4. Dewatering and other activities that could alter groundwater flow or quality must be avoided within SPZs unless a detailed hydrogeological risk assessment demonstrates no adverse impact.

Within Stockport, there are two groundwater source protection zones (SPZs) as identified by the Environment Agency54. Groundwater source protection zones are split into classification of zones, 1, 2 and 3, with zone 1 being the most sensitive. Groundwater provides a third of the drinking water in England, and it is crucial that these sources are protected to ensure that water is completely safe to drink, if groundwater becomes polluted it can be very expensive and extremely difficult or impossible to clean.

Whilst development in source protection zones is not precluded, the council will seek to ensure that any new development is in line with the Environment Agency's guidance and delivers high-specification drainage solutions. It is recognised that the costs of these solutions may contribute towards development costs, but these should be factored into any development appraisal when valuing land prior to purchase for development.

Development involving the excavation of land or the extraction of materials from the ground will be permitted where it is demonstrated that the stability of surrounding land (and buildings or structures upon it) is not compromised and where relevant policies of the Greater Manchester Joint Minerals Development Plan Document (or any superseding document) are met.

Where development is proposed on brownfield land, it should be presumed that land contamination may be present, and a risk assessment must therefore be undertaken to ensure the site is suitable for its intended use.

Development proposals must assess and address risks from all forms of ground contamination, including those arising from historic industrial use, landfill, and other sources. Where development is proposed on land that may be affected by contamination, a site-specific risk assessment must be undertaken in accordance with Environment Agency guidance and relevant British Standards.

Proposals on land which is known to be unstable or contaminated, or where there is a reasonable likelihood of instability or contamination, will only be permitted where a land contamination/stability report demonstrates that such