PPS 6 Planning Archaeology and the Built Heritage·Page 19·3.15
Design Mitigation Measures
Mitigation may involve design alterations such as modified foundations to avoid disturbing remains, careful siting of landscaped areas, or sealing archaeological remains under buildings or landscaping to preserve them in situ.
Mitigation may require design alterations to development schemes, for example, the use of foundations which avoid disturbing the remains altogether or minimise the potential damage, or by the careful siting of landscaped or open space areas. There are techniques available for sealing archaeological remains underneath buildings or landscaping, thus securing their preservation for the future even though they remain inaccessible for the time being.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/PPS 6 - Planning Archaeology and the Built Heritage.pdf