Data Sources

Most of the data used in the production of the Catchment management plans was made available through the CaBA Open data and can be downloaded from here. Further relevant datasets are available to view and download from Defra’s Magic map site.

Land cover data is from the Centre for Ecology and Hydrology Land Cover Map 2007 (LCM2007), released in July 2011. It is derived from satellite images and digital cartography with land cover categories based on UK Biodiversity Action Plan Broad Habitats.

The riparian shade maps were produced by the Environment Agency from aerial imagery, as pat of the ‘Keeping Rivers Cool’ initiative.

Data on where chemical, biological and invasive species monitoring has taken place and on past and current projects has been collected from our partner organisations. If you have any information to add to the map, please get in touch. 

Understanding the Data

Defining the status of a waterbody

Under the Water Framework Directive monitoring data is used to classify the overall condition of a waterbody as ‘High’, ‘Good’, ‘Moderate’, ‘Poor’ or ‘Bad’. The aim is to get all waterbodies to at least ‘Good’ status.

Chemical status is determined by checking levels of priority or hazardous substances  such as pesticides and heavy metals. Chemical status is classified as either ‘Good’ or ‘Fail’. If any one of these substances exceeds the compliance standard the waterbody will fail. These substances are only monitored where there are known discharges.

Ecological status classifications are based on 1. Biological data (fish, invertebrates or algae) 2. Physicochemical conditions, (dissolved oxygen, phosphorus, nitrate or ammonia) 3. Concentrations of specific pollutants, such as zinc or arsenic. If these suggest the site is ‘High’ status the hydrolmorphology is also considered to check the site is near-natural. Ecological status is determined by the worst scoring component. However, physicochemical elements can only influence status down to moderate. Only biological elements can determine poor or bad status.

Overall status is the worst scoring component of ecological and chemical status. It may be impossible for some waterbodies to achieve good status because of modifications such as reservoirs or flood protection. These are classified as heavily modified waterbodies.

This information was taken from the EA monitoring strategy document.

The maps show the overall classification and classification for selected elements. Detailed information on classification of each water body can be found on the Environment Agency’s Catchment Data Explorer.

SCIMAP modelling

Fine sediment loads in rivers are a common problem for water quality and habitat. We need to be able to work out where the sediment is coming from. We need to identify the areas that are generating sediment and the pathways by which these are connected to the river or stream.

The SCIMAP model uses land cover, rainfall and topography data to estimate where sediment is being generated that will end up in the watercourses. It is a tool to help target work towards high risk areas. It uses patterns of soil moisture and saturation to predict where there are pathways of overland flow that will carry sediment to the watercourse.

SCIMAP was developed by Durham and Lancaster Universities, supported by the Natural Environment Research Council, DEFRA and the Environment Agency.

Find out more here.

Source apportioning of Phosphate

Human activity can cause pollution of water bodies with nitrate and phosphate. Diffuse runoff from agricultural land and point sources such as waste water effluent contribute nutrients. The measures needed to reduce nutrient pollution depend on the source. Therefore, it is important to identify the proportion of phosphate inputs attributable to different sectors.

The modelling was carried out by DEFRA using national and regional data to estimate inputs from industrial discharges, waste water discharges, sewer outfalls, storm tank discharges, mine waters, arable runoff, livestock inputs, atmospheric and urban runoff. The models do not account for changes in flow levels throughout the year and are intended to be an indicative advisory tool rather than a precise measure.

For a helpful summary click here or for more detail click here.