DISTRIBUTION SYSTEMS FOR WATERWORKS. 117 
so that, although it will suffer damage from future earthquakes, 
this damage will not be at all fatal, and the city will not burn up as 
a result of it. 
DISTRIBUTION SYSTEMS FOR WATERWORKS. 
In a city subjected to earthquakes it seems practically impossible 
to suggest any method of construction which will make the mains 
and distributing pipes at all times perfectly secure. In my judgment 
the only remedy is to have within the city itself a large storage 
capacity, distributed among various reservoirs, and to have a more 
than ordinarily complete gridiron of mains with gate valves to cut 
out any main at every intersection. Further, the mains should be 
larger than would ordinarily be required, so that if a portion of the 
gridiron were shattered it could be cut out, but the water could be 
brought in undiminished quantities to the perimeter of the shat- 
tered area from all undamaged parts of the gridiron; that is, the 
mains should be so large that, although the water would have farther 
to travel in this case, there would be an adequate supply for fighting 
fire, if necessary, in the area where the mains were shattered. 
It would seem that in a city like San Francisco a special system 
of high-pressure salt-water mains, supplied from a pumping station, 
would be the best solution of the fire-fighting problem so far as the 
congested district is concerned. This plan has been recommended by 
the National Board of Fire Underwriters, and it is probably the 
wisest one under the circumstances. The pumping station should, 
of course, be protected from earthquake damage in every possible 
way. Perhaps it should be a floating station. The salt-water mains 
should be so laid out and so interconnected that nothing short of gen- 
eral destruction of the entire system could wholly shut off the water 
from any considerable area. 
In a city like San Francisco, where there is practically no damage 
from freezing, it would seem worth while to run the mains exposed 
everywhere, so that breaks could be located almost immediately. As 
these breaks would ordinarily occur only in scattered localities, and 
would not be very great in extent themselves, it ought to be possible 
to repair them in time to prevent any general destruction of the city 
by fire. Running the mains exposed would, of course, introduce diffi- 
cult problems at street crossings, but there is little doubt that such 
problems could be solved successfully if they were seriously studied. 
All this means greatly increased expense in the distribution sys- 
tem, but in a situation such as that of San Francisco it seems to be 
required. 
The earthquake effects at San Francisco also indicate clearly that 
& special study should be made of the problem of promptness in 
emergency repairs to the conduits and mains. It seems certain that, 
7171— Bull. 324—07 9 
