width of 100 m (328 ft) over most of its length and is 

 used pmiiarily for barge traffic; the Calcasieu Ship 

 Channel, with a depth of 1 2 m (39 ft) and a width of 

 120 m (394 ft); and the Sabine Ship Channel, 13 m 

 (43 ft) deep and 120 m (394 ft) wide. The latter two 

 were dredged across the beachline removing the natural 

 shallow (1 m) (3.3 ft) sill that historically prevented 

 saltwater intrusion into Calcasieu and Sabine lakes. 

 The ecological impacts of these navigation canals is 

 described in Part 3.3. Accidental oO spills do occur in 

 these navigation channels. The probability of oil spills 

 from tanker traffic has been evaluated in Part 3.2.2. 

 Spoil accumulations from the continued dredging to 

 maintain these large channels are significant (table 

 3.44). Between 1952 and 1974, 5,365 ha (13,257 a) 

 of land have been covered with dredged material as- 

 sociated with these three waterways. Dredged material 



3.2.8 GOVERNMENT 



The responsibility for management of the coastal 

 resources of the Chenier Plain rests with many govem- 

 ment agencies; responsibilities are not always clearly 

 defined. Governments, from the local level to the Fed- 

 eral level, have different functions; most policy deci- 

 sions have significant environmental repercussions. 

 The decisions can be as simple as the decision to pave 

 a parking lot or as complex and far-reaching as to con- 

 struct a major ship channel or to develop geothermal 

 energy reserves. 



Often the repercussions of a pohcy decision have 

 little relationship to the funding levels involved. Ex- 

 penditure of a small amount of energy or money by a 

 government agency may control massive shifts in 



Table 3.44. Comparison of area covered by dredged material in each basin in 1952 and 1974. 



Comparison made for 1954 and 1974. 



from Other activities, e.g., small recreation channels, 

 pipeline channels, and access channels will substan- 

 tially increase this figure. The impact of spoil disposal 

 is discussed in parts 3.3.6 and 3.4.3. 



Highways and Railroads. Highways and railroads 

 through the coastal zone affect the ecosystem primar- 

 ily through obstruction of, or change in, waterflow 

 patterns. Embankments cut off natural water flows, 

 sometimes inadvertently impounding wetlands. An 

 example is the dividing line between the Calcasieu 

 and Memientau basins; it follows a higliway because 

 that highway effectively blocks most east to west 

 water movement across large expanses of wetland. 

 There are 300 km (186 mi) of canals associated with 

 transportation embankments in the Chenier Plain 

 (table 3.45). 



Table 3.45. Length (km) of canals associated with 

 transportation embankments in the 

 basins. 



Basin 



Vermilion 



Chenier 



Mermentau 



Calcasieu 



Sabine 



East Bay 



Total 



Length 



8.13 

 27.29 

 40.31 

 131.14 

 67.55 

 27.1 



301.52 



60 



