TM 5-820-3/AFM 88-5, Chap. 3
CHAPTER 8
CONSTRUCTION DRAINAGE
aid in maintaining satisfactory drainage during the
8-1. General.
construction period.
Proper consideration of drainage during construc-
tion can frequently prevent costly delays and future
a. Maximum use will be made of existing ditches
failures. Delays can occur not only because of
and drainage features. Where possible, grading op-
damaged or washed-out facilities but because of
erations will proceed downhill, both for economic
shut-down resulting from environmental consider-
grading and to use natural drainage to the greatest
ations. Proper construction drainage is critical to
extent.
efficient and timely completion of earthwork.
b. Temporary ditches will be required to facili-
8-2. Planning.
tate construction drainage. A particular effort will
Efforts to control delays or damages caused by
be made to drain pavement subgrade excavations
construction drainage must begin in the planning
and base courses to prevent detrimental saturation.
stage and carry through design and construction.
Careful considerations will be given to the drainage
Guide specifications have been developed by Divi-
of all construction roads, equipment areas, borrow
sion offices, but it is impractical to prescribe fixed
pits, and waste areas.
rules to cover all eventualities. Protective measures
cannot generally be reduced to biddable contract
c. Temporary retention structures will be re-
items.
quired in areas where open excavation can lead to
excessive erosion or discharge of turbid water to
8-3. Environmental degradation.
local streams.
Every construction activity can create environ-
mental impacts to some degree. Although the ef-
d. Random excavation will be held to a mini-
fects are usually temporary, it is important to
mum, and finished surfaces will be sodded or
minimize damage by anticipating problems and
seeded immediately.
applying protective standards of performance.
e. Installation of final storm drain facilities and
8-4. Protective measures.
backfilling operations will be planned and timed to
Control of runoff problems during construction can
render maximum use during the construction
be costly. Consideration of the following items will
period.
8-1
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