Tetra Tech Hires Doug Smith to Manage Infrastructure Business Group

Mr. Smith spent the previous 24 years, from 1980 to 2004, at Black& Veatch, where he was promoted to President of the Europe WaterDivision, a $350 million per year business. While at Black & Veatch,Mr. Smith focused on large program business development andacquisition integration. From 1976 to 1979, Mr. Smith was adjunctprofessor of Civil Engineering at the University of Colorado, Boulder,and director of Public Utilities for the City of Boulder. Mr. Smithholds a BS in Engineering from Kansas State University, a MS in CivilEngineering from the University of Colorado, and a JD from theUniversity of Denver. Mr. Smith is a licensed Professional Engineer.

Dan Batrack, Tetra Tech's CEO, said, "We are very pleased thatDoug has decided to join our management team. His experience isperfectly suited to our goal of building a strong infrastructurebusiness focused on water -- Tetra Tech's core competency."

About Tetra Tech (www.tetratech.com)

Tetra Tech is a leading provider of consulting, engineering andtechnical services. With over 7,000 associates located in the UnitedStates and internationally, the Company supports commercial andgovernment clients in the areas of resource management andinfrastructure. Tetra Tech's services include research anddevelopment, applied science and technology, engineering design,program management, construction management, and operations andmaintenance.

Any statements made in this release that are not based onhistorical fact are forward-looking statements. Any forward-lookingstatements made in this release represent management's best judgmentas to what may occur in the future. However, Tetra Tech's actualoutcome and results are not guaranteed and are subject to certainrisks, uncertainties and assumptions ("Future Factors"), and maydiffer materially from what is expressed. For a description of FutureFactors that could cause actual results to differ materially from suchforward-looking statements, see the discussion under the section "RiskFactors" included in the Company's Form 10-K and 10-Q filings with theSecurities and Exchange Commission.