1. Once we place any network at some location and design network. But if we would like to change location of the network , we are not able to modify the same. i.e. Northing and Easting of the Upstream and Downstream side of the channel section.
Correct, once you place a structure you cannot edit the Northing/Easting of that structure through the Edit/Review b. You can only move the structure using the Drainage > Structures > Move command. You can select the structure and use the NE= key-in to precisely set the position of the structure.
2. We are not able to assign different type/ size of section like Trapezoidal or Rectangular channel section within single network. For example if there is a need to provide a Trapezoidal channel section with base width 0.3m for starting 0.5 km , base width 0.5m for next 0.5 km and then after 0.5km rectangular section for total network length of 1.5 km.
You should be able to adjust the structure type. You can make this change in the Drainage Options while placing the structures or you should be able to select the Edit/Review of that structure and edit the channel to change the Channel Type. Are you not getting an option when you do an Edit/Review and you try to drop down the Channel Type to edit the structure?
3. We are not able to provide curvilinear drain in the network i.e. drainage centerline is parallel to out track alignment along the track curvature.
The only type of curved structure we can place is a Curved Pipe. We do not have an option to place a curved channel.
If the intent of the design is to produce a 3D representation of the structures, you can utilize the Roadway Designer, Corridor Modeling, or Apply Linear Template Drop (depending on the version of the software) in order to model the channels to scale in the plan. This doesn't design the network for flows or capacity but it will allow you to have a graphical design of the network from graphic which can be a curved alignment. But it will still place templates and stroke the design if placing templates. The best option may be to model using surface editing tools so you can create parallel features and sloped features from a source graphic.
4. We are not able to show different network in one L-section i.e. network1, network2, etc.
You can project multiple networks onto a profile if the profile is created from a source geometry. You have to perform the projection to all the networks individually because the From/To structures must be in the same network. If you are wanting to project the structures you create a profile utilizing the main source alignment and then use the Create Profile command to project the structures onto an existing profile. You can project any network onto the profile (one network at a time). If you are wanting to create a profile down the different network centerlines, you will either create multiple profiles or you can create a source alignment down the centerline of the networks to have a single source alignment. Then you can display/project the structures from multiple separated networks into the same profile.