The site's initial condition and history, factors influencing the project's orientation
Cross-issues in the restoration of a heavily modified watercourse

The orientation of the project will necessarily depend first and foremost on its immediate environment and the various constraints that arise from it. The scenarios studied will not be the same, depending on whether the project is located in an agricultural zone or a highly urbanized area, whether the land is under control or not, whether there are conflicts of use, etc.

• The historic heart of Sarcelles, probably dating back to Gallo-Roman times, the "village" is today a rather residential area with a relatively fragile economic activity in the form of its shops. Traditionally, the town of Sarcelles grew up on the banks of the river, where the population and activities were concentrated. Traces of flooding by the Petit Rosne go back at least as far as 1926.