The EPA has issued their report Research 260: Impact of Cattle Access to Watercourses: Literature Review on Behalf of the COSAINT Project
The report found variable results within and between studies in relation to the impact of cattle access and exclusion on a variety of water quality parameters. The evidence for the benefits of excluding cattle from watercourses seems particularly strong in relation to hydromorphology, sedimentation and bacterial parameters. Conclusions in relation to the impact of cattle access on nutrient parameters are particularly variable, with several studies finding nutrient impacts related to cattle access/exclusion and others observing only minimal or insignificant results.
Degradation of freshwater resources and loss of freshwater biodiversity, as a result of physical alteration, habitat loss, water abstraction, the
introduction of non-native species, overexploitation and pollution, are of major global concern. Nutrient enrichment along with excess sediment inputs are the primary water quality issues for most freshwater ecosystems in the world, with anthropogenic activities,
including land use and agriculture, being among the primary sources of pollutants to freshwater systems.
Agricultural pollutants originate predominantly from diffuse sources, such as the spreading of organic and inorganic fertilisers, as well as point sources, which include cattle access points. Although there has been much research in relation to the impact of diffuse sources of agricultural inputs, there has been little attempt to collate or review studies in relation to the impact of cattle access to watercourses on environmental parameters.