Long period wave data have been collected at an offshore wave gage and system harbor gages for ov... more Long period wave data have been collected at an offshore wave gage and system harbor gages for over eight years in the Los Angeles/Long Beach Harbor region. These expansion of the harbors. In particular, the data have been used to select long period spectra for reproduction in a physical model of the harbors. In particular, the data have been used to select long period spectra for reproduction in a physical model of the harbors. They included two storm conditions representative of storms from the west and a summer spectrum from the south. These long period spectra were used to program model wave generators and wave data were collected at locations in the model which corresponded to prototype gage locations. A comparison of model and prototype correaltion. Also long wave information short period waves (southern hemisphere swell, hurricanes, or winter storms) on the nature of the long period component of the waves. Wave statistics were used to interpret effects of energy level on wave transformation into the harbors and correlate long and short wave spectrum.
Expansion of harbor facilities frequently involves placement of additional landfill and the deepe... more Expansion of harbor facilities frequently involves placement of additional landfill and the deepening of channels and mooring areas. A numerical tidal circulation model was used in the study of the proposed '2020 Master Plan' designed to meet the Los Angeles and Long Beach (LA-LB) Harbors needs by the year 2020. This paper examines the effect of this plan on harbor tidal circulation and discusses the significance of increased harbor depth on the change in harbor flow patterns and the resultant change in harbor circulation.
RA SAGER, WC SEABERGH IN: SYMPOSIUM ON MODELING TECHNIQUES, VOLUME I 2, 1975. ... MASONBORO INLET... more RA SAGER, WC SEABERGH IN: SYMPOSIUM ON MODELING TECHNIQUES, VOLUME I 2, 1975. ... MASONBORO INLET IS A NATURALLY OCCURRING ENTRANCE THROUGH A SANDY BARRIER BEACH ALONG THE NORTH CAROLINA COAST. ...
... show that (a) AMAX, the largest value of a obtained during a full wave period, is less than 0... more ... show that (a) AMAX, the largest value of a obtained during a full wave period, is less than 0.4 rad, and (b) AFINISH, the maximum value of a at the finis~f a wave period, is smaller than the starting value of a (listed in column 8); col~ 10 lists a 'tN()!t answer otherwise. ...
In response to the expansion of oceanborne world commerce, the Ports of Los Angeles and Long Beac... more In response to the expansion of oceanborne world commerce, the Ports of Los Angeles and Long Beach, California, in coordination with the Los Angeles District of the U.S. Army Corps of Engineers, have been conducting planning studies for harbor development to accommodate future needs. The Corps is charged with responsibility for providing deeper navigation channels and determining the effects of harbor expansion on the environment, while both Ports plan construction of new landfills, basins, and berthing facilities. The Los Angeles-Long Beach Harbors Model Enhancement Program was developed to significantly upgrade the Corps' capability to determine effects of this expansion based on state-of-the-art modeling technology. This paper presents highlights of the study, including objectives, tasks, and products provided. Major elements of the Model Enhancement Program include tidal circulation and water quality, harbor resonance, and moored ship motion. The results of the Model Enhance...
Final report regarding studies of weir jetties as an alternative for jetty design at tidal inlets... more Final report regarding studies of weir jetties as an alternative for jetty design at tidal inlets. "The hydraulic model investigation was performed to study important design parameters for a weir jetty system including weir length, elevation, orientation with respect to the shoreline and the conventional portion of the jetty structure, tidal currents over the weir section, flow patterns in the vicinity of the weir section, sediment movement over the weir and effects of the weir jetty on accretion, and erosion upcoast of the jetty system" (abstract, para. 2).
: Little Lake Harbor, Michigan, was constructed as a harbor of refuge for small craft on the sout... more : Little Lake Harbor, Michigan, was constructed as a harbor of refuge for small craft on the south shore of Lake Superior. However, the existing breakwaters have not prevented a heavy influx of sediment into the entrance channel and shoaling makes navigation difficult and dangerous. A 1:75-scale (undistorted) hydraulic model, reproducing the harbor, breakwater structures, entrance channel, adjacent shoreline for 1 mile both east and west of the harbor, and underwater contours out to -30 ft, was used to investigate various plans proposed to minimize or eliminate channel shoaling. The model simulated wind waves, wave-generated currents, seiche action, seiche-generated currents, and the movement of sediment (by the use of a crushed coal tracer). From an analysis of prototype data on water-level variation in Lake Superior and the harbor basin, it was determined that seiche oscillations with periods near the inlet-bay Helmholtz period occurred frequently. These oscillations could generat...
The shifting channels at the entrance to Willapa Bay make bar navigation unreliable, and the loca... more The shifting channels at the entrance to Willapa Bay make bar navigation unreliable, and the local port is having difficulty attracting commercial users. The Seattle District requested the U.S.Army Engineer Research and Development Center (ERDC) conduct a study to determine the technical feasibility of maintaining a reliable channel (28-ft depth including advance dredging and over-dredging allowance) over the entrance bar and into Willapa Bay. The strong wave and tidal current environment require innovative approaches to sustain a reliable channel via dredging and adjusting to relatively long- term cycles of channel morphology. This paper reviews the channel engineering and morphological analysis required to determine viable alternatives that might provide a reliable channel.
potential use of a physical model facility dedicated to the study of inlets and equipped to repre... more potential use of a physical model facility dedicated to the study of inlets and equipped to represent the most significant physical processes at and around inlets. BACKGROUND: An inlet is a region connecting two or more large bodies of water by a relatively short and narrow channel. The water bodies may be an ocean and lagoon, a large lake and a bay, or a river entering a sea or lake. Many processes at inlets can be examined in a thorough and efficient manner in a dedicated inlet physical model. FACILITIES: As part of the Coastal Inlets Research Program, an idealized inlet was constructed in a 46-m- (150-ft-) wide by 99-m- (325-ft-) long concrete basin with 0.6-m- (2-ft-) high walls. The approach was to design an inlet with simplified bathymetry and fairly steep beach slopes so that additional features (such as an ebb shoal) can easily be added. Also, it was anticipated that a fine sand serve as both a tracer and as a fully mobile bed that can be placed over the concrete bottom in a...
Long period wave data have been collected at an offshore wave gage and system harbor gages for ov... more Long period wave data have been collected at an offshore wave gage and system harbor gages for over eight years in the Los Angeles/Long Beach Harbor region. These expansion of the harbors. In particular, the data have been used to select long period spectra for reproduction in a physical model of the harbors. In particular, the data have been used to select long period spectra for reproduction in a physical model of the harbors. They included two storm conditions representative of storms from the west and a summer spectrum from the south. These long period spectra were used to program model wave generators and wave data were collected at locations in the model which corresponded to prototype gage locations. A comparison of model and prototype correaltion. Also long wave information short period waves (southern hemisphere swell, hurricanes, or winter storms) on the nature of the long period component of the waves. Wave statistics were used to interpret effects of energy level on wave transformation into the harbors and correlate long and short wave spectrum.
Expansion of harbor facilities frequently involves placement of additional landfill and the deepe... more Expansion of harbor facilities frequently involves placement of additional landfill and the deepening of channels and mooring areas. A numerical tidal circulation model was used in the study of the proposed '2020 Master Plan' designed to meet the Los Angeles and Long Beach (LA-LB) Harbors needs by the year 2020. This paper examines the effect of this plan on harbor tidal circulation and discusses the significance of increased harbor depth on the change in harbor flow patterns and the resultant change in harbor circulation.
RA SAGER, WC SEABERGH IN: SYMPOSIUM ON MODELING TECHNIQUES, VOLUME I 2, 1975. ... MASONBORO INLET... more RA SAGER, WC SEABERGH IN: SYMPOSIUM ON MODELING TECHNIQUES, VOLUME I 2, 1975. ... MASONBORO INLET IS A NATURALLY OCCURRING ENTRANCE THROUGH A SANDY BARRIER BEACH ALONG THE NORTH CAROLINA COAST. ...
... show that (a) AMAX, the largest value of a obtained during a full wave period, is less than 0... more ... show that (a) AMAX, the largest value of a obtained during a full wave period, is less than 0.4 rad, and (b) AFINISH, the maximum value of a at the finis~f a wave period, is smaller than the starting value of a (listed in column 8); col~ 10 lists a 'tN()!t answer otherwise. ...
In response to the expansion of oceanborne world commerce, the Ports of Los Angeles and Long Beac... more In response to the expansion of oceanborne world commerce, the Ports of Los Angeles and Long Beach, California, in coordination with the Los Angeles District of the U.S. Army Corps of Engineers, have been conducting planning studies for harbor development to accommodate future needs. The Corps is charged with responsibility for providing deeper navigation channels and determining the effects of harbor expansion on the environment, while both Ports plan construction of new landfills, basins, and berthing facilities. The Los Angeles-Long Beach Harbors Model Enhancement Program was developed to significantly upgrade the Corps' capability to determine effects of this expansion based on state-of-the-art modeling technology. This paper presents highlights of the study, including objectives, tasks, and products provided. Major elements of the Model Enhancement Program include tidal circulation and water quality, harbor resonance, and moored ship motion. The results of the Model Enhance...
Final report regarding studies of weir jetties as an alternative for jetty design at tidal inlets... more Final report regarding studies of weir jetties as an alternative for jetty design at tidal inlets. "The hydraulic model investigation was performed to study important design parameters for a weir jetty system including weir length, elevation, orientation with respect to the shoreline and the conventional portion of the jetty structure, tidal currents over the weir section, flow patterns in the vicinity of the weir section, sediment movement over the weir and effects of the weir jetty on accretion, and erosion upcoast of the jetty system" (abstract, para. 2).
: Little Lake Harbor, Michigan, was constructed as a harbor of refuge for small craft on the sout... more : Little Lake Harbor, Michigan, was constructed as a harbor of refuge for small craft on the south shore of Lake Superior. However, the existing breakwaters have not prevented a heavy influx of sediment into the entrance channel and shoaling makes navigation difficult and dangerous. A 1:75-scale (undistorted) hydraulic model, reproducing the harbor, breakwater structures, entrance channel, adjacent shoreline for 1 mile both east and west of the harbor, and underwater contours out to -30 ft, was used to investigate various plans proposed to minimize or eliminate channel shoaling. The model simulated wind waves, wave-generated currents, seiche action, seiche-generated currents, and the movement of sediment (by the use of a crushed coal tracer). From an analysis of prototype data on water-level variation in Lake Superior and the harbor basin, it was determined that seiche oscillations with periods near the inlet-bay Helmholtz period occurred frequently. These oscillations could generat...
The shifting channels at the entrance to Willapa Bay make bar navigation unreliable, and the loca... more The shifting channels at the entrance to Willapa Bay make bar navigation unreliable, and the local port is having difficulty attracting commercial users. The Seattle District requested the U.S.Army Engineer Research and Development Center (ERDC) conduct a study to determine the technical feasibility of maintaining a reliable channel (28-ft depth including advance dredging and over-dredging allowance) over the entrance bar and into Willapa Bay. The strong wave and tidal current environment require innovative approaches to sustain a reliable channel via dredging and adjusting to relatively long- term cycles of channel morphology. This paper reviews the channel engineering and morphological analysis required to determine viable alternatives that might provide a reliable channel.
potential use of a physical model facility dedicated to the study of inlets and equipped to repre... more potential use of a physical model facility dedicated to the study of inlets and equipped to represent the most significant physical processes at and around inlets. BACKGROUND: An inlet is a region connecting two or more large bodies of water by a relatively short and narrow channel. The water bodies may be an ocean and lagoon, a large lake and a bay, or a river entering a sea or lake. Many processes at inlets can be examined in a thorough and efficient manner in a dedicated inlet physical model. FACILITIES: As part of the Coastal Inlets Research Program, an idealized inlet was constructed in a 46-m- (150-ft-) wide by 99-m- (325-ft-) long concrete basin with 0.6-m- (2-ft-) high walls. The approach was to design an inlet with simplified bathymetry and fairly steep beach slopes so that additional features (such as an ebb shoal) can easily be added. Also, it was anticipated that a fine sand serve as both a tracer and as a fully mobile bed that can be placed over the concrete bottom in a...
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Papers by William Seabergh