The bottom is full of underground cables and pipes for gas, water, electricity and telephone, which are not always properly mapped. It is therefore common for these to be damaged during excavation work, which not only causes a lot of social nuisance, but also entails a lot of costs, can cause environmental damage and can also be dangerous. Since the introduction of the WION, it has been mandatory in the Netherlands to report earthworks to the Land Registry, stating where and how deep will be dug. All cable and pipeline managers must have mapped their pipeline network and be able to provide it if Kadaster so requests. The excavator is obliged to check these drawings by means of digging trial trenches; a time-consuming and expensive job!