before they departed an area. Primarily because the 

 region had received large rainfall totals for several days 

 prior, significant and fatal flooding on the upper 

 Frio and Nueces rivers resxilted. Direct precipitation 

 in the delta from the storm's landfall totaled only 

 about 0.6 cm (0.24 inches) (August 21 to 23). 

 Nevertheless, a modest peak in stage and discharge in 

 Rincon Bayou occurred on August 23 and 24, primarily 

 due to the storm surge (Figure 3-8). Because a 

 relatively small amount of precipitation fell in the lower 

 Nueces watershed associated with the landfall of 

 Charley, the Nueces River at Calallen recorded only 

 a modest peak on August 8. 



However, as previously mentioned, Charley did result 

 in a broad flooding event in the western basin. The 

 Nueces River at Calallen began to respond to this 

 flooding on September 4, and crested on September 14 

 (Event 23). Flow through the Nueces Overflow 

 Channel generally followed that of the river, but 

 fluctuated on a hourly and daily basis. This oscillation 



was primarily due to the complicating effect of a 

 second storm surge associated with Tropical Storm 

 Frances, which made landfall near San Antonio Bay on 

 September 10. The arrival of Frances may be observed 

 in Figure 3-11, when, during September 7 through 10, 

 stage and flow in Rincon Bayou increased dramatically, 

 while stage in the Nueces River remained essentially 

 constant. Similarly, when the surge subsided after 

 September 10, discharge through the overflow channel 

 dropped sharply, even though flow in the Nueces River 

 at Calallen increased significantiy. Direct precipitation 

 in the delta from Tropical Storm Frances totaled 

 5.7 cm (2.26 inches) from September 9 to 12. 

 Flow in the Nueces River continued to remain above 

 19.8 mVs (700 cfs) (Events 23 and 24) for several 

 weeks after the landfall of Frances as a result of the 

 storm's heavy rain in the upper watershed. Flow in 

 Rincon Bayou was also generally positive during this 

 period but not substantial (less than 0.28 m'/s, or 

 10 cfs). As with the previous events, flow in Rincon 



300 



250 



Q) 



O) 



i_ 



CD 

 « 



CD 

 "D 



0) 

 C3) 



CD 

 I— 

 CD 

 > 

 < 



200 



150 



Landfal of Tropical Storm Frances 



100 



3.0 



Flow in Rincon Bayou (Rincon gauge) 



Flow in Nueces River in 10's of cfs (Calallen gauge) 



Water level in Nueces Bay (White Point gauge) 



Figure 3-11: Selected hydrographic data for Event 23 (September 1 through 31, 1998). 



3-18 ♦ Hydrography 



