The survey was carried out as an extension intensive surveys of the River Yare earlier in 1987. Also, public concern over the inadequacy of sewage disposal facilities in the Yarmouth area. At present, thirty outfalls discharge crude sewage into the lower River Bure, causing some organic enrichment to the lower River Bure. The survey was carried out in the first week in June 1987. Eight sites were sampled with a cylindrical corer (15cms diam by 20cms deep). Three replicates were taken from the mid horizontal distance point between high and low tides. Cores were taken soon after low water on each occassion. A sub sample from each sample was taken for sediment analysis, the remainder was sieved through a 500 micron sieve. The survey suggests sewage enrichment of the lower estuary increases the productivity but does not adversely affect the species diversity. It was also postulated that much of the mercury discharged through the Norwich sewage works during the previous twenty years has accumulated in the sediments of Breydon Water. The estuary was found to support a healthy, but undiverse invertebrate fauna. The lack of diversity was thought to be due to the homogeneity of the sediment types and the lack of extremes of salinity within Breydon Water. Breydon Water satisfied the biological, chemical, and aesthetic criteria for a class A estuary under the UK Estuarine Classification Scheme. Breydon Water is important as an over-wintering ground for waders, wildfowl and gulls.