DKAIIfAGE OF JEFFEKSON COUNTY, TEXAS. 17 



Although the Intercoastal Canal must be constructed before the 

 reclamation of districts Nos. 24, 25, 26, 27, 28, 29, 30, and 32 can be 

 carried out according to the plans presented herein, the cost of its 

 construction is not charged to these districts. They are dependent 

 upon the Intercoastal Canal for outlet, but since that waterway wUl 

 be a benefit to the whole county as weU as to adjoining counties and 

 as it is possible that Federal appropriations will be made to help carry 

 out this work no estimate is made of its cost. Should a different route 

 be selected for the canal, the plans for the drainage of the above- 

 named districts must be changed accordingly. 



CITIES AND TOWNS. 



The city of Beaumont is not included in any drainage district under 

 the present arrangement. Some parts of the city will receive direct 

 benefit when certain ditches of district No. 10 are constructed, but 

 just what this benefit will be depends in part upon the location and 

 construction of sewers. The greater part of Beaumont is drained into 

 the Neches River and may be considered as a separate and inde- 

 pendent drainage district. Port Arthur also is excluded from any 

 of the enumerated drainage districts. It hes on very low ground and 

 is affected by the same conditions as districts Nos. 16 and 17, but it 

 has already buUt its own drainage system, including open ditches and 

 pumping plant. The towns of Sabine and Sabine Pass and the half- 

 mile strip of land connecting them, which have been filled in by suction 

 dredges working in the Sabine Pass channel, are also excluded from 

 any of the numbered districts. 



DRAINAGE DITCHES. 



CAPACITIES AND DIMENSIONS. 



The first step in designing the drains for each district to be drained 

 wholly or partly by gravity was to determme the area that will be 

 drained by each ditch, including the areas drained by each main 

 ditch at the points where laterals or submains will enter. For each 

 pumping district only the whole area and the area drained by each 

 main ditch was determined. The rate of run-off from each such area 

 was computed by P^'roscoln's formula, as previously described, to find 

 the required capacity of each ditch. 



A profile along the route of each ditch was platted from the data on 

 the map, and the grades of tlio ditch bottoms were determined from 

 those profiles. The Chczy formula, F= C^RS, was used in comput- 

 ing tlie sizes of the ditches, 6' being determined by Kutter's formula 

 witli O.O'iO as the value of the roughness coefficient n. AU laterals 

 in fiunifjjng districts were made of such size that they could be con- 

 78948'-'— Bull. 193—15 3 



