most of the wetlands. The refuge contains about 

 57,000 ha (140,850a) of fresh and brackish marshes. 



Impoundments are a significant feature. Im- 

 pounded marslilands make up 14% of the inland area. 

 Three large fresh marsh impoundments total about 

 13,700 ha (33,853a) in the Sabine Refuge. The 

 largest of these is 10,000 ha (24,711a) and is main- 

 tained by a system of spillways and dikes. In other 

 areas, weirs control water flow through wetlands that 

 are not fuUy impounded. In addition to the impound- 

 ments in the Sabine Refuge, approximately 4,000 ha 

 (9,884a) of wetlands have been impounded near 

 Taylor Bayou which drains into the Port Arthur 

 Canal. A portion of these impoundments is within 

 the J. D. Murphree State WildUfe Management Area 

 and the Big Hill Reservoir upstream from the Sabine 

 Basin boundaries. 



The hydrology and hydrography of the Sabine 

 Basin is among the most complex in the Chenier 

 Plain. Freshwater input to the Sabine estuary is from 

 precipitation (net annual rain surplus is 43 cm or 

 17 in) and by runoff from the Sabine and Neches 

 rivers (fig. 348). Combined annual inflow into Sabine 

 Lake from these two rivers and the ungauged runoff 

 below the river gauges at RuHff and Evadale varies 

 from less than 4 x 10^ m-' (1.4 x lO' ' ft^) to greater 

 than 30 x 10^ m^ (1.06 x lO'^ ft^). This is equiva- 

 lent to an average flow rate of 130 to 950 m /sec 

 (4,590 to 33,550 ft^/sec). These are the largest in- 

 flows into the Chenier Plain, four times as much as 

 any other basin. 



Tides are well developed with a 40 cm (15.75 in) 

 mean range at Sabine Pass and attenuation upstream 

 to Sydney Island (figs. 347 and 3-49). The con- 

 struction of the Sabine-Neches ship channel along the 

 western edge of Sabine Lake has had a strong influence 

 on tidal action and salt water intrusion into the basin. 

 Sah water enters through Sabine Pass from the Gulf 

 and fonns a dense wedge extending up the bottom of 

 the Sabine-Neches Ship Canal and the Neches and 

 Sabine rivers. Direct tidal exchange occurs in Sabine 

 Lake at its southern end and to a lesser extent at the 

 northwest corner of the lake when tidal action pro- 

 duces a hydrauhc gradient strong enough to push salt 

 water into the lake through the Sabine-Neches Canal 

 (fig. 347). 



Freshwater flows are also affected by the ship 

 channel. Freshwater moving down the Sabine and 

 Neches rivers enters tlie upper lake area, but an esti- 

 mated average of 80% of this flow (Ward 1973) by- 

 passes Sabine Lake by traveling down the Sabine- 

 Neches Canal to the Gulf as a fresliwater layer, on 

 top of the denser saline waters in the bottom of the 

 channel (Espey-Huston 1976). The predominant 

 north-south winds and tidal currents tend to push the 

 remaining fresh river water to the east side of the lake 

 where it fomis a large pool surrounded by more saline 

 water (fig. 3-50). Water within the main body of the 

 lake flows seaward at Sabine Pass and to a lesser 

 extent flows into the northern end of the Sabine- 

 Neches Canal. 



It appears that much of the time a portion of the 



water which bypasses Sabine Lake flows toward East 

 Bay through the GIWW. Since the Sabine-Neches 

 Canal has a controlled depth of 12.2 m (40 ft) com- 

 pared to a depth of 3.7 m (12 ft) in the GIWW, the 

 less saline water flowing near the surface of the 

 Sabine-Neches Canal flows into the GIWW but the 

 underlying saltwater remains in the deeper ship 

 channel. Because of the small tidal range in the 

 GIWW, winds and/or abnormally large freshwater in- 

 flows from upstream can create a significant flow to- 

 wards Galveston Bay. Under average conditions a 

 maximum flow rate of 113ni^/sec (3,991 ft ^ /sec) 

 and a maximum current velocity of 0.4 m/sec (1.3 ft/ 

 sec) can be expected (James et al. 1977). 



Freshwater input from upstream has little impact 

 on water levels in the basin. Rather, seasonal water 

 levels are controlled by variations in Gulf waters 

 (fig. 3-49). The Sabine Pass water level record for 1974 

 shows a late spring peak, with a less well-developed 

 late summer high. As is typical along the northern 

 Gulf coast, mean water levels are low in winter. No 

 long term uninterrupted records are available for 

 analysis of annual mean water level, but water levels 

 are expected to increase at a rate of about 2 cm/yr 

 (0.79 in/yr). 



The higli volume of freshwater inflows into 

 Sabine Lake from the Sabine and Neches rivers leads 

 to a short flushing time about 20 days, ignoring tides. 

 The ratio of the tidal prism to river discharge over a 

 tidal cycle gives an index of the importance of tidal 

 forces versus river discharge for basin flushing. For 

 Sabine, the annual mean ratio is 3.2; for January 

 1974 it was 0.78; and in October 1973 it was 20.3 

 These ratios show that tidal action contributes to the 

 flushing of Sabine Lake. 



Wetlands are a significant feature of the Sabine 

 Basin although their loss rate is high. A large expanse 

 of this habitat occurs between Orange and Beaumont 

 on the north shore of Sabine Lake. Some of the most 

 productive wetlands are located adjacent to the 

 Neches River near the city of Beaumont. Prime habitat 

 for wintering waterfowl stretches southward from 

 Sabine Lake towards the East Bay Basin. These wet- 

 land areas, particulariy in the vicinity of Sea Rim 

 State Park, serve as the key waterfowl areas on the 

 Texas Coast. Lard (1978) reported that the 1977 

 winter waterfowl inventory showed in excess of 

 200,000 ducks and 140,000 geese in Jefferson and 

 Chambers counties. Early flights of ducks and geese 

 use this area for resting and feeding before proceeding 

 on to Mexico and South America. The inland lakes 

 and ponds provide excellent habitat for many bird 

 species. Most common are the roseate spoonbills; 

 common, snowy, and cattle egrets; great blue, Uttle 

 blue, Louisiana, and green herons; and black-, and 

 yellow-crowned night herons. In addition, six species 

 of rail reside here sometime during the year. 



In the surrounding area white-tailed deer, musk- 

 rat, mink, nutria, raccoon, skunk, bobcat, grey fox, 

 oppossum, and the river otter are abundant. The 

 alligator, and possibly the red wolf, are now resident 

 species south of Sabine Lake. At one time the South- 

 em bald eagle, Attwater's prairie chicken and the 



135 



