SSA and Trench Drains

[acadzn]

In using SSA 2011, would I be correct to assume that there is no way to model a sloping trench drain with varying depth and analyze its impact on an existing (previously modeled) storm system? I modeled my system and when I went to add the drains I went the route of attempting to assign a subbasin to a rectangular conveyance link, subbasins cannot be applied to conveyance links. I looked at trying the caltrans grated line but it seems that structures like this only have one invert and no variable depth option.

How would I go about modeling the trench drain?

Thanks,

Matt

[jmiller0621]

Sub-basins are not applied to links, but to the junctions (with their inverts) at each end.

You could input the trench drain cross section as an Open Channel-User Defined.

[Matt.Anderson]

The CalTrans Slotted Drain only functions as a Surface Inlet.  It is capable of determining the gutter spread and inlet efficiencies as well as peak flow bypassing the inlet. 

[jsnyderT7SHV]

I have a trench drain transversing a 30' wide driveway.  Cross slopes are 3.5% longitudinal slope is 2%.  I have defined my grate/inlet having a width of 30', length of 1'.  If I keep my gutter width the program standard of 2', program is telling me that I have bypass flow for a known flow entered of 0.80 cfs. because the spread flow is 3.5'  It appears as if the program ignores the grate width outside of the gutter width.   Because if I replace the 2' gutter width with 5', it produces the same spread, same height but takes the additional grate capture into case and has 0 bypass.  Is this correct?