(1) When, by the making of any improvement scheme, any land in the area comprised in the scheme which is not required for the execution thereof will, in the opinion of the municipal council be increased in value, the municipal council, in framing the scheme, may declare that a betterment fee shall be payable by the owner of the land or any person having an interest therein in respect of the increase in value of the land resulting from the execution of the scheme.

(2) Such increase in value shall be the amount by which the value of the land, on the completion of the execution of the scheme, estimated as if the land were clear of buildings exceeds the value of the land, prior to the execution of the scheme estimated in like manner, and the betterment fee shall be one-third of such increase in value.