Yes^^ I recommend using dummy 2D inline structures if you are looking for the best results. Just do a weir with a height of 0.01-ft above the terrain. Make sure you either use the 2D equation or drop the weir coefficient to 0.2 or lower if you expect complete submergence
Im aware of that 1D method, however you are not dealing with a 1D complete model. You have a 1D2D model that you are looking to remove the 2D area and combine reaches. There is no easy or quick way to do this.
I have gotten this a couple times and its SO annoying and I still don’t know the actual cause. You can try deleting the .hdf geo file and try re running. The only other option I completed was continue deleting bridges until the error no longer exists then re adding them one by one and re running after each
Its your computational interval of 1 hour. Reference your cell size to come up with a more appropriate computation interval and that will increase your run time. This is based on the courant criteria
Theres no real easy way to do this other than extend all the reaches and create a 1D junction and additional cross sections. Then make sure to update the flow distribution.