Sand cunets include the sand packs under roads and around infrastructure such as sewers and pipes. These cunettes often have a draining effect on the environment causing the groundwater level to drop locally.
By constructing sheet piling or clay dams, drainage of groundwater through sand cofferdams can be prevented and the influence of the cofferdam on the adjacent area can be reduced. Underground constructions influence the groundwater flow and result in localized raising or lowering of the groundwater level. The effects of this in times of low groundwater levels and in times of flooding must be carefully considered in every situation.
Relevant laws and regulations are the WRO/Building Plan. Depending on whether it is public or private land, the municipality or the plot owner is responsible for construction, management and maintenance.