Project Name
Project Number
UEPH Complex
Statement of Work
26 November 2001
treatment, the contractor shall determine if an on-site storm water retention/detention is required,
based on the requirements of the [insert appropriate agency].]
4-11
STORM DRAINAGE COLLECTION SYSTEMS AND GRADING.
4-11.1
Location of Connections to Existing Systems. [Insert installation specific connection
location requirements.] [The contractor shall select the connection location. Establish the location
for the connection based upon economics, design requirements, and downstream capacity.]
Connect with a manhole or appropriate drainage structure.
4-11.2
Building Connections. Connection to building roof or area drain lines shall be
designed and constructed in accordance with the International Building Code [2000 or latest
edition].
4-11.3
Storm Sewer System. The storm sewer gravity drainage collection system shall be
designed and constructed in accordance with the requirements of [Insert the state or local agency
having jurisdiction] [Insert the appropriate State Department of Transportation Drainage Manual]
[Insert the appropriate State Department of Transportation Road and Bridge Specifications]. Storm
sewer system shall be designed for a minimum of a 10-year return frequency and pipes shall be
sized for full flow. The minimum velocity of flow in conduits during a design storm shall be 45
meters per minute [2.5 fps]. The pipe capacity shall be determined so that the calculated hydraulic
grade line of the storm sewer drainage system(s) shall not exceed the curb flow line grade in
pavements and the finished site grades.
4-11.4
Manholes. Manholes shall be located at intersections and changes in alignment or
grade. Intermediate manhole maximum spacing shall be 75 m [250 ft] for pipes 900mm [3 ft] or less
in diameter or box drains with the smallest dimension less than 900 mm [3 ft]. Maximum spacing
for intermediate manholes on larger pipes and drain boxes shall be 150 m [500 ft]. Manholes and
manhole appurtenances shall be [pre-cast concrete] [insert other acceptable materials] and shall
conform to the [agency having jurisdiction] [Insert base standard]. Shape manhole inverts to the
shape of the pipe with cast in place concrete after installing pipes. The manhole lid shall have a
600mm [2 ft]. minimum opening as measured from the face of the wall or ladder where applicable.
4-11.5
Drainage of Grass Areas. Except at personnel and overhead doors, the difference in
grade between the finish floor elevation and the surface of the ground immediately adjacent to the
building shall be a minimum of 150 mm [6 in]. Minimum slopes across grass surfaces shall be one
percent. In grass areas, overland sheet flow shall be held to a maximum length of 30 m [100 feet];
then, a swale or an inlet must be used. Minimum slopes in swale centerlines shall be 0.5 percent.
Maximum swale side slopes shall be 1V: 4H and maximum swale depth shall be 600 mm [24 in].
Ditches shall not be permitted. Storm drain pipe, sheet flow surfaces, and swales shall be designed
to prevent standing water under normal conditions.
4-11.6
Minimum cross slopes in streets and roads shall 1:48 [1/4":1'] and the maximum cross slope shall
be 1:32 [3/8":1'']. Minimum sheet flow slopes across parking area and other paved areas shall be 1
percent. Curbs and gutters shall be installed at a minimum longitudinal slope of 0.30 percent.
Pavement collectors for storm water shall be by curb inlets and gutters, or drop inlets. Field inlets
and an underground collection system shall drain open areas. Ditches shall not be permitted. Gutter
spread (or inlet approach spread) in roads shall not exceed 3 m [10 ft] when measured from the
SOW-92
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