DRAIN ACE OF JEFFERSON COUNTY, TEXAS. 9 
flow (hio to storm tides, the river marshes which are periodically 
submerged when the Neches overflows, the higlier lands in the north 
half of the county which are frequently inundated by excessive 
ramstonns, and the necessity of coordinating drainage improvements 
with existnig systems of imgation canals, make the designing of a 
proper drahiage plan for this coujity unusually difficult. 
The lii*st consideration in plannijig the drainage of a large area is 
to divide it into such districts that each can be drained just as soon 
as the hnidowners are ready to undertake the improvements, without 
regard to progress in adjoinmg units. Natural watershed lines ordi- 
narily determme the boundaries of districts to be drained by gravity, 
while piunping units are usually planned to secure the greatest econ- 
omy in cost of admmistration, construction, and operation. The prin- 
cipal faults with the gravity districts heretofore planned have been 
that they were established without due regard to the natural features 
that shoidd determine the drainage units, and that ditches were 
designed without properly considering the areas that they would need 
to drain. 
In Jefferson County the division into practicable drainage districts 
is complicated by the fact that Taylors Bayou is the natural outlet 
for 597 square miles, practically two-thirds of the county. Tide 
water extends up this stream and some of its branches for 25 miles 
from Sabme Lake. Because the ground is so level, it is impossible 
to secure a greater slope for the water surface below the North Fork 
than 0.15 foot per mile at mean tide elevation. To provide capacity 
for the water that will come to it, this bayou must be considerably 
enlarged, and to spread the cost of this work equitably over all the 
land drained by the watercourse is no mean undertaking. 
The most practicable drainage plan could not be determined with- 
out having considered both irrigation and water transportation. 
This is particularly true of the latter, and in designing the drainage 
system hereua recommended due consideration has been given to the 
proposed Intercoastal Canal and to the improvement of several of the 
larger streams for transportation purposes. The plan recommended 
is believed to be such that the lands may be improved in logical 
sequence and without unduly burdening the property owners who 
must pay for the reclamation, and at the same time such as will 
result in the most effective and economical improvements. The fol- 
lowing pages show in detail how the various factors which enter into 
the plan for drainage and accessory results are provided for. Hy- 
draulic problems and methods of construction affecting the design 
of the drainage works are discussed, and estimates of cost are pre- 
sented for each drainage unit. 
78948°— Bull. 193—15 2 
