5.0 FREIGHT MOVEMENT BY WATER

This chapter presents the data sources and methodology for estimating freight movement by water, both domestic and international. The data sources and their limitations to estimate freight tonnage and value for the estimation year are also described.

5.1 Domestic Waterborne Freight

5.1.1 Data Sources

One of the main data sources for use in developing the methodology and providing provisional estimates is the Internal U.S. Waterway Monthly Indicators data (http://www.iwr.usace.army.mil/ndc/wcsc/wcmthind.htm) published by the U.S. Army Corps of Engineers (USACE), Navigation Data Center (NDC). The USACE provides data on U.S. waterborne commerce, including the transport of goods by inland barge and ship over the nation's navigable rivers, across the Great Lakes, and within the U.S. Intra-Coastal Waterway. Domestic O-D movements are created by USACE from its Vessel Operating Reports, as well as from its Lock Performance Monitoring System (Lock Performance Monitoring System) database. Data are in theory reported by all vessels and provide estimates of annual tons moved by 5-digit commodity code for all commodities transported on U.S. waterways on a dock-to-dock basis. The NDC indicator is seasonally adjusted in terms of millions of short tons. Estimates for future years based on these historical data would represent the annual totals of domestic freight movement by waterway.

The NDC also publishes data on waterborne tonnage by state and ports. These reports list tonnages for Domestic, Foreign, Imports, Exports, and Intra-State waterborne movements (http://www.iwr.usace.army.mil/ndc/wcsc/statenm00.htm).

The following are some comments and inconsistencies noted in the data

• The public domain commodity codes employed in the data sources used were converted to STCG codes. Of the 46 STCG commodity codes, less than 12 are moved by water.
• In some states, certain commodities were inconsistently moved from or to that state from year to year. As such, some data points are missing for some commodities, which makes it necessary to base estimates for the current year on educated assumptions.
• The data sources do not contain information on the value of domestic waterborne commodity movements. For the estimation year, value can be estimated based on weight/value from 2002 benchmark data and corrected for the effect of inflation using the Consumer Price Index (CPI) published by the BLS.

5.1.2 Methodology

Provisional estimates of the volumes domestic waterborne freight were developed by calculating the total tonnages originating and destined for each state and then broken down by commodity between origin state and destination states. The state estimates are further disaggregated into FAF zones. The equivalent dollar values of these volumes were then estimated based on information on value per unit weight developed from 2002 FAF benchmark data. The steps involved in the methodologies are described in the following subsections.

5.1.2.1 Weight Estimates

The growth factor approach was used in developing the estimates of tonnage of freight movements with the FAF 2002 data as benchmark. This involved the following steps:

1. Estimate the growth factor for each state of origin and state of destination pair between 2002 and the estimation year. These growth factors are derived from total tonnages of commodity movements between each O-D pair.
2. Apply the growth factors in step 1 to the 2002 state O-D tonnages to obtain state totals for the provisional year of interest.
3. Estimate each commodity group's share of the state total tonnages originating from and destined to that state based on the previous year's provisional estimates. Then distribute the estimated state total tonnages among the commodity groups originating from or destined to that state.
4. Determine each FAF zone's share of the state's total tonnage of each commodity originating from and destined to that state based on the previous year's provisional estimate. Different factors are derived for freight originating from and destined to each FAF zone.
5. Expand the state-to-state estimates by commodity that were developed in the previous steps among the FAF zones in each state based on distribution of the 2002 FAF² data among the FAF zones. This approach assumes that a commodity's percent share of total tonnage in a FAF zone in the estimation year will be the same as in the base year.

5.1.2.2 Value Estimates

Because no information is available on commodity dollar values for domestic movements, weight/value ratios derived from the 2002 FAF² benchmark data were used together with the estimated volumes of the freight to estimate the dollar values. These rates were used as the basis in estimating the value of commodities moved by water in provisional estimation years.

5.2 International Waterborne Freight

5.2.1 Data Sources

The USACE generates the monthly Waterborne Databank that contains statistics on U.S. waterborne imported and exported freight. This databank is published in the Preliminary Foreign Waterborne Cargo Summary report that is available on the USACE web site at http://www.iwr.usace.army.mil/ndc/usforeign/pcsfiles.htm. The summary report contains information on weight and value information by type of service on U.S. waterborne imports and exports, along with year-to-date figures. Inbound and outbound in-transit data are not included.

The NDC of the USACE also publishes data on commodity movements. This database shows waterborne tonnage for principal U.S. ports and all 50 states and U.S. territories (http://www.iwr.usace.army.mil/ndc/wcsc/statenm00.htm). These reports list tonnages for Domestic, Foreign, Imports, Exports, and Intra-State waterborne traffic. This database presents a breakdown of freight tonnage by state and by port of entry/exit.

5.2.2 Methodology

Provisional estimates were developed for the volume and value of commodity movements from/to the ports of exit/entry and the seven destinations/origins outside the United States (i.e., Canada, Mexico, Europe, Latin America, Middle East, Asia, and Rest of World). The estimation process involves the following steps.

1. The first step is to group the foreign origins and destinations (i.e., countries) into the seven foreign destinations/origins outside the United States prior to calculating the growth rates.
2. Calculate the growth rates in freight tonnage between 2002 and the provisional estimation year in waterborne imports and exports through each of the U.S. ports of entry/exit and FAF foreign destinations and origins.
3. Apply the growth rates calculated above to the 2002 FAF benchmark freight tonnage to estimate the volume of freight by FAF O-D foreign region for the provisional year.
4. The growth rates in the tonnage of freight are applied to the 2002 tonnage of freight to derive the freight tonnage for the provisional year. This is done at the FAF O-D-port of exit or entry-commodity level of detail.
5. Apply the tonnage growth rates to the 2002 value/weight ratios to derive the growth in freight value for the estimation years. The value/weight ratios are calculated at the FAF O-D-port of exit/entry-commodity level of detail. The result of this effort provides the growth in the freight value in 2002 dollars for the provisional years.
6. Derive the growths in the current dollar value of freight by adjusting the growth in freight value in 2002 dollars by the changes in prices. The commodity export and import price indexes are used for this purpose. The price indexes are obtained from the BLS. The export price indexes by type of commodity are used to estimate the current dollar value of export freight, and the import price indexes are used to estimate the value of import freight. The BLS reports the price indexes in HS commodity classification method.
7. Add the growth in the current and constant dollar (i.e., 2002) value of freight to the 2002 freight values to derive the estimation year's value of freight in current and constant dollars, respectively.