53 STAT.] 76TH CONG. , 1ST SESS.-CH. 418-AUG. 4, 1939 of remaining years, as of the date of the amendment made pursuant to this Act, in which installments of said construction charges would become due and payable under said existing repayment contract or other form of obligation to pay construction charges. SEC. 4 . (a) In connection with any existing project on which con- struction charges are payable to the United States, the Secretary is hereby authorized to negotiate and enter into a contract or an amenda- tory contract, in a form satisfactory to him, with an organization, satisfactory in form and powers to him, representing the water users of the project contract unit involved, which contract shall provide for the payment of construction charges on said project contract unit in the manner hereinafter provided in this section. The negotiation and execution of such a contract shall be undertaken only upon request by duly authorized representatives of the water users involved for such a contract and upon a determination by the Secretary that, in his judgment, such a contract is both practicable and in keeping with the general purpose of this Act. (b) All of the construction charges for the project contract unit remaining unaccrued on the date of the contract entered into pursuant to this section or on any later date agreed upon shall be merged in a total and general repayment obligation of the organization. Said repayment obligation of said organization shall be scheduled in such annual installments as, in the judgment of the Secretary, constitute an equitable, practicable, and definite consolidated schedule of the existing obligations in said project contract unit to pay construction charges: Provided, That said schedule of installments shall be so arranged that in the judgment of the Secretary it does not involve for any of said construction charges merged into said general obliga- tion an extension of the time permitted under the existing obligations for payment of said charges excepting the adjustment of the repay- ment period permitted for certain charges by the last sentence of this subsection. For the purpose of scheduling said installments of said general obligation in accordance with this subsection, in connection with each project contract unit under an existing contract made pur- suant to section 4 of the Act of December 5, 1924 (43 Stat. 672, 701), the Secretary shall fix a weighted average gross crop return per acre, of which 5 per centum shall be the measure for determining the sched- ule of the unaccrued construction charges in a definite number of annual installments. In the event the said existing obligations to pay construction charges in said project contract unit or units are based in part on section 4 of the Act of December 5, 1924 (43 Stat. 672, 701), and in part on other Acts of the Federal reclamation laws, said charges may be consolidated into two general repayment contract obligations of said organization, each of which shall be scheduled in such installments as, in the judgment of the Secretary, constitute an equitable, practicable, and definite consolidated schedule of all of the respective parts of said existing obligations to pay construction charges. Any of said unaccrued construction charges, which under said existing obligations are payable on the basis of a definite period, first may be adjusted by the Secretary, if in his judgment such adjust- ment is both practicable and in keeping with the general purpose of this Act, to a repayment basis of a longer definite period fixed in each case by him: Provided, That for any such construction charges said longer period shall not exceed the limitations contained in the proviso of section 3 of this Act. (c) For each project contract unit where a repayment contract is entered into pursuant to this section, a census of annual returns shall be taken each year. The normal returns each year, for each such 1189 Construction charges on existing projects, amendatory contract form provi- sions. Unaccrued charges on date of new con- tract, merger into a total repayment obli- gation. Repayments in an- nual installments. Proiso. Arrangement of schedules of in- stallments. Measure for deter- mining schedule of installments. 43 Stat. 701. Consolidation where existing con- tracts are under dif- ferent Acts. Repayment install- ments. Readjustment of ex- isting payment peri- ods. Proviso. Limitation. Census of nnual ratuns.