Evaluation of Catchments’ Similarity by Penalization in the Context of Engineering Tasks—A Case Study of Four Slovakian Catchments

The present study deals with the similarity of catchments, which is a preliminary investigation before performing various water resource analyses and computations regarding other catchments, e.g., catchments’ similarity may be utilized in the context of analogous calculations of river flows in catchments without measured flows. In this paper, the penalization method of evaluating similarity is proposed; this method is appropriate for tasks in which fewer catchments are analyzed for engineering purposes. In addition to the various physical characteristics of the catchment, the “catchment’s calibrability” property is also formulated and evaluated. A methodology that used specific flows from catchments in a case study from Slovakia successfully verified the proposed penalization method. This verification confirmed that physical similarity, as evaluated using the proposed penalization methodology, also helps to identify hydrological similarity, i.e., finding the most similar catchment to a given catchment in terms of the rainfall-runoff process. Such a finding can be helpful, e.g., in the computation of the mentioned flows in ungauged catchments. Determining unmeasured flows can help to solve many engineering tasks, such as various technical calculations during the design of small reservoirs, defining the potential of a given stream for supplying irrigation, flood protection, etc.