Hi I am new to HEC-RAS, I apologise in advance for the daft questions I am about to ask!
My first model is from survey data in the *.csv format, the only other information I have is an OS map where the topography is represented on contour lines at 5m spacings. okay onto the daft questions:-
reach lengths
is this chainage? i.e. the horizontal distance between two river stations OR, is it the length of a 3D line joining two river stations?
cross sections
does a cross section have to be straight? my colleague tells me that if my cross sections bend that HEC_RAS will flatten the profile stretching the river. this cant be true can it. so many examples do not have straight cross sections.
I have cross sections crossing at a tight bend in the river. what’s the best practice in this situation?
when I add a point point to a cross section (station, elevation) how does hec-ras decide where the point goes in the x and y directions?
topography
does anyone know the best way to convert contour lines (polylines) into a format that hecras likes?
many many thanks (help)