Tetra Tech JV Awarded $30 Million Lamèque Wind Energy Contract

Tetra Tech, Inc. (NASDAQ: TTEK) announced that its Tetra Tech Canada Construction entity is part of a joint venture with ACCIONA Infrastructures Canada Inc. that has been awarded a $30 million contract to provide turn-key construction services for the Lamèque Wind Power Project in the province of New Brunswick, Canada. Tetra Tech’s client for this project is ACCIONA Energy North America.

The 45-megawatt (MW) wind farm comprises thirty (30) 1.5-MW ACCIONA Windpower wind turbines and is expected to be commissioned in early 2011. Tetra Tech will provide construction management services for the access roads, foundations, turbine transportation and erection, electrical collection system and substation facilities, and the operations and maintenance building.

ACCIONA Energy and ACCIONA Infrastructure are part of the ACCIONA Group, one of Spain’s leading business corporations. ACCIONA operates in infrastructure, renewable energy, water treatment, and services in more than 30 countries on the five continents.

Its corporate motto, “Pioneers in Sustainable Development,” reflects the Company’s commitment to contributing to economic growth, social progress, and environmental balance. ACCIONA is a sector leader in the Dow Jones Sustainability Index, and posted revenues of more than €6.5 billion in 2009. The Company has a workforce of more than 30,000 and is quoted on the IBEX 35 blue chip index (ANA.MC).

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 energy. With more than 10,000 employees worldwide, Tetra Tech’s capabilities span the entire project life cycle.

www.acciona-na.com

www.tetratech.com