Three tidal gages were constructed to collect hydraulic and water-quality properties that could be used to compute the tidal flux of the Pearl River and Lake Pontchartrain estuarine systems in Mississippi and Louisiana. The gages record continuous tidal stage, velocity, water temperature, specific conductance, and salinity, and transmit these data via the GOES satellite for output to a USGS real-time Internet portal. A 25-hour tidal study was completed during a maximum slack tide period in September 2001, which measured hydraulic and water-quality properties. These data were correlated with data recorded by the gages. Relations were developed for stage and area, and for an index acoustic velocity signal and average velocity. Continuous tidal inflow/outflow was computed for all three gages. Tidal effects were attenuated using a ninth-order Butterworth low-pass filter. Net inflows were recorded at two of three sites during the tidal study. The data will be used to help calibrate a regional RMA2 flow model.