1903.) | HAUPT—DEEPER NAVIGABLE CHANNELS. 211 
the silt comes from within, two jetties give much greater promise 
of success, and the great work of Captain James B. Eads in open- 
ing the South Pass by parallel jetties curving to the westward has 
proven to be a boon to the country. These jetties were built under 
adverse conditions, as payments were conditioned upon results to 
be secured, and as the first pair of jetties did not suffice to give the 
requisite depth, it became necessary to build spurs, then a second 
line of works, and finally a second series of spurs before the legal 
depths were obtained. This, however, resulted in an over-con- 
traction of that outlet, and has caused the retarded currents to drop 
their sediment in the Pass above the jetties instead of beyond them, 
involving dredging. 
Probably the most successful work of this kind at a river’s mouth 
is that completed at the mouth of the Panuca river, Tampico, 
Mexico, where in two years’ time two parallel straight jetties were 
constructed about a mile and a quarter long across a bar, having 
depths varying from five to twelve feet, and as soon as they were 
finished a severe flood flushed the channel so completely that the 
depths of twenty-seven feet have remained ever since, the littoral 
current here being sufficiently strong to remove the sediment car- 
ried out beyond the jetties. The engineer of this work was E. L. 
Costhell, C.E. 
At Aransas Pass, a purely tidal inlet on the Texas coast, a single 
reaction breakwater, in an incomplete condition, has produced a 
progressive deepening by the control of feeble tides, unaided by 
dredging, and at a cost of less than one-third that of the estimated 
project, thus fully demonstrating the great practical utility of the 
single reaction jetty system at”the only point where an opportunity 
has been afforded for a test on a large scale in this country, after 
about fifteen years of persistent effort The Consulting Engineers 
of this work were Messrs. H. C. Ripley, Geo. Y. Wisner, and the 
writer. 
