HomeMy WebLinkAboutDrainage Info MITCHELL
M
MORGAN
City of College Station 22 Jan 2015
City Engineer/Development Services
P.O.Box 9960
College Station,Texas 77842
Attn: Alan Gibbs,P.E.
RE: Drainage Design A&M Consolidated High School Gym Expansion
Dear Alan,
The following drainage information is being provided for the building expansion(primarily gym
expansion)of A&M Consolidated High School at 1801 Harvey Mitchell Parkway South in College
Station.
Background
The site is currently developed as a high school with parking lots, sports facilities,and one single
structure which houses the cafeteria, gym,auditorium,and classrooms. Smaller portable buildings have
been located onsite and have been recently removed in anticipation of this building expansion project.
Drainage from the existing site drains primarily in 3 major directions as seen on Exhibit 1. In the area of
this expansion project the drainage discharges primarily in one direction to Detention Pond#2 which then
discharges in a channel between Madera and Guadalupe streets. In addition,there is an existing storm
sewer in the area of the expansion that picks up flow from roof drains on the building and discharges that
flow across Welsh Avenue.
Proposed Site Improvements
Six portable buildings and a covered walkway will be removed to create room for the proposed
renovations. The renovations consist of additional bathrooms, a dance gym, concessions stand/ticket
office, lobby,corridor into the gymnasium,and a new entranceway. The attached Exhibit 2 illustrates the
current and proposed impervious conditions for the site.Exhibit 3 is a Google Earth image showing these
portable buildings that have recently been removed.
In addition to the building expansion,there will be utility relocations associated with the project. There is
an electrical line that will be relocated around the proposed building. The electrical line will require an
associated public utility easement as it is a public electrical line. Flowlines and slopes were checked on
the sanitary sewer line. It cannot be relocated from under the building because the line cannot meet
minimum service line grades per building code. Therefore,the private sanitary sewer line will be left in
place and reconstructed with required materials and embedment to meet building code requirements.
Removal of the six portable buildings and covered sidewalk will result in a decrease of 7,555 square feet
of impervious cover. The proposed renovations will result in a 7,219 square feet increase in impervious
cover. Overall the site will see a decrease in impervious cover of 336 square feet.
3204 EARL RUDDER FREEWAY SOUTH•COLLEGE STATION TX 77845• 979 260 6963 979 260 3564 FIRM#1443
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