Data Applications

Tidal Datum Definition. Water-level datums have their origins in the need to reduce depth soundings taken at different stages of the tide during hydrographic surveys to a common level. In recent years, greater emphasis has been placed on the need of the land surveyor engaged in waterfront boundaries determined by tidal definition. NOS has established the procedures needed to compute tidal datums in normal tidal regimes. However, at many locations along the Texas coast, the astronomical tide is often masked by local meteorological conditions and long-term trends in the Gulf of Mexico. These conditions make the standard procedures difficult to apply and increase the degree of labor required to produce a tidal datum. CBI-DNR and NOS have worked together to improve the applicability of the procedures to the Texas coast and to reduce the need for manual processing. CBI-DNR has developed Web-based software that automates the computations of datums from water-level data stored in the CBI-DNR database. This software and the daily quality-control procedures allow CBI-DNR to quickly produce tidal datums with little manual intervention.

Littoral Boundary Definition. The tidal datums described above are used in the determination of littoral boundaries between submerged and privately owned lands. Bench-mark leveling is performed annually at each TCOON station to ensure station stability and to relate water-level information to reference points on land. CBI-DNR publishes bench-mark elevation sheets on its Web site that indicate the elevation of bench marks above tidal datum planes; surveyors then use these elevations for precisely locating littoral boundaries. As a recent example of the use of TCOON data for boundary definition, the Texas General Land Office used TCOON data to successfully defend against a lawsuit challenging its ownership of lands along the Laguna Madre, saving the state millions of dollars in oil and gas revenues.

Navigation and Marine Safety. The ready availability of TCOON data has great value to navigation interests. Information provided by TCOON is augmented with current meter data from other systems to provide near-real-time reports of conditions in heavily trafficked shipping channels in several Texas ports. One such system is the Corpus Christi Real-Time Navigation System sponsored by the Port of Corpus Christi. CBI-DNR has installed acoustic doppler current profiler instruments at key locations along the Corpus Christi Ship Channel; near-real-time data from these instruments and TCOON platforms allow ship pilots to better navigate large vessels in and out of Corpus Christi Bay. Access to the near-real-time data is provided via automated touch-tone voice response systems running on CBI-DNR computers; pilots call a local telephone number to receive a digitized voice summary of the latest current, water-level, and meteorological conditions for the stations in Corpus Christi Bay. The NOS-sponsored Houston/Galveston Physical Oceanographic Real-Time System (PORTS) makes similar use of TCOON stations to assist pilots in Galveston Bay, and the Freeport FlowInfo system monitors currents and water levels for Port Freeport.

Recently the Corpus Christi National Weather Service Office funded the installation of an offshore station for collection of meteorological and wave data. Prior to the installation of this station, the local weather office had limited data in the 15 to 20-mile offshore region from which to produce its marine forecasts. The new offshore platform provides forecasters with vital information needed to produce accurate marine forecasts.

Channel Dredging and Maintenance. The United States Army Corps of Engineers Galveston District uses TCOON data to plan and execute its maintenance of Federally authorized channels and waterways along the Texas coast, including ship channels and the Gulf Intracoastal Waterway. Navigation channel maintenance and operation activities require knowledge of water level, tidal datums, and other environmental parameters before, during, and after dredging. Convenient access to real-time and historical data is needed in order to conduct these activities.

Oil-Spill Response. One of the more significant applications of TCOON data uses its near-real time capabilities to calibrate circulation and oil-spill trajectory models with recently collected observations. The Texas Water Development Board has developed an automated system that models water currents in Corpus Christi Bay and Galveston Bay using TCOON data. Each night, the latest water level measurements are automatically downloaded from the TCOON Web site via the Internet, and these measurements are used to generate a new set of model calculations that predict the currents for the following three days. These current predictions are then fed as input to a trajectory model called SpillSim that predicts where oil will move if a spill occurs in these bays. Oil-spill emergency response teams use information from these models to deploy clean-up teams and other resources to minimize a spill's impact.

Hurricane and Storm PreparationAn initial and ongoing application of CBI-DNR's tide stations has been to provide timely water-level data to assist the City of Corpus Christi and the local Corpus Christi National Weather Service Office with hurricane or storm preparedness. Local officials use TCOON data as input for decisions regarding inundation of low-lying areas along the coast, road closures, and evacuations. Software has been developed to allow the local National Weather Service Office to seamlessly integrate near-real-time CBI observations into its weather forecasting systems to better predict the effects of an incoming storm. Because the A&M-CC campus is evacuated if a hurricane threatens the area, CBI-DNR can move its data-collection system to local emergency operations centers to continue collection and distribution of TCOON data during the storm event.

Recreation and Benefit to the General Public. As part of its public service mission, CBI-DNR has endeavored to find applications for TCOON that provide benefit to the general public; several of these applications are described here. A particularly successful application of TCOON data has been CBI-DNR's WindInfo system. WindInfo is a telephone voice-response system (361-992-WIND) that provides the general public with wind and water conditions for any station in CBI-DNR's observation networks. In 1993, WindInfo received over 60,000 calls from windsurfers, sailors, fishermen, and other recreational enthusiasts desiring near-real-time information along the coast.