1 Introduction 



The U.S. Coast Guard (USCG) Station, Port Huron, is located in Port Huron, 

 Michigan, at the extreme southern portion of Laice Huron where the laive empties 

 into the St. Clair River (Figures 1, 2, and 3). This location is ideal for the USCG 

 to conduct rescue operations for the heavy summer recreational boat traffic on 

 lower Lake Huron and the upper St. Clair River. However, because the station is 

 located in the dynamic lake-to-river transition region, sediment shoaling is so 

 severe that rescue operations from the station's boat basin are limited and frequent 

 dredging is required. The existing boat basin configuration is designed to berth a 

 12.5-m (41 -ft)' vessel (which draws approximately 1.5 m (5 ft)), but because of 

 the sedimentation, the USCG can only operate its rigid hull inflatable boat. 



Since the present basin was constructed in 1996, dredging is required approxi- 

 mately every 3 months, hi addition, the existing configuration and type of con- 

 struction (vertical sheet-pile walls) contribute to undesirable reflective wave 

 energy inside the basin from wind waves and vessel-generated waves from ship 

 traffic. Strong currents in combination with waves also cause problems for navi- 

 gating into the basin. 



The USCG wants to identity a solution that will reduce the dredging fre- 

 quency and improve navigation into and out of the basin as well as improve 

 mooring of vessels at the basin dock. In recent years, the USCG has sought 

 U.S. Army Corps of Engineers (USAGE) permits for multiple dredging opera- 

 tions, but no long-tenn plan had been identified to address the chronic sedimenta- 

 tion and wave energy problem. At the suggestion of the U.S. Army Engineer 

 District, Detroit, and the Michigan Department of Environmental Quality (State 

 permitting agency), the USCG through the Detroit District contracted with the 

 U.S. Army Engineer Waterways Experiment Station (WES) to study the entrance 

 sedimentation and harbor resonance problems and make recommendations on 

 steps to take to reduce shoaling at the basin entrance and minimize harbor wave 

 action. 



The objective of the WES study was twofold: (a) conduct field investigations 

 to collect data to analyze existing coastal processes, and (b) conduct a physical 



Units of measurement in the text of this report are shown in SI units, followed by non- 

 Si (British) units in parentheses. In addition, a table of factors for converting non-SI 

 units of measurement used in figures, tables, plates, and photographs in this report to 

 SI units is presented on page viii. 



Chapter 1 Introduction 



