EXHIBIT 10.1


                  SECOND AMENDMENT TO ASSET PURCHASE AGREEMENT


                  SECOND AMENDMENT TO ASSET PURCHASE AGREEMENT, dated as of
April 28, 2003 (this "Second Amendment"), by and among Tetra Tech, Inc., a
Delaware corporation ("Tetra Tech"), Tetra Tech FW, Inc., a Delaware corporation
and a direct wholly-owned Subsidiary of Tetra Tech ("Purchaser"), Foster
Wheeler, Ltd., a Bermuda corporation ("FW Ltd."), Foster Wheeler, LLC, a
Delaware limited liability company and an indirect wholly-owned Subsidiary of FW
Ltd. ("FW LLC"), Foster Wheeler USA Corporation, a Delaware corporation and an
indirect wholly-owned Subsidiary of FW Ltd. ("FW USA", and together with FW Ltd.
and FW LLC, the "FW Guarantors"), Foster Wheeler Environmental Corporation, a
Texas corporation and a direct wholly-owned Subsidiary of FW USA ("FWENC"), and
Hartman Consulting Corporation, a Delaware corporation and a direct wholly-owned
Subsidiary of FWENC ("Hartman", and together with FWENC, the "Sellers"). Tetra
Tech, Purchaser, each of the FW Guarantors and each of the Sellers are
individually referred to herein as a "Party" and collectively referred to herein
as the "Parties". Capitalized terms used herein and not otherwise defined herein
shall have the respective meanings assigned to them in the Asset Purchase
Agreement (as defined below).


                              W I T N E S S E T H :
                               - - - - - - - - - -


                  WHEREAS, Tetra Tech, Purchaser, the FW Guarantors and the
Sellers are parties to an Asset Purchase Agreement, dated as of February 17,
2003 and amended as of March 7, 2003 (as in effect on the date hereof, but prior
to giving effect to this Second Amendment, the "Asset Purchase Agreement"); and

                  WHEREAS, the Parties wish to amend the Asset Purchase
Agreement as herein provided;


                  NOW, THEREFORE, the Parties agree as follows:

I. Amendments to the Asset Purchase Agreement.

                  1. Schedule 2.3(h) to the Asset Purchase Agreement (Assumed
Liabilities) is hereby amended by deleting in its entirety item number 6,
Hopkins v. Hopkins, Civil Action No. ED-050357, Superior Court of California,
County of San Diego, and inserting the following new language in lieu thereof:

                  "6. Intentionally Omitted."

                  2. Schedule 2.4(k) to the Asset Purchase Agreement (Excluded
Liabilities) is hereby amended by adding thereto the following new item at the
end thereof:

                  "15. Hopkins v. Hopkins, Civil Action No. ED-050357, Superior
                  Court of California, County of San Diego."




II.      Miscellaneous.

                  1. This Second Amendment is limited as specified and shall not
constitute a modification, acceptance or waiver of any other provision of the
Asset Purchase Agreement or any other related document or agreement.

                  2. This Second Amendment may be executed in two (2) or more
counterparts, all of which shall be considered one and the same agreement and
shall become effective on the date (the "Second Amendment Effective Date") when
two (2) or more counterparts have been signed by each of the Parties and
delivered (including, without limitation, by way of facsimile transmission) to
the other Parties.

                  3. THIS SECOND AMENDMENT AND THE LEGAL RELATIONS BETWEEN THE
PARTIES SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE OF NEW YORK, WITHOUT REGARD TO THE CONFLICT OF LAWS RULES THEREOF.

                  4. This Second Amendment shall be binding upon and shall inure
to the benefit of the parties hereto and their respective heirs, executors,
administrators, successors and permitted assigns.

                  5. From and after the Second Amendment Effective Date, all
references in the Asset Purchase Agreement and in any other related document or
agreement to the Asset Purchase Agreement shall be deemed to be references to
the Asset Purchase Agreement as modified hereby.

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                                      -2-



                  IN WITNESS WHEREOF, each Party has caused its name to be
hereunto subscribed by its officer thereunto duly authorized all as of the day
and year first above written.


                              TETRA TECH, INC.


                              By: /s/ James M. Jaska
                                 ----------------------------------------------
                                  Name:      James M. Jaska
                                  Title:     President


                              TETRA TECH FW, INC.


                              By: /s/ James M. Jaska
                                 ----------------------------------------------
                                  Name:      James M. Jaska
                                  Title:     President


                              FOSTER WHEELER, LTD.


                              By: /s/ Steven I. Weinstein
                                 ----------------------------------------------
                                  Name:      Steven I. Weinstein
                                  Title:     Vice President & Deputy General
                                                   Counsel

                              FOSTER WHEELER, LLC


                              By: /s/ Steven I. Weinstein
                                 ----------------------------------------------
                                  Name:      Steven I. Weinstein
                                  Title:     Vice President & Deputy General
                                                   Counsel



                              FOSTER WHEELER USA CORPORATION


                              By: /s/ Brian K. Ferraioli
                                 ----------------------------------------------
                                  Name:      Brian K. Ferraioli
                                  Title:     President


                              FOSTER WHEELER ENVIRONMENTAL CORPORATION


                              By: /s/ Bernard H. Cherry
                                 ----------------------------------------------
                                  Name:      Bernard H. Cherry
                                  Title:     Chairman, President & CEO




                              HARTMAN CONSULTING CORPORATION


                              By: /s/ Bernard H. Cherry
                                 ----------------------------------------------
                                  Name:      Bernard H. Cherry
                                  Title:     Chairman, President & CEO