CONTRIBUTION, CONVEYANCE AND ASSUMPTION AGREEMENT

Exhibit 10.1

Execution Copy

CONTRIBUTION, CONVEYANCE AND ASSUMPTION AGREEMENT

BY AND AMONG

ENTERPRISE PRODUCTS OPERATING L.P.,

DEP HOLDINGS, LLC,

DUNCAN ENERGY PARTNERS L.P.,

DEP OLPGP, LLC

AND

DEP OPERATING PARTNERSHIP, L.P.

DATED AS OF FEBRUARY 5, 2007

TABLE OF CONTENTS

CONTRIBUTION, CONVEYANCE AND ASSUMPTION AGREEMENT

     THIS CONTRIBUTION, CONVEYANCE AND ASSUMPTION AGREEMENT (this “ Agreement ”) dated as of February 5, 2007, is made and entered into by and among Enterprise Products Operating L.P., a Delaware limited partnership (“ EPD OLP ”), DEP Holdings, LLC, a Delaware limited liability company (the “ General Partner ”), Duncan Energy Partners L.P., a Delaware limited partnership (“ MLP ”), DEP Operating Partnership, L.P., a Delaware limited partnership (“ OLP ”), and DEP OLPGP, LLC, a Delaware limited liability company (“ OLP GP ”). The above-named entities are sometimes referred to in this Agreement each as a “ Party ” and collectively as the “ Parties .” Certain capitalized terms used are defined in Article I hereof.

RECITALS

     WHEREAS, the General Partner and EPD OLP have formed MLP, pursuant to the Delaware Revised Uniform Limited Partnership Act (the “ Delaware LP Act ”), for the purpose of engaging in any business activity that is approved by the General Partner and that lawfully may be conducted by a limited partnership organized pursuant to the Delaware LP Act.

     WHEREAS, in order to accomplish the objectives and purposes in the preceding recital, the following actions have been taken prior to the date hereof:

          1. EPD OLP formed the General Partner, under the terms of the Delaware Limited Liability Company Act (the “ Delaware LLC Act ”), to which EPD OLP contributed $1,000 in exchange for a 100% membership interest in the General Partner.

          2. The General Partner and EPD OLP formed MLP, under the terms of the Delaware LP Act, to which the General Partner contributed $60 and EPD OLP contributed $2,940.00 in exchange for a 2% general partner interest and 98% limited partner interest, respectively in MLP.

          3. MLP formed OLP GP, under the terms of the Delaware LLC Act, to which MLP contributed $1,000 in exchange for a 100% membership interest in OLP GP.

          4. OLP GP and MLP formed the OLP, under the terms of the Delaware LP Act, to which OLP GP contributed $0.01 and MLP contributed $999.99 in exchange for a 0.001% general partner interest and 99.999% limited partner interest, respectively in OLP.

          5. EPD OLP and Enterprise Products OLPGP, Inc., a Delaware corporation “ EPD OLPGP ”), formed Mont Belvieu Caverns, L.P., a Delaware limited partnership (“ Mont Belvieu LP ”), under the terms of the Delaware LP Act, to which EPD OLPGP contributed $0.01 and EPD OLP contributed $999.99 in exchange for a 0.001% general partner interest and 99.999% limited partner interest, respectively, in Mont Belvieu LP.

          6. EPD OLP formed South Texas NGL Pipelines, LLC, a Delaware limited liability company (“ South Texas NGL ”), under the terms of the Delaware LLC Act, to which EPD OLP contributed $1,000 in exchange for a 100% membership interest in South Texas NGL.

          7. Mont Belvieu LP filed the necessary certificates and documents, under the terms of the applicable laws of the State of Delaware and under the Delaware LP Act and the Delaware LLC Act, pursuant to which Mont Belvieu LP was converted into a Delaware limited liability company named Mont Belvieu Caverns, LLC (“ Mont Belvieu LLC ”) effective January 10, 2007, with EPD OLP and EPD OLPGP owning 99.999% and 0.001% of the membership interests, respectively.

          8. MLP, OLP and certain other OLP subsidiaries have entered into a credit Agreement, dated as of January 5, 2007, with Wachovia Bank, as Administrative Agent and Lender, and the other Lenders named theretin (the “ Credit Facility ”), to, among other things, allow the MLP to borrow up to $300 million under the Credit Facility (i) initially, in an amount not to exceed $210 million, (A) for distribution to EPD OLP in connection with the contributions of assets under this Agreement contemplated in connection with the initial public offering of common units by the MLP (the “ IPO ”), and for payment of transaction and related offering expenses related to the transaction contemplated by this Agreement, the IPO and the Credit Facility, and related transactions, and (ii) thereafter, as a backstop for commercial paper and for working capital, acquisitions, capital expenditures and other company purposes.

          9. EPD OLP, EPD OLPGP, Enterprise Products Texas Operating, LP, a Texas limited partnership (“ Texas Operating ”) and Mont Belvieu LLC have entered into a Contribution, Conveyance and Assumption Agreement, dated as of January 23, 2007 but effective on February 1, 2007, pursuant to which (i) Texas Operating (a) contributed and conveyed its Mont Belvieu East and Mont Belvieu West storage assets to Mont Belvieu LLC in exchange for membership interests in Mont Belvieu LLC, and (b) immediately upon receipt thereof distributed such Mont Belvieu membership interests 1% to EPD OLPGP and 99% to EPD OLP, and (ii) EPD OLP contributed and conveyed its Mont Belvieu North storage assets and assigned certain storage contracts for a continuation of its 99.999% membership interest, each as set forth on the schedules thereto. The limited liability company agreement of Mont Belvieu LLC was amended to adjust the membership interests to reflect the relative capital accounts of EPD OLP and EPD OLPGP after giving effect to the capital contributions.

          10. EPD OLP, Enterprise GC, L.P., a Delaware limited partnership (“ Enterprise GC ”), Enterprise Holding III, LLC (“ Holdings III ”), Enterprise GTM Holdings LP (“ GTM Holdings ”), Enterprise GTMGP, LLC (“ GTMGP ”) and South Texas NGL have entered into a Contribution, Conveyance and Assumption Agreement, executed January 23, 2007 but effective on January 1, 2007, pursuant to which (i) Enterprise GC has conveyed the South Texas NGL pipeline assets, as set forth on the schedules thereto, to South Texas NGL, in exchange for membership interests of South Texas NGL, (ii) Enterprise GC distributed all of such South Texas NGL membership interests 99% to GTM Holdings and 1% to Holdings III, (iii) Holdings III distributed all of its South Texas NGL membership interests to GTM Holdings, (iv) GTM Holdings distributed all of its resulting South Texas NGL membership interests 99% to EPD OLP and 1% to GTMGP, (v) GTMGP distributed all of its membership interests to GTM, (vi) GTM distributed all of such membership interests to EPD OLP, and (vii) GTMGP distributed all of such membership interests to EPD OLP, with the result that EPD OLP remained the sole member of South Texas NGL.

     WHEREAS, concurrently with the consummation of the transactions contemplated hereby (the “ Closing ”), each of the following matters shall occur:

          1. Each of Acadian Gas, LLC, a Delaware limited liability company (“ Acadian Gas ”), South Texas NGL, Sabine Propylene Pipeline L.P, a Texas limited partnership " Sabine LP " ), Enterprise Lou-Tex Propylene Pipeline L.P., a Texas limited partnership (“ Lou-Tex LP ”), and Mont Belvieu LLC will distribute its cash on hand, if any, to its respective members and partners.

          2. After giving effect to such distributions of cash on hand, EPD OLP, for itself and on behalf of the General Partner for its respective interest in each of the Subject Interests to MLP in exchange for a continuation of the General Partner’s 2% general partner interest in MLP, will contribute the following equity interests in its subsidiaries to MLP: (a) a 66% membership interest in Acadian Gas, (b) a 66% membership interest in South Texas NGL, (c) a 66% general partner interest in Sabine LP, (d) a 66% general partner interest in Lou-Tex LP and (e) a 66% membership interest in Mont Belvieu LLC (collectively, the “ Subject Interests ”).

          3. The public, through the Underwriters, will contribute $256,620,000 net of the underwriters’ discounts and commissions and a $1,000,000 structuring fee (the “ Offering Proceeds ”), to MLP in exchange for 13,000,000 Common Units representing a 62.8% limited partner interest in MLP.

          4. MLP will use the net Offering Proceeds to (a) pay transaction expenses associated with the transactions contemplated by this Agreement in the estimated net amount of approximately $2.9 million (exclusive of the underwriters’ discounts and commissions and structuring fees, but net of a reimbursement for certain expenses received from the underwriters), (b) distribute an amount to EPD OLP as a portion of the cash consideration equal to:

          (i) the Offering Proceeds, less

          (ii) $2.9 million (the estimated net transaction expenses), less

          (iii) the product of 66% multiplied by the difference between (x) $101.7 million and (y) the actual construction and acquisition costs paid by EPD OLP or its Affiliates with respect to (A) the South Texas NGL pipeline (excluding the original pipeline purchase costs of approximately $97.7 million) owned by South Texas NGL as of the date hereof and (B) the Mont Belvieu brine production and above-ground storage projects included in or for the benefit of the assets owned by Mont Belvieu Caverns as of the date hereof, prior to the contribution of interests in South Texas NGL and Mont Belvieu Caverns to us pursuant to this Agreement at the Closing (as defined below)(such amount, the “ Distributable Proceeds ”),

(c) provide approximately $18.9 million to make a capital contribution to South Texas NGL in connection with the planned expansions to the South Texas NGL pipeline, and (d) provide approximately $9.3 million to make a capital contribution to Mont Belvieu LLC in connection with planned construction projects to expand brine production capacity and above-ground storage reservoirs.

          5. MLP will issue 7,301,571 Common Units to EPD OLP as partial consideration for the contribution of the Subject Interests.

          6. MLP will contribute the Subject Interests and to OLP as a capital contribution.

          7. MLP will borrow approximately $200 million under the Credit Facility and distribute $198.9 million of such funds under the Credit Facility to EPD OLP as partial consideration for the contribution of the Subject Interests.

          8. If the Underwriters exercise their option to purchase up to an additional 1,950,000 Common Units, MLP shall use proceeds of that exercise, after deducting underwriters’ discounts and commissions and structuring fees, to redeem an equal number of Common Units owned by EPD OLP.

          9. The agreements of limited partnership and the limited liability company agreements of the aforementioned entities will be amended and restated to the extent necessary to reflect the applicable matters set forth above and as contained in this Agreement.

     NOW, THEREFORE, in consideration of their mutual un