IWM is consequently designed for management of hydrological based catchment areas. The management of the resources human, biomass, soil, water and energy requires close cooperation with local, regional and national authorities. Due to the fact that these authorities are usually scattered by political boundaries (national or international) the IWM approach is facing the challenge that two or more local or regional authorities governs parts of one catchment area. Trans-boundary water management is a widespread topic, but usually discussed for international water management options, such as occurring at the Nile River or Amu Darya. However, also on sub-catchment level political structures need to be considered.
Trans-boundary water management needs effectively be addresses for surface and for groundwater management.