However, as benefits could not be estimated and monetised for all categories, the numbers provided were expressed as underestimates of the real benefits. The analysis showed that the estimated benefits are significantly less than the estimated costs, and that costs increase more than the benefits (van der Veeren, 2010). Source: Ministerie van Verkeer en Waterstaat, 2007, cited in van der Veeren, 2010). It also raised ethical and general liability considerations (in particular with regards to the responsibility of today’s citizens to keep an adequate state of the aquatic ecosystem for future generations) that justified the need for action even if costs were higher than (measured) benefits.