Piffi" Page 



3-1 Location of hydrographic gauging stations in the 



Nueces Delta and upper Nueces Bay. 3-3 



3-2 View of the Nueces River at Calallen Diversion Dam. 3-4 



3-3 View of the Rincon gauge (Station 0821 1 503). 3-4 



3-4 Hydrographic data for 1994. 3-10 



3-5 Hydrographic data for 1995. 3-11 



3-6 Hydrographic data for 1996. 3-12 



3-7 Hydrographic data for 1997. 3-13 



3-8 Hydrographic data for 1998. 3-14 



3-9 Hydrographic data for 1999. 3-15 



3-10 Selected hydrographic data for Events 12, 13 and 14 



(October 2 through November 3, 1996). 3-16 



3-11 Selected hydrographic data for Event 23 



(September 1 through 31, 1998). 3-18 



3-12 Discharge into the tidal flats area through the road 



crossing at the north end of the Rincon Overflow 

 Channel during Event 16 (June 27, 1997). 13-19 



3-13 Visual satellite image showing the location of 

 Hurricane Bret in relation to the Nueces 

 Watershed just before landfall (August 22, 1999). 3-20 



3-14 The Nueces Overflow Channel looking southwest. 3-21 



3-15 The Rincon Overflow Channel. 3-22 



3-16 The low water crossing at the head of the upper 



Rincon Bayou channel. 3-22 



3-17 Typical view of the Nueces Overflow Channel 



during tidal exchange. 3-23 



3-18 View of the upper Rincon Bayou (background) 



during a typical positive-flow event (Event 16). 3-23 



3-19 View of diverted fresh water in the tidal flats area in 

 the upper Nueces Delta during activation of the 

 Rincon Overflow Channel (Event 16). 3-24 



4-1 Location of water column sampling stations in the 



upper Nueces Delta. 4-2 



4-2 Salinity at all water column stations (except 



Station 62) for each sampling date. 4-5 



4-3 Average salinity at each sampling site for each 



sampling date. 4-7 



4-4 Nitrate concentrations at all water column stations 



(except Station 62) for each sampling date. 4-8 



4-5 Ammonium concentrations at all water column 



stations (except Station 62) for each sampling date. 4-9 



4-6 Nitrate concentrations at all water column stations 



(except Station 62) for each sampling date. 4-9 



Contents V vii 



