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An Investigation in to the Nutrient Enrichment of Tickenham, Nailsea and Kenn Moors SSSI

Tickenham, Nailsea and Kenn Moors SSSI form part of the North Somerset Levels, an area of low-lying floodplain draining to the Bristol Channel. They are characterised by a mosaic of wet lowland pasture, drained by a system of artificial drainage ditches known as rhynes. The areas are of importance notably for their peat deposits and for the ecological and conservation value of the ditch network and surrounding grassland.

SSSIs have favourable condition targets, including water quality parameters that must be met for the site to be recorded as in ‘favourable condition’. Favourable condition is required for SSSIs in order to meet the Government’s Biodiversity 2020 objectives. In addition, both sites are Waterbodies under the Water Framework Directive, which requires progress towards ‘good chemical and ecological status’ for all defined waterbodies by 2015.

Diffuse pollution, in the form of elevated nutrient inputs, mainly from agricultural sources, is a major cause for failure of many sites to reach these targets, and a number of factors have been identified as potentially affecting water quality targets at these sensitive sites.

PAA was commissioned by Natural England to investigate the sources of nutrient enrichment, largely from high levels of phosphates and nitrates, in Tickenham, Nailsea and Kenn Moors SSSI. A sampling network was established and over a 14 month period water samples were systematically taken and analysed for nutrient loads from the rivers and drainage ditch network.

A pattern started to emerge that showed that some parts of the SSSIs had nutrient ‘hotspots’ and this has enabled a more targeted approach to remediation. Based on the findings of the monitoring, Wessex Water are to set up a continuous monitoring operation on one of the drainage channels identified in the study as one of the problem watercourses.

PAA has worked on a wide range of projects investigating problems related to high nutrient levels in rivers and wetlands and has in-house specialists to provide advice on the causes and the most effective remediation strategies. Please contact us for more information, or feel free to download one of our relevant fliers below:

Water Framework directive and Water Quality Assessment
Applied Hydrology & Development
Aquatic Invertebrates & Biological Water Quality Monitoring
Wetlands – Sustainable Drainage