Section 5G. The Massachusetts Water Resources Authority, on July first of each year, shall pay over to the division of watershed management, an amount to be held in trust for payment to each city or town in which property of the Quabbin watershed, Wachusett Watershed, Sudbury Watershed and Ware River watershed is held by said division for purposes of a water supply or the protection of its sources, said amount to equal that which such city or town would receive in taxes upon the fair cash valuation of the land, which shall not include buildings or other structures except in the case of land taken for the purposes of protecting the sources of an existing water supply, the valuation for each year being reduced by all abatements thereon; provided that in no event shall any city or town receive an amount less than the payment received from the metropolitan district commission in the prior fiscal year. Said division shall pay such amounts without further appropriation to such city or town no later than August first of each year. Payments made by said Authority pursuant to the provisions of this section for the year when a city or town shall have made a general revaluation of all its real property for purposes of taxation shall not be less than payment made to said city or town for the year immediately preceding the general revaluation. Whenever a city or town in which such land is located shall have made a general revaluation or reassessment of all of its real property for purposes of taxation, the valuation of such land for the purpose of payments authorized by this section shall be determined by the assessors of said city or town as of January first, between January first and June first, in the year succeeding such revaluation or reassessment by dividing the amount of the payment authorized by this section for the year last preceding the revaluation or reassessment by the commercial class tax rate of said city or town for the year of the revaluation or reassessment, so that payment with respect to such land shall remain substantially the same as that made prior to such revaluation or reassessment; provided, however, that notwithstanding any other provision of this section, the valuation of such land, held by and for the division of watershed management, for the purpose of payments in lieu of taxes pursuant to this section, shall be determined by the commissioner of revenue in accordance with the provisions of sections thirteen to seventeen, inclusive, of chapter fifty-eight. In no event shall any city or town receive an amount less than the payment received from the metropolitan district commission in the prior fiscal year. The city, town, district, or authority owning such land, or said division of watershed management, if aggrieved by the determination of the assessors, may within six months after written notice thereof appeal to the appellate tax board. Any part of such land or buildings from which any revenue in the nature of rent is received shall be subject to taxation.

If such land is part of a larger tract which has been assessed as a whole, its assessed valuation in any year shall be taken to be that proportional part of the value of the whole tract which the value of the land so acquired, exclusive of buildings, bore in such year to the value of the whole tract.

The Massachusetts Water Resources Authority on July first of each year, shall pay over to the said division of watershed management, an amount to be held in trust for payments in lieu of taxes to the towns of Belchertown, Hardwick, New Salem, Pelham, Petersham and Ware for watershed lands of the Quabbin Reservation which were included in the former towns of Dana, Greenwich, Enfield, and Prescott. Said amounts to be held in trust as payments in lieu of taxes shall be made only on lands which are above the high water mark of the total acreage in question that is held by each community; provided however, that the sum of said payments shall not be less than fifty thousand dollars annually, and shall be valued in accordance with the provisions of sections thirteen to seventeen, inclusive, of chapter fifty-eight. In no event shall any city or town receive an amount less than the payment received from the metropolitan district commission in the prior fiscal year.