A heavy demand exists for sporthunting, and 

 saltwater sportfishing in the Chenier Plain, since the 

 demand projected from telephone surveys far exceeded 

 the available supply (figure 3-30). In addition, the 

 hunting supply may be overstated, since some of the 

 refuge land and some privately owned land is closed 

 to hunting. 



The saltwater sportfishing supply-demand rela- 

 tionship survey determined that an average Louisiana 

 fisherman felt he needed to catch 4.5 kg (10 lb) of 

 fish a day [0.9 kg (2 lb)/hr based on 5-hr day] to sat- 

 isfy his requirements (U.S. Army Corps of Engineers, 

 unpublished). The demand figures are based on this 

 estimate. However, in recent censuses in Sabine Lake 

 and Galveston Bay, Texas (Heffeman et al. 1976, 

 Breuer et al. 1978), it was found that fishermen were 

 landing only about 0.22 kg (0.50 lb)/hr in Sabine Lake 

 and 0.3 kg (0.66 lb)/hr in Galveston Bay. 



Saltwater Sportllstiing 



Sporthunting 



o 300 



Figure 



3-30. Supply of and demand for saltwater fish- 

 ing and sporthunting by basin, in the 

 Chenier Plain, excluding the Nearshore 

 Gulf Habitat (U.S. Army Corps of Engi- 

 neers, unpublished). 



3.5.3 SURFACE WATER 



Surface water and ground water aquifers extend- 

 ing beyond the Chenier Plain boundaries have been 

 discussed earlier in general tenns (parts 2.4 and 3.3). 

 This section evaluates the adequacy of surface water 

 supplies. 



Surface Water Quantity. The sources of fresh sur- 

 face water are rain and upstream runoff into each basin. 

 The largest amount of this freshwater is absorbed and 

 evaporated by natural vegetation. One important rea- 

 son for the high productivity of Chenier Plain vegeta- 

 tion is the normally abundant water supply. Fresh 

 surface water is also required by wildUfe species. After 



the requirements of the natural biota, agriculture is 

 the largest user of freshwater in the Chenier Plain, fol- 

 lowed by industrial and residential use. Table 3.63 

 summarizes an approximate annual budget for water 

 sources and uses and assumes that all water was evenly 

 spread over the total basin surface. Rainfall amounts 

 to II 3 to 1 46 cm (44 to 5 7 in)/y r and is supplemented 

 by riverine inflows that significantly affect the water 

 budgets. East Bay has the least rainfall and no signifi- 

 cant river inputs. As a result, its total surface fresh- 

 water supply is only 113 cm (44 in)/yr. In contrast, 

 because of their large river systems, the Sabine and 

 Calcasieu basins have nearly 400 cm ( 1 57 in) of fresh 

 water each year. Eighty-four to 97 cm (33 to 38 in) 

 of this water is evaporated, mostly by plants. How- 

 ever, this water reenters the basin in various forms of 

 precipitation. In comparison, total use by agriculture 

 and industry is less than 21 cm (8 in), excluding the 

 Sabine Basin where 70 cm (28 in) is used per year. 

 The use figures are somewhat inflated since much of 

 the industrial water is returned to the stream from 

 which it was pumped, and about 407c of the agricul- 

 tural water is returned. Ignoring these return flows, 

 all basins but East Bay, Texas have net annual sur- 

 pluses of more than 76 cm (30 in). East Bay has al- 

 most nosurplus(17cm, 6.7 in), and estimated deficits 

 [periods when soil moisture was insufficient to sup- 

 ply maximum evapotranspiration as calculated by the 

 method of Borengasser (1977)] accumulated over an 

 average year are 24.5 cm (9.6 in). Thus, fresh surface 

 water is a critical factor in the East Bay Basin. Other 

 basins have sufficient supplies on an annual basis, pri- 

 marily because of riverine inputs. However, the sum- 

 mer agricultural demands in the Mermentau Basin ex- 

 ceed the summer surplus. During this period, surface 

 water levels fall and salt intrusion would occur if con- 

 trol structures were not present (part 3.6.3). 



Surface water surpluses help to maintain the 

 freshwater head necessary to prevent serious saltwater 

 intrusion, and to flush the lower estuaries. Hence the 

 term "surplus" is a misnomer. Without this water 

 moving through the basins and offshore, the estuaries 

 and wetlands would be significantly more saline and 

 the entire character of the coastal region would be 

 different. 



Surface Water Quality. The chemical composi- 

 tion of a water body reflects local and basin-wide 

 chemical inputs. A disturbance in the chemical com- 

 position of an aquatic system, either through the in- 

 troduction of a foreign substance or through an in- 

 crease in concentration of a natural component, may 

 be followed by a change in the biotic community. 

 Thus, the biotic composition of an aquatic system re- 

 flects the water quality of that system. 



Eutrophication. A complete evaluation of water 

 quality in Chenier Plain basins would require the con- 

 sideration of phosphorus and nitrogen; ion balance 

 (the relative abundance of sodium and potassium to 

 magnesium and calcium); trace metals-mercury, co- 

 balt, zinc, cadium, iron, manganese, chromium, cop- 

 per, and lead (at a minimum); numerous organic pes- 

 ticides and petrochemical compounds; the dissolved 

 gases (oxygen and ammonia); and bacterial concen- 

 trations. The available data are too fragmentary for a 



90 



