Slovenia is a highly affluent country. This is showed on some parts, as problem with occasional flooding on extreme events. On the second hand, a human was changing floodplains for his own dedicated use and that is how the place for a spillover events was took away from rivers. In years during 2007 and 2010, events like these took place on major part of a country. That also initiated aspirations for regulation of flood security and protections of citizens and property. I tried to introduce appropriateness of sustainable arranging on such areas in a thesis. Firstly, I tried to present myself all of it together with laws, that are valid on this field. I analysed hereinafter, what sustainable arranging and ecoremediations are and what does it mean for water retention on a certain area and tried to show how this influences on height of flood peak time at such extreme events. I also tried to develop idea, how to enrich certain area with such encroachment and how we can use it in other purposes, like recreation, tourism and educational intention. All together was than checked with a program Hec Ras, with 2D modeling, in a chosen section of flood river Vipava.