Tetra Tech Awarded $240 Million USACE Transatlantic Programs Center Architecture-Engineering and Construction Services Contract

Tetra Tech, Inc. (NASDAQ: TTEK) announced today that it has been awarded a contract to provide architecture-engineering (A-E) and construction services to support the U.S. Army Corps of Engineers (USACE) Transatlantic Programs Center (TAC). Tetra Tech will support TAC in execution of the USACE’s mission in the Middle East, the Gulf, Central Asia, and Africa. The indefinite delivery contract was awarded for one year and may be extended up to four optional years at the government’s direction. Tetra Tech is one of four awardees announced on December 15, 2008. The maximum value of the contract for the entire performance period for all awardees is $240 million.

Under this contract, Tetra Tech will provide a wide variety of engineering services including design, planning, engineering and environmental studies, construction management, and other technical support services. These services will support a variety of projects including the design of airfields, force protection structures, and other facilities to support the military.

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.