Table 3.2. Human population distribution in the Chenier Plain 

 basins and adjacent northern parishes (counties). 



Calculated from 1970 Census (U.S. Department of Commerce 1973), by summing the population of all cities with population 

 1000, then prorating the rural population of individual wards (divisions in Texas) by the areal proportion within a basin boundary. 



Inland area exclusive of open water. 



Includes population north of the Chenier Plain boundary. 



East Bay plus about one- fifth of Harris County, Texas. 



Approach. Typically, each sector has an eco- 

 nomical and ecological impact on the Chenier Plain 

 region. Each important activity is identified and its 

 magnitude in relationship to die economic sector is 

 discussed. The sectors and resulting activities are 

 summarized in matrix form in table 3.1. The effect 

 of each activity on the ecosystem is discussed in 

 sections dealing with hydrology, land-modifying 

 processes, and natural resource productivity. 



3.2.2 MINERALS 



Production. Mineral extraction particularly oil and 

 gas, is the major industry on the Chenier Plain. The dol- 

 lar value of minerals extracted in 1974 was six times 

 greater than the total value of the renewable resources 

 (table 3.3). On a statewide basis, more than 96% of the 

 mineral production value is derived from the mineral 

 fuels, natural gas and crude oil (Jones and Hough 

 1974). Although the doUar value is stOl increasing, 

 the volume of production peaked in 1970 and has 

 been decUning since 1971 (fig. 3-2). A second trend 

 is the depletion of inland (coastal) production and 

 the development of new weUs farther and farther off- 

 shore in Federal waters of the Gulf of Mexico. 

 Within the Chenier Plain, the total value of minerals 

 extracted in 1974 was $438 million. Most of this 

 production was within the "intermediate" zone 

 defined by the Louisiana Department of Conservation 

 (Melancon 1977). This zone includes most of the 

 coastal marshland. Production in the nearshore Gulf 

 is, with the exception of the Vermihon Basin, a 

 rather small proportion of total production. (Details 

 of 1974 production and cumulative production by 

 field in the Chenier Plain are in appendix 6.2). 



Table 3.3. Annual value of major resources of 

 the Chenier Plain. 



1974 production (Melancon 1977). 



1974 production (U.S. Department of Agriculture 1975). 



'^Based on 1963-1973 commercial production (U.S. Depart- 

 ment of Commerce 1976), see table 3.29. 



Based on calculations shown in tables 3.32 and 3.33. 



The oil and gas production and value in 1974 

 was highest in the Mermentau Basin (60x10^^ 

 kcal, $114 million), followed by the Chenier and 

 East Bay basins (table 3.4). The Chenier and Mer- 

 mentau basins sustain the most intense mineral 

 extraction per unit of area. 



Human Activities that Affect the Environment. 



Pollutants : Mineral extracfion results in discharges 

 of brine into coastal and estuarine waters, and also in 

 oil spills. The latter include chronic low level spills, 

 and major spills. 



Brine water is discharged into wells, pits, and 

 nonpotable water bodies in the Louisiana portion of 

 the Chenier Plain (table 3.5 and appendix 6.2). For 

 areas close to the coast, disposal into saline waters is 

 the most economical practice. The environmental 



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