NOAA PORS Programme

NOAA operates a real-time monitoring system for water levels, currents, salinity and windspeed/-direction in various ports of the USA. The system (PORTS), although focused on enhancing safe navigation and efficient maritime commerce, has great potential to significantly improve the efficiency of hydrographic surveys through the availability of real-time water levels and salinity. Not only online observations but also forecast models are supported, while the observations are also freely available to the public.

As ships become larger and the number of ships transiting our seaports increases, the two constant requirements of safe navigation and efficient vessel movement become increasingly important. The NOAA PORTS (Physical Oceanographic Real-Time System) Program provides observations of real-time water levels, currents, salinity, and wind speed and direction at locations specifically selected by the mariners, enhancing their ability to navigate safely while taking advantage of actual depths, favourable current and wind conditions (Figure 1).
These observations, subjected to rigorous quality control/quality assurance protocols, are also used to support navigation-focused operational forecast models of water levels and currents, and environmental applications such as hazardous material spill response. With a supporting test and evaluation programme, PORTS will soon include measurements of bridge clearances and visibility, and new and innovative techniques to help provide observations from important but difficult to instrument locations.

Need for Actual Data
While technology has provided the ability to precisely fix and monitor their position in a harbour during a transit, the professional mariner has a critical need for direct knowledge of factors affecting vessel movement and of actual rather than predicted available water depth. PORTS fills that void.
Astronomically-based tide and tidal current predictions do not consider effects of atmospheric conditions, even though the differences induced by these conditions may be significant. As shown in Figures 2 and 3, the recent passage of Hurricane Claudette introduced dramatic changes in both water depth and tidal currents in
the Houston-Galveston port area. Mariners require direct knowledge of the actual prevailing conditions at specific locations of primary concern to them. The availability of actual water-levels and currents (both shown with actual and predicted values plotted when accessed via Internet) and prevailing winds from instruments installed at locations they have selected allows mariners better to plan for actual conditions and make ‘go’ or ‘no-go’ decisions. PORTS observations are updated at six-minute intervals and are made publicly accessible on the Internet at www.tidesandcurrents. noaa.gov in both graphic and text format, or by toll-free phone calls. Professional mariners make use of both methods.
In addition to enhancing navigation safety, PORTS directly supports the more efficient vessel movement of goods in a seaport. Specifically, PORTS allows mariners to take full advantage of the actual (rather than predicted) available water depth and prevailing favourable current and meteorological conditions for advance planning and actual transits. Pilots have provided anecdotal information crediting their use of PORTS for shaving as much as five to six hours off transit times, and allowing for one foot of additional draft on a regular basis.

Economic Benefits and Navigation Safety

Depending on cargo and vessel size, this extra foot can translate into tens to hundreds of thousands of dollars of cargo carried. As maritime commerce strives to take advantage of every foot of available water depth, PORTS is increasingly becoming an ‘industry standard’. Economic benefits and navigation safety go hand in hand. Grounding can easily block a major channel and shut down a port, resulting in the loss of millions of dollars each day.
The creation of a PORTS system represents a unique effort. A team of NOAA scientists and engineers work with the local maritime community to determine the specific observations required and the locations of these observations. NOAA designs the system through an iterative process involving the users, making modifications and presenting final recommendations to the maritime community. Included in the recommendations is an estimate of the total cost of the installation and the annual recurring costs for operating the system.
While NOAA funds the considerable team effort to work with users in determining the requirements to meet their needs and actually design the complete PORTS installation, it is the local maritime community which provides NOAA with funds to purchase and install instruments and data systems and for ongoing operation of the PORTS system. The programme is user-driven and user-funded.

Assuring Accurate Observations

The most unique aspect of PORTS is the care taken to assure accurate observations. A rigorous quality control programme allows NOAA to stand behind the observations, without disclaimer, in the same way NOAA stands behind the soundings on a nautical chart. The data stream and the data are monitored continuously at NOAA facilities in Silver Spring, Maryland (Figure 4) by a computer-based real-time monitoring system utilising artificial intelligence decision-making logic. This constant monitoring through automated checks is enhanced and supported by trained technicians on watch, providing continuous oversight and performing additional checks.
If these technicians detect a problem with the accuracy of the real-time observations, dissemination is stopped and not restarted until re-certified by on-call oceanographers and engineers. The technicians provide a daily update of operational status to NOAA staff and users. This quality control operation is funded entirely by NOAA.
Operational models relying on real-time information from PORTS stations are a recent and major addition to PORTS. While under development in several locations, operational models are already in place in the Chesapeake Bay, and New York/New Jersey Harbour. The Chesapeake Bay model predicts actual water levels 24 hours in advance, and has been operating and in use by ships in the Chesapeake Bay for over a year. The New York/ New Jersey Harbour model has been in operation since the spring of 2003 and provides predictions of both currents and water levels 36 hours in advance.
Both operational models allow ships to accommodate maximum cargo loads and better plan the loading and unloading of cargo, a process that takes many hours, or to avoid a transit when unusually low water-levels are forecast. The New York/New Jersey Harbour model provides the added benefits of currents and longer forecast time. Houston-Galveston is the next projected location for an operational model, and will include salinity.

Rigorous Standards
Before any sensor is accepted for use with PORTS, it must meet rigorous standards for data accuracy and reliability, demonstrate suitability for operational use in a harsh environment and be practical. A separate programme associated with PORTS is charged with testing and evaluating other sensors to meet new needs expressed by mariners. Conductivity sensors for salinity have been modified and hardened for continuous use and are deployed in several PORTS installations. Horizontal Acoustic Doppler Current Profilers have been evaluated and are deployed operationally, with air-gap sensors for actual clearance under bridges in the final stages of evaluation before deployment. Test and Evaluation of visibility sensors, including evaluation of digital cameras, continues. Final acceptance and operational deployment of buoy-mounted current meters (Figure 5) is expected by this autumn.

PORTS Includes Ten Installations
The PORTS Program started with the first complete system installed in Tampa Bay in 1991 and has grown to include a total of ten installations. PORTS installations are operating in Narragansett Bay, New York/New Jersey Harbour, Delaware River and Bay, Chesapeake Bay, Tampa Bay, Houston-Galveston, Los Angeles/Long Beach, San Francisco Bay, Anchorage, and Soo Locks in the Great Lakes. The installations range from small ones with only one or two stations to the large ones covering the Chesapeake Bay from the mouth to the Chesapeake and Delaware Canal, and the Delaware River and Bay from the mouth of the Bay to well upriver beyond Philadelphia.
Two small installations are planned for New Haven, Connecticut, and Tacoma, Washington, and complete designs and budget estimates have been prepared for two major locations in Louisiana and one location in Alaska; they only await funding. At least two other harbours are known to have an active interest in a PORTS installation.
Although PORTS specifically focuses on enhancing safe and efficient maritime commerce, the real-time data provided by the programme may also significantly enhance the efficiency of hydrographic survey operations. The availability of accurate data in real-time allows rapid incorporation of tide correctors for immediate data reduction in lieu of post-processing. With the expanded water-level network typical in a PORTS system, the number of subordinate stations required to support a survey may be greatly reduced. Survey vessels may also utilise the observations and trends to plan underway operations.
Other uses include environmental applications such as supporting oil spill response. In March 1996, for example, the Houston-Galveston PORTS provided the US Coastguard and NOAA HAZMAT with critical real-time observations during a time of unusual meteorological conditions at the time of a major oil spill. These observations directly led to proper identification of areas at risk for oil pollution and prompt and efficient deployment of response and containment equipment and personnel.
Based upon correspondence, web-site hits and phone calls, the very diverse groups associated with marine recreation (sailing clubs, sport fishing or wind surfers) are avid users of the PORTS observations. These observations are available to the public through the NOAA website (www. tidesandcurrents.noaa.gov) with toll-free numbers shown on the individual PORTS pages.