PDM Descriptor objects can be specified as part of the Subcatchment data and are used to define the rainfall-runoff model parameters when using a runoff surface with runoff volume type of PDM.
A particular PDM descriptor is associated with a subcatchment by selecting the PDM descriptor ID in the PDM Descriptor field of the Subcatchments Grid or in the Surface parameters section of the Subcatchment property sheet. A PDM descriptor can be associated with more than one subcatchment.
For information on PDM, see the Probability Distributed Model (PDM) topic.