Identification of hydromorphological reference sites using the new REFCON method, with an application to rivers in the Czech Republic

Abstract

This paper presents a new approach to establishing reference sites and determining hydromorphological characteristics for establishing type-specific hydromorphological reference conditions for rivers in the Czech Republic – the REFCON method – as well as its application. This method is based on hydromorphological river types. Using available maps and field surveys, it determines potential reference sites for establishing reference conditions, and subsequently, on the basis of an assessment of anthropogenic impacts using set criteria, it identifies stream reference sites. Reference sites and river types are validated using field survey data. This method also identifies characteristics of channel pattern, flow, riverbed structures, sediment, and variability of cross-sectional profiles used for establishing type-specific hydromorphological reference conditions.Reference conditions can be expressed using threshold values of individual characteristics (e.g., channel slope, entrenchment ratio, specific stream power); they can also be described qualitatively, that is, verbally (e.g., channel pattern, valley type). Nonetheless, reference conditions are always an expression of a set of characteristics or conditions that should be valid for a given river type.One of the expected results of applying this method is the creation of a reference site database for assessing hydromorphological status of streams. This database will serve for proposing stream restoration measures and also as a database of stream sections in need of protection from potential human impact.