Macrophytes (water plants visible to the naked eye) can indicate the impact of pressures such as increased nutrients, flow pressures, channel alterations etc. The species present and their abundance give an indication as to the health of a river. This dataset is made up of species lists and their percentage cover value for each survey conducted across Wales by Natural Resources Wales and former Environment Agency Wales. These surveys are conducted as part of on-going monitoring of river water quality for legislative requirements and to meet business drivers.