DEAINAGB OF JEFFEESOlsT COUNTY, TEXAS. 9 



flow due to storm tides, the river marshes which are periodically 

 submerged when the Neches overflows, the higher lands in the north 

 half of the county which are frequently inundated by excessive 

 rainstorms, and the necessity of coordinating drainage improvements 

 with existmg systems of nTigation canals, make the designing of a 

 proper drainage plan for this county unusually difficult. 



The first consideration in planning the drainage of a large area is 

 to divide it into such districts that each can be drained just as soon 

 as the landowners are ready to undertake the improvements, without 

 regard to progTess in adjoinmg imits. Natural watershed lines ordi- 

 narily determine the boundaries of districts to be drained by gravity, 

 while pumping units are usually planned to secure the greatest econ- 

 omy in cost of administration, 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 should determine the drainage units, and that ditches were 

 designed without properly considering the areas that they would need 

 to drain. 



In Jefllei-son 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 dramed by the watercourse is no mean undertaking. 



Tlie 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 hcreui 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 bo such that the lauds may be improved in logical 

 sequence and without ujiduly burdening the j^roperty owners who 

 must pay for tho reclamation, and at the same time such as will 

 result in tho most efTectivo and economical improvements. Tlie fol- 

 lowing pjigcs show in detail how tlio various factors which enter into 

 the plan, for drainage and accessory results are provided for. Hy- 

 draulic pr()1)leins and meiliods of construction afTecihig tlve dc^sign 

 of the fh'aiiiiige works are (hscussed, and estiniat(!S of cost are pre- 

 sented for i".i(;\\ (h'ainag(! unit. 

 78048"— IJull. Ifjri— 15 2 



