Tetra Tech Wins $100 Million NAVFAC Southwest Remedial Action Contract

(PASADENA, Calif., Nov. 29, 2005) -- Tetra Tech, Inc. (NASDAQ:TTEK) announced today that it was awarded the $100 million U.S. Department of the Navy, Naval Facilities Engineering Command Southwest (NAVFAC Southwest) Remedial Action Contract (RAC) IV. This is the second consecutive time that NAVFAC Southwest has awarded the RAC to Tetra Tech. Under this five-year indefinite delivery/indefinite quantity contract, Tetra Tech will provide technical environmental services and program management to support NAVFAC Southwest at active U.S. Navy and Marine Corps bases, as well as bases that are impacted by the U.S. Department of Defense's current and previous rounds of Base Realignment and Closure (BRAC). Under RAC IV, Tetra Tech will provide cost-reimbursable services for remedial action, removal action, remedial design, operation and maintenance of treatment systems, and unexploded ordnance activities. Work will be performed primarily at active and BRAC-impacted sites across the western coast of the United States, including U.S. Navy bases in Alaska, Arizona, California, New Mexico, Nevada, Oregon, Utah and Washington. About Tetra Tech (www.tetratech.com) Tetra Tech is a leading provider of consulting, engineering and technical services. With over 7,000 associates located in the United States and internationally, the Company supports commercial and government clients in the areas of resource management and infrastructure. Tetra Tech's services include research and development, applied science and technology, engineering design, program management, construction management, and operations and maintenance. Any statements made in this release that are not based on historical fact are forward-looking statements. Any forward-looking statements made in this release represent management's best judgment as to what may occur in the future. However, Tetra Tech's actual outcome and results are not guaranteed and are subject to certain risks, uncertainties and assumptions ("Future Factors"), and may differ materially from what is expressed. For a description of Future Factors that could cause actual results to differ materially from such forward-looking statements, see the discussion under the section "Risk Factors" included in the Company's Form 10-K and 10-Q filings with the Securities and Exchange Commission. Contact: Tetra Tech, Inc. Mike Bieber, 626-351-4664

Source: Tetra Tech, Inc.
Date: Nov 29, 2005