The Panama Canal.

Progress, Volume III, Issue I, 1 November 1907, Page 26

The Panama Canal.

It will be remembered that the estimated area of the great storage lake, which is to be formed by the construction of the Gatun dam, was 1 10 square miles. This calculation was based upon the preliminary reconnaissances of the area to be flooded, and was understood to be only approximate The detailed surveys of the Isthmus, which have now been completed, show that the area of the lake will be more than double the original estimate, or 225 square miles. The larger lake represents some ver} material advantages in favour of the 85-foot high level canal as now being constructed, advantages which will be felt both in the wet and the dry season. In the first place, the lake will have sufficient capacity to receive and retain all the flood waters, even those of such heavy floods as occurred in December of last year ; and secondly, it will be possible to handle this water with considerably less fluctuation in the canal level. It is estimated that the increased lake area w ill double the amount of water that will be impounded in the lake at the commencement of the dry season. The statistics of past years show that, even in years of extremely small rainfall, the run-of+ from the area draining into the lake amounts, during the rainy season, to 7200 cubic feet rer second ; and this will be sufficient to raise the le\el of the lake the 4 feet which it will be lowered during the dry season Tt is true that because of the increased area of the lake, the evaporation will be double what it would have been from a lake of only 110 square miles area , but since the total supply impounded will also? be doubled it is estimated that, after deducting I " the loss by evaporation, there will be sufficient water available for fifty-six' lockages?" a r day, instead of twenty six, which was the number estimated as a-\ ailable with the smaller lake.