‘This chapter describes simple dams, weirs and sluices, the construction of which may be suitable for involving volunteers. Some of these structures may come within the Construction (Design and Management) Regulations 1995, and will require to be notified to the Health and Safety Executive. The Environment Agency (or equivalent) may also need to be consulted. Engineering or other specialist advice may be necessary for some projects. Canal locks and sluices are too specialised to be included, and advice on these installations should be sought from British Waterways or the Waterways Recovery Group.