Prepared by MERRILL CORPORATION




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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 



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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 


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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





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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
	 	 



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	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
	 	 



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	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
	 	 




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	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
	 	 
	

 	
 	

 	
 	

 




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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




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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