Sedimentation survey of Lago Dos Bocas, Puerto Rico, June 1985

A survey of the sedimentation of Dos Bocas reservoir, in central Puerto Rico, was conducted during July 1985. The survey showed that the capacity of the reservoir has declined from 30,420 acre-ft in 1942 to about 19,620 acre-ft. Sediment is accumulating in the reservoir at an average rate of about 251 acre-ft/yr, or about 0.83%/yr of the original capacity. The expected usable life of the reservoir on the basis of the long-term sedimentation rate is about 78 years. However, the sedimentation rate appears to have increased significantly since 1979. During the last six years, the average sedimentation rate has exceeded 600 acre-ft/yr. If this rate is maintained, the expected usable life of the reservoir would be about 32 years. (Author 's abstract)