Clearly, the presence of unstable ground can have a profound effect on the development of an area such as Ripon. The city now has a planning zonation to take account of the gypsum subsidence problems.
Ripon planning areas
In the main subsidence-prone area, new developments require substantial site investigation to avoid the worst areas. They also need reinforced foundation designs to prevent their sudden failure and collapse. In this belt, the new Ripon bypass has a special plastic reinforcing net within its embankments, while the new Ure Bridge is designed to withstand the sudden loss of one upright support.
The reinforced bridge at Ripon designed to withstand subsidence and the loss of any one support without failing, the road leading up to it is also protected by layers of geogrid material in the embankments. NERC copyright, photographer A.H.Cooper.
The use of sacrificial piers and extended foundations in bridge construction to protect against subsidence failure.
Although the planning process has adapted to the subsidence problem, the insurance business has not. There is a need for comprehensive subsidence insurance cover for the people of the area. Currently, insurance covers the property, not the land and any liability laid against it. The risk to any individual building is fairly small, but the lack of insurance cover for these problems is devastating to those affected. In some states of the USA subsidence insurance is compulsory, here it is largely unavailable.