Strategy Sought for HEC-RAS X-Sections

[chicopee]

X-section cuts thru a river and its banks, floodplain and one of its tributaries and adjacent banks.(High waters will occupy floodplain and the tributary)

1)Is it appropriate to use the cross section profile to analyze separately the river and the tributary as long as respective ineffective flow area limits are established ?

Note, I received a warning message about restricted channel when I established the ineffective flow area limits in order to evaluate river flow conditions.

2) Using the same X-section cut of item 1) to analyze the tributary, the orientation of that cross section was totally different than the one for the river which tells me that the reference point is the tributary RS point. Is that correct and must I develop a new cut?

3) A separate X-Section was developed for that same river and its bifurcated branch. Is it best to neglect that bifurcated branch channel which during low water conditions may carry 5% to 10% of the flow. High water levels will overwhelm the bifurcated branch.

Again restricted channel message appeared when establishing ineffective flow area in order to analyze the main channel.