restore the opportunity for natural freshwater flow 

 events from the Nueces River into the delta. 



Monitoring Program 



The second objective of the demonstration project was 

 to monitor any resulting changes in the hydrography 

 and productivity of the delta from freshwater flow 

 events. The data collection program was therefore 

 designed to monitor hydraulic conditions in the study 

 area, as well as those biological parameters that would 

 be most responsive to project diversions: namely, 

 water column productivity, benthic communities and 

 vegetation communities. Each of these monitoring 

 elements were regularly sampled at various stations in 

 the upper delta (Table 1-1). The biological monitoring 

 program was initiated in October of 1994, some 

 12 months before the Nueces Overflow Channel was 

 opened. This initial 12-month period served as a 

 baseline period before the effects of the demonstration 

 project began. The hydraulic monitoring began with 

 the installation of gauging instrumentation in April of 

 1996. In addition to the data direcdy collected as part 

 of the demonstration project, the measurements of 

 other monitoring and research efforts were also 



Figure 1-8: View of the low water crossing at the head 

 of Rincon Bayou. This access road was one of several 

 road improvements made as part of the demonstration 

 project. The photo was taken on June 26, 1997, during the 

 first significant flow event. 



Photo courtesy of the Bureau of Reclamation. 



Table 1-1: Summary of the annual monitoring program conducted as part of the demonstration project. 



Monitoring 

 Element 



Response Variables 



Schedule 



Stations 



Hydrography 



Water Column 

 Productivity 



Benthic 

 Communities 



Vegetation 

 Communities 



precipitation; and stage, velocity and calculated disctiarge through the 

 Nueces Overflow Channel 



water quality (conductivity, temperature, depth, dissolved oxygen, 

 calculated density, total suspended solids and water clarity) 



nutrients (orthophosphates, dissolved silicon, nitrate, nitrite, 

 ammonium, particulate carbon and nitrogen (PC/PN), dissolved 

 organic nitrogen (DON)) 



phytoplankton (species composition and size fractionation of major 

 producing groups, biomass and growth rate of suspended species and 

 of microphytobenthos (benthic phytoplankton)) 



macrofauna (species composition, density and biomass) 



meiofauna (species composition, density and biomass) 



pore water and open water (salinity, nitrate, nitrite, ammonium and 

 temperature) 



macrophyte communities (species composition, percent cover and 

 leaf-area) 



macrophyte communities (above-ground biomass, below-ground 

 biomass and calculated root/shoot ratios) 



Monthly 



Chapter One ♦ 1-7 



