An investigation into illegal discharge of sewage from boats in the broads

In response to concerns expressed by the Environment Agency and Broads Authority, this project aimed to assess the risk of illegal sewage discharge from boats into the waterways of the Broads, East Anglia. The Broads are an internationally important wetland, consisting of marshes, fenland, rivers and shallow lakes. A popular area for boating, sewage discharge from boats could have deleterious impacts on the environment, health and public perception. Water was tested for evidence of faecal pollution at a mooring site at Thorpe Island, River Yare, identified as at risk from illegal sewage disposal from boats. Continuous monitoring of ammonia, ammonium and dissolved oxygen up and downstream of the moorings took place at half hourly intervals over six weeks. Thermotolerant coliforms, ammonia, phosphorous and dissolved oxygen were manually sampled at Thorpe Island and nearby Whitlingham sewage treatment works. Definitive evidence of pollution from boats was not found, either sewage was not illegally discharged during the study period, or methods were inadequate to identify the occurrence of faecal pollution with certainty. The distribution of sewage disposal facilities available for boats was also analysed. The navigable waterways of the Broads were categorised in terms of the risk of illegal sewage disposal due to distance from disposal facilities. The south eastern reaches of the River Bure and western reaches of the River Waveney were identified as being at most risk. Recommendations are made to identify areas of the Broads at risk from pollution due to factors other than distance from sewage disposal facilities. Any further water quality studies should be carried out in these areas and improvements to the methods are suggested. Future management should include raising awareness of boaters about issues surrounding sewage disposal and the consideration of the provision of either mobile or static sewage disposal facilities in areas where current provision is deemed inadequate.