valuable shallow water habitat (Benefield 1976). 

 Viable finfish, shrimp, and oyster fisheries depend on 

 thisestuarine area. 



The marsh areas in East Bay Basin have been used 

 for cattle grazing since the turn of the century (U.S. 

 Army Corps of Engineers 1900). However, the eco- 

 logical effects of cattle grazing in marshes need more 

 study. 



The most critical resource of the basin is water. 

 Rainfall deficits always occur in summer, even in wet 

 years, and can be severe in dry years, (fig. 3-52). Sur- 

 face water quality appears to be adequate, judging 

 from tlie phosphorus loading rates, even though the 

 renewal time of the bay is long, approximately 577 

 days. Ground water supply, i.e., safe annual yield, in 

 tlie Neches-Trinity coastal basin which includes the 

 East Bay area is about 13 x lO^m^ (4.6 x lO^ft^). In 

 1974 about 5.3 x lO^m^ (1.9 x 10^ ft^) was pumped 

 within the Trinity-Neches basin. Another 5.1 x 10 m^ 

 (1.8 X 10* ft^) was pumped from outside that basin 

 but was used in it (Texas Water Development Board 

 1977). Most of the latter was for manufacturing and 

 industrial use north of the East Bay Basin. Artesian 

 well pressures are decUning and saltwater intrusion is 

 occurring near the Gulf (Wessebnan 1971). In the 

 Texas City area just west of East Bay, 1 to 1.5 m(3.3 

 to 4.9 ft) of land subsidence has occurred as a result 

 of ground-water withdrawal and oil and gas extrac- 

 tion (Fisher et al. 1972). Similar subsidence can be 

 expected in the East Bay Basin, particularly with con- 

 tinued ground-water withdrawal. 



151 



