harbor. These gauges would collect data for 15 min on 3-hr intervals and would 

 begin obtaining data on 15 October 1994 and extend through the winter season. 



In June 1995, a recovery attempt was made for the prototype gauges. A 

 response was received from the acoustic pinger from the southernmost DWG, but 

 the buoy did not surface when the acoustic release was triggered. For the northern- 

 most DWG, the acoustic pinger did not respond, nor did the buoy surface when the 

 release was triggered. Extensive grappling for the two DWGs yielded no gauges. In 

 addition, the nondirectional pressure gauge attached to the dock in the harbor was 

 no longer there. The current meter in the harbor was deployed in a water depth of 

 4.3 m (14 ft); however, the depth at the site during retrieval efforts was only 0.6 m 

 (2 ft). This shoaling may be related to harbor dredging that occurred m April 1995. 

 An additional attempt to recover the DWGs occurred on 14 September 1995. WES 

 personnel accompanied a team of National Oceanographic and Atmospheric 

 Adminisfration (NOAA) divers to the locations where the DWGs were deployed. 

 These locations were determined by a hand-held global positioning system (GPS) 

 unit. The divers deployed and searched a 30-m (100-ft) radius in the vicinity of 

 each gauge location but were unable to locate them. Ice conditions reported during 

 the 1994-95 winter season by the locals were some of the worst in memory. It is 

 possible that the wave gauges were destroyed by storm wave and/or ice conditions. 

 Wave activity at the locations of the DWGs could also have buried the gauges in 

 sand. The current meter in the harbor was probably buried due to the dredging that 

 occurred in the spring of 1995. 



During the period September 1994 through mid- April 1995, prototype wave data 

 were obtained sporadically inside the harbor with pressure gauges that were 

 mounted to the Unisea vessel, a permanently moored, floating crab processor. This 

 vessel is moored immediately south of the northernmost dock in the harbor and is 

 shown in Figure 3. Gauges were placed on the bottom and tied to the vessel's stem 

 and bow. They collected data in 17.5-min bursts. Data obtained were analyzed by 

 WES personnel and included peak wave periods and significant wave heights 

 (average height of highest one third of the waves). 



Wave hindcast study 



In the absence of incident prototype wave data approaching the harbor, a wave 

 hindcast study was performed at WES to determine hindcast wave information 

 seaward of the St. Paul Harbor main breakwater. The Wave Information Studies 

 (WIS) wave model was used to produce the wave information (Hubertz 1992). The 

 hindcasting was performed in two stages: An initial stage using a relatively coarse 

 input grid over the entire Bering Sea (Figure 15) to achieve model calibration; and a 

 final stage using a finer resolution grid covering the St. Paul Island vicinity 

 (Figure 16) to produce wave climatology for St. Paul Harbor. 



Calibration of the wave model was achieved in the initial stage of the study by 

 comparison of model output and measured wave data obtained from NOAA buoy 

 46035, located in the central Bering Sea. Grid spacing was 0.5 deg. Global wind 



20 



Chapter 2 Monitoring Program 



