MIL-HDBK-1005/7A
d) A minimum distance of at least 100 ft from the
outer edge of the catchment or related structures to subsurface
sources of contamination (such as septic tanks and cesspools)
where the ground surface is used as a catchment area.
e) Locate as far from sources of air pollution as
possible (for example, dust, soot, salt water spray).
4.6.5.1
Application.
Such areas are to be used only:
a)
Where there is no other adequate source of fresh
water.
b)
Rainfall is sufficient to supply the required
yield.
4.6.5.2
Types
a) Open Ground Surface Area. The catchment area
should be graded to facilitate collection of rainwater and to
eliminate depressions causing ponding, and should be paved with
impervious materials to prevent seepage losses. The collected
waters should be conveyed to a closed storage reservoir.
b) Roof Surface Area. Such areas should be used for
installations with small demand for water, or to supplement
ground surface areas.
4.6.5.3
Structures
a) Ground Surface Paving. Selection of the type
depends on soil conditions at the site. Use either concrete or
soil cement.
b) Training Wall. P rovide adequate training walls
around the catchment area. Provide curbs and gutters outside
the catchment for protection against erosion, scouring, and
contamination during heavy rain.
c) Spillway.
Provide an emergency spillway to
prevent overtopping.
d) Ponding Basin. Where feasible, make the basin
integral with the catchment area. Size it in conjunction with
the peak flow rates and capacity for discharging to storage.
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