Section 11. The secretary of environmental affairs shall establish a program to assist the cities and towns, which have established conservation commissions under section eight C of chapter forty, in acquiring lands and in planning or designing suitable public outdoor facilities as described in sections two B and two D. He may, from funds appropriated to carry out the provisions of section three, reimburse any such city or town for any money expended by it in establishing an approved project under said program in such amount as he shall determine to be equitable in consideration of anticipated benefits from such project, but in no event shall the amount of such reimbursement exceed eighty per cent of the cost of such project. No reimbursement shall be made hereunder to a city or town unless a project application is filed by such city or town with the secretary setting forth such plans and information as the secretary may require and approved by him, nor until such city or town shall have appropriated, transferred from available funds or have voted to expend from its conservation fund, under clause fifty-one of section five of chapter forty, an amount equal to the total cost of the project, nor until the project has been completed, to the satisfaction of the secretary, in accordance with said approved plans. Any reimbursement received by a city or town under this section shall be applied to the payment of indebtedness, if any, incurred in acquiring land for such conservation project.