The Land Drainage Act
Provision made under the Land Drainage Act 1991 Chapter II item 40 empowers the North Level District Internal Drainage Board to make a drainage rate in respect of agricultural land and buildings.
The full details regarding the internal drainage board and its function are

Cleansing the main drain
written into the Land Drainage Act 1991 Chapter 59, a copy of which can be obtained from HMSO.
To summarise, the act empowers the Internal Drainage Board to levy a rate against the occupiers of land, which could be used for agricultural/horticultural purposes, including grazing. The rate levied is set each year at the January meeting of the North Level District Internal Drainage Board and is available for public inspection. The actual demand is sent out during May and applies to the period of 1 April that year until the 31 March the following year. The Act also empowers the Board to levy the rate due for the whole of the year against an occupier who has occupied the land for any part of the year.
The rate is calculated by assessing a uniform amount per pound throughout the district based on the annual value of the agricultural land or agricultural buildings in respect of which it is made. Further specific details can be found in part IV section 41 of the Act.