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Exhibit 10.2    
    


 
 

TETRA TECH, INC.    
    
    FOURTH 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 May 12, 2005 


To
the Holders of the Senior Notes of

Tetra Tech, Inc. Named in the Attached Schedule I (the "Noteholders") 


Ladies
and Gentlemen: 


        Reference
is made to the Note Purchase Agreements, each dated as of May 15, 2001, as amended by the First Amendment to Note Purchase Agreement dated as of September 30,
2001, the Second Amendment to Note Purchase Agreement dated as of April 22, 2003 and the Third Amendment to Note Purchase Agreement dated as of December 14, 2004 (collectively, as in
effect immediately prior to the effectiveness hereof, the "Existing Note Agreement", and as amended hereby, the "Note
Agreement"), by and between Tetra Tech, Inc., a Delaware corporation (the "Company"), and each of the Noteholders
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 (collectively, as in effect immediately prior to
the effectiveness hereof, the "Existing Series A Notes", and as amended hereby, the "Series A
Notes") and $18,000,000 aggregate principal amount of its 7.08% Senior Secured Notes, Series B, due May 30, 2008 (collectively, as in effect immediately prior to
the effectiveness hereof, the "Existing Series B Notes", and as amended hereby, the "Series B
Notes" and, together with the Series A Notes, the "Notes"). Capitalized terms used and not otherwise defined herein shall
have the meanings ascribed to them in the Existing Note Agreement. 


        The
Company has requested that the Noteholders agree to amend certain provisions of the Note Agreement, and the Noteholders have agreed to such amendments on the terms and subject to the
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 Noteholders agree as follows: 


1.     AMENDMENT OF NOTE AGREEMENT  


        Subject to the satisfaction of the conditions set forth in Section 4 of this Fourth Amendment, the Noteholders and the Company hereby agree as follows: 


        1.1.    Amendment of Section 1.    Section 1 of the Existing Note Agreement
is hereby amended by deleting the parenthetical expression "(individually, a "Subsidiary Guarantor" and collectively, the
"Subsidiary Guarantors") in the seventh line thereof. 







 



        1.2.    Amendment of Section 7.1(a).    (a) Section 7.1(a) of the
Existing Note Agreement is hereby amended and restated to read in its entirety as follows: 



        "(a)    Interim Statements.    



        (i)    Quarterly
Statements—Promptly when available, and in any event not later than the earlier of (A) 45 days after the
end of each Fiscal Quarter (other than the last Fiscal Quarter of each Fiscal Year) and (B) one Business Day after the date required to be filed with the SEC, duplicate copies of, 



        (1)   a
consolidated balance sheet of the Company and its Subsidiaries as at the end of such quarter, 


        (2)   consolidated
statements of income of the Company and its Subsidiaries for such quarter and (in the case of the second and third quarters) for the portion of the Fiscal
Year ending with such quarter, and 



        (3)   consolidated
statements of cash flows of the Company and its Subsidiaries for such quarter or (in the case of the second and third quarters) for the portion of the
Fiscal Year ending with such quarter, 




setting
forth in each case in comparative form the figures for the corresponding periods in the previous Fiscal Year, all in reasonable detail, prepared in accordance with GAAP applicable to quarterly
financial statements generally, and certified by a Senior Financial Officer as fairly presenting, in all material respects, the financial position of the companies being reported on and their results
of operations and cash flows, subject to changes resulting from year-end adjustments, provided that delivery within the time period specified above of copies of the Company's Quarterly
Report on Form 10-Q prepared in compliance with the requirements therefor and filed with the SEC shall be deemed to satisfy the requirements of this Section 7.1(a)(i); 


        (ii)   Monthly
Statements—Promptly when available, and in any event not later than 30 days after the end of each fiscal month
in each Fiscal Year of the Company (other than the last month of
any Fiscal Quarter) ending after July 3, 2005 and prior to the Covenant Compliance Date, duplicate copies of, 



        (A)  consolidated
balance sheet of the Company and its Subsidiaries as at the end of such fiscal month, 



        (B)  consolidated
statements of income of the Company and its Subsidiaries for such fiscal month and for the portion of the Fiscal Year ending with such fiscal month, and 


        (C)  consolidated
statements of cash flows of the Company and its Subsidiaries for such fiscal month and for the portion of the Fiscal Year ending with such fiscal month, 




setting
forth in each case in comparative form the figures for the corresponding periods in the previous Fiscal Year, all in reasonable detail, prepared in accordance with GAAP; and 



        (iii)  Additional
Current Asset Information—Contemporaneously with the furnishing of the financial statements required pursuant to
subsection (a)(i) above, 



        (A)  a
summary of the accounts receivable of the Company and its Subsidiaries (including a list of the 10 customers with the largest receivable balances); and 


        (B)  a
list of bonded jobs of the Company and its Subsidiaries with a value in excess of $1,000,000 (and specifying any related billed and unbilled receivables with respect
to such jobs), in each case as of the end of the applicable Fiscal Quarter; and 





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        (C)  an
updated organizational chart listing all Subsidiaries and the jurisdictions of their organization; and" 




        (b)   Each
reference in the Existing Note Agreement to "Section 7.1(a)" is hereby amended to be a reference to "Section 7.1(a)(i)". 





        1.3.    Amendment of Section 7.1(b).    Section 7.1(b) (Annual Financial
Statements) of the Existing Note Agreement is hereby amended by deleting the phrase "within 105 days after the end of each Fiscal Year of the Company" and replacing it with "promptly when
available, and in any event not later than the earlier of (A) 105 days after the end of each Fiscal Year and (B) one Business Day after the date required to be filed with the
SEC". 


        1.4.    Amendment of Section 7.1(c).    Section 7.1(c) of the Existing Note
Agreement is hereby amended and restated to read in its entirety as follows: 



        "(c) [Intentionally
Omitted]." 




        1.5.    Amendment of Section 8.6.    The definition of "Remaining Scheduled
Payments" set forth in Section 8.6 of the Existing Note Agreement is hereby amended and restated in its entirety to read as follows: 



        "Remaining Scheduled Payments" means, with respect to the Called Principal of any Note, all payments of such Called Principal and interest
thereon (calculated at the non-default rate of interest in effect with respect to such Note immediately prior to the effectiveness of the Fourth Amendment) that would be due after the
Settlement Date with respect to such Called Principal if no payment of such Called Principal were made prior to its scheduled due date, provided that if such Settlement Date is not a date on which
interest payments are due to be made under the terms of the Notes, then the amount of the next succeeding scheduled interest payment will be reduced by the amount of interest accrued to such
Settlement Date and required to be paid on such Settlement Date pursuant to Section 8.2 or 12.1." 




        1.6.    Amendment of Section 10.1.    Section 10.1 of the Existing Note
Agreement is hereby amended and restated to read in its entirety as follows: 



        "10.1    Adjusted Leverage Ratio; Priority Debt.  



        The Company will not permit at any time: 



        (a)   the
Adjusted Leverage Ratio, as of the last day of any Computation Period, to be greater than (a) 2.75 to 1 for any Computation Period ending before
April 2, 2006; (b) 2.50 to 1 for the Computation Period ending on April 2, 2006; and (c) 2.25 to 1 for any Computation Period ending on or after July 2, 2006. 


        (b)   Priority
Debt to exceed 15% of Adjusted Consolidated Net Worth." 





        1.7.    Amendment of Section 10.2.    Section 10.2 of the Existing Note
Agreement is hereby amended and restated to read in its entirety as follows: 



        "10.2    Fixed Charge Coverage Ratio; Minimum Adjusted EBITDA.



        (a)   The
Company will not permit the ratio of (i) the result of (A) Adjusted EBITDA minus (B) Capital
Expenditures, in each case for any Computation Period described in the table below, to (ii) the sum of (A) Interest Expense plus
(B) all income taxes (including any franchise tax and any other tax based upon gross or net income or receipts) paid by the Company and its Subsidiaries  plus (C) all required payments of
principal of Indebtedness of the Company and its Subsidiaries, in each case during such Computation Period (and
 




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determined
on a consolidated basis), to be less than the ratio set forth opposite such Computation Period in such table: 




	Computation Period
 
	 	Ratio

	the Computation Period ending on April 2, 2006	 	1.05 to 1
	any Computation Period ending on or after July 2, 2006 through and including June 29, 2008	 	1.10 to 1
	the Computation Period ending September 28, 2008	 	1.15 to 1
	any Computation Period ending on or after December 28, 2008	 	1.25 to 1






For
the avoidance of doubt, the ratio described in this Section 10.2(a) shall not be measured prior to the Computation Period ending on April 2, 2006. 



        (b)   The
Company will not permit Adjusted EBITDA for any period set forth in the table below to be less than the amount set forth opposite such period: 




	Period
 
	 	Amount

	the Fiscal Quarter ending July 3, 2005	 	$	13,000,000
	the period of two consecutive Fiscal Quarters ending October 2, 2005	 	$	28,000,000
	the period of three consecutive Fiscal Quarters ending January 1, 2006	 	$	45,000,000
	the Computation Period ending April 2, 2006	 	$	64,000,000
	any Computation Period ending on or after July 2, 2006	 	$	70,000,000






        1.8.    Amendment of Section 10.3.    Section 10.3 of the Existing Note
Agreement is hereby amended and restated to read in its entirety as follows: 



        "10.3    Minimum Net Worth.  



        The Company will not permit Net Worth at any time to be less than the sum of (a) $245,000,000, plus (b) 50% of the sum of Consolidated Net
Income for each Fiscal Quarter, beginning with the Fiscal Quarter ending July 3, 2005 and ending with the most recently-ended Fiscal Quarter for which the Company has delivered financial
statements (provided that if Consolidated Net Income is less than zero for any Fiscal Quarter, for purposes of this Section 10.3, Consolidated Net Income will be deemed to be
zero for such Fiscal Quarter) plus (c) 100% of the Net Cash Proceeds of any equity issued by the Company or any Subsidiary (on a consolidated
basis) after April 3, 2005." 




        1.9.    Amendment of Section 10.4.    Section 10.4 (Liens) of the Existing
Note Agreement is hereby amended by deleting the parenthetical expression in the second line thereof "(unless, concurrently with the incurrence, assumption or creation of such Lien, the Company makes,
or causes to be made, effective provision whereby the Notes are equally and ratably secured by a Lien on the same property or assets, including the execution of an intercreditor agreement, in form and
substance satisfactory to holders of the Notes, between such holders and the holders of other Debt secured by a Lien in such property)". 


        1.10.    Amendment of Section 10.5.    Section 10.5 of the Existing Note
Agreement is hereby amended and restated to read in its entirety as follows: 



        "10.5    Asset Dispositions.


        The
Company will not, and will not permit any Subsidiary to, sell, transfer, convey, lease or otherwise dispose of, or grant options, warrants or other rights with respect to, any of its
assets, or sell, assign, pledge or otherwise transfer any receivables, contract rights, general intangibles, chattel paper or instruments, with or without recourse, except for (a) dispositions
of inventory or obsolete assets in the ordinary course of business consistent with past practices and (b) other dispositions of 



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assets,
provided that (i) no disposition described in this clause (b) shall be made if a Default or Event of Default exists or would result therefrom; and (ii) after giving effect
to any disposition pursuant to this clause (b), the aggregate fair market value of all assets disposed of pursuant to this clause (b) shall not exceed (x) at any time from and
after July 21, 2004, 2.5% of Consolidated Total Assets as of the end of the most recent Fiscal Year, and (y) $10,000,000 in any Fiscal Year." 




        1.11.    Amendment of Section 10.6.    Section 10.6 of the Existing Note
Agreement is hereby amended and restated to read in its entirety as follows: 



        "10.6    Mergers and Consolidations; Acquisitions.


        The
Company will not, and will not permit any Subsidiary to, be a party to any merger or consolidation, or purchase or otherwise acquire all or substantially all of the assets or any
stock of any class of, or any partnership or joint venture interest in, any other Person (or of any division or business unit of any Person), except (a) any such merger or consolidation of or
by any wholly-owned Subsidiary
into the Company or any other Wholly-Owned Subsidiary, (b) any such purchase or other acquisition by the Company or any Wholly-Owned Subsidiary of the assets or stock of any Wholly-Owned
Subsidiary, and (c) acquisitions of all of the assets or stock of Persons which are in the same or a similar line of business as the Company and its Subsidiaries; provided that any acquisition
described in this clause (c) must satisfy all of the following conditions: (i) each Person so acquired shall comply with all of the terms of this Agreement and the other Financing
Documents that are applicable to such Person; (ii) either the required majority of the board of directors (or other equivalent governing body) of the Person so acquired incumbent at the time
such acquisition is proposed has acquiesced to the acquisition, or the acquisition is otherwise deemed in the reasonable judgment of the Required Holders to be a "friendly" acquisition;
(iii) no Default or Event of Default shall have occurred and be continuing at the time of, or would result from the making of, such acquisition; (iv) the aggregate consideration
(including assumed debt and stock of the Company) for any one such acquisition or series of such related acquisitions shall not exceed (A) during the period beginning April 3, 2005 and
continuing through April 2, 2006, $5,000,000; and (B) thereafter, $50,000,000; (v) if such acquisition is made after April 2, 2006, then the Company's Adjusted Leverage
Ratio shall have been less than 1.75 to 1 as of the last day of the most recently ended Fiscal Quarter for which financial statements are available pursuant to Section 7.1(a); and
(vi) substantially contemporaneously with any such acquisition of stock, the Company shall grant, or cause the applicable Person(s) to grant, to the Collateral Agent, for the benefit of the
holders of Notes, a first priority perfected security interest in all of the stock so acquired." 




        1.12.    Amendment of Section 10.7.    Section 10.7 of the Existing Note
Agreement is hereby amended and restated to read in its entirety as follows: 



        "Section 10.7    Disposition of Stock of Subsidiaries.



        (a)   The
Company will not permit any Subsidiary to issue its capital stock, or any warrants, rights or options to purchase, or securities convertible into or exchangeable
for, such capital stock, to any Person other than the Company or another Wholly Owned Subsidiary, except (i) for directors' qualifying shares, (ii) to satisfy local ownership
requirements, (iii) in satisfaction of valid preemptive or contractual rights of minority stockholders in connection with the simultaneous issuance to the Company or a Subsidiary whereby the
Company and its Subsidiaries maintain the same proportionate ownership interest and (iv) the issuance of stock convertible into stock of the Company by Tetra Tech Canada Ltd. in
connection with an acquisition. 


        (b)   The
Company will not, and will not permit any Subsidiary to, sell, transfer or otherwise dispose of any shares of capital stock of a Subsidiary, except (i) for
directors' 




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qualifying
shares, (ii) to satisfy local ownership requirements, (iii) the sale of all shares of capital stock of a Subsidiary which is permitted under Section 10.5 and
(iii) stock convertible into stock of the Company by Tetra Tech Canada Ltd. in connection with an acquisition. 



        (c)   If
a Subsidiary at any time ceases to be such as a result of a sale or issuance of its capital stock, any Liens on property of the Company or any other Subsidiary
securing Indebtedness owed to such Subsidiary, which is not contemporaneously repaid, together with such Indebtedness, shall be deemed to have been incurred by the Company or such other Subsidiary, as
the case may be, at the time such Subsidiary ceases to be a Subsidiary." 





        1.13.    Amendment of Section 10.8.    Section 10.8 of the Existing Note
Agreement is hereby amended and restated to read in its entirety as follows: 



        "Section 10.8    Excluded Subsidiaries.


        The
Company shall not permit the Excluded Subsidiaries, collectively, to (a) own at any time more than 2.5% of Consolidated Total Assets, (b) have more than 2.5% of the
consolidated revenues of the Company and its Subsidiaries in any Fiscal Quarter or (c) be liable for more than 2.5% of the consolidated liabilities of the Company and its Subsidiaries. For
purposes of this Section 10.8, all intercompany assets, revenues and liabilities that would be properly eliminated in consolidation shall be deemed to be zero." 




        1.14.    Additional Covenants to be Added to Section 10.    The following new
Sections are hereby added to the Existing Note Agreement immediately following Section 10.10 thereof to read in their entireties as follows: 



        "Section 10.11    Limitations on Indebtedness.  



        The Company will not, and will not permit any Subsidiary to, create, incur, assume or suffer to exist any Indebtedness, except: 



        (a)   obligations
arising under the Financing Documents; 


        (b)   Indebtedness
in respect of Capital Leases; 


        (c)   unsecured
Indebtedness of Subsidiaries to the Company or to any other Subsidiary; 


        (d)   Hedging
Agreements entered into by the Company or any Subsidiary with the Collateral Agent or any Bank or any Affiliate thereof; provided that all such Hedging
Agreements are entered into to protect against bona fide business risks and not for speculation; 


        (e)   Guaranties
in respect of any obligation of the Company or any Subsidiary permitted under this Agreement; 


        (f)    Indebtedness
in respect of taxes, assessments or governmental charges to the extent that payment thereof shall not at the time be required to be made in accordance with
Section 9.4; 


        (g)   Indebtedness
outstanding on the date hereof or hereafter incurred in connection with Liens permitted by Section 10.4, and extensions, renewals and refinancings of
any Indebtedness described in this clause (g) so long as the principal amount thereof is not increased; 


        (h)   Subordinated
Indebtedness; 


        (i)    Indebtedness
under the Credit Agreement; 




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        (j)    Indebtedness
constituting a portion of the deferred purchase price for any acquisition permitted by Section 10.6(c); and 


        (k)   other
Indebtedness not exceeding in the aggregate $10,000,000." 




        "Section 10.12    Restricted Payments.


        The
Company will not, and will not permit any Subsidiary to, (a) declare or pay any dividends on any of its capital stock (other than stock dividends), (b) purchase or
redeem any such stock or any warrants, units, options or other rights in respect of such stock, (c) make any other distribution to shareholders, (d) prepay, purchase, redeem or defease
any Subordinated Indebtedness, (e) make any payment on or in respect of any Subordinated Indebtedness (other than scheduled payments of interest made in the form
of additional Subordinated Indebtedness or common stock), or (f) set aside funds for any of the foregoing; provided that (i) any Subsidiary may declare and
pay dividends to the Company or to any other Wholly-Owned Subsidiary and (ii) so long as no Default or Event of Default exists or would result therefrom and, after giving effect thereto (and
any incurrence of Indebtedness in connection therewith), the Adjusted Leverage Ratio will be less than 1.75 to 1, the Company may, at any time after April 2, 2006, repurchase shares of its
capital stock for immediate retirement in an aggregate amount, for all such repurchases made on or after July 21, 2004, not to exceed 10.0% of Net Worth (measured as of the end of the Fiscal
Quarter immediately preceding any such purchase)." 


        "Section 10.13    Loans and Advances.


        The
Company will not, and will not permit any Subsidiary to, make any loan or advance; except for (i) loans or advances by the Company to any Subsidiary or by any Subsidiary to
the Company, (ii) loans and advances to officers and employees of the Company and its Subsidiaries for travel, entertainment, relocation and similar ordinary business purposes in an aggregate
amount not exceeding $500,000 at any time outstanding and (iii) other loans and advances in an aggregate amount not exceeding $5,000,000 at any time outstanding." 


        "Section 10.14    Minimum Revolver Availability.


        The
Company will not, at any time, permit the Commitment Amount (as defined in the Credit Agreement) to be less than $125,000,000. The terms of the Commitment (as defined in the Credit
Agreement) shall be as set forth in the Credit Agreement on the Fourth Amendment Effective Date, or shall be on such other terms as are reasonably satisfactory to the Required Holders." 



        "Section 10.15    Most Favored Lender Status.


        If
at any time the Company or any Subsidiary is a party to or shall enter into any agreement, instrument or other document (excluding the Credit Agreement, as in effect on the Fourth
Amendment Effective Date) relating to Indebtedness of the Company or such Subsidiary (each such agreement, instrument or other document herein referred to as a "More Favorable
Lending Agreement"), which agreement, instrument or other document includes covenants (whether affirmative or negative, and whether maintenance or incurrence) or defaults or
events of default (excluding any customary covenant or default relating to collateral contained in any agreement, instrument or document secured by Liens permitted by Section 10.4(e) or (h))
that are more restrictive than those contained in this Agreement or are not provided for in this Agreement (each such covenant or default or event of default herein referred to as
"More Favorable Provision"), then the Company shall promptly, and in any event within 5 Business Days of entering into or becoming party to any such
More Favorable Lending Agreement (or within 5 Business Days of obtaining knowledge of any More Favorable Lending Agreement), so advise and notify each holder of a Note in writing. Such writing shall
include a verbatim statement of such More Favorable Provision. Thereupon, unless waived in writing by the Required Holders within 5 Business Days of 



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such
holders' receipt of such notice, such More Favorable Provision shall be deemed incorporated by reference in this Agreement as if set forth fully herein, mutatis mutandis, effective as of the date
when such More Favorable Provision became effective under such More Favorable Lending Agreement (each such More Favorable Provision as incorporated herein is herein referred to as an
"Incorporated Provision") and no such Incorporated Provision may thereafter be waived, amended or modified under this Agreement without the prior
written consent of the Required Holders. Thereafter, upon the request of the Required Holders, the Company and the Required Holders shall enter into an additional agreement or an amendment to this
Agreement (as the Required Holders may request), evidencing the incorporation of such Incorporated Provision substantially as provided for in such More Favorable Lending Agreement; provided, that no
such additional agreement or amendment shall in any way be required to make each Incorporated Provision effective. Each Incorporated Provision shall (i) remain unchanged herein notwithstanding
any subsequent waiver, amendment or other modification of the More Favorable Lending Agreement giving rise to such Incorporated Provision (except to the extent that an amendment or other modification
results in such provision being more restrictive than such Incorporated Provision, in which case such Incorporated Provision shall be amended or modified to become equally restrictive), and
(ii) be deemed deleted from this Agreement at such time as the applicable More Favorable Lending Agreement shall be fully terminated and no amounts shall be outstanding thereunder so long as at
the time such More Favorable Lending Agreement shall have been so terminated no Default or Event of Default exists hereunder." 


        "Section 10.16    Further Assurances.


        The
Company shall take, and cause each Subsidiary to take, such actions as are necessary, or as the Required Holders or the Collateral Agent may reasonably request, from time to time
(including the execution and delivery of guaranties, security agreements, pledge agreements, control agreements, financing statements and other documents, the filing or recording of any of the
foregoing, the delivery of stock certificates and other collateral with respect to which perfection is obtained by possession, the execution and delivery of appropriate stock powers or other transfer
instruments and the delivery of appropriate legal opinions with respect to any of the foregoing) to ensure that (i) the obligations of the Company hereunder and under the other Financing
Documents are (x) secured by all account
receivables of the Company, all equity interests in Subsidiaries owned by the Company and all of the Company's cash, deposit accounts, investment property and financial assets and all proceeds of the
foregoing and (y) unconditionally guaranteed by all Subsidiaries (including, promptly upon the acquisition or creation thereof, any Subsidiary acquired or created after the date hereof) by
execution of a counterpart of the Subsidiary Guaranty; and (ii) the obligations of each Subsidiary under the Subsidiary Guaranty are secured by all account receivables of such Subsidiary, all
equity interests in other Subsidiaries owned by such Subsidiary and all of such Subsidiary's cash, deposit accounts, investment property and financial assets and all proceeds of the foregoing;
provided that unless the Required Holders otherwise request in writing, (a) no Foreign Corporation (as defined below) or Excluded Subsidiary shall be required to execute the Subsidiary
Guaranty, pledge any equity interest or grant a security interest in any property; and (b) neither the Company nor any Subsidiary shall be required to pledge more than 65% of the stock of any
Foreign Corporation. For purposes of the foregoing, (A) a "Foreign Corporation" is any corporate Subsidiary which is incorporated in a jurisdiction other than, and does substantially all of its
business outside of, the United States, and (B) the terms "investment property" and "financial assets" shall have the respective meanings given to them in the Uniform Commercial Code of any
applicable jurisdiction." 


        "Section 10.17    Quarterly Conference Call.


        Within
45 days following the end of each Fiscal Quarter, beginning with the Fiscal Quarter ending July 3, 2005 and continuing through the Fiscal Quarter ending
April 2, 2006, the Company, in consultation with the holders of Notes and the Banks, shall arrange a conference call with the holders of Notes and the Banks during which Senior Financial
Officers of the Company shall review the consolidated financial and operating results of the Company for such Fiscal Quarter and such other information regarding the financial condition, operations,
business, assets or prospects of the Company and its Subsidiaries as any holder of Notes may reasonably request." 



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        "Section 10.18    Unconditional Purchase Obligations.


        The
Company will not, and will not permit any Subsidiary to, enter into or be a party to any contract for the purchase of materials, supplies or other property or services, if such
contract requires that payment be made by it regardless of whether or not delivery is ever made of such materials, supplies or other property or services; provided that the Company or any Subsidiary
may enter into any such contract so long as (i) the aggregate amount of all payments to be made under such contract does not exceed $2,000,000 and (ii) the aggregate amount of all
payments to be made under all such contracts in any Fiscal Year by the Company and its Subsidiaries does not exceed $5,000,000." 


        "Section 10.19    Inconsistent Agreements.


        The
Company will not, and will not permit any Subsidiary to, enter into any material agreement containing any provision which (a) would be violated or breached by the performance
by the Company or any Subsidiary of any of its obligations hereunder or under any other Financing Document, (b) would prohibit the Company or any Restricted Subsidiary from granting to the
Collateral Agent, for the benefit of the holders of Notes and certain other parties, a Lien on any of its assets (other than (i) the Credit Agreement and (ii) customary negative pledge
provisions arising in connection with Liens permitted by Section 10.4(e) and (h) that apply only to the specific property subject to any such Lien and the proceeds thereof) or
(c) would prevent any Subsidiary from paying cash dividends, or making other cash distributions, to its parent." 




        1.15.    Amendments of Section 11—Events of Default.    



        (a)   Section 11(c)
is hereby amended and restated in its entirety to read as follows: 



        "(c) the
Company defaults in the performance of or compliance with, any term contained in Section 7.1(e), Section 9.5, any of Sections 10.1 through 10.19,
inclusive; or". 




        (b)   Section 11(l)
is hereby amended by deleting the period at the end of such section and replacing it with "; or". 



        (c)   new
Sections 11(m), 11(n) and 11(o) are hereby added to Section 11 immediately following Section 11(l) to read in their entireties as follows: 



        "(m) default
in the payment when due, or in the performance or observance of, any material obligation of, or material condition agreed to by, the Company or any Subsidiary
Guarantor with respect to any purchase or lease of goods or services exceeding $5,000,000 (except only to the extent that the existence of any such default is being contested by the Company or such
Subsidiary in good faith and by appropriate proceedings and appropriate reserves have been made in respect of such default); or" 


        "(n) any
Change in Control shall occur; or" 


        "(o) the
Company shall fail to comply with or to perform any covenant incorporated herein pursuant to Section 10.15 and such failure shall continue beyond any
applicable grace period specified in the applicable More Favorable Lending Agreement; or any event shall occur or condition shall exist that (subject to the giving of any notice and/or the lapse of
any applicable grace period specified in the applicable More Favorable Lending Agreement) constitutes an event of default under any provision of any More Favorable Lending Agreement incorporated
herein pursuant to Section 10.15.". 




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        1.16.    Amendment of Section 22.1.    Section 22.1 of the Existing Note
Agreement is hereby amended and restated to read in its entirety as follow: 



        "22.1.    Release of Subsidiary Guarantors and Subsidiary Stock.


        You
and each subsequent holder of a Note agree to, and to direct the Collateral Agent to, release any Subsidiary Guarantor from the Subsidiary Guaranty or the capital stock of any
Subsidiary Guarantor from the Pledge Agreement (i) if such Subsidiary Guarantor ceases to be a Subsidiary as a result of a sale, lease, transfer or other disposal of assets (including by way of
merger) permitted by Section 10.5, 10.6 or 10.7 or (ii) at such time as the Banks direct the Collateral Agent to release such Subsidiary from the Subsidiary Guaranty or release such
capital stock from the Pledge Agreement; provided, however, that you and each subsequent holder will not be required to release a Subsidiary Guarantor from the Subsidiary Guaranty or the capital stock
of a Restricted Subsidiary from the Pledge Agreement under the circumstances contemplated by clause (ii), if (A) a Default or Event of Default has occurred and is continuing,
(B) such Subsidiary Guarantor is to become a borrower under the Credit Agreement or (C) such release is part of a plan of financing that contemplates such Subsidiary Guarantor
guaranteeing, or the capital stock of such Subsidiary Guarantor securing, any other Indebtedness of the Company. Your obligation to release a Subsidiary Guarantor from the Subsidiary Guaranty or the
capital stock of a Subsidiary Guarantor from the Pledge Agreement is conditioned upon your prior receipt of a certificate from a Senior Financial Officer of the Company stating that none of the
circumstances described in clauses (A), (B) and (C) above are true." 




        1.17.    Schedule B—Additions and Modifications.    The following
definitions in Schedule B to the Note Agreement are amended to read in their entirety, or are added to such Schedule B, in each case in appropriate alphabetical order, as follows: 



        "Applicable Interest Rate" means, a per annum interest rate equal to 



        (a)   prior
to the Fourth Amendment Effective Date and from and after the Covenant Compliance Date, with respect to the Series A Notes, 7.28%, and with respect to the
Series B Notes, 7.08%, and 


        (b)   from
and after the Fourth Amendment Effective Date to and including the Covenant Compliance Date, with respect to the Series A Notes, 8.28%, and with respect to
the Series B Notes, 8.08%. 




        "Adjusted EBITDA" means, for any period, the sum of Adjusted Consolidated Net Income for such period, plus, to the extent deducted in
determining such Adjusted Consolidated Net Income, (x) federal, state, local and foreign income, value added and similar taxes, (y) Interest Expense and (z) depreciation and
amortization expense; provided that Adjusted EBITDA shall be calculated on a pro forma basis (in accordance with Article 11 of Regulation S-X of the SEC) giving effect to
(a) any acquisition made by the Company or any Subsidiary during such period so long as, and to the extent that, (i) the Company delivers to each holder of Notes a summary in reasonable
detail of the assumptions underlying, and the calculations made, in computing Adjusted EBITDA on a pro forma basis and (ii) the Required Holders do not object to such assumptions and/or
calculations within 10 Business Days after receipt thereof; and (b) any divestiture of a Subsidiary, division or other operating unit made during such period. If the Company or any Subsidiary
makes any acquisition of a Person or assets which would result in a negative adjustment to Adjusted EBITDA for any period, the Company shall, upon request of the Required Holders, deliver the
information required pursuant to clause (a)(i) of the preceding sentence so that the calculation of Adjusted EBITDA will give effect to such acquisition. Notwithstanding any other
provision of this Agreement, (A) Adjusted EBITDA for the Computation Period ending July 3, 2005 shall be equal to Adjusted EBITDA for the Fiscal Quarter ending on such date multiplied by
four; (B) Adjusted 



10







 

EBITDA
for the Computation Period ending October 2, 2005 shall be equal to Adjusted EBITDA for period of two consecutive Fiscal Quarters ending on such date multiplied by two; and
(C) Adjusted EBITDA for the Computation Period ending January 1, 2006 shall be equal to Adjusted EBITDA for the period of three consecutive quarters ending on such date multiplied by
11/3. 


        "Change in Control" means that (a) any Person or group (within the meaning of Rule 13d-5 of the SEC under the
Securities Exchange Act of 1934 as amended) shall become the beneficial owner (as defined in Rule 13d-3 of the SEC under the Securities Exchange Act of 1934 as amended) of 20% or
more of the Voting Stock of the Company or (b) a majority of the members of the board of directors of the Company shall cease to be Continuing Members. 


        "Continuing Member" means a member of the board of directors of the Company who either (a) was a member of the Company's board of
directors on the date hereof and has been such continuously thereafter or (b) became a member of such board of directors after the date hereof and whose election or nomination for election was
approved by a vote of the majority of the Continuing Members then members of the Company's board of directors. 


        "Covenant Compliance Criteria" means the completion by the Company and its Subsidiaries of three consecutive Fiscal Quarters (the first of
which can not be any earlier than July 3, 2005) in respect of which, as of the end of each such Fiscal Quarter, both: 



        (a)   the
Adjusted Leverage Ratio set forth in Section 10.1(a) for the Computation Periods ending at such times is less than or equal to 2.25 to 1; and 


        (b)   the
Fixed Charge Coverage Ratio set forth in Section 10.2 for the Computation Periods ending at such times is equal to or greater than 1.25 to 1. 




        "Covenant Compliance Date" means the date after the Covenant Compliance Criteria have been met on which the holders of Notes receive the
certificate of a Senior Financial Officer described in Section 7.2 demonstrating compliance with the Covenant Compliance Criteria as of the Fiscal Quarter then most recently ended. 


        "Excluded Subsidiary" means any Subsidiary designated as such on Schedule II to the Fourth Amendment and any other Subsidiary
designated in writing by the Company to the holders of Notes. 


        "Financing Documents" means this Agreement, the Notes, the Subsidiary Guaranty, the Pledge Agreement, the Security Agreement and each
other agreement, document or instrument pursuant to which the Company or any Subsidiary Guarantor grants collateral to the Collateral Agent for the benefit of the holders of Notes and certain other
parties." 


        "Fourth Amendment" means that certain Fourth Amendment to Note Purchase Agreement, dated as of May 12, 2005, among the Company and
the holders of Notes party thereto. 


        "Fourth Amendment Effective Date" means May 12, 2005. 


        "Incorporated Provision" is defined in Section 10.15. 


        "More Favorable Lending Agreement" is defined in Section 10.15. 


        "More Favorable Provision" is defined in Section 10.15. 


        "Net Cash Proceeds" means, with respect to any issuance of equity securities by the Company or any Subsidiary, the aggregate cash proceeds
received by the Company or such Subsidiary pursuant to such issuance, net of the direct costs relating to such issuance (including sales and underwriter's discounts and commissions and legal,
accounting and investment banking fees). 



11







 




        "Net Worth" means, at any time, the consolidated stockholders' equity of the Company and its Subsidiaries determined at such time in
accordance with GAAP. 


        "Priority Debt" means, as of any date, the sum (without duplication) of (a) outstanding Indebtedness of Subsidiaries that are not
Subsidiary Guarantors (other than Indebtedness owed to the Company or another Subsidiary) and (b) Indebtedness of the Company and its Subsidiaries secured by Liens not otherwise permitted by
Sections 10.4(a) through (i). 


        "SEC" means the Securities and Exchange Commission of the United States of America. 


        "Security Agreement" means the Second Amended and Restated Security Agreement, dated as of May 12, 2005, among the Company, certain
Subsidiaries and the Collateral Agent, as amended, restated, supplemented or otherwise modified from time to time." 


        "Subsidiary Guarantor" means any Subsidiary that has entered into the Subsidiary Guaranty (or shall have been required under the terms of
Section 10.16 to have entered into the Subsidiary Guaranty), whether in connection with the Closing or thereafter pursuant to the Company's obligations under Section 10.16 or otherwise. 



        "Subordinated Indebtedness" means Indebtedness of the Company having maturities and other terms, and which is subordinated to the
obligations of the Company and its Subsidiaries hereunder and under the other Financing Documents in a manner, approved in writing by the Required Holders. 


        "Wholly Owned Subsidiary" mean, at any time, any Subsidiary 100% of all of the equity interests and voting interests (except directors'
qualifying shares) of which are owned by any one or more of the Company and the Company's other Wholly Owned Subsidiaries at such time. 




        1.18.    Schedule B—Deleted Definitions.    



        (a)   Deletions. The following definitions in Schedule B to the Existing Note Agreement are
hereby deleted: 



        Disposition



        Excluded
Sale and Leaseback Transactions 


        Restricted
Subsidiary 


        Significant
Subsidiary 


        Unrestricted
Subsidiary 




        (b)   Treatment of Certain Deleted Definitions in Note Purchase Agreement.



        (i)    "Restricted
Subsidiary" and "Restricted Subsidiaries". Each reference in the Existing Note Purchase Agreement to "Restricted Subsidiary" and
"Restricted Subsidiaries", other than any such reference in
Section 11 thereof, is hereby amended to be, and shall hereafter be deemed to be, a reference to "Subsidiary" and "Subsidiaries" (including, any such reference contained within the defined
terms "Wholly-Owned Restricted Subsidiary" and "Wholly-Owned Restricted Subsidiaries"), as applicable. Any such reference in Section 11 of the Existing Note Agreement is hereby amended to be,
and shall hereafter be deemed to be, a reference to "Subsidiary Guarantor" or "Subsidiary Guarantors", as applicable. 


        (ii)   "Significant
Subsidiary". Each reference in the Existing Note Purchase Agreement to "Significant Subsidiary" and "Significant Subsidiaries"
in the Existing Note Agreement, is hereby amended to be, and shall hereafter be deemed to be, a reference to "Subsidiary Guarantor" and "Subsidiary Guarantors", as applicable. 




12







 







2.     AMENDMENT OF NOTES  


        Subject to the satisfaction of the conditions set forth in Section 4 of this Fourth Amendment, the Noteholders and the Company hereby agree as follows: 


        2.1.    The Series A Notes.    The Existing Series A Notes shall be deemed
to be, automatically and without any further action, amended and restated in their entirety as set forth on Exhibit 1A; except that the date, registration number and principal amount set forth
in each Existing Series A Note shall remain the same. 


        2.2.    The Series B Notes.    The Existing Series B Notes shall be deemed
to be, automatically and without any further action, amended and restated in their entirety as set forth on Exhibit 1B; except that the date, registration number and principal amount set forth
in each Existing Series B Note shall remain the same. 


3.     REAFFIRMATION; REPRESENTATIONS AND WARRANTIES  



        3.1.    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 Fourth Amendment. 


        3.2.    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 September 30, 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 Noteholders and (d) for other changes that could not reasonably be
expected to have a Material Adverse Effect. 


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


        3.4.    Authorization and Enforceability.    The execution, delivery and performance by
the Company of this Fourth Amendment and the Amended Security Agreement (and the performance by its Subsidiaries of their obligations under the Subsidiary Guaranty, the Pledge Agreement and the
Amended Security Agreement, in each case after giving effect to this Fourth 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, the Notes, the Fourth
Amendment, the Pledge Agreement, the Security Agreement and the Subsidiary Guaranties each constitute the legal, valid and binding obligations of the Company and each Subsidiary party thereto,
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). 


4.     EFFECTIVE DATE  


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



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


13







 



        4.2.    Amendment to Security Agreement.    The Company, its Subsidiaries and the
Collateral Agent shall have entered into a Second Amended and Restated Security Agreement, in the form attached hereto as Exhibit 2 (the "Amended Security
Agreement"), and the Noteholders shall have received a duly executed copy thereof. 


        4.3.    Opinion of Counsel.    The Company shall have delivered to the Noteholders an
executed opinion of counsel addressed to them in the form attached hereto as Exhibit 3. 


        4.4.    Amendment Fee.    Each Noteholder shall have received payment of an amendment fee
equal to 0.35% of the principal amount of the outstanding Notes held by such Noteholder. 


        4.5.    Expenses.    The Company shall have paid all fees and expenses of special counsel
to the Noteholders contemplated by Section 5.8 (to the extent then billed). 


        4.6.    Credit Agreement.    The Required Banks (as defined in the Credit Agreement) and
the Company shall have entered into a Second Amendment to the Credit Agreement in form and substance satisfactory to the Noteholders, and the Noteholders shall have received an executed copy of such
amendment. 


5.     MISCELLANEOUS  


        5.1.    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. 


        5.2.    Effect of Agreement.    Except as expressly provided herein, (a) no terms
or provisions of the Note Agreement or any other agreement are waived, modified or changed by this Fourth Amendment, and (b) the terms of this Fourth Amendment shall not operate as a waiver or
amendment by the Noteholders of, or otherwise prejudice the Noteholders' rights, remedies or powers under, the Note Agreement or under any applicable law, and all of such rights, remedies and powers
are hereby expressly reserved. 


        5.3.    Temporary Waiver.    The Required Holders hereby waive through June 15,
2005 any non-compliance with Section 10.16 of the Note Agreement resulting from non-perfection of the Collateral Agent's security interest in cash, deposit accounts,
investment property and financial assets so long as the Company is diligently taking such actions as are necessary, or as the Collateral Agent or the Required Holders may reasonably request, to
perfect such security interests. 


        5.4.    Reference to the Note Agreement.    Upon the final effectiveness of this Fourth
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 words of
like import referring to the Note Agreement, shall mean and be a reference to the Note Agreement, as amended hereby. 


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


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


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


        5.8.    Expenses.    Without limiting the provisions of Section 15.1 of the Note
Agreement, the Company agrees to pay the reasonable costs and expenses of the holders of Notes (including reasonable attorneys' fees and charges) in connection with the preparation, execution and
delivery of this Fourth Amendment and the documents contemplated hereby. 


[remainder
of page intentionally blank; next page is signature page] 


14









  





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



	TETRA TECH, INC.	 
	

By:	

/s/  DAVID W. KING      
 Name: David W. King

Title: Chief Financial Officer and Treasurer	

 




S-1







 


	NOTEHOLDERS:	 
	

The foregoing is agreed to as of the date thereof.	

 
	
MASSMUTUAL ASIA LIMITED	

 
	

By:	

Babson Capital Management LLC as Investment Adviser	

 
	

By:	

/s/  ELISABETH A. PERENICK      
 Name: Elisabeth A. Perenick

Title: Managing Director	

 
	
MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY	

 
	

By:	

Babson Capital Management LLC as Investment Adviser	

 
	

By:	

/s/  ELISABETH A. PERENICK      
 Name: Elisabeth A. Perenick

Title: Managing Director	

 




S-2







 


	
C.M. LIFE INSURANCE COMPANY	

 
	

By:	

Babson Capital Management LLC as Investment Sub-Adviser	

 
	

By:	

/s/  ELISABETH A. PERENICK      
 Name: Elisabeth A. Perenick

Title: Managing Director	

 




S-3







 


	
PRUDENTIAL RETIREMENT CEDED BUSINESS TRUST	

 
	

By:	

Prudential Investment Management, Inc., as Investment Manager	

 
	

By:	

/s/  JOSEPH ALOUF      
 Name: Joseph Alouf

Title: Vice President	

 
	
UNITED OF OMAHA INSURANCE COMPANY	

 
	

By:	

/s/  EDWIN H. GARRISON, JR.      
 Name: Edwin H. Garrison, Jr.

Title: First Vice President	

 
	
MUTUAL OF OMAHA LIFE INSURANCE COMPANY	

 
	

By:	

/s/  EDWIN H. GARRISON, JR.      
 Name: Edwin H. Garrison, Jr.

Title: First Vice President	

 




S-4







 


	
HARTFORD LIFE INSURANCE COMPANY	

 
	

By:	

Hartford Investment Services, Inc., its Agent and Attorney-in-Fact	

 
	

By:	

/s/  EVA KONOPKA      
 Name: Eva Konopka

Title: Senior Vice President	

 
	
NATIONWIDE LIFE INSURANCE COMPANY	

 
	

By:	

/s/  MARK W. POEPPELMAN      
 Name: Mark W. Poeppelman

Title: Authorized Signatory	

 
	
NATIONWIDE LIFE AND ANNUITY INSURANCE COMPANY	

 
	

By:	

/s/  MARK W. POEPPELMAN      
 Name: Mark W. Poeppelman

Title: Authorized Signatory	

 




S-5







 


	
NATIONWIDE LIFE INSURANCE COMPANY OF AMERICA (formerly Provident Mutual Life Insurance Company)	

 
	

By:	

/s/  MARK W. POEPPELMAN      
 Name: Mark W. Poeppelman

Title: Authorized Signatory	

 
	
SECURITY FINANCIAL LIFE INSURANCE CO.	

 
	

By:	

/s/  KEVIN W. HAMMOND      
 Name: Kevin W. Hammond

Title: Senior Director—Investments	

 
	
THE CANADA LIFE ASSURANCE COMPANY, as beneficial owner	

 
	

By:	

/s/  EVE HAMPTON      
 Name: Eve Hampton

Title: Vice President, Investments, U.S. Operations	

 
	

By:	

/s/  TAD ANDERSON      
 Name: Tad Anderson

Title: Manager, Investments, U.S. Operations	

 




S-6







 


	
CANADA LIFE INSURANCE COMPANY OF NEW YORK, as beneficial owner	

 
	

By:	

/s/  EVE HAMPTON      
 Name: Eve Hampton

Title: Vice President, Investments, CLAC	

 
	

By:	

/s/  TAD ANDERSON      
 Name: Tad Anderson

Title: Manager, Investments, CLAC	

 
	
THRIVENT FINANCIAL FOR LUTHERANS (successor by merger to Lutheran Brotherhood)	

 
	

By:	

/s/  GLEN J. VANIC      
 Name: Glen J. Vanic

Title: Portfolio Manager	

 
	
MODERN WOODMEN OF AMERICA	

 
	

By:	

/s/  MICHAEL E. DAU CFA      
 Name: Michael E. Dau CFA

Title: Manager, Fixed Income Division	

 




S-7







 
 
 

CONFIRMATION    
    


        Each
of the undersigned acknowledges receipt of the foregoing Fourth Amendment and confirms the continuing validity and enforceability against such undersigned of each of the Note
Agreement, the Notes, the Subsidiary Guaranty, the Pledge Agreement and the Security Agreement, in each case to the extent such undersigned is a party thereto. 



	
TETRA TECH, INC.	

 
	

By:	

/s/  DAVID W. KING      
 Name: David W. King

Title: Chief Financial Officer and Treasurer	

 




S-8







 

ADVANCED MANAGEMENT TECHNOLOGY, INC.

ARDAMAN & ASSOCIATES, INC.

COSENTINI ASSOCIATES, INC.

ENGINEERING MANAGEMENT CONCEPTS, INC.

EVERGREEN UTILITY CONTRACTORS, INC.

EXPERT WIRELESS SOLUTIONS, INC.

FHC, INC.

HARTMAN & ASSOCIATES, INC.

KCM, INC.

MFG, INC.

RIZZO ASSOCIATES, INC.

SCIENCES INTERNATIONAL, INC.

TETRA TECH CANADA LTD.

TETRA TECH CONSTRUCTION SERVICES, INC.

TETRA TECH CONSULTING & REMEDIATION, INC.

TETRA TECH EM INC.

TETRA TECH NUS, INC.

TETRA TECH RMC, INC.

THE THOMAS GROUP OF COMPANIES, INC.

VERTEX ENGINEERING SERVICES, INC.

WHALEN & COMPANY, INC.

WESTERN UTILITY CONTRACTORS, INC.



	

By:	

/s/  DAVID W. KING      
 Name: David W. King

Title: Treasurer	

 
	
GEOTRANS, INC.

SCM CONSULTANTS, INC.

TETRA TECH EC, INC.	

 
	

By:	

/s/  DAVID W. KING      
 Name: David W. King

Title: Assistant Treasurer	

 




S-9









 
 

SCHEDULE I    
    



	Series A Noteholders
 
	 	Outstanding

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 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
	Nationwide Life Insurance Company of America (formerly Provident Mutual Life Insurance Company)	 	 	5,000,000
	Security Financial Life Insurance Co.	 	 	2,000,000





	Series B Noteholders
 
	 	Outstanding

Principal

Amount

	The Canada Life Assurance Company	 	$	6,960,000
	Canada Life Insurance Company of New York	 	 	240,000
	Thrivent Financial for Lutherans (successor by merger to Lutheran Brotherhood)	 	 	4,800,000
	Modern Woodmen of America	 	 	2,400,000









 
 

SCHEDULE II    
    
    Excluded Subsidiaries


America's
Schoolhouse Consulting Services, Inc.

Chen Northern, Inc.

Contract Operations—2, Inc.

Foster Wheeler Environmental Corporation

Kansas City Testing Laboratory, Inc.

KCM International, Inc.

LAL Corporation

Nebraska Testing Corporation

River Corridor Closure, LLC

SCM Architecture and Planning PC

SCM Staff Placement Specialists, Inc.

SulTech

Tetra Tech Caribe, Inc.

Tetra Tech Consulting & Remediation, Inc.

Tetra Tech Executive Services, Inc.

Tetra Tech International (BVI) Ltd.

Tetra Tech Leasing, LLC

Tetra Tech Technical Services, Inc.

Tetra Tech Wired Communications of California, Inc.

Thomas Aquatics, LLC

Thomas Communications & Technologies, LLC

Thomas Environmental Services, LLC

Thomas Management Services, LLC

Western Utility Cable, Inc.

Whalen do Brasil, Ltda.

Whalen Service Corps Inc.

Whalen/Sentrex LLC 









 
 

Exhibit 1A    
    


 
 

FORM OF SERIES A NOTE    
    


TETRA
TECH, INC. 


ADJUSTABLE
RATE SENIOR SECURED NOTE,

SERIES A, DUE MAY 30, 2011 



	No. R-[            ]	 	[Date]
	$[            ]	 	PPN: 88162G A* 4







        FOR
VALUE RECEIVED, the undersigned, TETRA TECH, INC. (herein called the "Company"), a corporation organized and existing under the laws of the State of Delaware, promises to pay
to [            ], or registered assigns, the principal sum of
$[            ] on May 30, 2011, with interest (computed on the basis of a 360-day year of twelve 30-day months) (a) on the unpaid
balance thereof at the Applicable Interest Rate per annum from the date hereof, payable semiannually, on May 30 and November 30 in each year, commencing with the May 30 or
November 30 next succeeding the date hereof (except that no interest payment shall be made on May 30, 2001), until the principal hereof shall have become due and payable, and
(b) to the extent permitted by law on any overdue payment (including any overdue prepayment) of principal, any overdue payment of interest and any overdue payment of any Make-Whole
Amount (as defined in the Note Purchase Agreement referred to below), payable semiannually as aforesaid (or, at the option of the registered holder hereof, on demand), at a rate per annum from time to
time equal to the greater of (i) 2% over the Applicable Interest Rate or (ii) 2% over the rate of interest publicly announced by Bank of America, N.A. from time to time in Chicago,
Illinois as its "base" or "prime" rate. 


        Payments
of principal of, interest on and any Make-Whole Amount with respect to this Note are to be made in lawful money of the United States of America at the principal
office of Bank of America, N.A. in Chicago, Illinois or at such other place as the Company shall have designated by written notice to the holder of this Note as provided in the Note Purchase Agreement
referred to below. 


        This
Note is one of a series of Senior Secured Notes (herein called the "Notes") issued pursuant to the Note Purchase Agreements dated as of May 15, 2001 (as from time to time
amended, collectively, the "Note Purchase Agreement"), between the Company and the respective Purchasers named therein and is entitled to the benefits thereof. Each holder of this Note will be deemed,
by its acceptance hereof, (i) to have agreed to the confidentiality provisions set forth in Section 20 of the Note Purchase Agreement and (ii) to have made the representation set
forth in Section 6.2 of the Note Purchase Agreement. 


        This
Note is a registered Note and, as provided in the Note Purchase Agreement, upon surrender of this Note for registration of transfer, duly endorsed, or accompanied by a written
instrument of transfer duly executed, by the registered holder hereof or such holder's attorney duly authorized in writing, a new Note for a like principal amount will be issued to, and registered in
the name of, the transferee. Prior to due presentment for registration of transfer, the Company may treat the person in whose name this Note is registered as the owner hereof for the purpose of
receiving payment and for all other purposes, and the Company will not be affected by any notice to the contrary. 


        The
Company will make required prepayments of principal on the dates and in the amounts specified in the Note Purchase Agreement. This Note also is subject to optional prepayment, in
whole or from time to time in part at the times and on the terms specified in the Note Purchase Agreement but not otherwise. 


        If
an Event of Default, as defined in the Note Purchase Agreement, occurs and is continuing, the principal of this Note may be declared or otherwise become due and payable in the manner,
at the 







 



price
(including any applicable Make-Whole Amount) and with the effect provided in the Note Purchase Agreement. 


        Payment
of the principal of, and interest and Make-Whole Amount, if any, on this Note, and all other amounts due under the Note Purchase Agreement, is guaranteed pursuant to
the terms of a Guaranty dated as of May 15, 2001 of certain Subsidiaries of the Company. 



        This
Note shall be construed and enforced in accordance with, and the rights of the parties shall be governed by, the law of the State of Illinois excluding
choice-of-law principles of the law of such State that would require the application of the laws of a jurisdiction other than such State. 



	

 	
TETRA TECH, INC.
 
	

 	

By:	

 
	 	 	

	 	Name:	 
	 	 	

	 	Title:	 
	 	 	





2









 
 

Exhibit 1B    
    


 
 

FORM OF SERIES B NOTE
  
    TETRA TECH, INC.
  
    ADJUSTABLE RATE SENIOR SECURED NOTE,
  SERIES B, DUE MAY 30, 2008    




	No. R-[            ]	 	[Date]
	$[            ]	 	PPN: 88162G A@ 2





        FOR
VALUE RECEIVED, the undersigned, TETRA TECH, INC. (herein called the "Company"), a corporation organized and existing under the laws of the State of Delaware, promises to pay
to [            ], or registered assigns, the principal sum of $[            ] on May 30, 2008, with interest (computed on
the basis of a
360-day year of twelve 30-day months) (a) on the unpaid balance thereof at the Applicable Interest Rate per annum from the date hereof, payable semiannually, on
May 30 and November 30 in each year, commencing with the May 30 or November 30 next succeeding the date hereof (except that no interest payment shall be made on
May 30, 2001), until the principal hereof shall have become due and payable, and (b) to the extent permitted by law on any overdue payment (including any overdue prepayment) of
principal, any overdue payment of interest and any overdue payment of any Make-Whole Amount (as defined in the Note Purchase Agreement referred to below), payable semiannually as aforesaid
(or, at the option of the registered holder hereof,
on demand), at a rate per annum from time to time equal to the greater of (i) 2% over the Applicable Interest Rate or (ii) 2% over the rate of interest publicly announced by Bank of
America, N.A. from time to time in Chicago, Illinois as its "base" or "prime" rate. 


        Payments
of principal of, interest on and any Make-Whole Amount with respect to this Note are to be made in lawful money of the United States of America at the principal
office of Bank of America, N.A. in Chicago, Illinois or at such other place as the Company shall have designated by written notice to the holder of this Note as provided in the Note Purchase Agreement
referred to below. 


        This
Note is one of a series of Senior Secured Notes (herein called the "Notes") issued pursuant to the Note Purchase Agreements dated as of May 15, 2001 (as from time to time
amended, collectively, the "Note Purchase Agreement"), between the Company and the respective Purchasers named therein and is entitled to the benefits thereof. Each holder of this Note will be deemed,
by its acceptance hereof, (i) to have agreed to the confidentiality provisions set forth in Section 20 of the Note Purchase Agreement and (ii) to have made the representation set
forth in Section 6.2 of the Note Purchase Agreement. 


        This
Note is a registered Note and, as provided in the Note Purchase Agreement, upon surrender of this Note for registration of transfer, duly endorsed, or accompanied by a written
instrument of transfer duly executed, by the registered holder hereof or such holder's attorney duly authorized in writing, a new Note for a like principal amount will be issued to, and registered in
the name of, the transferee. Prior to due presentment for registration of transfer, the Company may treat the person in whose name this Note is registered as the owner hereof for the purpose of
receiving payment and for all other purposes, and the Company will not be affected by any notice to the contrary. 



        The
Company will make required prepayments of principal on the dates and in the amounts specified in the Note Purchase Agreement. This Note also is subject to optional prepayment, in
whole or from time to time in part at the times and on the terms specified in the Note Purchase Agreement but not otherwise. 


        If
an Event of Default, as defined in the Note Purchase Agreement, occurs and is continuing, the principal of this Note may be declared or otherwise become due and payable in the manner,
at the 







 



price
(including any applicable Make-Whole Amount) and with the effect provided in the Note Purchase Agreement. 



        Payment
of the principal of, and interest and Make-Whole Amount, if any, on this Note, and all other amounts due under the Note Purchase Agreement, is guaranteed pursuant to
the terms of a Guaranty dated as of May 15, 2001 of certain Subsidiaries of the Company. 


        This
Note shall be construed and enforced in accordance with, and the rights of the parties shall be governed by, the law of the State of Illinois excluding
choice-of-law principles of the law of such State that would require the application of the laws of a jurisdiction other than such State. 



	

 	
TETRA TECH, INC.
 
	

 	

By:	

 
	 	 	

	 	Name:	 
	 	 	

	 	Title:	 
	 	 	





2









 
 

Exhibit 2    
    


 
 

SECOND AMENDED AND RESTATED SECURITY AGREEMENT    
    


        THIS SECOND AMENDED AND RESTATED SECURITY AGREEMENT (this "Agreement") dated as of May 12, 2005 is among
TETRA TECH, INC. (the "Company"), each subsidiary of the Company listed on the signature pages hereof, such other subsidiaries of the Company as
from time to time become parties hereto (together with the Company, collectively the "Debtors" and individually each a
"Debtor") and BANK OF AMERICA, N.A. ("Bank of America"), in its capacity as Collateral Agent (as defined
below) for the Benefited Parties (as defined in the Intercreditor Agreement referred to below). 


 
 

W I T N E S S E T H:    



        WHEREAS,
the Company, various financial institutions (together with their respective successors and assigns, the "Banks") and Bank of
America, as agent for the Banks (in such capacity, the "Credit Agent"), have entered into an Amended and Restated Credit Agreement dated as of
July 21, 2004 (the "Credit Agreement"); 


        WHEREAS,
the Company has entered into a Note Purchase Agreement dated as of May 15, 2001 (the "Note Agreement"), pursuant to which
certain note purchasers (the "Noteholders") purchased $92,000,000 of the Company's 7.28% Senior Secured Notes, Series A, due May 30, 2011,
and $18,000,000 of the Company's 7.08% Senior Secured Notes, Series B, due May 30, 2008 (together, the "Senior Notes"); 



        WHEREAS,
pursuant to an Amended and Restated Guaranty dated as of May 15, 2001 (the "Guaranty"), certain subsidiaries of the
Company have guaranteed all obligations of the Company under the Credit Agreement, all obligations of the Company under the Note Agreement and certain other obligations of the Company; 


        WHEREAS,
the Credit Agent, the Noteholders and Bank of America, as collateral agent, have entered into an Intercreditor Agreement dated as of May 15, 2001 (the
"Intercreditor Agreement"; capitalized terms used but not defined herein shall have the respective meanings assigned thereto in the Intercreditor
Agreement), pursuant to which (i) such parties have agreed that all Benefited Obligations shall be guaranteed and secured on a pari passu basis
and (ii) Bank of America shall act as collateral agent for the holders of the Benefited Obligations (in such capacity, together with any successor in such capacity, the
"Collateral Agent"); 


        WHEREAS,
the obligations of the Company in respect of the Benefited Obligations and the obligations of each other Debtor under the Guaranty are to be secured pursuant to this Agreement; 


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



        1.    Definitions and Interpretation.    For purposes of this Agreement, (a) in addition to terms defined in
the preamble and recitals above, the terms Account, Account Debtor, Certificated
Security, Chattel Paper, Commodity Account, Commodity
Contract, Deposit Account, Financial Asset, General
Intangibles, Instruments, Investment Property,  Securities Account, Security, Security Entitlement and
Uncertificated Security have the respective meanings assigned to such terms in the UCC (as defined below), (b) the rules of interpretation set
forth in clauses (a), (c)(i) and (d) of Section 1.2 of the Credit Agreement shall apply as if set forth in full herein, mutatis
mutandis, and (c) the following terms have the following meanings, respectively: 



        Collateral—see Section 2. 


        Default means the occurrence of any of the following events: (a) any Event of Default; (b) any event which, if it continues
uncured will, with lapse of time or notice or both, constitute an Event of Default under Section 12.1.4 of the Credit Agreement, Section 11(g) or 11(h) of the Note 








 




Agreement
or any substantially similar provision of any other Financing Agreement; or (c) any warranty of any Debtor herein is untrue or misleading in any material respect and, as a result
thereof, the Collateral Agent's security interest for the benefit of the Benefited Parties in any material portion of the Collateral is not perfected or the Collateral Agent's rights and remedies with
respect to any material portion of the Collateral are materially impaired or otherwise materially adversely affected. 



        Liabilities means, (a) as to the Company, all Credit Obligations, all Senior Note Obligations and all other Benefited Obligations;
and (b) with respect to each other Debtor, all obligations of such Debtor under the Guaranty. 


        Permitted Lien means any Lien that is expressly permitted pursuant to Section 10.8 of the Credit Agreement (but excluding any Lien
on any Account or on the stock of any Subsidiary of any Debtor). 


        UCC means the Uniform Commercial Code as in effect from time to time in the State of Illinois. 




        2.    Grant of Security Interest.    As security for the payment of all Liabilities, each Debtor hereby assigns to the
Collateral Agent for the benefit of the Benefited Parties, and grants to the Collateral Agent for the benefit of the Benefited Parties a continuing security interest in, the following, whether now or
hereafter existing or acquired (the "Collateral"): all of such Debtor's Accounts, Commodity Accounts, Commodity Contracts, Deposit Accounts, Financial
Assets, Investment Property, money (of any jurisdiction), Securities (whether Certificated or Uncertificated Securities), Securities Accounts and Security Entitlements; all of such Debtor's General
Intangibles arising out of or related to any of the foregoing; all of such Debtor's Chattel Paper and Instruments evidencing any obligation arising out of or relating to any of the foregoing; all
interest of such Debtor in any goods the sale or lease of which shall have given rise to, and in all guaranties and property securing payment or performance under, any Account or other property
described above; all of such Debtor's books and records relating to any of the foregoing; and all proceeds (including all insurance proceeds) of any of the foregoing. 


        3.    Warranties.    Each Debtor warrants that: (i) no financing statement (other than any which may have been
filed on behalf of the Collateral Agent or in connection with Permitted Liens) covering any of the Collateral is on file in any public office; (ii) such Debtor is and will be the lawful owner
of all Collateral, free of all liens and claims whatsoever, other than the security interest hereunder and Permitted Liens, with full power and authority to execute and deliver this Agreement, to
perform such Debtor's obligations hereunder and to subject the Collateral to the security interest hereunder; (iii) such Debtor's true legal name as registered in the jurisdiction in which such
Debtor is organized or incorporated, jurisdiction of organization or incorporation, organizational identification number as designated by the jurisdiction of its organization or incorporation, chief
executive office and principal place of business are as set forth on Schedule I hereto (and such Debtor has not maintained its chief executive
office or principal place of business at any other location at any time after January 1, 2001 (or, in the case of any Person which becomes a Debtor after the date hereof, 135 days prior
to the date such Person executes and delivers a counterpart hereof)); (iv) except as described in Schedule II, such Debtor is not now
known and has not, during the five years preceding the date of execution and delivery hereof by such Debtor, been known by any trade name; and (v) except as disclosed on  Schedule III hereto,
during the five years preceding the date of execution and delivery hereof by such Debtor, such Debtor has not been known by
any legal name different from the one set forth on the signature page of this Agreement, nor has such Debtor been the subject of any merger or other corporate reorganization. 



        4.    Collections, etc.    Until such time during the existence of a Default as the Collateral Agent shall notify such
Debtor of the revocation of such power and authority, each Debtor (a) will, at its own expense, endeavor to collect, as and when due, all amounts due under any of the Collateral, including 


2







 



the
taking of such action with respect to such collection as the Collateral Agent may reasonably request or, in the absence of such request, as such Debtor may deem advisable, and (b) may
grant, in the ordinary course of business, to any party obligated on any of the Collateral, any rebate, refund or allowance to which such party may be lawfully entitled, and may accept, in connection
therewith, the return of goods, the sale or lease of which shall have given rise to such Collateral. The Collateral Agent, however, may, at any time that a Default exists, whether before or after any
revocation of such power and authority or the maturity of any of the Liabilities, notify any parties obligated on any of the Collateral to make payment to the Collateral Agent of any amounts due or to
become due thereunder and enforce collection of any of the Collateral by suit or otherwise and surrender, release or exchange all or any part thereof, or compromise or extend or renew for any period
(whether or not longer than the original period) any indebtedness thereunder or evidenced thereby. Promptly following any request of the Collateral Agent during the existence of a Default, each Debtor
will, at its own expense, notify any parties obligated on any of the Collateral to make payment to the Collateral Agent of any amounts due or to become due thereunder. 


        Upon
request by the Collateral Agent during the existence of a Default, each Debtor will establish a deposit account with the Collateral Agent (an "Assignee
Deposit Account") and will forthwith, upon receipt, transmit and deliver to the Collateral Agent, in the form received, all cash, checks, drafts and other instruments or
writings for the payment of money (properly endorsed, where required, so that such items may be collected by the Collateral Agent) which may be received by such Debtor at any time in full or partial
payment or otherwise as proceeds of any of the Collateral for deposit in the Assignee Deposit Account as security for payment of the Liabilities. Except as the Collateral Agent may otherwise consent
in writing, any such items which may be so received by any Debtor will not be commingled with any other of its funds or property, but will be held separate and apart from its own funds or property and
upon express trust for the Collateral Agent until delivery is made to the Collateral Agent. 


        No
Debtor shall have any right to withdraw any funds deposited in the applicable Assignee Deposit Account. The Collateral Agent may, from time to time, in its discretion, and shall upon
request of the applicable Debtor made not more than once in any week, apply all or any of the then balance, representing collected funds, in the Assignee Deposit Account, toward payment of the
Liabilities, whether or not then due, in such order of application as is set forth in the Intercreditor Agreement, and the Collateral Agent may, from time to time, in its discretion (subject to the
terms of the Intercreditor Agreement), release all or any of such balance to the applicable Debtor. 


        The
Collateral Agent is authorized to endorse, in the name of the applicable Debtor, any item, howsoever received by the Collateral Agent, representing any payment on or other proceeds
of any of the Collateral. 


        Each
Debtor hereby appoints the Collateral Agent as the attorney-in-fact for such Debtor for the purpose of carrying out the provisions of this Agreement and
taking any action and executing or completing any instrument which the Collateral Agent may deem reasonably necessary or advisable to accomplish the terms hereof, which appointment as
attorney-in-fact is irrevocable and coupled with an interest; provided that the Collateral Agent shall not exercise its rights as such attorney-in-fact
unless a Default exists. 


        5.    Certificates, Schedules and Reports.    Each Debtor will from time to time, as the Collateral Agent may request,
deliver to the Collateral Agent a schedule identifying each Account of such Debtor (not previously so identified) subject to the security interest hereunder, and such additional schedules and such
certificates and reports respecting all or any of the Collateral at the time subject to the security interest hereunder, and the items or amounts received by such Debtor in full or partial payment of
any of the Collateral, all to such extent as the Collateral Agent may reasonably request. Any such schedule, certificate or report shall be executed by a duly authorized officer of such Debtor 


3







 



and
shall be in such form and detail as the Collateral Agent may specify. Any such schedule identifying any Account subject to the security interest hereunder shall be accompanied (if the Collateral
Agent so requests) by a true and correct copy of the invoice evidencing such Account and by evidence of shipment or performance. 


        6.    Agreements of the Debtors.    Each Debtor (a) will, upon request of the Collateral Agent, execute such
financing statements and other documents (and pay the cost of filing or recording the same in all public offices deemed appropriate by the Collateral Agent) and do such other acts and things
(including the delivery to the Collateral Agent of all Certificated Securities and Instruments (other than checks and similar items that are deposited in the ordinary course of business)), all as the
Collateral Agent may from time to time reasonably request, to establish and maintain a valid security interest in the Collateral (free of all other liens, claims and rights of third parties
whatsoever, other than Permitted Liens) to secure the payment of the Liabilities (and each Debtor hereby authorizes the Collateral Agent to file any financing statement without its signature, to the
extent permitted by applicable law, and/or to file a copy of this Agreement as a financing statement in any jurisdiction; (b) after the occurrence and during the continuance of any
Default, will execute and file such assignment of claims forms under or pursuant to the federal assignment of claims statute, 31 U.S.C. § 3726, as may be necessary or desirable, or as the
Collateral Agent may from time to time request, in order to perfect and preserve the security interests and other rights granted or purported to be granted to the Collateral Agent hereby (free of all
other liens, claims and rights of third parties whatsoever), (c) will keep, at its address shown on Schedule I hereto, its records
concerning the Collateral, which records will be of such character as will enable the Collateral Agent or its designees to determine at any time the status of the Collateral, and no Debtor will,
unless the Collateral Agent shall otherwise consent in writing, duplicate any such records at any other address; (d) will furnish the Collateral Agent such information concerning such Debtor,
the Collateral and the Account Debtors as the Collateral Agent may from time to time reasonably request; (e) will permit the Collateral Agent and its designees, from time to time, to inspect,
audit and make copies of and extracts from all records and all other papers in the possession of such Debtor pertaining to the Collateral and the Account Debtors, and will, upon request of the
Collateral Agent during the existence of a Default,
deliver to the Collateral Agent all of such records and papers; (f) will, upon request of the Collateral Agent, stamp on its records concerning the Collateral, and add on all Chattel Paper
constituting a portion of the Collateral, a notation, in form satisfactory to the Collateral Agent, of the security interest of the Collateral Agent hereunder; (g) will not change its
jurisdiction of organization or incorporation or its name, identity or corporate structure such that any financing statement filed to perfect the Collateral Agent's interest under this Agreement would
become seriously misleading, unless such Debtor shall have given the Collateral Agent not less than 10 days' prior notice of such change (provided that this  Section 6(g) shall not be deemed to
authorize any change or transaction prohibited under the Credit Agreement); and (h) will not sell,
lease, assign or create or permit to exist any lien on or security interest in any Collateral other than liens and security interests in favor of the Collateral Agent and Permitted Liens. 


        7.    Remedies.    Whenever a Default exists, the Collateral Agent may from time to time exercise any rights and
remedies available to it under the UCC or any other applicable law or otherwise available to it. Without limiting the foregoing, whenever a Default exists the Collateral Agent may, to the fullest
extent permitted by applicable law, without notice, advertisement, hearing or process of law of any kind, (a) sell any or all of the Collateral, free of all rights and claims of any Debtor
therein and thereto, at any public or private sale, and (b) bid for and purchase any or all of the Collateral at any such sale. Each Debtor hereby expressly waives, to the fullest extent
permitted by applicable law, any and all notices, advertisements, hearings or process of law in connection with the exercise by the Collateral Agent of any of its rights and remedies upon a Default.
If any notification of intended disposition of any of the Collateral is required by law, such notification, if mailed, shall be deemed reasonably and properly given if mailed at least ten days before
disposition, postage prepaid, addressed 


4







 



to
the applicable Debtor either at its address shown on Schedule I hereto or at any other address of such Debtor appearing on the records of the
Collateral Agent. Any proceeds of any of the Collateral may be applied by the Collateral Agent to the payment of expenses in connection with the Collateral, including reasonable attorneys' fees and
legal expenses, and any balance of such proceeds shall be applied by the Collateral Agent toward the payment of the Liabilities in accordance with the Intercreditor Agreement. 


        8.    General.    The Collateral Agent shall be deemed to have exercised reasonable care in the custody and
preservation of any of the Collateral in its possession if it takes such action for that purpose as any applicable Debtor requests in writing, but failure of the Collateral Agent to comply with any
such request shall not of itself be deemed a failure to exercise reasonable care, and no failure of the Collateral Agent to preserve or protect any rights with respect to such Collateral against prior
parties, or to do any act with respect to the preservation of such Collateral not so requested by any Debtor, shall be deemed a failure to exercise reasonable care in the custody or preservation of
such Collateral. 


        No
delay on the part of the Collateral Agent in exercising any right, power or remedy hereunder shall operate as a waiver thereof nor shall any single or partial exercise of any such
right, power or remedy preclude any other or further exercise thereof or the exercise of any other right, power or remedy. No amendment, modification or waiver of, or consent with respect to, any
provision of this Agreement shall in any event be effective unless the same shall be in writing, and signed and delivered by the party
to be bound thereby, and then such amendment, modification, waiver or consent shall be effective only in the specific instance and for the purpose for which given. 


        Each
Debtor agrees to pay all expenses (including reasonable attorney's fees and legal expenses) paid or incurred by the Collateral Agent in endeavoring to collect the Liabilities of
such Debtor, or any part thereof, and in enforcing this Agreement against such Debtor, and such obligations will themselves be Liabilities. 



        No
delay on the part of the Collateral Agent in the exercise of any right or remedy shall operate as a waiver thereof, and no single or partial exercise by the Collateral Agent of any
right or remedy shall preclude other or further exercise thereof or the exercise of any other right or remedy. 


        This
Agreement shall remain in full force and effect until all Liabilities have been paid in full and all commitments to create Liabilities have terminated. If at any time all or any
part of any payment theretofore applied by the Collateral Agent or any other Benefited Party to any of the Liabilities is or must be rescinded or returned by the Collateral Agent or such other
Benefited Party for any reason whatsoever (including the insolvency, bankruptcy or reorganization of any Debtor), such Liabilities shall, for the purposes of this Agreement, to the extent that such
payment is or must be rescinded or returned, be deemed to have continued in existence, notwithstanding such application by the Collateral Agent or such other Benefited Party, and this Agreement shall
continue to be effective or be reinstated, as the case may be, as to such Liabilities, all as though such application by the Collateral Agent or such other Benefited Party had not been made. 


        This
Agreement has been delivered at Chicago, Illinois, and shall be construed in accordance with and governed by the laws of the State of Illinois applicable to contracts made and to be
fully performed in its such state. Whenever possible, each provision of this Agreement shall be interpreted in such manner as to be effective and valid under applicable law, but if any provision of
this Agreement shall be prohibited by or invalid under applicable law, such provision shall be ineffective to the extent of such prohibition or invalidity, without invalidating the remainder of such
provision or the remaining provisions of this Agreement. 


        The
rights and privileges of the Collateral Agent hereunder shall inure to the benefit of its successors and assigns. 


5







 



        This
Agreement may be executed in any number of counterparts and by the different parties hereto 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 Agreement. At any time after the date of this
Agreement, one or more additional persons or entities may become parties hereto by executing and delivering a counterpart to the Collateral Agent of this Agreement. Immediately upon such execution and
delivery (and without any further action), each such additional person or entity will become a party to, and will be bound by all the terms of, this Agreement. Delivery of a counterpart hereof, or a
signature page hereto, by facsimile shall be effective as delivery or an original signed counterpart. 



        ANY LITIGATION BASED HEREON, OR ARISING OUT OF, UNDER OR IN CONNECTION WITH THIS AGREEMENT OR ANY OTHER FINANCING AGREEMENT, SHALL BE BROUGHT AND MAINTAINED
EXCLUSIVELY IN THE COURTS OF THE STATE OF ILLINOIS OR IN THE UNITED STATES DISTRICT COURT FOR THE NORTHERN DISTRICT OF ILLINOIS; PROVIDED THAT ANY SUIT
SEEKING ENFORCEMENT AGAINST ANY COLLATERAL OR OTHER PROPERTY MAY BE BROUGHT, AT THE COLLATERAL AGENT'S OPTION, IN THE COURTS OF ANY JURISDICTION WHERE SUCH COLLATERAL OR OTHER PROPERTY MAY BE FOUND OR
IN ANY JURISDICTION IN WHICH A BANKRUPTCY, INSOLVENCY OR OTHER SIMILAR LEGAL OR EQUITABLE PROCEEDING IS PENDING AGAINST ANY ONE OR MORE OF THE DEBTORS. EACH DEBTOR HEREBY EXPRESSLY AND IRREVOCABLY
SUBMITS TO THE JURISDICTION OF THE COURTS OF THE STATE OF ILLINOIS AND OF THE UNITED STATES DISTRICT COURT FOR THE NORTHERN DISTRICT OF ILLINOIS FOR THE PURPOSE OF ANY SUCH LITIGATION AS SET FORTH
ABOVE. EACH DEBTOR FURTHER IRREVOCABLY CONSENTS TO THE SERVICE OF PROCESS BY REGISTERED MAIL, POSTAGE PREPAID, TO THE ADDRESS SET FORTH ON SCHEDULE I  HERETO (OR SUCH OTHER ADDRESS AS IT
SHALL HAVE SPECIFIED IN WRITING TO THE COLLATERAL AGENT AS ITS ADDRESS FOR NOTICES HEREUNDER) OR BY PERSONAL SERVICE WITHIN OR WITHOUT THE
STATE OF ILLINOIS. EACH DEBTOR HEREBY EXPRESSLY AND IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW OR HEREAFTER HAVE TO THE LAYING OF VENUE OF ANY SUCH
LITIGATION BROUGHT IN ANY SUCH COURT REFERRED TO ABOVE AND ANY CLAIM THAT ANY SUCH LITIGATION HAS BEEN BROUGHT IN AN INCONVENIENT FORUM.



        THE DEBTORS, THE COLLATERAL AGENT AND (BY ACCEPTING THE BENEFITS HEREOF) THE BENEFITED PARTIES HEREBY WAIVE ANY RIGHT TO A TRIAL BY JURY IN ANY ACTION OR
PROCEEDING TO ENFORCE OR DEFEND ANY RIGHTS UNDER THIS AGREEMENT, ANY FINANCING AGREEMENT AND ANY AMENDMENT, INSTRUMENT, DOCUMENT OR AGREEMENT DELIVERED OR WHICH MAY IN THE FUTURE BE DELIVERED IN
CONNECTION HEREWITH OR THEREWITH OR ARISING FROM ANY FINANCING RELATIONSHIP EXISTING IN CONNECTION WITH ANY OF THE FOREGOING, AND AGREE THAT ANY SUCH ACTION OR PROCEEDING SHALL BE TRIED BEFORE A COURT
AND NOT BEFORE A JURY.


6







 

        IN
WITNESS WHEREOF, this Agreement has been duly executed as of the day and year first above written. 



	 	 	TETRA TECH, INC.
	

 	
 	

 	

 
	 	 	By:	/s/  DAVID W. KING      
 David W. King

Chief Financial Officer and Treasurer
	

 	
 	

 	

 
	 	 	ADVANCED MANAGEMENT TECHNOLOGY, INC.

ARDAMAN & ASSOCIATES, INC.

COSENTINI ASSOCIATES, INC.

ENGINEERING MANAGEMENT CONCEPTS, INC.

EVERGREEN UTILITY CONTRACTORS, INC.

EXPERT WIRELESS SOLUTIONS, INC.

FHC, INC.

HARTMAN & ASSOCIATES, INC.

KCM, INC.

MFG, INC.

RIZZO ASSOCIATES, INC.

SCIENCES INTERNATIONAL, INC.

TETRA TECH CANADA LTD.

TETRA TECH CONSTRUCTION SERVICES, INC.

TETRA TECH CONSULTING & REMEDIATION, INC.

TETRA TECH EM INC.

TETRA TECH NUS, INC.

TETRA TECH RMC, INC.

THE THOMAS GROUP OF COMPANIES, INC.

VERTEX ENGINEERING SERVICES, INC.

WHALEN & COMPANY, INC.

WESTERN UTILITY CONTRACTORS, INC.
	

 	
 	

 	

 
	 	 	By:	/s/  DAVID W. KING      
 David W. King

Treasurer
	 	 	 	 





7







 

	

 	
 	

GEOTRANS, INC.

SCM CONSULTANTS, INC.

TETRA TECH EC, INC.
	

 	
 	

 	

 
	 	 	By:	/s/  DAVID W. KING      
 David W. King

Assistant Treasurer
	 	 	 	 



8







 

	

 	
 	

BANK OF AMERICA, N.A.,

as Collateral Agent
	

 	
 	

 	

 
	 	 	By:	/s/  PAUL FOLINO      

	 	 	Name:	Paul Folino
	 	 	Title:	Assistant Vice President
	 	 	 	 





9







 

	

 	
 	

ADDITIONAL SIGNATURE PAGE to the Second Amended and Restated Security Agreement dated as of May 12, 2005 (the "Security Agreement") among Tetra Tech, Inc., Bank of America, N.A., as Collateral Agent, and
various Subsidiaries of Tetra Tech, Inc.
	

 	
 	

 	

 
	 	 	The undersigned is executing a counterpart of the Security Agreement for purposes of becoming a party hereto (and attached hereto are supplemental schedules setting forth information with respect to the undersigned required
to make the representations and warranties with respect to the undersigned set forth in the Security Agreement accurate as of the date hereof).
	

 	
 	

 	

 
	 	 	[                              ]
	

 	
 	

 	

 
	 	 	By:	 
	 	 	

	 	 	Name:	 
	 	 	Title:	 




10









 
 

SCHEDULE I
  TO SECURITY AGREEMENT    
    


 
  CORPORATE INFORMATION
  [TO BE INSERTED]    
    


Debtor's
Federal employment identification number: 


Debtor's
jurisdiction of organization: 


Debtor's
true and correct name as registered in its jurisdiction of organization: 


Debtor's
organizational identification number in its jurisdiction of organization: 


Debtor's
chief executive office: 


Debtor's
principal place of business: 







 
 

SCHEDULE II
  TO SECURITY AGREEMENT    
    


 
  Tradenames
  [TO BE ATTACHED]    
    







 
 

SCHEDULE III
  TO SECURITY AGREEMENT    
    


 
  Prior Legal Names    
    


The
following companies were merged into Tetra Tech, Inc. and were formerly known as: 


Simons,
Li & Associates, Inc.

IWA Engineers

C.D.C. Engineering, Inc.

Flo Engineering, Inc. 



Tetra
Tech EM Inc. (f/k/a PRC Environmental Management Inc.) 


HSI
GeoTrans, Inc. (f/k/a Hydro-Search, Inc. and GeoTrans, Inc.) 


Cosentini
Associates, Inc. (f/k/a L.M.W. Associates, Inc.) 


MFG, Inc.
(f/k/a McCulley, Frick & Gilman, Inc.) 


Wahlen &
Company, Inc. (CommSite Development Corporation was merged into Whalen & Company, Inc.) 



Tetra
Tech NUS, Inc. (f/k/a NUS Acquisition Corp. and Halliburton NUS Corporation) 









 
 

Exhibit 3    
    


May 12,
2005 


To
the Financial Institutions

listed On Schedule I hereto

(the "Noteholders") 



	Re:
	Tetra Tech, Inc. and certain of its Subsidiaries




Ladies
and Gentlemen: 


        I
have acted as counsel to Tetra Tech, Inc., a Delaware corporation (the "Company"), and the subsidiaries of the Company listed on  Exhibit A
attached hereto (collectively the "Guarantors" and, together with the Company, each an
"Obligor" and collectively the "Obligors") in connection with the Fourth Amendment to Note Purchase
Agreement, dated as of May 12, 2005 (the "Fourth Amendment") among the Company and the Noteholders, pursuant to which the following documents
were amended: (a) the Note Purchase Agreements, each dated as of May 15, 2001, (collectively, as previously amended and after giving effect to the Fourth Amendment, the
"Note Agreement") between the Company and the Noteholders; (b) $92,000,000 in aggregate principal amount of the Company's 7.28% Senior Secured
Notes, Series A, due May 30, 2011 (collectively, after giving effect to the Fourth Amendment, the "Series A Notes"); and
(c) $18,000,000 aggregate principal amount of the Company's 7.08% Senior Secured Notes, Series B, due May 30, 2008 (collectively, after giving effect to the Fourth Amendment, the
"Series B Notes", and together with the Series A Notes, the "Notes"). Capitalized terms
used herein without definition have the same meanings as in the Note Agreement. 


        This
opinion is delivered to you pursuant to Section 4 of the Fourth Amendment. In connection with this opinion, I have examined and relied upon the following documents: 



	(a)
	the
Note Agreement;



	(b)
	the
Notes;



	(c)
	the
Fourth Amendment;



	(d)
	the
Confirmation dated May 12, 2005 issued by the Obligors and attached to the Fourth Amendment; and



	(e)
	the
Second Amended and Restated Security Agreement dated as of the date hereof among the Obligors and the Collateral Agent (the "Amended Security
Agreement"). 




The
documents referred to in items (c), (d) and (e) above are called the "Amendment Documents;" the Note Agreement, the Notes and the
Amendment Documents are called the "Note Documents." 


        In
addition, I have examined such other records, documents, certificates and instruments as I have deemed necessary or appropriate as a basis for the opinions expressed below. In my
examination I have assumed the genuineness of all signatures (other than signatures of the officers of the Obligors), the legal capacity of natural persons, the authenticity of all documents submitted
to me as originals, the conformity to original documents of all documents submitted to me as certified or photostatic copies, and the authenticity of the originals of such copies. As to any facts
material to this opinion that I did not independently establish or verify, I have relied upon certificates of public officials and statements and representations of officers and other representatives
of the Obligors. 


        To
the extent that the obligations of any Obligor may be dependent upon such matters, I have assumed for purposes of this opinion that (a) each Noteholder and the Collateral Agent
(individually a "Note Party" and collectively, the "Note Parties") is duly incorporated or formed,
validly existing and in good standing under the laws of its jurisdiction of incorporation or formation, (b) each Note Party has the corporate or other organizational power and authority to
execute and deliver the Fourth Amendment and, in the case of the Collateral Agent, the Amended Security Agreement, (c) each Note Party has duly authorized, executed and delivered the Fourth
Amendment and, in the case of the Collateral Agent, the Amended Security Agreement, (d) each Note Party has the requisite corporate or 







 



other
organizational power and authority to perform its obligations under each Note Document to which it is a party, and (e) each Note Document constitutes the legal, valid and binding
obligation of each Note Party that is a party thereto, enforceable against such Note Party in accordance with its terms. 



        I
have investigated such questions of law for the purpose of rendering this opinion as I have deemed necessary. I am an attorney admitted to practice in the State of California. I
express no opinion as to matters under or involving the laws of any jurisdiction other than the laws of the State of California, United States federal law and the State of Delaware General Corporation
Law, as such laws presently stand (the "Subject Laws"). I am not opining on, and I assume no responsibility as to, the applicability to or effect on any
of the matters covered herein of the laws of any other jurisdiction. With regard to the opinions set forth in paragraphs 1 and 2, I note that certain Guarantors are incorporated in jurisdictions other
than California and Delaware. To the extent my opinions in paragraphs 1 and 2 are governed by laws other than the laws of the State of California and the Delaware General Corporation Law, I have
assumed that the laws of the State of California govern these matters. I express no opinion with respect to federal securities or state securities or "blue sky" laws or state or federal antifraud,
antitrust or environmental laws. In addition, I am not expressing any opinion as to the effect of noncompliance by any Note Party with any state or federal laws or regulations applicable to the
transactions contemplated by the Note Documents because of the nature of their respective businesses. I also assume that each Note Party will act in good faith and in a commercially reasonable manner. 



        For
purposes of California usury laws, I have assumed, with your permission, that each of the Noteholders is an admitted incorporated insurer, a licensed finance lender, or by reason of
its own business and financial experience, it has the capacity to protect its own interests in connection with the Amendment Documents. 


        Based
upon and subject to the foregoing and the limitations, qualifications and exceptions set forth below, I am of the opinion that: 


        1.     The
Company is a corporation duly organized, validly existing and in good standing under the laws of the State of Delaware, and each Guarantor is duly organized and
validly existing in good standing under the laws of the jurisdiction of its organization. Each Obligor is duly qualified to transact business as a foreign corporation and is in good standing in each
other jurisdiction in which it owns or leases property of a nature, or transacts business of a type, that would make such qualification necessary, except where the failure so to qualify would not have
a Material Adverse Effect. Each Obligor has the corporate power and authority to own its property and to carry on its business as now being conducted. Each Obligor has the corporate power and
authority (a) to execute and deliver each Amendment Document to which it is a party and (b) to perform its obligations under each Note Document to which it is a party and to carry out
the transactions contemplated thereby. 


        2.     The
execution and delivery by each Obligor of each Amendment Document to which it is a party, and the performance by each Obligor of its obligations under each Note
Document to which it is a party, have been duly authorized and approved by all necessary corporate or other organizational action. Neither the execution and delivery by any Obligor of the Amendment
Documents to which it is a party nor the consummation by any Obligor of the transactions contemplated by the Note Documents will breach, be in conflict with, or constitute a default under
(a) any Obligor's Certificate of Incorporation, Articles of Incorporation or Bylaws, as the case may be, (b) any contractual restriction (other than with respect to financial ratios or
tests or any aspect of the financial condition or results of operation of any Obligor as to which I express no opinion) contained in any agreement, indenture, instrument or other document that is
material to the Company and its Subsidiaries considered as a whole, (c) any judgment, order, injunction or decree known to me, or (d) to my knowledge, any 


2







 



federal,
California or Delaware General Corporation Law statute, rule or regulation (including usury laws). 



        3.     No
authorization, approval or other action by, and no notice to or filing with, any federal, California or Delaware governmental authority or regulatory body is required
for the execution and delivery by any Obligor of any Amendment Document or the performance by any Obligor of any Note Document, except for routine filings that may be required after the date hereof to
maintain good standing (corporate or otherwise) or to perfect Liens under the Amended Security Agreement. 


        4.     (a)    Each
Amendment Document has been duly executed and delivered by each Obligor that is a party thereto, and each Note Document constitutes the legal, valid
and binding obligation of Obligor that is a party thereto, enforceable against such Obligor in accordance with its terms. 



        (b)   With
respect to the enforceability of the choice of law to govern each of the Note Documents, although there is no controlling precedent and the matter is not free from
doubt, a California court or a federal court sitting in the State of California in a properly litigated action should respect the choice of Illinois law as the governing law and should apply Illinois
law. 




        5.     To
my knowledge, other than as disclosed in the Company's financial statements, there are no outstanding judgments against any Obligor, and there is no action, suit or
proceeding pending or threatened against any Obligor, which is reasonably likely to have a Material Adverse Effect. 


        In
rendering the opinions set forth above, I have assumed that the laws of the State of California would apply despite the selection of Illinois law as the governing law in the Note
Documents. In making the foregoing assumption, I do not intend to imply that a California court would not give effect to such selection of Illinois law. 


        The
opinions expressed herein are subject to the following qualifications and comments: 


        A.    Each
Note Document is subject to the effect of (i) bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium or other similar laws relating to or
affecting the rights of creditors generally and (ii) the application of general principles of equity (regardless of whether enforcement is considered in proceedings at law or in equity). 



        B.    I
express no opinion as to the effect of the laws of any jurisdiction (other than the Subject Laws) wherein any Note Party may be located which limit rates of interest
that may be charged or collected by such Note Party. 


        C.    Insofar
as certain provisions of the Note Documents may provide for indemnification, enforceability thereof may be limited by public policy considerations. 


        D.    The
provisions of the Note Documents that permit any Note Party to take action or make determinations, or to benefit from indemnities and similar undertakings of any
Obligor may be subject to a requirement that such actions be taken or such determinations by made, and any action or inaction by any Note Party that may give rise to a request for payment under such
an undertaking be taken or not taken, on a reasonable basis and in good faith. 


        E.    I
express no opinion as to (i) whether provisions of any Note Document that relate to the subject matter jurisdiction of the federal or state courts of Illinois to
adjudicate any controversy related to such Note Document or the transactions contemplated thereby, (ii) any waiver of inconvenient forum set forth in any Note Document, or (iii) any
waiver of jury trial found in any Note Document. 


        F.     My
opinions in paragraphs 2 and 3 above as to compliance with certain statutes, rules and regulations are based upon a review of those statutes, rules and regulations
which, in my experience, are normally applicable to transactions of the type contemplated by the Note Documents and statutes, rules and regulations applicable to corporations conducting businesses
similar to those conducted by the Obligors. 


3







 



        This
opinion letter is rendered only to, and is solely for the benefit of, the Noteholders (and their respective successors and assigns, including, without limitation, any future holder
of a Note) in connection with the transactions related to the Note Documents and may not be relied upon by such Persons for any other purpose, or by any other Person for any purpose, in each case
without my prior written consent. 



	 	 	 	Very truly yours,
	 	 	 	 
	 	 	 	 
	 	 	 	/s/  JANIS B. SALIN      
 Janis B. Salin

Vice President and General Counsel
	 	 	 	 
	Attachments:	Schedule I

Exhibit A	 	 




4








Schedule I  


Opinion Addressees  



Massachusetts
Mutual Life Insurance Company

c/o Babson Capital Management LLC

1295 State Street

Springfield, MA 01111 


C.M.
Life Insurance Company

c/o Babson Capital Management LLC

1295 State Street

Springfield, MA 01111 


MassMutual
Asia Limited

c/o Babson Capital Management LLC

1295 State Streete

Springfield, MA 01111 


Prudential
Retirement Ceded Business Trust

c/o Prudential Capital Group

Four Embarcadero Center

Suite 2700, 27th Floor

San Francisco, CA 94111 


United
of Omaha Life Insurance Company

4—Investment Loan Administration

Mutual of Omaha Plaza

Omaha, NE 68175-1011 


Mutual
of Omaha Insurance Company

4—Investment Loan Administration

Mutual of Omaha Plaza

Omaha, NE 68175-1011 


Hartford
Life Insurance Company

c/o Hartford Investment Management Company

P.O. Box 1744

Hartford, CT 06144-1744 


Nationwide
Life Insurance Company

One Nationwide Plaza (1-33-07)

Columbus, Ohio 43215-2220



Nationwide
Life and Annuity Insurance Company

One Nationwide Plaza (1-33-07)

Columbus, Ohio 43215-2220



Nationwide
Life Insurance Company of America

One Nationwide Plaza (1-33-07)

Columbus, Ohio 43215-2220 


Security
Financial Life Insurance Co.

4000 Pine Lake Road

P.O. Box 82248

Lincoln, NE 68501-2248 










The
Canada Life Assurance Company

330 University Ave. SP-11

Toronto, ON M5G 1R8



Canada
Life Insurance Company of New York

330 University Ave. SP-11

Toronto, ON M5G 1R8 


Thrivent
Financial For Lutherans

625 Fourth Avenue South

Minneapolis, MN 55415



Modern
Woodmen of America

1701 First Avenue

Rock Island, IL 61201 







Exhibit A  


Subsidiaries  



	Subsidiary
 
	 	State Of Domicile

	GeoTrans, Inc.	 	Virginia
	

Tetra Tech EM Inc.	
 	

Delaware
	

KCM, Inc.	
 	

Washington
	

SCM Consultants, Inc.	
 	

Washington
	

Whalen & Company, Inc.	
 	

Delaware
	

Tetra Tech NUS, Inc.	
 	

Delaware
	

MFG, Inc.	
 	

Delaware
	

Tetra Tech Canada Ltd.	
 	

Ontario
	

Tetra Tech Construction Services, Inc.	
 	

Colorado
	

Cosentini Associates, Inc.	
 	

New York
	

Evergreen Utility Contractors, Inc.	
 	

Washington
	

eXpert Wireless Solutions, Inc.	
 	

Delaware
	

FHC, Inc.	
 	

Oklahoma
	

Rizzo Associates, Inc.	
 	

Massachusetts
	

Tetra Tech RMC, Inc.	
 	

Delaware
	

Vertex Engineering Services, Inc.	
 	

Massachusetts
	

Western Utility Contractors, Inc.	
 	

Illinois
	

Sciences International, Inc.	
 	

Delaware
	

The Thomas Group of Companies, Inc.	
 	

Delaware
	

Hartman & Associates, Inc.	
 	

Florida
	

Ardaman & Associates, Inc.	
 	

Florida
	

Tetra Tech EC, Inc.	
 	

Delaware
	

Engineering Management Concepts, Inc.	
 	

California
	

Advanced Management Technology, Inc.	
 	

Virginia
	

Tetra Tech Consulting & Remediation, Inc.	
 	

Delaware














QuickLinks



Exhibit 10.2


TETRA TECH, INC. FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT



CONFIRMATION


SCHEDULE I

SCHEDULE II Excluded Subsidiaries



Exhibit 1A


FORM OF SERIES A NOTE



Exhibit 1B


FORM OF SERIES B NOTE TETRA TECH, INC. ADJUSTABLE RATE SENIOR SECURED NOTE, SERIES B, DUE MAY 30, 2008




Exhibit 2


SECOND AMENDED AND RESTATED SECURITY AGREEMENT

W I T N E S S E T H



SCHEDULE I TO SECURITY AGREEMENT

CORPORATE INFORMATION [TO BE INSERTED]

SCHEDULE II TO SECURITY AGREEMENT

Tradenames [TO BE ATTACHED]

SCHEDULE III TO SECURITY AGREEMENT

Prior Legal Names



Exhibit 3