Tetra Tech Awarded AFCEE Worldwide Environmental Restoration and Construction Contract

Tetra Tech, Inc. (NASDAQ: TTEK) announced today that it has been awarded the Air Force Center for Engineering and the Environment (AFCEE) Worldwide Environmental Restoration and Construction (WERC 09) contract to provide environmental and construction services at U.S. Air Force installations worldwide. The contract ceiling of $3 billion will be shared by 20 awardees.

WERC 09 is a five-year indefinite delivery/indefinite quantity contract. This contract is primarily for environmental requirements that include completion of a conceptual design, construction, implementation, demolition, repair, and operation and maintenance of installed systems prior to delivery to the government. Tetra Tech may be tasked to execute a variety of environmental restoration, pollution prevention, compliance, conservation, design, construction, demolition, and/or emergency response projects, including projects to support base realignment and closure (BRAC) and other activities.

Since December 2003, Tetra Tech has performed more than $400 million of work for AFCEE under a WERC 09 predecessor contract.

About Tetra Tech (www.tetratech.com)

Tetra Tech is a leading provider of consulting, engineering, program management, construction and technical services addressing the resource management and infrastructure markets. The Company supports government and commercial clients by providing innovative solutions focused on water, the environment and alternative energy. With more than 8,500 associates located in the United States and internationally, Tetra Tech’s capabilities span the full project life cycle.

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.