HydPy-Exch

The HydPy-Exch model family enables instances of other model types to exchange data more flexibly.

Usually, model instances eventually receive inflow and pass outflow to other models without knowing anything about them. One exception is the highly specialised application model dam_v004, which calculates its discharge to a dam_v005 instance based on some knowledge of the other model’s internal state. One purpose of HydPy-Exch is to facilitate similar exchanges between different model instances more modularly. Application model exch_weir_hbv96, for example, simulates a weir. Conceptionally, it enables a bidirectional water exchange between two lakes, where the flow direction depends on the difference of the lakes’ water levels. Technically, we can combine exch_weir_hbv96 with all model types, calculating (something like) water level information and accepting an additional inlet that can supply positive and negative values. Due to this flexible approach, we do not need to implement the weir formula to different dam models. On the downside, this looser coupling often comes with some limitations. One example is numerical accuracy, which might be suboptimal due to solving the interconnected differential equations of different model instances sequentially (we might improve this later).

Besides such explanation requiring models, HydPy-Exch also provides straightforward models like exch_branch_hbv96, which distributes its inflow to multiple locations.

Available models:

• exch » HydPy-Exch (base model)
• exch_branch_hbv96 » HydPy-Exch-Branch-HBV96 (branch model adopted from IHMS-HBV96)
• exch_weir_hbv96 » HydPy-Exch-Weir-HBV96 (weir model adopted from IHMS-HBV96)
• exch_waterlevel » HydPy-Exch-WL (submodel for querying the water level from a remote node)