How to open SQD or GMB files?

I have GIS Data in .sqd or alternatively .gmb format. How can they be imported in EPANET (eventually using the Matlab Toolkit if necessary)?

I don’t know those formats, but if you can somehow open that in qgis there are several epanet related plugins that can transform shapefiles to .inp files. You just have to look for the word “epanet” in the plugin search engine, I don’t recommend any one in particular because I don’t know exactly how the format in which you have the information is.