Bridges

Bridges can be modeled in scenarify by using two primary modeling methods: culverts and cut-outs.

When modeling a bridge with culverts, water can pass beneath the structure using a simplified hydraulic analysis of the culverts, while flow over the structure is simulated with the full 2D surface water model. The culvert flow computation follows the approach described in Discharge Computation.

Alternatively, bridges can be modeled using cut-outs, which involve creating openings in the terrain by burning in the culverts. This method offers a straightforward setup but removes the bridge deck and its obstructive effect on the flow. For a detailed comparison of these approaches, see Culverts vs Burn-Ins.

By using Bridge actions, a bridge is modeled with a culvert beneath it and a bridge deck that obstructs flow below while allowing overtopping flow across the deck. This approach also allows the terrain to be optionally burned in to guarantee smooth transitions at the culvert sides. Furthermore, the bridge deck is represented even when the bridge is already burned into the existing DTM.

Bridge piers can be included in the terrain or through wall actions to further improve the accuracy of the results.