model a gutter as a v ditch.

The program says the Irregular gutter is not valid for the GVF-Ration solver. 

The goal of my scenario is to find the spread of a valley gutter/channel between two lanes. 

Hello Brian,

Can you provide a photo or illustration to clarify what you are trying to model here?

Hello Brian,

Can you provide a photo or illustration to clarify what you are trying to model here?

Here are a couple figures and my model.

 IH 90 drainage.zipPDF

Thanks for the information. In the model you provided, you have the catchbasin nodes (where the inlet is located) set to use a grate inlet with a v-shaped gutter, and the gutter links between them are also set to use a v-shape.

The setup of the v-shaped gutter appears to match your sketch showing 10% gutter slopes and 2% road slopes, on each side. However, HEC-22 seems to define the v-shape gutter as having a curb and gutter slope (which would both be your 10% sides), and one road slope on one side - see the help topic "V-shaped gutter cross section" -

where:
Sx1 = Curb side slope
Sx2 = Gutter cross slope
Sx3 = Road cross slope

So, if your ditch has a road on each side (2%) and you anticipate the depth in the gutter rising high enough to extend into the road, you may need to compensate by adjusting the road cross slope value, given the above diagram. (so that the spread / top width of flow is correct) 

Also, since your grates have a flat bottom, consider changing the catchbasin (inlet) gutter definition to the Ditch type, and the inlet type to the "ditch" as well (you currently have it set as a grate). This assumes a flat-bottomed cross section (because of the flat bottom of the grate) with slopes extending on each side. This may be more appropriate, because the spread and depth reported at the catchbasin element represent the depth and spread just on the upstream side of the inlet location itself, where the spread tends to be at its highest (before some flow is captured), and where the cross sectional view has a flat bottom due to grate inlet.

See: Modeling a Drainage Ditch

However, the ditch inlet type only assumes a single right side slope and single left side slope. So, you might want to approximate the single side slope, or assume the v-notch shape that you were previously assuming (which might be OK if the ditch has a v-shape just upstream of the grate location), but with the above note about the three slope assumptions in mind.

When I tried to model the inlet as a ditch inlet with a 3x3 grate then a trapezoid ditch with a 0.5' bottom I get a message saying inlet opening width cannot be larger than ditch bottom width. Do I use the Trapezoid gutter as inlet properties and the V shaped gutter as gutter properties? Or would I use a trapezoid gutter type with the small bottom? Is the inlet spread the spread on both sides of a line extending upwards at 10:1

IH 90 Temp Widening Ditch Inlet Concept.stswpkg.zip

Hello Brian,

I didn't see the user notification that you mentioned. However, it does appear that none of the catchments are attached to an outfall. Some adjustment to the connection of the system may be needed to assure that the results are accurate. For instance, you may want to connect all of the catch basins with a link (such as a conduit or gutter) and have an outfall at the end of the system.

Also, are there supposed to be conduits to convey subsurface flow?

Otherwise, it might be useful to get a screenshot of the user notification you are seeing.

Regards,

Scott