Table 3.35. Population of parishes (counties) over- 

 lapping the Chenier Plain region (U.S. 

 Department Commerce, Bureau of Census 

 1973). 



Employment. Manufacturing and mining are the 

 major areas of employment in the Chenier Plain re^on 

 (fig. 3-12). The $32 million payroll for the Sabine 

 Basin is indicative of its industrial character. Manu- 

 facturers are the major employers in this basin, pri- 

 marily those engaged in refining and petrochemical- 

 related manufacturing. This is true also in the Calcasieu 

 and East Bay basins although the total payroll is 

 smaller. The large petrochemical complex at Lake 

 Charles, Louisiana, lies outside of the Chenier Plain 

 and will be treated as an outside influence on the re- 

 gion. 



Oil and gas industries are the major employers in 

 the eastern basins and account for about 40% of the 

 total payroll value. As indicated, the agricultural, fish- 

 ing, and trapping sectors are under-represented in these 

 employment data. 



Industrial and Urban Activities that Affect the 

 Environment. Major environmental impacts of indus- 

 trial and urban areas are effluent discharges (both 

 domestic and industrial), habitat loss, and surface and 

 groundwater use. In addition, construction activities 

 increase runoff of sediments and nutrients into wet- 

 lands and streams, and this runoff is accelerated by 



drainage canals constructed in low areas (Gael and 

 Hopkinson 1978). 



Habitat loss : In the Chenier Plain, the major 

 urban-industrial land occupied 26,137 ha (64,586 a) 

 or 3.5% of the total land area in 1974 (table 3.36). 

 This is an increase of 5 ,446 ha ( 1 3 ,45 7 a), or 26%, since 

 1952. The urbanized land is concentrated in the west- 

 ern half of the Chenier Plain, primarily in Texas. How- 

 ever, the Calcasieu Basin has shown the most rapid 

 conversion of land to industrial and urban use between 

 1952 and 1974;most of this urbanization has occurred 

 at the expense of weflands (1,233 ha) (3,047 a) and 

 agriculture (2,901 ha) (7,168 a) (table 3.37). Five 

 hundred forty-six hectares of upland forest habitat 

 were also cleared between 1952 and 1974 for urban 

 use. 



Urban and industrial discharges : The per capita 

 water and energy requirements and effluent produc- 

 tion from typical urban situations have been sum- 

 marized in a number of studies (table 3.38). Because 

 of the low population density in the Chenier Plain, 

 domestic sewage loading rates within the basin must 

 be low, but the total watershed includes several densely 

 populated areas. In the rural areas, septic tanks or no 

 treatment at all are the rule, and no records of dis- 

 charge rates are available. Table 3.39 contains esti- 

 mates of discharge (stated as phosphorus) for the 

 Chenier Plain basins. Estimates were detennined from 

 discharge data from treatment plants, and industrial 

 point sources (appendix 6.4) and urban runoff. Much 

 of the total load of phosphorus entering the Chenier 

 Plain is from the heavily populated areas of the Sabine 

 Basin and the Lake Charles area just north of the Cal- 

 casieu Basin. 



Industrial discharges vary greatly and may be 

 much more toxic than domestic sewage. Particularly 

 damaging to the ecosystem are heavy metal bypro- 

 ducts of manufacturing, and synthetic organic toxins 

 that the natural biota can rarely degrade. Plates 5 A 

 and 5B show the location of these discharges within 

 the Chenier Plain. The effects are often localized, e.g., 

 in the Calcasieu ship channel, sediments have accumu- 

 lated high concentrations of certain heavy ipetals. 

 The effects of these discharges are discussed in part 

 3.5.3. 



Table 3.36. Area and changes in urban-industrialized land in the Chenier Plain. 



53 



