3.1.3 BASIN RENEWABLE RESOURCE PRO- 

 DUCTIVITY (RRP) 



A basin's RRP is determined by the kinds of 

 habitats it contains, their areal extent, and their 

 juxtaposition (since many species require access to 

 two or more habitats during their Ufe cycle). The 

 RRP submodel (fig. 3-1) consists of four main com- 

 ponents: producers (Cj), consumers (C,), refugia 

 (C3), and storage (C4). Components C, (producers) 

 and C2 (consumers) reflect the "quality of the basin," 

 which is related to the kinds of renewable resources 

 that a basin can support. For example, the inland 

 open water habitat can be in a balanced state with 

 respect to nutrient input and use, and support many 

 species, or it can be degraded by excessive nutrient 

 loading into a dangerous eutrophic state and support 

 few species. If environmental changes (such as modi- 

 fied flooding regimes or eutrophication) occur, the 

 quaUty of a given habitat will be modified. Changed 

 quality leads to such changes in community struc- 

 ture as the increase of undesirable fish species in 

 waters of a dangerous eutrophic state. 



As some habitat types decrease in size, it is 

 important to preserve natural areas. These serve as 

 refugia (C3) that are important in maintaining a 

 diverse gene pool. 



Freshwater wetlands and water bodies (C4) are 

 especially valuable for storing surface water, which is 

 used by man for many purposes. For example, 

 much of the irrigation water for rice in Louisiana 

 and Texas is stored in fresh marshes. In the Chenier 

 Plain this freshwater supply is in contact with ground- 

 water aquifers. Ground-water aquifers often extend 

 beyond basin boundaries, thereby becoming a re- 

 gional resource. 



As water flows over wetlands, many chemical 

 transformations occur. Inorganic nutrients, that could 

 cause dangerous eutrophic states, undergo important 

 changes. The nutrients may be taken up during plant 

 growth or by bacteria. Some of these nutrients may 

 be exported later as organic detritus. Phosphorus may 

 physically bind with sediments, and nitrogen com- 

 pounds may be denitrified. These processes are im- 

 portant in determining the load of nutrients a basin 

 can assimilate and the resulting quaUty of water 

 within the basin (Hutchinson 1969). 



3.1.4 SOCIOECONOMIC PROCESSES 



Basin-level socioeconomic processes (fig. 3-1) 

 have been organized into seven components: (D,) 

 fish and wildlife resources harvested by man 

 both commercially and for sport; (Dj) agricultural 

 activities; (D3) mineral extraction, primarily pe- 

 troleum and natural gas; (D4) the total human 

 population, its energy and material requirements, 

 and its waste production; (Dj) all commerce and 

 industry such as manufacturing, refining, and retail 

 sales, along with the concomitant waste release; 

 (Dg) transportation activities that facilitate mineral 

 extraction and other industries but also may disrupt 

 natural ecosystems by such alterations as dredging 



and leveeing; and (D^) government services, including 

 government subsidies for transportation, flood control 

 projects, refuge acquisition, and sewage treatment 

 plants. In general, all these socioeconomic processes 

 require large quantities of freshwater for irrigation, 

 human consumption, and industrial processing. 



Human activities are a major influence on basin 

 level processes. For this reason, the socioeconomic 

 sectors are described in part 3.2, and the effects of 

 their activities are identified and quanfified where 

 possible. In part 3.3 through 3.5, basin level pro- 

 cesses are elaborated and the influence of human 

 activities on these processes is considered. The 

 dynamics of individual basins of the Chenier Plain 

 are summarized in part 3.6. 



3.2 SOCIOECONOMICS 



3.2.1 INTRODUCTION 



Techniques. Analysis of the ^economics of the 

 Chenier Plain region has required extensive modifi- 

 cafion of existing data. The boundaries of the Chenier 

 Plain region and basins were drawn along lines dic- 

 tated by the natural physiography of the region. 

 Socioeconomic data, on the other hand, are collected 

 by political unit. Therefore, the primary data are 

 usually from the parishes (counties) of the region 

 (volume 2, appends 6.2). In the text, socioeco- 

 nomic data are displayed by basin. The assumptions 

 made in converting parish-based to basin figures are 

 stated either in the figure legends or in the accom- 

 panying appendixes. 



The second problem, inherent in studies of this 

 kind, is that of comparing diverse materials in com- 

 mon temis. A comparison of shrimp and Gulf men- 

 haden is a good example, because they are harvested 

 for different purposes. The annual harvest of men- 

 haden in pounds far exceeds the harvest of shrimp, 

 but the dollar value of the shrimp fishery exceeds 

 that of menhaden. Menhaden are processed into fish 

 meal or oil, while shrimp are processed for human 

 consumption. The immense harvest of menliaden 

 could have much more severe environmental reper- 

 cussions than the harvest of shrimp; yet from an 

 economic viewpoint, shrimp is the more important 

 commodity. This problem pervades the analysis of 

 the socioeconomic sectors. We have, in general, 

 relied on dollar values as an index of the magnitude 

 of different man-related activities in the Chenier 

 Plain, but it should be remembered that this does not 

 necessarily signify the relative environmental impact 

 of those activities. 



The various socioeconomic sectors, e.g., trans- 

 portation and mineral extraction, can influence 

 natural basin processes through activities they gen- 

 erate. Since several different sectors may generate 

 the same kind of activity, the environmental impact 

 of one sector may be difficult to distinguish. 

 Because canal dredging and spoil is an impact that 

 results from eight different economic sectors (table 

 3.1), it is difficult to establish each sector's relative 

 impact on the environment. 



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