You can specify whether a storage will operate as a weir by right-clicking Storage and choosing Convert to Weir. Notice the icon change and enabling of Upstream Reach (Figure 10). The upstream reach represents the storage relationship in the stretch of river that the weir inundates. You can define the storage in the same manner as a link, which may be important for constituent modelling. If you do not want to configure storage routing through a weir, you can define the upstream storage relationship as 0. Refer to Links for configuring groundwater, loss/gain etc.
The weir-related data entered for the storage node refers to the volume of the upstream reach that is inundated for a given operating level of the weir. The outlet relationships of the weir allow you to define a default outlet, which represents the main downstream flow path from the weir. For a re-regulating weir, this should be a Gated Spillway. Ensure that you incorporate the rating curve further downstream of the default outlet to constrain the maximum outlet capacity of the Gated Spillway.
Figure 1. Weir
Figure 2. Weir, Upstream reach
