Dynamically Setting the Pit Losses using Hare Equation. Needs Pit Inflow Capacity

[RudyFrom3]

I have raised this in PySWMM ... but probably is best placed here ?

pyswmm/pyswmm#134

This as mentioned also requires a cleaner method to determine the flow into a pit inlet?
As suggested a rating curve, or Weir/Orifice Combination equation would suffice ??

[RudyFrom3]

Given a Depth of Flow from either a 1D link or an external 2D model, either a Rating Curve, or possibly better,.... code including the weir/orifice and submerged weir would identify the flow into a pit (node) {or storage} from which pit losses coefficients can be determined using the connected links and link flows as per the method described in pyswmm/pyswmm#134 This will provide many benefits to SWMM including a far more efficient way to model inlet capacity at inlet pits and a robust method to get dynamically allocated Pit Loss coefficients assigned.

[lrntct]

It seems to me that there are to different things here:
1 - calculating the flow from/two a surface model
2 - calculating the pit loss due to the node inflow

I'll open an issue for the first one.

[RudyFrom3]

In resolving #124 related to the Pit Top object being created,

1. above is now somewhat resolved. As explained in Calculate the flow from/to a surface model #111 the need to confirm the Pit Inlet Flow against the Pipe Capacity (Given that there maybe one or more upstream pipes at a node now requires thought about the energy loss in the pit and the down stream pipe capacity to accept ALL of the flow, from the combination of upstream pipes and the Pit Inflow. If the capacity is such that not all the Pit Inflow is able to be accepted, then the Pit Inflow has to be adjusted down, and this adjusted value is used to abstract the volume from the 2D domain. This is very important to both the 1D & 2D models to maintain accurate volumetric accounting. We can not have a situation were water is artificially lost or gained for example. The losses in the pit, are usually determined by a single FIXED value of energy loss coefficient. However dynamic methods are available such as those described by Clive Hare, as raised in Dynamically Calculated Pit Energy Loss Coefficients pyswmm#134 . There is value in considering that approach.