brown pelican were common in the area but they 

 have not been recorded for several years. The pere- 

 grine falcon uses the area for feeding and resting. 

 The Texas Parks and Wildlife Department lists five 

 species of sea turtles as indigenous to the area. 



Other general features of the basin are included 

 in table 3.72. 



Socioeconomics. As elsewhere in the Chenier 

 Plain, oil and gas are the most valuable products in 

 the Sabine Basin. The 1974 value of oil and gas pro- 

 duction was $51 million, an estimated $7.4 million 

 for sport fishing and hunting, $6.2 million for agricul- 

 tural products, and $2.2 million for corrmiercial fin- 

 fishes, shellfishes and furs. 



Manufacturing industries are the major employ- 

 ers in the basin. The total employment payroll of 

 $32 mUUon for the basin is far greater than that for 

 other basins (fig. 3-12). 



Waterbome traffic is much greater in this basin 

 than elsewhere in the Chenier Plain. Traffic increased 

 dramatically in 1976 over previous years, mostly due 

 to increased imports of crude oil and to petrochemi- 

 cal exports. 



Effects of Human Activities on the Environment. 



fiydrologic effects : The population concentration and 

 heavy industrial development have modified the basin 

 dramatically. A combination of port development and 

 the construction of reservoirs has significantly modi- 

 fied the hydrodynamic regime, especially affecting 

 sediment and nutrient transport. 



Prior to construction of the Sabine-Neches Canal, 

 the entire flow of the Sabine and Neches rivers was 

 directed tlirough Sabine Lake. The water from both 

 the Neches and Sabine rivers is now diverted from 

 Sabine Lake into the Sabine-Neches Canal. A second 

 effect of port development is the intrusion of salt- 

 water up the dredged channels, including the Sabine- 

 Neches Ship Channel, into the north end of Sabine 

 Lake. Other interconnecting canals with their asso- 

 ciated spoil deposits and ridges have further modified 

 circulation, particularly on the west side of the lake. 

 Total canal length is 2,002 km (1,244 mi) covering an 

 area of 3,365 ha (8,315a) or 1.4% of the basin's total 

 land area. 



In addition to the increasing amounts of water 

 being diverted from the Sabine and Neches rivers, the 

 completion of the two large reservoirs upstream has 

 had a major impact on the basin. White and Perret 

 (1973) relate habitat loss in the basin to resulting 

 salinity changes, changes in the timing of the fresh- 

 water inflow from the reservoirs, and the reduction of 

 suspended sediments normally introduced by the 

 rivers. The average sahnity for Sabine Lake at three 

 locations for the year prior to the filling of the 

 Toledo Bend Reservoir (May 1967 to April 1968) was 

 1 1 .7 %o . When the total discharge of the Sabine River 

 was reduced to 2.4 m^/sec (84.8 ft^/sec) (fig. 3-50) 

 the salinity was 2.4°/oo. Since that time river dis- 

 charge has been dramatically curtailed during the 



spring of the year, because the water impounded in 

 the reservoir is released later in the summer. 



Habitat effects : Nearly 17% of the Sabine Basin 

 wetlands (20,532 ha or 50,736a) has been lost since 

 1952. Direct habitat alterations have been reviewed 

 by Wiesema and Mitchell (1973). These authors have 

 attributed habitat loss to the following modifications: 



1 . The leveeing of Keith Lake in 1967 which 

 cut off 21,992 ha (54,343a) of marshland 

 from Sabine Lake. (Note: Keith Lake was 

 reopened by the Texas Parks and Wildlife 

 Department in 1976); 



2. Widening of the Sabine-Neches Canal to 

 60 m (1 97 ft), from the mouth of the Neches 

 River to the mouth of the Sabine River; 



3. Enlargement of Port Arthur Canal to a depth 

 of 12 m (39 ft) (below mean low tide) and 

 to a width of 1 50 m (492 ft); 



4. Realignment of the 120 m (394 ft) wide 

 Sabine-Neches Canal, construction of a tum- 

 ing point at Port Arthur, and deepening this 

 channel to 12 m (39 ft); 



5. Realignment of Sabine Pass Channel and en- 

 largement of this channel to a depth of 1 2 m 

 (39 ft) and a width of 1 50 m (492 ft); 



6. Construction of two disposal areas in Sabine 

 Lake, one of 1 ,250 ha (3,089a) and the other 

 of800 ha (1,977a); 



7. Construction of approximately 1 ,200 m 

 (3,937 ft) of earth levee at Port Arthur to 

 an average elevation of 4.5 m (14.8 ft); 



8. Construction of 4,000 m (13,123 ft) of con- 

 crete flood waU and 8,760 m (28,740 ft) of 

 earth levee at Port Arthur to an average ele- 

 vation of 4.6 m (15.1 ft); 



9. The dredging of approximately 3,600 ha 

 (8,896a) of shell along the eastern edge of 

 Sabine Lake southwest of Johnson's Bayou; 



10. The deepening of the ship channel from 

 Beaumont from 10.8 m (35.4 ft) to 12 m 

 (39.4 ft); 



11. The construction of levees and removal of 

 marsh by the U.S. Army Corps of Engineers, 

 particularly along Taylor's Bayou; 



12. The impoundment of 10,000 ha (24,711a) 

 of marshes in Louisiana which apparently 

 had connections with Sabine Lake prior to 

 construction of Gray's Ditch and Trail. 



Of the 20,532 ha (50,736a) of wetland lost since 

 1952 (16.9% of the 1952 wetland area), 9,569 ha 

 (23,646a) were impounded; 1,647 ha (4,070a) were 

 used for canals or spoil deposits; and 777 ha (1,920a) 

 were used for urban and agricultural purposes. The re- 



139 



