Boston Harbor Navigation Channel Improvement Project; Field Data Collection Program Final Report

A field data collection program in Boston Harbor, MA, was conducted for the U.S. Army Engineer District, New England, during the late fall and winter of 2004/2005. The purpose of the program was to obtain data needed to validate a numerical hydrodynamic model (ADvanced CIRCulation (ADCIRC) model) of Boston Harbor and adjacent areas. The currents calculated by the verified model were input to a ship simulator used to assess the design of the Boston Harbor navigation improvement project. A total of four water-level recorders and two acoustic profiling current meters were deployed on 10 November 2004. The water-level recorders were located adjacent to a bridge between Chelsea and East Boston in Boston's inner harbor, at the seaward end of Boston North Channel, at Gallops Island, and at the Hull Yacht Club in Allerton Harbor. The current meters were located at the seaward end of Boston North Channel and near the location where Boston's main navigation channel enters the inner harbor. Data from these instruments were supplemented by tide data from a National Oceanic and Atmospheric Administration (NOAA) tide gage in the inner harbor, and NOAA wind measurements at Logan Airport. In addition, daylight current transect surveys using a downward looking acoustic profiling current meter attached to a survey vessel were conducted on 11 November 2004 and 8 February 2005. Five transect survey lines across the main navigation channel were surveyed. All instrumentation was recovered on 7 and 8 February 2005. Maximum-measured ebb tidal currents in the harbor were 0.9 to 3.84 ft/sec. Maximum-measured flood currents were 0.77 to 3.61 ft/sec. In general, the ebb currents were stronger than the flood currents. The data from the current meter deployed at the seaward end of Boston North Channel were analyzed to evaluate the importance of the wind-driven and tide-induced residual currents. The results of the analysis were that combined, these currents are small (5 to 22 percent of the ebb currents and 6 to 26 percent of the flood currents) compared to the maximum-measured tidal currents within the harbor. The tide-induced residual current at the seaward end of the navigation channel was estimated to be 0.07 ft/sec. The technical literature shows that tide-induced residual currents within the harbor, in the vicinity of the navigation channel, are stronger than they are at that location, with speeds of about 0.33 ft/sec. The largest currents at the seaward end of the navigation channel resulting from the action of the wind during major storms were associated with outflow of the storm surge from within the harbor. The analyses showed that during a major storm in December 2004, the currents were 0.54 ft/sec toward 70 deg, and during one of the worst storms (in terms of wind speed) in recent history, which occurred in January 2005, they were 0.56 ft/sec toward 69 deg (both speeds include an estimated tide-induced residual vector of 0.07 ft/sec toward 90 deg). The maximum water-level range is defined as the largest change in elevation from high-water to the low-water immediately following, that was recorded at a gage location. The maximum water-level range includes wind effects, as well as the astronomical tide. The range was 13.9 ft at the bridge between Chelsea and East Boston, 13.5 ft at Gallops Island, 14.1 ft at the Hull Yacht Club, and 13.9 ft at the NOAA gage.

Language

  • English

Media Info

  • Media Type: Web
  • Edition: Final Report
  • Pagination: 150p

Subject/Index Terms

Filing Info

  • Accession Number: 01052040
  • Record Type: Publication
  • Report/Paper Numbers: ERDC/CHL TR-07-3
  • Files: TRIS
  • Created Date: Jun 28 2007 4:25PM