Great Lakes Dredge & Dock Corporation Schedules Announcement for 2007 First Quarter Results

  
    
  
  
    
      Great Lakes Dredge & Dock Corporation (NASDAQ:GLDD)(NASDAQ:GLDDW) today 
      announced that it will release its financial results for the quarter 
      ended March 31, 2007 on Wednesday May 9, 2007 at 7:00 a.m. C.D.T. A 
      conference call with the Company will be held the same day at 10:00 a.m. 
      C.D.T. to discuss the Company’s first quarter 
      results and review operational highlights and other business 
      developments. The call in number is 888-515-2235. The call can also be 
      heard on the Great Lakes website, www.gldd.com 
      under Events and Presentations on the investor relations page. The 
      conference call will be available by replay for two weeks, by calling 
      888-203-1112 and providing passcode 6342322. A copy of the press release 
      will be available on the Company’s website.
    
    
      Great Lakes Dredge & Dock Corporation is the largest provider of 
      dredging services in the United States and the only U.S. dredging 
      company with significant international operations, averaging 18% of the 
      Company’s total dredging revenue over the last 
      three years. Great Lakes is a leader in each of the U.S. markets in 
      which it competes: capital, maintenance and beach nourishment dredging. 
      Great Lakes also owns an 85% interest in North American Site Developers, 
      Inc., one of the largest U.S. providers of commercial and industrial 
      demolition services. Additionally, the Company owns a 50% interest in a 
      marine sand mining operation in New Jersey which supplies sand and 
      aggregate used for road and building construction. Great Lakes has a 
      117-year history of never failing to complete a marine project and owns 
      the largest and most diverse fleet in the industry, comprising over 180 
      specialized vessels.