XS with LIDs connected to Storage Area

[p_veni]

I have a scenario where the flow from the storm sewer (modeled as LIDDED xs’s in the RAS model) needs to be routed to offline storage area and the flow should be contained in the basin. I used the culvert option within the lateral structure to connect it. But for some reason the basin’s lateral structure is recording xxx cfs of lateral weir overflow into the basin. I tried to increase the weir elevation to avoid overflow from the weir but that did not help. How can I establish an appropriate LID/1D storage area connection. Appreciate any inputs. Thanks

[Anonymous]

As a test, set the outflow to “out of system” then check if flow still goes over the weir.

[p_veni]

I changed it to out of the system. Yes, flow is still going over the weir.

[Anonymous]

If all of the flow is going into the storage area, you can directly connect the end of the reach, that has the lidded cross sections, directly to the storage area and avoid using the lateral structure.

If you have flow over the lateral structure when you shouldn’t, it sounds like the weir elevation of the lateral structure needs to be increased. The weir elevation needs to be above the energy grade line or else you can get flow. Even if you select water surface on the lateral structure, it still needs to be above the hydraulic grade line if you don’t want flow over it.

[Author]

Posts