The Netherlands is situated in a Delta area, in which water management is a very important issue. Water management is necessary to keep the rivers under control, provide fresh water and to protect against flooding. For water management and navigation hundreds of hydraulic structures are built, such as storm surge barriers, ship locks, sluices and pumping stations. They are an integral part of the water network. Most of the hydraulic structures have a projected life time of about 100 years. After this period substitution due to aging becomes necessary. The hydraulic structures in the Netherlands are aging, so the need for a substitution strategy is growing. Objectives of a very long term (100 years) substitution strategy are to provide a higher quality network, at lower costs for building and maintenance and to be prepared for future developments. Future developments include climate change, demographic and economic developments and changes in de functions of the water system. This paper discusses the potential benefits of an integrated proactive substitution strategy. Several explorations are carried out to get support for the development of a proper strategy for the whole asset. These are dealing from inventories of the condition of the present asset, learning from others and case studies to a PhD project on ‘Very Long Term Development of the Dutch Inland Waterway System’ to provide a sound knowledge base for the desired substitution strategy. The explorations mentioned above are still in progress. No final results are available yet. But the interests are high, since the total asset value is estimated at 15 billion Euros (price level 2002), which is a lot of money for a small country.@en