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Assessment of the natural State of the flow regime

The flow regime: the driving force of water dynamics

In addition to water quality and the spatial and structural conditions of waters, the rate of flow is the third decisive influencing factor for the ecological state of watercourses. Human uses not only affect the flow rate, but also the time distribution over the day and the year. Furthermore, they can lead to changes in the sediment regime and affect water temperatures.

Purpose and content of the Hydrology-Flow Regime module

The Hydrology - Flow Regime module for the so-called spatial step R (regional scale), HYDMOD-R for short, within the Modular Stepwise Procedure is the method for describing the hydrological conditions of a region by identifying water resources management measures and assessing their effects on the flow regime. It results in a statement on the hydrological state of the river system of a watershed, with the individual river reaches as reference for classification. It assesses and classifies the natural state of the flow regime using nine assessment indicators, covering various characteristics from the areas of the low flow, medium flow and high flow regime. The anthropogenic measures responsible for changes in the flow regime largely derive from hydropower utilization and urban water resources management. In order to inventory the water related measures, HYDMOD-R provides a typology for such measures along with significance criteria. The assessment is carried out using the nine assessment indicators initially at the sites with human measures. Subsequently these classifications at the individual sites are used to assess and classify the river reaches. 

The HYDMOD-R package

The use of HYDMOD-R requires a number of hydrological parameters. In many cases however it can be assumed that the data available are scarce. For this reason, a series of hydrological fundamentals and estimation procedures have been elaborated parallel to the method development. Finally a computer program was also developed aiming to facilitate the application for the user. HYDMOD-R can therefore be regarded as a package. It focuses on the actual assessment method. In addition various estimating procedures are provided. Finally the package is complemented by the electronic tool (HYDMOD-FIT) made available for IT-supported application, standardisation and facilitation for the user. In addition, GIS support-files for the cartographic representation of the assessment results are provided.

Grafik E

The “package” module hydrology – flow regime (HYDMOD-R)



Wasserentnahme an der Linth

Water abstraction on the Linth River

Modul Hydrologie - Abflussregime
Module Hydrologie – régime d’écoulement
  • Description de la méthode niveau R [6.5 MB]
An English summary of the HYDMOD-R methodology
  • Draft status 2005 (presented for the Headwater 2005 conference). HYDMOD-F methodology in English [0.6 MB]