C=0.3), Tc= 10 min.
Proposed Flow Data: 5,300 s.f. impervious(C=0.9) and Tc=10 min.
Intensity[I=(b(Tc+dye]determined for each storm events is based on the associated b,d,e coefficients.
Based upon the above information, the storm water runoff from this project will be increased.
During the 100-year storm, the increase is less than 0.5 cfs. Therefore, the storm water runoff
due to the larger building is insignificant compared to the total runoff of the entire park area and
will have no impact on the adjacent or downstream properties.
N- 1%
catqlot
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Carol Cotter
June 15, 2007
Page 2
If you have any questions or need any additional information, please do not hesitate to call.
Sincerely,
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J. Dale Browne, Jr, P.E. P J.DALE BROWNE,JR.
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