HomeMy WebLinkAbout02-00500149- 00074292July 15, 2002
2551 Texas Ave. South, Ste. A, College Station, TX 77840
Ofc: 979.693.5359 Fax: 979.693.4243 Email: mdgcs@mdgcs.com Web: www.mdgcs.com
Spencer Thompson
Development Services
City of College Station
P.O. Box 9960
College Station, Texas 77842
Re: CSISD - Rock Prairie Elementary; Temporary Building No. 213evelopment Permit
MDG Job No. 000156
Dear Spencer:
Attached id a revision of the plan on the above referenced project, which illustrates the proposed new
temporary building. Accompanying is a hydraulic computation sheet showing increases runoff from the
proposed additional impervious cover. The 100-year rainfall event will increase run-off at the site by 0.38
cfs. This amount is trivial and should require no additional detention.
These revisions have been illustrated on an excerpt from the original site plan, in the same manner as the
first approved revision submitted February 12, 2001. Please call Greg Taggart or me if you have any
questions.
Sincerely,
MUNICIPAL DEVELOPMENT GROUP
Lenwood S. Ada
Project Manager
000156-c.02
TEMPORARY BUILDINGS
GENERAL INFORMATION
Description: Drainage basin upstream of proposed site.
Drainage Area (AMAJOR) = 0.036 acres
TIME OF CONCENTRATION (T„)
GIVEN
Maximum Travel Distance (DMAJOR) = 500 ft
/5eC
Velocity of Runoff (VMAJOR) = 1.00 ft
Coefficient of Runoff (CMAJOR) = 0.90
° NOTE: Minimum Tc allowed= 10 min.
2 YEAR FREQUENCY RATE OF DISCHARGE (Q)
Coefficient (e) = 0.806
Coefficient (b) = 65
Coefficient (d) = 8
5 YEAR FREQUENCY RATE OF DISCHARGE (Q)
Coefficient (e) = 0.785
Coefficient (b) = 76
Coefficient (d) = 8.5
10 YEAR FREQUENCY RATE OF DISCHARGE (Q)
Coefficient (e) = 0.763
Coefficient (b) = 80
Coefficient (d) = 8.5
25 YEAR FREQUENCY, RATE OF DISCHARGE (Q)
Coefficient (e) = 0.754
Coefficient (b) = 89
Coefficient (d) = 8.5
50 YEAR FREQUENCY. RATE OF DISCHARGE (Q)
Coefficient (e) = 0.745
Coefficient (b) = 98
Coefficient (d) = 8.5
100 YEAR FREQUENCY. RATE OF DISCHARGE (Q
RESULT
Tc(MAJOR) _ 8.3 min.
Rainfall Intensity (12) = 6.327"/h,
Q 0.207 Cfs
Rainfall Intensity (15) = 7.693n /h,
0.251 cfs
Rainfall Intensity (110) = 8.635x/,,
0:282 '0
Rainfall Intensity (125) = 9.861 'n /h,
25 _ 0.322 cfs
Rainfall Intensity (150) = 11.148"/hr
050 = 0.364 efs
Coefficient (e) = 0.73 Rainfall Intensity (Iloo) 11.639 n/hr
Coefficient (b) = 96i = 0.3$4 cfs
Coefficient (d) = 8