Towards a Stream Classification System for the Canadian Prairie Provinces

Abstract

Temporary streams on the Canadian Prairies have a dry streambed with some regularity. Attributes that capture these zero flows could be used to better compare temporary streams with perennial streams from the same area, and contribute to a broader stream classification. This case study of observed variability in flow rates of prairie streams is a step towards the goal of establishing a stream classification system that would be widely useful for practitioners who need to address prediction in ungauged basins in this region. Such a classification system could support inferences that need to be made for streams that are either not currently gauged or for which the period of record is either too short or too discontinuous to allow an understanding of the potential streamflow responses. An approach to streamflow classification that relies solely on hydrometric record may be of particular value for temporary streams that are common in the southern Canadian Prairie Provinces. Similarity of hydrometric station streamflow response within groups is illustrated using both common techniques such cumulative annual and daily mass curve analysis, and a novel streamflow metric, the ratio of the magnitude of the third quartile monthly flow totals to the maximum of the monthly total flow for the period of record is also examined. The purpose of this case study is to demonstrate that by applying conventional analytical techniques in innovative ways the practicing hydrologist can better infer the behavior of streams in areas that are either ungauged, have been gauged only for a short period of time, or are gauged intermittently. While a complete classification system for these streams would include physical, biological, and chemical properties in addition to those that can be determined from hydrometric records, the grouping of hydrologically similar sites is a first step. Such analysis also provides insight into anticipated stream response that will allow for improving design and operation of hydrometric networks. The analysis presented is restricted to data from the Canadian Reference Hydrologic Basin Network (RHBN).