Connectivity Rules for Storm and Sanitary Models
While there are numerous node elements, there are only four link elements in the Bentley Storm and Sanitary Sewer models. These include
Not all node elements can be connected to all link types. For example, a pump cannot be expected to take suction from a gutter.
In the layout tool, in order to protect the user from building model that can't solve, the user is limited in the elements that can be selected as the next node type. The downstream nodes that are allowed for each link type are listed below:
Conduit
Pressure Pipe
- Pressure Junction
- Pump
- Variable Speed Pump Battery
- Air Valve
- Wet well
- Catch Basin
- Manhole
- Transition
- Outfall
Channel
Gutter
Lateral
In addition, even if the model allows a user to connect elements, their behavior may depend on the active solver. For example, while a pump can be hooked to a conduit, it will work in the implicit and explicit solvers but not in the GVF solvers which expect the pump to be connected to a Pressure Pipe. For another example, Air Valve and Variable Speed Pump Battery elements were created for Pressure Pipes in the GVF-convex solvers and require some considerations when used with the other solvers.
Polygon elements like catchments and pond outlets must be connected in special ways. Inflows to a pond are modeled as outfalls where the Boundary Condition Type for the outfall is a Boundary Element and the boundary element is the pond. Outflow from a pond is modeled as a Pond Outlet Structure. Ponds cannot be connected to one another pond.
Unlike ponds, catchments can be connected in series by making one catchment the Outflow element of an upstream catchment. Catchments can also have LID (low impact development) elements within them. The LID would then have the catchment as its Parent Catchment.
Outfall elements cannot be connected downstream to links but must either be the terminal node or associated with a pond. When using the explicit solver, only one conduit can be connected to an outfall. An outfall cannot be connected to other elements through a gutter.
Pumps can only have one link on the suction side and one on the discharge side. In the GVF-rational solver, there can only be a single pump element representing a station, with no pumps in parallel or in loops.