Page 275 - Water Engineering Hydraulics, Distribution and Treatment

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8.6 Types of Distributing Reservoirs
from the reservoir includes a bypass with a swing check valve
Plan
seating against the inflow.
Swing check
Where natural elevation is not high enough, water is
stored in concrete or steel standpipes and elevated tanks.
In cold climates, steel is most suitable. Unless the steel
in reinforced concrete tanks is prestressed, vertical cracks,
leakage, and freezing will cause rapid deterioration of the
structure. Ground-level storage in reinforced concrete or
steel tanks in advance of automatic pumping stations is an
alternative.
The useful capacity of standpipes and elevated tanks
½˝
is confined to the volume of water stored above the level
of wanted distribution pressure. In elevated tanks, this level
generally coincides with the tank bottom; in standpipes, it
may lie much higher. Steel tanks are welded or riveted. Their
Strainer
structural design and erection have become a specialized
activity of certain tank manufacturers.
Altitude valve
Elevation The function of elevated tanks and spheroidal tanks can
be expressed to aesthetic advantage in their architecture with-
Figure 8.8 Altitude valve on supply to distribution reservoir.
out resorting to ornamentation (Figs. 8.9 and 8.10). Stand-
pipes are simple cylinders. A veneer or outer shell of concrete
or masonry may make them attractive. They may be designed
Overflow capacity should equal the maximum rate of inflow.
as parts of multipurpose structures. The lower level may serve
Altitude-control valves on reservoir inlets (Fig. 8.8) will auto-
for offices, warehouses, or other functions. At the top, sight-
matically shut off inflow when the maximum water level is
seeing or restaurant facilities may convert a potential eyesore
reached. An arrangement that does not interfere with draft
into a center of attraction.

Figure 8.10 The mushroom-shaped concrete water tower in
3
Figure 8.9 Water storage tank (Source: http://en.wikipedia.org/ Helsinki, Finland. It is 52 m high and can hold 12,000 m of water
wiki/Image:Louisville_water_tower.jpg). (Source: http://en.wikipedia.org/wiki/Water_supply_network).