Figure 1-6: View of the private road crossing 

 separating the upper and central Rincon Bayou 

 channels. This pre-existing structure (constructed 

 between September 1992 and March 1993) was not part of 

 the demonstration project. The photo was tal<en on June 

 26, 1997, during the first significant flow event. During 

 larger events, the structure backed water up in the upper 

 Rincon Bayou (left), as indicated by the difference in water 

 levels on either side of the road. 



Photo courtesy of the Bureau of Reclamation. 



Figure 1-7: View of the Rincon Overflow Channel. The 



view is looking northeast from Rincon Bayou (foreground), 

 showing the channel's outlet into the tidal flats 

 (background). The photo was taken on June 26, 1997, 

 during the first significant flow event. 



Photo courtesy of the Bureau of Reclamation. 



wide, with a bottom elevation of 1 .22 m (4.0 ft) msl on 

 the upstream (south) end and 0.91 m (3.0 ft) msl on 

 the downstream (north) end. In addition, the 

 downstream end of the channel was crossed with an 

 elevated road over eight 24'-diameter HDPE culverts. 

 The acmal bottom elevations of the channel at the end 

 of the demonstration period were about 1.14 m 

 (3.75 ft) and 0.76 m (2.50 ft) msl, respectively. The 

 primary purpose of the Rincon Overflow Channel was 

 to provide a "spillway" during larger flow events that 

 would divert floodwater around the private road 

 crossing, thereby improving diversion and distribution 

 of fresh water within the delta during larger events. 



In addition to these two principal features, numerous 

 access road improvements were made as part of 

 Reclamation's agreement with the pri%'ate landowners 

 in the delta. These included the installation of cattle 

 guards, placement of culverts in low areas, and 

 rehabilitation of a low water crossing over the upper 

 end of Rincon Bayou (Figures 1-4 and 1-8). This last 

 feature was improved by raising the crest elevation 

 from about 1.5 m (5.0 ft) msl to about 2.1 m (7.0 ft) 

 msl, and adding thirteen 36"-diameter HDPE culverts 

 in two locations to allow passage of flow events. The 

 purpose of these road improvements was to preserve 

 landowner access to the upper delta during the term of 

 die demonstration project and to minimize the 

 resistance to water moving into the delta during 

 discharge events. 



Several other diversion alternatives were considered at 

 the beginning of the study. These included: 1) either a 

 total or partial diversion of the Nueces River into the 

 delta, 2) delivery of a continuous flow of fresh water 

 from the existing municipal infrastructure of either the 

 San Patricio Municipal Water District or the 

 O.N. Stevens Treatment Plant, 3) diversion of either 

 river or groundwater through wind or solar pumping, 

 or 4) some combination of the above. A detailed 

 analysis of each of these alternatives was presented in 

 the Plan of Study for the demonstration project 

 (Bureau of Reclamation 1993). Each of these alterna- 

 tives would have supplied some measure of fresh water 

 into the upper delta and esmary. However, none of the 

 alternatives would have adequately met the first 

 objective of the demonstration project, which was to 



1-6 



Introduction 



