What is the role of land use for downstream pollution and flooding?

Loe Pool Forum’s partnership with Exeter University’s Centre for Geography, Environment and Society has enabled mutually beneficial research opportunities. Geography students are granted data access and assistance on real world catchment problems and Loe Pool Forum benefit from insightful and useful reports. One recent research collaboration has been on the issue of land use and its relationship with downstream pollution and flooding risks.

Megan Angus, BSc Geography, conducted her dissertation on this issue in 2015. Megan has kindly written a summary of her research for this blog; and presented the final dissertation to Loe Pool Forum. You can read the full dissertation here: An investigation into managing land use and pollution upstream, to improve water quality and minimise flood risk in the Cober catchment, Cornwall.ation into managing land use and pollution upstream

My dissertation focussed on addressing the effects that land use in the upper Cober catchment has on water quality and flood risk downstream. The dissertation aimed to address these research objectives that follow;

  • To identify and map the areas of the upper Cober catchment that pose a ‘high risk’ to water quality and flood risk downstream.
  • Suggest appropriate measures to take in reducing the risk to water quality and flood risk.

    MA - FIG 1

    Figure 1.

Field observations were collected and combined with secondary data including water quality data an mapping files from reputable organisations (eg: Environment Agency, Natural England). This was used in ArcGIS to map the areas that present a high diffuse pollution risk to the rest of the catchment. To identify and map ‘high risk’ areas, field work observations were collected and combined with secondary data using ArcGIS. Spatial analysis tools were used to deduce the high risk area. Please see Fig 1, Fig 2 .

MA - FIG2

Figure 2.

Water quality and rainfall data was plotted against one another in order to establish which stream certain chemical elements and pollutants largely originated from. Knowing this allows appropriate management to be directed to the correct areas of the catchment. Graphical analysis suggested that copper and zinc originated from the Cober and aluminium slightly more so from Bodilly. All were recorded at a high concentration following rainfall, including nitrate and pH level.

MA - FIG3

Figure 3.

This research strongly recommends that land owners situated in the high risk area (Fig 1, 2) uptake schemes such as Catchment Sensitive Farming, Environmental Stewardship and New Environmental Land Management. For the areas that do not meet the criteria for such schemes, the study recommends that run-off attenuation features (bunds, ponds,  traps, leaky dams and physical wetlands) are introduced with particular focus on land falling into the mining risk area,  see Fig 3.

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