Summary of GREAT LAKES DREDGE & DOCK CORP

Item 5.02. Departure of Directors or Certain Officers; Election of Directors;
Appointment of Certain Officers; Compensation Arrangements of Certain Officers and Other Events.

On August 17, 2012, Great Lakes Dredge & Dock Corporation (the "Company") announced that William S. (Bill) Steckel, 55, has been appointed Senior Vice President and Chief Financial Officer effective Monday August 20, 2012. Bruce Biemeck, who has served as President and CFO since September 2010, will resign his position as Chief Financial Officer and remain as President and Chief Operating Officer of the Company. Mr. Steckel will report to Chief Executive Officer Jonathan Berger.

From 2010 until joining Great Lakes, Mr. Steckel was the principal at WSS Strategic Advisors, a firm that provided financial and strategic advisory services to public and private companies. From 2008 to 2010, Mr. Steckel was with Daystar Technologies, Inc. (NASDAQ: DSTI), a developer of technology for solar photovoltaic products, where he served as CEO, president, CFO and treasurer. From 2006 to 2008 he was with Norwood Promotional Products, a supplier of custom imprinted products to the advertising and promotional products industry, where he served as senior vice president, CFO and treasurer. Prior to 2006, Mr. Steckel served in various management positions with Invensys (FTSE: ISIS) in its Lambda Power, Seibe Climate Controls and CTS Corporation Divisions.

In connection with the appointment, Mr. Steckel will be paid an annual base salary of $300,000, subject to increases by the Board. Mr. Steckel will be eligible to participate in the second amended and restated Great Lakes Dredge & Dock Company, LLC Annual Bonus Plan (the "Annual Bonus Plan") for an incentive award in a target amount equal to 40% of his annual base salary. Actual bonuses can range from 0% -200% of this target (between 0% and 80% of his base salary). In addition, Mr. Steckel will be entitled to incentive awards granted under the 2007 Long Term Incentive Plan, as amended and restated (the "2007 Plan") with a target payout equal to 40% of his annual base salary. A more detailed description of our 2007 Plan is contained in our proxy statement dated April 4, 2012. Mr. Steckel will also be eligible to participate in any employee benefit plan offered by the Company generally available to other executive officers or salaried employees.

The changes in senior management are described in the press release issued by the Company on August 17, 2012, attached hereto as Exhibit 99.1.