Flow through culverts

[Ecobabe]

Hi there,

I am trying to model the connection of an old drainage channel to the bank of a main river by using a culvert, under steady state. I have looked at using a lateral structure but this was proving difficult and no water was going through the drainage channel. A normal culvert was working fine however after changing the culvert elevation, it seems now, that by me initially putting in a junction, HEC assumes that water flow is just simply seperated into the flow rates I am entering. It is not taking into accont the culvert as the connection.

Is the there any way of doing this so that I can define the water flow through the culvert that will be sitting above the bed level of the main channel so that the water surface elevation changes through the culvert when the flow changes?

Look forward to hearing your ideas.

Thanks

[Paul M]

i am a bit confused. are you looking to model flow from the main channel flowing back upstream through the culvert? if so, i think you need to model as a lateral structure. if you are modeling flow in the positive flow direction down the channel, thru the culvert and into the river, you need at least 2 (maybe 3?) cross-sections downstream of the culvert BEFORE the junction to the mainchannel. if the culvert is submerged by the main channel, you made need to use a little imagination to create these cross-sections. if i have a correct picture of what you are doing, for these cross-sections, no matter what their shape, the model will flood them out anyway. i would just look at the results and see if they make sense. good luck.