You can read more about what GHydraulics is on epanet.de/ghydraulics/. Basically, it; - a free tool for water network design (works with EPANET) - a solution for the integration of EPANET and GIS. - supports / works on open-source and freely available GIS software package - Quantum GIS. With considering almost all popular scientific / technical software and tools are not free today, GHydraulics is a promising alternative for free software development... Thank you Steffen Macke for your efforts for the development and long-term support for GHydraulics.