by Kenny Macdonald
Inland ports in the region depend on a complex river system influenced by rainfall in a watershed the size of France, mountain snow melt rates, ocean tides, and even how hard the wind blows in eastern Oregon. The Port of Portland, in collaboration with the National Oceanographic and Atmospheric Administration and the Northwest River Forecast Center, forecasts river depths for pilots and shipping lines to help them make optimal decisions on arrival and departure timing. This is done through a system called LOADMAX.
For shippers and ports alike, deeper is better. Heavy loads mean higher profits as well as increased efficiency. In some cases, each foot of draft represents $100,000 worth of cargo in the hold. A propeller in deeper, denser water provides more bite per revolution than one near the surface. At the same time, no one wants to see a ship run aground.
LOADMAX takes readings at seven remote sensing stations along the river between Astoria and Vancouver. Using historical data and complex algorithms, the system offers an accurate forecast in the form of a matrix of numbers that represent feet of water over the Columbia River Datum, or CRD.
The CRD is a baseline of low water established by the U.S. Army Corps of Engineers in 1911 and represents the lowest of the low water potential of the river, only seen for about 18 to 30 hours per year, typically in the fall. It is a reference point for depths printed on nautical charts and slopes down from upstream, so the river bottom at 50 feet near Terminal 6 would be higher in absolute elevation than a 50-foot-deep bottom near Astoria. A LOADMAX number of 4.00, for example, indicates that the actual river level is four feet above CRD near that measurement station.
The rhythmic fluctuation of LOADMAX data can also tell the trained eye when the Columbia River Bar will be on its best behavior. Especially in winter when northern Pacific storms send huge swells toward the Oregon Coast, bar pilots prefer to schedule ship crossings on the incoming flood tide when the river's outflow does not oppose the push of the ocean - making breakers less likely on the bar.
Working together with shippers and pilots, the Port of Portland works to provide the LOADMAX information to maximize safety, efficiency and productivity.
Real time information from LoadMax is presented on the Port of Portlands website or from NOAA Northwest River Forcast Center (see below). Check the Other Fees section of our Services and Rate Sheet for the cost to receive this report. To sign up to receive daily LOADMAX reports email firstname.lastname@example.org.