Geometric Networks are generated in ArcCatalog by doing:

right click on the Feature Dataset containing your Network features > New > Geometric Network

Build your HydroNetwork using the HydroEdge and HydroJunction features. HydroEdge should have Complex Edges and HydroJunction can be created with the snapping option using a snapping tolerance of 1 or so.

5.1-Add IsOnNetwork Field to HydroJunction

Check for disconnections using the IsOnNetwork tool from the WAM toolbar

0 = Not attached to Network

1 = Attatched to Network

Locate, check, and correct disconnected Junctions by doing:

Option #1:

Using the "Find Disconnected" Tracing Task option from the Network Tool bar in ArcMap

Option #2:

Using the IsOnNetwork tool populate a Field (call it IsOnNetwork)

Check features with IsOnNetwork = 0 (Off = 0, Most likely they are not connected due to spatially coincident features!)

5.2-Rebuild HydroNetwork and repeat the process until there is no IsOnNetwork=0 in HydroJunction

5.3-Check MonitoringPoints have the right JunctionID by Joining MonitoringPoint with HydroJunction (using GageID as common field) and copying HydroJunction.HydroID into MonitoringPoint.JunctionID

Go onto next phase