Troubleshooting

This section provides guidance on common issues and troubleshooting tips when computing AFDR.

HEC-FIA Model Linking in HEC-RTS

To successfully link the necessary inputs for the HEC-FIA model within HEC-RTS, the associated HEC-RAS simulations must be computed first within the base watershed. This step generates the required HEC-RAS outputs—either gridded or HDF files depending on your simulation type—which are essential for HEC-RTS to recognize and connect the HEC-RAS outputs as inputs for the HEC-FIA simulation.

Instabilities with Unregulated HEC-RAS Conditions

When modeling unregulated flow conditions in watersheds with tandem reservoirs and disconnected reaches, you may encounter issues if using boundary conditions such as normal depth or a pre-project rating curve. These setups often cause instabilities and prevent the model from running. This is typically due to the fact that the real-time model was built under the assumption that pool elevations remain near or above the Conservation or Seasonal Pool. These assumptions may not hold true when simulating unregulated conditions, especially if updated bathymetry reveals more variable channel geometry.

If instabilities occur:

• Try replacing the problematic boundary condition with a constant pool elevation.
• Start the simulation at a reasonable elevation—either at the top of the inactive pool or within the conservation pool range.

This adjustment often helps stabilize the model and allows it to run successfully under unregulated conditions.