TTEXASEXAS C COASTALOASTAL O OCEANCEAN O OBSERVATIONBSERVATION N NETWORKETWORKDIVISION OF NEARSHORE RESEARCH-DR.GARY JEFFRESS, DIRECTOR

TEXAS A&M UNIVERSITY-CORPUS CHRISTI

HISTORYThe Division of Nearshore Research (DNR) at Texas A&M University-Corpus Christi has developed one of the most sophisticated water level and environmental observation systems available. In 1989 the university commenced the installation of a modern state-of-the-art water-level measurement system to provide real-time water-level and meteorological information to the City of Corpus Christi. The first measurement system installed was intended to assist local officials with preparations for incoming hurricanes and tropical storms. From this initial work, other state agencies began contracting the university to provide similar information for other areas along the Texas coast. Following a Texas Legislative mandate in 1991, this network of water level gauges became the Texas Coastal Ocean Observation Network (TCOON). As a result, TCOON expanded from an initial station in 1989 to over forty stations by 1992.OVERVIEWThe TCOON network utilizes the Next Generation Water Level Measurement System developed by the National Oceanic and Atmospheric Administration’s National Ocean

TCOON DATA APPLICATIONS

Tidal Datum Definition DNR has developed artificial Web-based processes that utilize the large tidal data sets collected from the TCOON network. These processes have greatly reduced the amount of time required to process data and determine tidal datums.

Littoral Boundary Definition Survey benchmarks are installed at all TCOON water level stations. An elevation record is maintained for every benchmark in the station’s local network. Tidal Datums produced by the station are referenced to each benchmark thus assisting surveyors in identifying and locating littoral property boundaries.

Navigation and Marine Safety Water current data are collected from several locations in the Corpus Christi Bay area. The data are merged with water level and meteorological data collected from the local TCOON stations and then provided in near-real-time to ships pilots via an automated touch-tone voice systems.

Channel Dredging and Maintenance Navigation channel maintenance and dredge activities require knowledge of water level and tidal datums before, during, and after dredging. The United States Army Corps of Engineers uses TCOON data to plan and execute the maintenance and dredging of navigation channels and waterways along the Texas coast.

Oil-spill Response An automated system developed by the Texas Water Development Board downloads TCOON data directly from the DNR Web site. The data are then used to generate three day water current circulation models in bays along the Texas Gulf Coast. SpillSim, a trajectory model, uses the information to predict where oil will move if an oil-spill occurs in Texas bays. The model information is then provided to emergency response teams.

Hurricane and Storm Preparation Local officials use TCOON data and DNR forecasts in the decision making process regarding inundation of low-lying areas along the coast, road closures, and evacuations. Software has been developed to allow the National Weather Service Office to seamlessly integrate TCOON data into its weather forecasting systems to better predict the effects of an incoming storm.

Recreation and Benefit to the General Public TCOON data are used heavily by windsurfers, sailors, fishermen, and other recreational enthusiasts. TCOON data are available to anyone via the DNR Web site; lighthouse.tamucc.edu and DNR’s WindInfo line (361-992-WIND).

TIDAL DATUMSA tidal datum is a vertical reference based on a specific stage of tide which serves as a baseline elevation to which sounding depths or topographic heights are referenced. The 19-year period includes an 18.6 year astronomical cycle that accounts for all significant variations in the moon and sun that cause slowly varying changes in the range of tide.

http://lighthouse.tamucc.edu/TCOON

Service (NOAA/NOS) for the National Water Level Observation Network. Today, TCOON has 26 stations which obtain reliable water-level data according to NOS standards.

DATA MANAGEMENTDNR maintains a central repository for all data collected by TCOON and other DNR environmental networks. Rigorous adherence to design principles has produced a system that is robust, stable, and flexible enough to accommodate a wide variety of observational-data needs and changes in requirements. DNR's extensive use of automation has resulted in a cost-effective, reliable, and flexible implementation of data management. Data acquisition, archiving, and distribution take place autonomously with only occasional operator intervention in cases of platform malfunction or data transmission errors. Daily data inspections result in timely platform repairs and excellent data quality. Furthermore, the use of automated systems for the majority of the data processing tasks makes it possible to provide environmental data to end-users in near-real time. Observations that pass the automated quality-control features of the system are generally made available to end-users within seconds of the data's arrival at DNR. For stations equipped with radio transmission facilities, this means that data are typically available to end-users within fifteen minutes of the actual time of measurement.

Some stations provide additional environmental data such as wind speed and direction, and air and water temperature. Water-level data and other environmental parameters are made available in near-real-time via DNR’s WindInfo line(361-992-WIND) and the DNR Web site (http://lighthouse.tamucc.edu/TCOON).

TCOON is presently operated by DNR under the direction of the Texas General Land Office, with the sponsorship of other agencies such as Texas Water Development Board and the U.S. Army Corps of Engineers. DNR activities are monitored by the National Oceanic and Atmospheric Administration (NOAA).

Each station has a set of bench marks surrounding it. One of the marks is considered the “primary bench mark” (PBM), and it has a known (fixed) elevation above the station datum, which is established when the station is installed.

The purposes of the bench marks are (1) to recover the station datum elevation even after the gauge has been removed, and (2) to provide fixed monuments from which other elevations (gauge, MHHW, MSL, NAVD88) at that station can be measured.

We have multiple bench marks at each station to verify that the PBM hasn’t moved. NOAA requires periodic levels to at least three benchmarks at each station, and DNRs internal standard is to have five.

If you want to know the height of one thing relativeto another, you just subtract the two heights.

Height of bench mark above STND=1.588-0=1.588 m

Height of bench mark above MHHW=1.588-0.944=0.644 m

Height of MHHW above NAVD88=0.944-0.196=0.748 m

benchmark

MHHW

NAVD88

STND

1.588 m above 0

0.944 m above 0

0.196 m above 0

0 m

Bench mark0.644 m aboveMHHW(1.588-0.944)

Bench mark1.392 m aboveNAVD88(1.588-0.196)

A bench mark is a brass survey disk permanently affixed usually to a stainless steel rod that has been driven 50 ft into the ground. Mark 5792 A 1988 is 0.644 m above STND.

1.588 – 0.644 = 0.944 m

0.944 m = elevation of MHHW above STND

All DNR stations have a station datum (STND) which is an arbitrary zero used internally to measure all other elevations, including water level, MHHW, MHW, MTL, MSL, and bench marks. You can see in this example that MHHW is 0.944 m above STND.

Wind Anemometer

Radio Antenna

Satellite Transmitter

Solar Panels

Data Collector

Water Level Sensor

TCOON Station Configuration