Provided alsoe That it shall and may be lawfull to and for the said Ann Offley and the Lords Owners or Proprietors of the said Lordship or Mannor of Blacon and of the Grounds or Marshes contiguous and adjacent to the Banks of the said River for the Time being to make and sett up one or more Sluce or Sluces or other Engines to carry off such Water as may flow or fall into the said Marshes or Grounds through or by the Banks of the said River soe as she or they soe erecting or setting up the same or the Owner of the said Marsh or Grounds upon reasonable Notice by the said Mayor and Citizens or some Officer appointed by them in writing to her or them in that behalfe given doe and shall at her and their owne respective Costs and Charges well and sufficiently secure repaire maintaine and defend the same Banks by the compasse and space of Fifteene Foot both above and below the said Sluces or Engines