Figure 2-14: The Nueces River Basin, including major drainages and reservoirs. 



Source of topographic base map: U.S. Geological Survey 1997. 



(1997) found little evidence for statistical trends in 

 precipitation along the Coastal Bend from 1968 

 through 1993. 



Recendy, two independent investigations were 

 conducted to quantify' changes in streamflow of the 

 Nueces River since 1940, one regarding inflow into 

 Nueces Estuary and the other regarding inflow into 

 Nueces Delta. The first study was conducted by 

 Asquith et al. (1997), who used streamflow in the 

 Nueces River near Mathis (located immediately below 

 Lake Corpus Chrisd) to generally represent estuary 

 inflow. After performing a statistical trend test on 

 daily flow values, it was concluded that the data 



showed strong exddence for a downward trend for the 

 period of 1940 to 1996. When analyzed in the 

 historical context of reservoir construction, it was 

 reported that the change in mean annual streamflow 

 during the period after the construction of Lake 

 Corpus Christi (1958 to 1982) was negligible (a 

 decrease of about 1%), but that the change during the 

 period after construction of Choke Canyon Dam (1982 

 to 1 996) was large (a decrease of about 55%) (Asquith 

 et al. 1997). Although their analysis used the 

 construction dates of large reser\'oirs to delineations of 

 the record, it was explained that the effects of 

 reservoirs were only partially responsible for the 

 observed differences between the time periods. 



2-16 ♦ Study Ana 



