This page provides an interface for exploring the Melbourne Stream Network dataset. It allows you to find reaches of interest and to download their catchment boundaries as a GIS file (.gpkg) and all environmental attributes for those reaches from the tables subc_env and cat_env.
However, it only allows extraction of data one site at a time. If you have multiple sites for which you wish to extract environmental data for, you would be better to map the sites and use their coordinates to extract their environmental data in a single using the reach/site stats app.
See Appendix D of the stream manual for a tutorial on how to use the app.
You can find the mwstr version 1.1 app here. It is less accurate in parts of the region, but retained to allow access to old reach codes.