not suited to any other type of pump. An air-lift pump can draw more water from a well,
with sufficient capacity to deliver it, than any other type of pump that can be installed in a
well. A number of wells in a group can be operated from a central control station where
the air compressor is located.
The principal disadvantages of air lifts are the necessity for making the well deeper
than is required for other types of well pumps, the intermittent nature of the flow from the
well, and the relatively low efficiencies obtained. Little is known of the efficiency of the
average air-lift installation in small waterworks. Tests show efficiencies in the neighbor-
hood of 45 percent for depths of 50 ft (15 m) down to 20 percent for depths of 600 ft (183
m). Changes in efficiencies resulting from different submergence ratios are shown in
Table 3. Some submergence percentages recommended for various lifts are shown in
Table 2.
This procedure is the work of Harold B. Babbitt, James J. Doland, and John L. Cleas-
by, as reported in their book, Water Supply Engineering, McGraw-Hill. SI values were
added by the handbook editor.
Water-Supply and Storm-Water System DesignWATER-SUPPLY SYSTEM FLOW-RATE
AND PRESSURE-LOSS ANALYSIS
A water-supply system will serve a city of 100,000 population. Two water mains
arranged in a parallel configuration (Fig. 9a) will supply this city. Determine the flow
rate, size, and head loss of each pipe in this system. If the configuration in Fig. 9a
were replaced by the single pipe shown in Fig. 9b, what would the total head loss be if
FIGURE 9. (a) Parallel water distribution system: (b) single-pipe distri-
bution system.