Document:

Prepared by MERRILL CORPORATION

QuickLinks
 -- Click here to rapidly navigate through this document
  

 
 

Exhibit 10.3    
  

 
 

SECOND AMENDMENT    
  

    THIS SECOND AMENDMENT (this "Amendment") dated as of August 13, 2001 is to the Credit Agreement (the
"Credit Agreement") dated as of March 17, 2000 among TETRA TECH, INC. (the "Company"),
various financial institutions and BANK OF AMERICA, N.A., as administrative agent (the "Agent"). Unless otherwise defined herein, terms defined in the
Credit Agreement are used herein as defined therein. 

    WHEREAS,
the parties hereto have entered into the Credit Agreement which provides for the Banks to make Loans to, and to issue Letters of Credit for the account of, the Company from
time to time; and 

    WHEREAS,
the parties hereto desire to amend the Credit Agreement as set forth below; 

    NOW
THEREFORE, in consideration of the premises and for other good and valuable consideration (the receipt and sufficiency of which are hereby acknowledged), the parties hereto agree
as follows: 

    SECTION
1 AMENDMENTS. Effective on (and subject to the occurrence of) the Amendment Effective Date (as defined below), the Credit
Agreement shall be amended as follows: 

    Section 1.1
Definitions. Section 1 of the Credit Agreement is amended by inserting the following definition in the
appropriate alphabetical order: 

    "Adjusted Leverage Ratio means, for any Computation Period, the Leverage Ratio for such Computation Period,  provided that for purposes of computing the Adjusted Leverage
Ratio, EBITDA
shall be adjusted by (x) adding back the special charge (but not more than $38,300,000) taken by the Company in the third Fiscal Quarter of Fiscal Year 2001 in connection with the bankruptcy of
Metricom, Inc., to the extent taken in such Computation Period; and (y) deducting any recovery received on the obligations which gave rise to the special charge referred to in  clause (x),
to the extent received during such Computation Period." 

    Section 1.2
Leverage Covenant. Section 10.6.3 of the Credit Agreement is amended by inserting the word "Adjusted" before
the words "Leverage Ratio" therein. 

    Section 1.3  Addition of Covenant. Section 10 of the Credit Agreement is amended by adding the following: 

    "10.23
Note Purchase Agreement Covenants. Comply with the terms set forth in Sections 10.1 (Indebtedness; Priority Debt), 10.2 (Fixed
Charge Coverage) and 10.3 (Adjusted Consolidated Net Worth) of the Note Purchase Agreement dated as of May 15, 2001 executed in connection with the Private Placement Debt, as such Note Purchase
Agreement is in effect on the date hereof (without giving effect to any amendment thereto or waiver thereof unless consented to by the Required Banks)." 

    Section 1.4  Events of Default. Clause (a) of Section 12.1.5 of the Credit Agreement is amended by adding the
following at the end thereof (after the reference to "10.21" and before the semi-colon): "and 10.23". 

    SECTION
2 REPRESENTATIONS AND WARRANTIES. The Company represents and warrants to the Agent and the Banks that (a) each warranty
set forth in Section 9 of the Credit Agreement is true and correct as if made on the date hereof, (b) the execution and delivery by the Company of this Amendment and the performance by
the Company of its obligations under the Credit Agreement as amended hereby (as so amended, the "Amended Credit Agreement") (i) are within the
corporate powers of the Company, (ii) have been duly authorized by all necessary corporate action, (iii) have received all 

1

 

necessary governmental approval and (iv) do not and will not contravene or conflict with any provision of law or of the charter or by-laws of the Company or any Subsidiary or of any
indenture, loan agreement or other material contract, or any judgment, order or decree, which is binding upon the Company or any Subsidiary, and (c) this Amendment and the Amended Credit
Agreement are the legal, valid and binding obligations of the Company, enforceable against the Company in accordance with their terms, except as enforceability may be limited by bankruptcy, insolvency
or other similar laws of general application affecting the enforcement of creditor's rights or by general principles of equity. 

    SECTION
3 EFFECTIVENESS. The amendments set forth in Section 1 shall
become effective, as of the day and year first above written, on such date (the "Amendment Effective Date") that the Agent shall have received each of
the following: (a) counterparts of this Amendment executed by the Company and the Required Banks; (b) a Confirmation in the form of  Exhibit A hereto signed by the Company and each
Subsidiary; (c) for the account of each Bank that has executed and delivered a
counterpart hereof to the agent (via facsimile or otherwise) by 1:00 PM (Chicago Time) on August 13, 2001, an amendment fee in an amount equal to 0.10% of such Bank's commitment; and
(d) such other documents as the Agent or any Bank may reasonably request. 

    SECTION
4 MISCELLANEOUS. 

    Section 4.1  Continuing Effectiveness, etc. As herein amended, the Credit Agreement shall remain in full force and effect and is
hereby ratified and confirmed in all respects. 

    Section 4.2
Counterparts. This Amendment may be executed in any number of counterparts and by the different parties on separate
counterparts, and each such counterpart shall be deemed to be an original but all such counterparts shall together constitute one and the same Second Amendment. 

    Section 4.3  Governing Law. This Amendment shall be a contract made under and governed by the laws of the State of Illinois
applicable to contracts made and to be performed entirely within such State. 

    Section 4.4
Successors and Assigns. This Amendment shall be binding upon the Company and the Agent and their respective
successors and assigns, and shall inure to the benefit of the Company and the Agent and the successors and assigns of the Agent. 

    Section 4.5
Expenses. The Company agrees to pay the reasonable costs and expenses of the Agent (including attorneys' fees) in
connection with the preparation, execution and delivery of this Amendment. 

    Delivered
at Chicago, Illinois, as of the day and year first above written. 

	 	 	TETRA TECH, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Chief Financial Officer

	

 	
 	

 	
 	

 
	 	 	BANK OF AMERICA, N.A., AS

ADMINISTRATIVE AGENT
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ KRISTINE D HYDE   

	 	 	Title:	 	Vice President

2

 

	

 	
 	

 	
 	

 
	 	 	BANK OF AMERICA, N.A., AS SWING LINE

BANK, ISSUING BANK AND AS A BANK
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JENNIFER L. GERDES   

	 	 	Title:	 	Vice President

	

 	
 	

 	
 	

 
	 	 	WELLS FARGO BANK, N.A., AS

DOCUMENTATION AGENT AND AS A BANK
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ RANDALL J. REPP   

	 	 	Title:	 	Vice President

	

 	
 	

 	
 	

 
	 	 	HARRIS TRUST AND SAVINGS BANK,

AS SYNDICATION AGENT AND AS A BANK
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ ISABELLA BATTISTA   

	 	 	Title:	 	Vice President

	

 	
 	

 	
 	

 
	 	 	THE FUJI BANK, LIMITED
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ STEVEN T. BRENNAN   

	 	 	Title:	 	Senior Vice President

	

 	
 	

 	
 	

 
	 	 	PACIFIC CENTURY BANK, N.A.
	

 	
 	

 	
 	

 
	 	 	By:	 	

	 	 	Title:	 	

3

 
 
 

EXHIBIT A
  
    CONFIRMATION
  
    Dated as of August 13, 2001    
  

    Each of the undersigned hereby acknowledges and agrees to the foregoing Second Amendment and the Amended Credit Agreement and hereby confirms the continuing
validity and enforceability of the Guaranty and the Security Agreement after giving effect thereto. 

	 	 	HSI GEOTRANS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Assistant Treasurer

	

 	
 	

 	
 	

 
	 	 	SCM CONSULTANTS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Assistant Treasurer

	

 	
 	

 	
 	

 
	 	 	TETRA TECH EM, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	WHALEN & COMPANY, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Chief Financial Officer

	

 	
 	

 	
 	

 
	 	 	TETRA TECH NUS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

4

 

	

 	
 	

 	
 	

 
	 	 	MFG, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	COLLINS-PINA CONSULTING ENGINEERS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	DEA CONSTRUCTION COMPANY, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	BAHA COMMUNICATIONS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	UTILITIES & C.C., INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

5

 

	

 	
 	

 	
 	

 
	 	 	ASL CONSULTING ENGINEERS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	ASL CONSULTING ENGINEERS ARIZONA, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	ASL CONSULTANTS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	COSENTINI ASSOCIATES, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	EVERGREEN UTILITY CONTRACTORS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	KCM, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Assistant Treasurer

6

 

	

 	
 	

 	
 	

 
	 	 	LC OF ILLINOIS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Treasurer

	

 	
 	

 	
 	

 
	 	 	MCNAMEE, PORTER & SEELEY, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Assistant Treasurer

	

 	
 	

 	
 	

 
	 	 	MCNAMEE INDUSTRIAL SERVICES, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Assistant Treasurer

	

 	
 	

 	
 	

 
	 	 	PDR ENGINEERS, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Title:	 	Chief Financial Officer

7

QuickLinks

Exhibit 10.3

SECOND AMENDMENT

EXHIBIT A CONFIRMATION Dated as of August 13, 2001Prepared by MERRILL CORPORATION

QuickLinks
 -- Click here to rapidly navigate through this document
  

 
 

Exhibit 10.5
  
    EXECUTION COPY    
  

 
 

TETRA TECH, INC.
  
    FIRST AMENDMENT TO
  NOTE PURCHASE AGREEMENT
  
    $110,000,000
  Senior Secured Notes
  
    $92,000,000
  7.28% Senior Secured Notes,

Series A, due May 30, 2011
  
    $18,000,000
  7.08% Senior Secured Notes,
  Series B, due May 30, 2008    

 
 

Dated as of September 30, 2001    

To
the Holders of the Senior Notes

of Tetra Tech, Inc. Named in

the Attached Schedule I 

Ladies
and Gentlemen: 

    Reference
is made to the Note Purchase Agreement dated as of May 15, 2001 (the "Note Agreement") between Tetra Tech, Inc., a Delaware corporation (the "Company"), and
you pursuant to which the Company issued $92,000,000 aggregate principal amount of its 7.28% Senior Secured Notes, Series A, due May 30, 2011 (the "Series A Notes") and
$18,000,000 aggregate principal amount of its 7.08% Senior Secured Notes, Series B, due May 30, 2008 (the "Series B Notes" and, together with the Series A Notes, the
"Notes"). You are referred to herein individually as a "Holder" and collectively as the "Holders". Capitalized terms used and not otherwise defined herein shall have the meanings ascribed to them in
the Note Agreement, as amended hereby. 

    The
Company has requested that the Note Agreement be amended to exclude a special charge related to the bankruptcy of Metricom, Inc. from Adjusted EBITDA for purposes of the
Indebtedness covenant. You have agreed to such amendment on the terms and conditions set forth herein. 

    In
consideration of the premises and for good and valuable consideration, the receipt and sufficiency of which are acknowledged, the Company and the Holders agree as follows: 

1.  AMENDMENT OF NOTE AGREEMENT  

    1.1.
Section 10.1(a). Section 10.1(a) of the Note Agreement is amended to read in its entirety as follows: 

    "(a) the
ratio of Consolidated Indebtedness (as of any date) to Adjusted EBITDA (for the Company's then most recently completed four fiscal quarters) to be greater that
2.75 to 1.00; provided, however, that for purposes of this Section 10.1(a), Adjusted EBITDA shall be adjusted by (x) adding back the special charge (but not more than $38,300,000) taken
by the Company in the fiscal quarter ended July 1, 2001 in connection with the bankruptcy of Metricom, Inc. to the extent taken during the Company's then most recently completed four
fiscal quarters and (y) deducting any recovery received on the obligations that gave rise to the special charge referred 

S–1

 

to in clause (x) to the extent received during the Company's then most recently completed four fiscal quarters; or" 

2.  REAFFIRMATION; REPRESENTATIONS AND WARRANTIES`  

    2.1.
Reaffirmation of Note Agreement. The Company reaffirms its agreement to comply with each of the covenants, agreements and other
provisions of the Note Agreement and the Notes, including the amendment of such provisions effected by this First Amendment. 

    2.2.  Note Agreement. The Company represents and warrants that the representations and warranties contained in the Note Agreement are
true and correct as of the date hereof, except (a) to the extent that any of such representations and warranties specifically relate to an earlier date, (b) for such changes, facts,
transactions and occurrences that have arisen since May 22, 2001 in the ordinary course of business, (c) for such other matters as have been previously disclosed in writing by the
Company (including in its financial statements and notes thereto) to the Holders and (d) for other changes that could not reasonably be expected to have a Material Adverse Effect. 

    2.3.  No Default or Event of Default. After giving effect to the transactions contemplated hereby, there will exist no Default or Event
of Default. 

    2.4.
Authorization. The execution, delivery and performance by the Company of this First Amendment have been duly authorized by all
necessary corporate action and, except as provided herein, do not require any registration with, consent or approval of, notice to or action by, any Person (including any Governmental Authority) in
order to be effective and enforceable. The Note Agreement and this First Amendment each constitute the legal, valid and binding obligations of the Company, enforceable in accordance with their
respective terms, except as such enforceability may be limited by (i) applicable bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium or other similar laws affecting the
enforcement of creditors' rights generally and (ii) general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law). 

3.  EFFECTIVE DATE  

    This First Amendment shall become effective as of the date set forth above upon the satisfaction of the following conditions: 

    3.1.
Consent of Holders to First Amendment. Execution by the Holders of at least a majority of the aggregate principal amount of the
Notes outstanding and receipt by the Holders of a counterpart of this First Amendment duly executed by the Company. 

    3.2.
Amendment Fee. Each Holder shall have received payment of an amendment fee equal to 0.1% of the principal amount of the
outstanding Notes held by such Holder. 

    3.3.
Expenses. The Company shall have paid all fees and expenses of special counsel to the Holders. 

4.  MISCELLANEOUS  

    4.1.  Ratification. Except as amended hereby, the Note Agreement, including the representations and warranties contained therein, shall
remain in full force and effect and is ratified, approved and confirmed in all respects as of the date hereof. 

    4.2.
Reference to and Effect on the Note Agreement. Upon the final effectiveness of this First Amendment, each reference in the Note
Agreement and in other documents describing or referencing the Note Agreement to the "Agreement," "Note Agreement," "hereunder," "hereof," "herein," or 

S–2

 

words of like import referring to the Note Agreement, shall mean and be a reference to the Note Agreement, as amended hereby. 

    4.3.
Binding Effect. This First Amendment shall be binding upon and inure to the benefit of the respective successors and assigns of
the parties hereto. 

    4.4.
Governing Law. This First Amendment shall be governed by and construed in accordance with Illinois law. 

    4.5.  Counterparts. This First Amendment may be executed in any number of counterparts, each executed counterpart constituting an
original, but altogether only one instrument. 

    IN WITNESS WHEREOF, the Company and the Holders have caused this First Amendment to be executed and delivered by their respective
officer or officers thereunto duly authorized. 

	 	 	TETRA TECH, INC.
	

 	
 	

 	
 	

 
	 	 	By:	 	/s/ JAMES M. JASKA   

	 	 	Name:	 	James M. Jaska

	 	 	Title:	 	Chief Financial Officer

S–3

 

HOLDERS: 

The
foregoing is agreed

to as of the date thereof. 

	MASSMUTUAL ASIA LIMITED	 	 
	By:	 	David L. Babson & Company Inc. as Investment Adviser	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ MARK A. AHMED   
	 	 
	Name:	 	Mark A. Ahmed
	 	 
	Title:	 	Managing Director
	 	 
	

 	
 	

 	
 	

 
	MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY	 	 
	By:	 	David L. Babson & Company Inc. as Investment Adviser	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ MARK A. AHMED   
	 	 
	Name:	 	Mark A. Ahmed
	 	 
	Title:	 	Managing Director
	 	 
	

 	
 	

 	
 	

 
	C.M. LIFE INSURANCE COMPANY	 	 
	By:	 	David L. Babson & Company Inc. as Investment Adviser	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ MARK A. AHMED   
	 	 
	Name:	 	Mark A. Ahmed
	 	 
	Title:	 	Managing Director
	 	 
	

 	
 	

 	
 	

 
	CONNECTICUT GENERAL LIFE INSURANCE COMPANY	 	 
	By:	 	CIGNA Investments, Inc. (authorized agent)	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ STEPHEN H. WILSON   
	 	 
	Name:	 	Stephen H. Wilson
	 	 
	Title:	 	Managing Director
	 	 

S–4

 

	

 	
 	

 	
 	

 
	LIFE INSURANCE COMPANY OF NORTH AMERICA	 	 
	By:	 	CIGNA Investments, Inc. (authorized agent)	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ STEPHEN H. WILSON   
	 	 
	Name:	 	Stephen H. Wilson
	 	 
	Title:	 	Managing Director
	 	 
	

 	
 	

 	
 	

 
	UNITED OF OMAHA LIFE INSURANCE COMPANY	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ EDWIN H. GARRISON JR.   
	 	 
	Name:	 	Edwin H. Garrison Jr.
	 	 
	Title:	 	First Vice President
	 	 
	

 	
 	

 	
 	

 
	MUTUAL OF OMAHA INSURANCE COMPANY	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ EDWIN H. GARRISON JR.   
	 	 
	Name:	 	Edwin H. Garrison Jr.
	 	 
	Title:	 	First Vice President
	 	 
	

 	
 	

 	
 	

 
	HARTFORD LIFE INSURANCE COMPANY	 	 
	By:	 	Hartford Investment Services, Inc., its Agent and Attorney-in-Fact	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ KURT H. NYMAN   
	 	 
	Name:	 	Kurt H. Nyman
	 	 
	Title:	 	Vice President
	 	 
	

 	
 	

 	
 	

 
	NATIONWIDE LIFE INSURANCE COMPANY	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ MARK W. POEPPELMAN   
	 	 
	Name:	 	Mark W. Poeppelman
	 	 
	Title:	 	Associate Vice President
	 	 

S–5

 

	

 	
 	

 	
 	

 
	NATIONWIDE LIFE AND ANNUITY INSURANCE COMPANY	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ MARK W. POEPPELMAN   
	 	 
	Name:	 	Mark W. Poeppelman
	 	 
	Title:	 	Associate Vice President
	 	 
	

 	
 	

 	
 	

 
	PROVIDENT MUTUAL LIFE INSURANCE COMPANY	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ JAMES D. KESTNER   
	 	 
	Name:	 	James D. Kestner
	 	 
	Title:	 	Vice President
	 	 
	

 	
 	

 	
 	

 
	SECURITY FINANCIAL LIFE INSURANCE CO.	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ KEVIN W. HAMMOND   
	 	 
	Name:	 	Kevin W. Hammond
	 	 
	Title:	 	Chief Investment Officer
	 	 
	

 	
 	

 	
 	

 
	THE CANADA LIFE ASSURANCE COMPANY	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ PAUL ENGLISH   
	 	 
	Name:	 	Paul English
	 	 
	Title:	 	Associate Treasurer
	 	 
	

 	
 	

 	
 	

 
	CANADA LIFE ASSURANCE COMPANY OF NEW YORK	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ PAUL ENGLISH   
	 	 
	Name:	 	Paul English
	 	 
	Title:	 	Associate Treasurer
	 	 

S–6

 

	

 	
 	

 	
 	

 
	LUTHERAN BROTHERHOOD	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ KERI L. REICH   
	 	 
	Name:	 	Keri L. Reich
	 	 
	Title:	 	Portfolio Manager
	 	 
	

 	
 	

 	
 	

 
	MODERN WOODMEN OF AMERICA	 	 
	

 	
 	

 	
 	

 
	By:	 	/s/ NICK S. COIN   
	 	 
	Name:	 	Nick S. Coin
	 	 
	Title:	 	Manager, Securities Division
	 	 
	

 	
 	

 	
 	

 

S–7

 
 
 

SCHEDULE I    
  

	Series A Holders
 
	 	Principal

Amount

	Massachusetts Mutual Life Insurance Company	 	$	21,500,000
	C.M. Life Insurance Company	 	 	3,000,000
	MassMutual Asia Limited	 	 	500,000
	Connecticut General Life Insurance Company	 	 	17,000,000
	Life Insurance Company of North America	 	 	3,000,000
	United of Omaha Life Insurance Company	 	 	12,000,000
	Mutual of Omaha Insurance Company	 	 	3,000,000
	Hartford Life Insurance Company	 	 	15,000,000
	Nationwide Life Insurance Company	 	 	7,000,000
	Nationwide Life and Annuity Insurance Company	 	 	3,000,000
	Provident Mutual Life Insurance Company	 	 	5,000,000
	Security Financial Life Insurance Co.	 	 	2,000,000

	Series B Holders
 
	 	Principal

Amount

	The Canada Life Assurance Company	 	$	8,700,000
	Canada Life Insurance Company of New York	 	 	300,000
	Lutheran Brotherhood	 	 	6,000,000
	Modern Woodmen of America	 	 	3,000,000

S–8

QuickLinks

Exhibit 10.5 EXECUTION COPY

TETRA TECH, INC. FIRST AMENDMENT TO NOTE PURCHASE AGREEMENT $110,000,000 Senior Secured Notes $92,000,000 7.28% Senior Secured Notes, Series A, due May 30, 2011 $18,000,000 7.08% Senior Secured Notes, Series B,
due May 30, 2008

Dated as of September 30, 2001

SCHEDULE I

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00032-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00032-of-00352.parquet"}]]