This is an example of problems that can arise when Underwater Cultural Heritage is not being considered (enough) in big construction projects on the seabed. Fortunately the notion to protect UCH worldwide is growing among planners, politicians and the general public, however, unfortunately not at this project. Turkey has signed the Valletta treaty of 1991 in which is stated that preservation of archaeological remains in situ is the best option. If preservation in situ is not possible excavation is the next option. When considered in advance this will be for the benefit of UCH as well as for the constructor.
The Marmaray example illustrates the significance of a database were data about Underwater Cultural Heritage is being collected (the known resource), and information is available were important UCH can be expected (the unknown resource). So that it can be a useful tool in the decision making process. The MACHU project is aiming at just that. MACHU is developing a GIS and database of shipwrecks and other archaeological sites on the seabed. It can especially serve as a tool for policymakers and planners as a decision-support system to know in advance if and what one can expect on the seabed in respect of Cultural Heritage.
Underwater Cultural Heritage can be – just like sites on land - managed in a pro-active way. Much of the resources are not situated in certain areas by accident. Their presence can be predicted on the bases of e.g. geological, archaeological and historical data.
The delay and problems that were caused by the finds of archaeological remains during the Marmaray project are a good example of the necessity of an (international) operating database and GIS that can act as a warning and decision system for policy makers and planners.