-------------------------------- OMB APPROVAL --------------------------------- UNITED STATES OMB Number: 3235-0145 SECURITIES AND EXCHANGE COMMISSION Expires: October 31, 2002 WASHINGTON, D.C. 20549 Estimated average burden hours per response....14.9 --------------------------------- SCHEDULE 13G UNDER THE SECURITIES EXCHANGE ACT OF 1934 (AMENDMENT NO. 3)* Tetra Tech, Inc. ---------------- (Name of Issuer) Common Stock, $.01 par value per share -------------------------------------- (Title of Class of Securities) 88162G103 -------------- (CUSIP Number) March 31, 2002 --------------- (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [X] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) * The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). Page 1 of 4 pages SCHEDULE 13G CUSIP No. 88162G103 ------------------------------------------------------------------------------------------------------------------------------ 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). A I M Management Group Inc., on behalf of itself and its wholly-owned subsidiaries, A I M Advisors, Inc., AIM Alternative Asset Management Company, Inc, A I M Capital Management, Inc., and AIM Private Asset Management, Inc. I.D. No. 74-1881407 ------------------------------------------------------------------------------------------------------------------------------ 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ------------------------------------------------------------------------------------- (b) ------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------ 3. SEC Use Only --------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------ 4. Citizenship or Place of Organization Delaware ------------------------------------------------------------------------------------------------------------------------------ 5. Sole Voting Power 254,327 Number of Shares ------------------------------------------------------------------------------------------------------ Beneficially Owned 6. Shared Voting Power by Each Reporting Person With ------------------------------------------------------------------------------------------------------ 7. Sole Dispositive Power 254,327 ------------------------------------------------------------------------------------------------------ 8. Shared Dispositive Power ------------------------------------------------------------------------------------------------------------------------------ 9. Aggregate Amount Beneficially Owned by Each Reporting Person 254,327 ------------------------------------------------------------------------------------------------------------------------------ 10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ------------------------------------------------------------------------------------------------------------------------------ 11. Percent of Class Represented by Amount in Row (9) 0.5% ------------------------------------------------------------------------------------------------------------------------------ 12. Type of Reporting Person (See Instructions) HC ------------------------------------------------------------------------------------------------------------------------------ Page 2 of 4 pages SCHEDULE 13G Item 1(a) NAME OF ISSUER: Tetra Tech, Inc. Item 1(b) ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES: 670 North Rosemead Blvd. Pasadena, CA 91107 Item 2(a) NAME OF PERSON FILING: A I M Management Group Inc. Item 2(b) ADDRESS OF PRINCIPAL BUSINESS OFFICE: 11 Greenway Plaza, Suite 100 Houston, Texas 77046 Item 2(c) CITIZENSHIP: State of Delaware Item 2(d) TITLE OF CLASS OF SECURITIES: Common Stock, $.01 par value per share Item 2(e) CUSIP NUMBER: 88162G103 Item 3 TYPE OF REPORTING PERSON: Parent Holding Company, in accordance with section 240.13d-1(b)(1)(ii)(G) Item 4(a) AMOUNT BENEFICIALLY OWNED AS OF MARCH 31, 2002: 254,327 Item 4(b) PERCENT OF CLASS: 0.5% Item 4(c) NUMBER OF SHARES AS TO WHICH THE PERSON HAS: (i) Sole power to vote or to direct the vote: 254,327 (ii) Shared power to vote or to direct the vote: N/A (iii) Sole power to dispose or to direct the disposition of: 254,327 (iv) Shared power to dispose or to direct the disposition of: N/A Item 5 OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS: This statement is being filed to report the fact that as of March 31, 2002, the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities. Item 6 OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON: N/A Page 3 or 4 pages Item 7 IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY: A I M Advisors, Inc., AIM Alternative Asset Management Company, Inc., A I M Capital Management, Inc., and AIM Private Asset Management, Inc., Investment Advisers registered under Section 203 of the Investment Advisers Act Item 8 IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP: N/A Item 9 NOTICE OF DISSOLUTION OF A GROUP: N/A Item 10 CERTIFICATION: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. SIGNATURE: After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. April 10, 2002 -------------- Date /s/ CAROL F. RELIHAN ---------------------------------------------------- Signature Carol F. Relihan Senior Vice President, Secretary and General Counsel A I M Management Group Inc. ---------------------------------------------------- Name/Title ** Please call Jesse Frazier at (713) 214-4780 with questions regarding this filing. Page 4 of 4 pages