 "Taxable land" consisted of any land that might be affected by flooding, and would therefore benefit from drainage measures.The Commissioners met for the first time on 6 June 1760, and planned the take-over of all of the drainage mills in the region, the construction of new ones, and the digging of the main drainage channels which would feed surface water to the mills and into the rivers.To finance these operations, there were empowered to borrow money, and to charge a drainage rate of 1 shilling (5p) per acre, rising to 1/6d (7.5p) after seven years.