16.13 Thanet's groundwater is extremely vulnerable to contamination as substances (natural substances and man-made chemicals) are able to pass rapidly through the thin soils and the natural fissures (cracks) in the chalk rock to the groundwater below the ground surface.

16.14 Once the chalk and groundwater is contaminated at a site by a substance it can take decades to clean-up. The Council and the Environment Agency have worked hard to prevent contamination by consistently applying Groundwater Protection policies to any proposed land-use changes in Thanet to reduce potential future impact.

16.15 Under the Water Framework Directive (WFD), the 'Kent Isle of Thanet Groundwater Body' has been classified as poor status for the groundwater quality and quantity. The groundwater is impacted by nitrates, pesticides, solvents and hydrocarbons at levels that are of concern. Thanet's groundwater is currently a candidate Water Protection Zone (WPZ). These zones are used in areas identified as being at high risk as a 'last resort' when other mechanisms have failed or are unlikely to prevent failure of WFD objectives. WPZs are a new regulatory tool to address diffuse water pollution. They are designed to help enforce measures to prevent pollution and improve water quality where standards set out in the Water Framework Directive (WFD) are not being met. It is hoped that sufficient measures can be taken, by various organisations and individuals, that will help remediate the problems with Thanet's groundwater and avoid a WPZ designation.

16.16 The poor groundwater quality cannot be attributed to just one source. In Thanet there are considerable risks to the groundwater from both urban and rural activities. These risks are intensified by the compact nature of the district. Hazards to Thanet's groundwater include petrol stations, gas works, drainage from roads, leakage from sewers, pesticide storage, septic tanks, sheep dips, and farm buildings. Uses that can cause pollution to the groundwater include dry cleaners, mechanics, scrap metal, photo processing, and some sustainable drainage systems.

16.17 Some methods of Sustainable Drainage can cause detriment to the groundwater. However, well designed SuDs in suitable locations can improve the volume of groundwater available without affecting the quality. Therefore discharges to the ground must be carefully designed to ensure that they are appropriate and do not cause further degradation. SuDs must be designed so that pollutants are removed prior to discharge, and where possible, properly designed in order to improve the groundwater quantity. Discharges to the ground in sensitive areas should be approved by the Environment Agency.

Policy SE04 - Groundwater Protection

Proposals for development within the Groundwater Source Protection Zones identified on the Policies Map will only be permitted if there is no risk of contamination to groundwater sources. If a risk is identified, development will only be permitted if adequate mitigation measures can be implemented.

Proposals for Sustainable Drainage systems involving infiltration must be assessed and discussed with the Environment Agency to determine their suitability in terms of the impact of any drainage into the groundwater aquifer.