Water Stewardship Information Sources
| Citation | Cheong, AL. 1998. Quantifying basin comparisons in the Queen Charlotte Islands. In: Hogan, D.L., P.J. Tschaplinski, and S. Chatwin (Editors). B.C. Min. For., Res. Br., Victoria, B.C. Land Manage. Handb. No. 41. |
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| Organization | FLNRO |
| URL | https://www.for.gov.bc.ca/hfd/pubs/docs/Lmh/Lmh41.htm |
| Abstract/Description or Keywords | Because of the subjectivity in previous methods of comparing drainage basins, there is a need to quantify such procedures. This study (Cheong 1992) attempted to formalize the analysis of similarity in an objective manner within the framework of a knowledge-based system. The 31 basin characteristics that were assessed can be categorized into four groups: landscape (e.g., geology); geometry (e.g., relief); topology (e.g., order); and history (e.g., mass wasting). A comprehensive similarity comparison procedure was developed to incorporate different levels of information (ordinal, interval and ratio) and standardization of mensuration. The three stages of the procedure are: 1. for ordinal information – binary test 2. for interval information – dijk = (wi (xij -xik)2/0.25*R) 3. for ratio information – dijk = (wi (xij -xik)2/σ) where dijk is the dissimilarity of variable i between basins j and k, wi is the weighting, x is the characteristics, and R and s are the range and the standard deviation of i, respectively. These similarity testing procedures were combined and developed into a knowledge-based system (Cheong 1992). The analysis was performed on 28 characteristics of 65 drainage basins from Rennell Sound and South Moresby Island. If only geometric and topologic parameters are used (interval and ratio data), basin similarity is not limited by proximity, and the most similar basin to a watershed in Rennell Sound may be on South Moresby. However, if certain landscape parameters are included in the analysis (such as geology or vegetation), this typically limits the scope of the analysis to a region in close proximity to the basin in question. The weighting of parameters in the analysis also affects the cluster structure and grouping of similar watersheds. The common assumption that the most similar basins are the ones in closest proximity is not always correct. Further work is required in determining the level of similarity needed to obtain two characteristically similar basins. While current research in common basin morphometric groupings in British Columbia suggests that the similarity test can be limited to approximately six characteristics, research on determining relevant characteristics at a smaller scale for the Queen Charlotte Islands needs to be expanded. |
| Information Type | abstract |
| Regional Watershed | Coast Region |
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| Project status | complete |
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