Arizona republican., 1902-11-18

issue report (Part " of the Twenty second annual report of the director)
 covering MT. Davis investigation in
 Nicaragua and Panama.
 The investigation of the water supply { for the Isthmian canal was as important
 la factor in the selection of the route
 as the survey of the physical features
 of the country through which it r~rst
 pass. If the original intention of the | French engineers to make the canal a
 tide-water passage had been carried out, the water supply of the country
 would not have been a factor to be con- i sidered, except for the embarrassment occasionally caused by extreme floods which might find their way into the canal. But when the tide water pro- ject was abandoned and it was decided i that a canal crossing the continental level of nearly 100 feet above the sea was the most feasible plan of construc- tion, it became of the utmost import ance to determine whether the natural supply of the region in the form of nearby streams would be sufficient to provide the amount of water neces- sary to operate the canal There will obviously be a constant drain on the waters of the summit level with every vessel passing through the locks which will be so considerable that large quantities of water must be secured to replcnish it. Careful estimates have placed this amount necessary to meer the losses from lockage, power. leakage means an unimportant factor in tropical climate-at an amount equal to a constant flow of 1,O7O cubic feet per second.
 According to the advance announce ment from the geological survey, MT. Davis report will show that the feasi- bility of the Panama route rests upon the magnitude and habit of the Chagres river, from which it must draw it's supply for the summit level, and from which it's lower levels will be in danger in times of flood. To q less de gree the Grande river, at the southern end of the line, is of similar importance.
 Before the Panama route could b. definitely recommended several import ant facts regarding the Chagres river had to be determined. First, the amount of it's minimum flow to find how little water might be expected at certain seasons to feed the summit lev el; second, the magnitude of its flood discharge, to show how much surplus water would have to be disposed of in times of freshet without injury to the canal or detention to its traffic; third, the possibility of storing water in res ervoirs for use in times of low water and fourth, a Knowledge Of the rainfall of the region, on which the flow of the streams depends.
 One of the first steps taken in the investigation was q careful review in Paris of the records of rainfall and stream flow kept by the engineers of ! the French Panama Canal companies, | both first and second, which, though fairly complete, were found lacking in respect to food records. The next step was to verify and extend these observa- tions. This was done by establishing gazing stations, where careful meas ! urements were made of the amount Of flow by means of current meters and | float rods and by gages set in the ! stream to record it's daily heights and 1 fuctuation from which the maximum. ! minimum, and mean discharges were computed.
 The projected canal from Colon to !, Panama is ~ miles long, and for more than half it's course it follows the val l ley of the Chagres river. Although ! the country is covered with heavy veg ! citation, the slopes are so precipitous and the rock is so near the surface that violent tropical rainfalls lasting only few hours cause heavy and sudden ! floods. This is the feature which ] makes the study of the flow Of the low l CT Chagres of such importance.
 The rainfall, though copious, was found to be peculiar on account of the i striking difference in it's amount on ! the northern and southern sides of the | isthmus, the mean yearly rainfall at | Colon being f3O inches while that ac Panama, less than 70 miles distant, | was only 66.S inches.
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