[ 41 ] 
The Silt Problem and Storage Reservoirs. 
9 
which is lower than the result obtained for the Brazos river, notwith- 
standing the black rises in the latter river carry mnch less sediment than 
the average. 
Recurring again to the enormous discharge of the Brazos for one year, 
amounting to more than seven and one-half million acre feet, it is clear 
that a storage reservoir on the lower reaches of the river would be out of 
the question even if a suitable site for a dam could be found, because it 
would be utterly impossible to construct a reservoir that would hold more 
than a small fraction of the total annual discharge, and the remainder 
that would have to be allowed to pass the dam would deposit a portion 
of its sediment on its way through the reservoir, just the same as occurred 
at the Austin dam where Professor Taylor has told us the lake was prac- 
tically half filled with sediment in seven years after it first filled. This 
same matter of silt will be a serious problem to contend with in the event 
that navigation of the Brazos should ever be attempted, because with 
every flood the channel will silt up in places and the construction of locks 
and dams will facilitate the deposit of sediment above the dams. During 
the past year and a half the channel of the river has been deepened con- 
siderably at the Jones’s bridge, where my observations were made, but on 
the subsidence of each flood it begins to silt up again. No better time 
could have been found for making a survey of the Brazos than we have 
had during the time the surveys have been carried on, if it be desired to 
produce a favorable impression as to the navigability of the stream, but 
when one considers that enough mud has passed the Jones’s bridge in one 
year to cover more than 7000 acres ten feet deep, after reducing the 
quantities given in the foregoing pages to the probable results at the end 
of the year, it can easily be seen that the attempt to form any kind of 
lake by damming the river must lead to the deposition of no inconsider- 
able amount of mud. Along the upper reaches of the river it is possible, 
no doubt, to construct storage reservoirs, and one such system was pro- 
jected in 1896, the dam to be situated in Knox county, and from the 
reservoir water was to have been taken not only down the Brazos valley, 
but also across the divide into the Wichita river valley as well. 
For the Wichita river it is seen that there is a possibility of construct- 
ing a reservoir which should have a capacity fairly large in comparison 
with the total discharge. The seven months covered above yield consid- 
erably more than the average discharge and the point at which observa- 
tions were made being forty miles below the site of the proposed dam the 
watershed at this latter point would probably be less than two- thirds of 
the watershed above the gauging station. 
I have not been able to make any comprehensive computations of the 
total silt discharged by any of the other streams upon which determina- 
tions have been made, and for the purposes of this paper it may be just 
