REPORT ON THE PANAMA CANAL 
203 
Slide was six and sixteen feet below the surface respectively. On the 
summit of Gold Hill, the ground water falls 40 feet below the surface 
in the dry season, as indicated by the zone of weathering. 
REMEDIAL MEASURES 
All slide material which reaches the Canal must, of course, be re- 
moved at a certain expense and inconvenience. This work is being 
prosecuted by the engineers with great vigor. They estimate that about 
9,000,000 cubic yards will have to be removed between the two Culebra 
SHdes; and the dredges can remove 1,000,000 cubic yards a month. But 
it must not be supposed that the Canal will remain closed for nine 
months; as soon as the channel has been sufficiently deepened and the 
movement of the sHdes becomes so slow that the dredges, even when in- 
terrupted by the passage of ships, can more than keep pace with them 
the Canal may be opened for navigation. This time is probably not 
far off. 
The Committee beheves that some sHding ground will continue to 
enter the Canal for several years to come, though in diminishing amounts. 
Any relatively inexpensive measures which tend to arrest the present 
active slides, or which promise to reduce the charge against maintenance 
of the Canal in the future are fully warranted. 
The composition of the rocks, their structural weakness, and earth- 
quakes are beyond the control of man, but a partial control of ground 
and rain water and the reHef of pressure by unloading certain areas are 
feasible, and the Committee will confine its suggestions to these measures. 
Control of the Water. — As early as the time of the first French Company 
the advantage of controlHng the water was recognized; and the New 
French Company made several attempts to keep the water out of the 
relatively small slides of their time by surface drains and tunnels, but 
with only partial success. The Committee beheves that every available 
and practicable device should be used to turn the water falling as rain 
from all ground that is sHding and prevent its entering adjacent ground, 
and it suggests the following measures: 
1. Covering Slopes with Vegetation. — Whether vegetation increases 
or decreases the amount of rainfall entering the ground is still a moot 
question. The Committee beheves, however, that threatening ground 
bordering the slides, quiescent sHdes, and, so far as practicable, active 
sHdes themselves, should be sufficiently covered with vegetation to pre- 
vent surface wash. 
2. Closing Peripheral Cracks. — Before extensive movements of the 
