River types NRW and LAWA

Streams and rivers in North Rhine-Westphalia are divided into river types, which are defined by the geological conditions in the subsoil, the altitude, the gradient, the settlement and by physico-chemical measured values. This classification is part of the technical basis for the planning of measures for the near-natural development of rivers, the assessment of the ecological status, the delimitation of water bodies and the implementation of the objectives under the EC Water Framework Directive. The type assignment has essentially been based on cartographic data, which are largely unchangeable by humans. Current research results were used as support. Geologie (Digitale Geologische Karte NRW 1:100.000) Naturraum (Karten der Fließgewässerlandschaften „BRD“ und „NRW“ und naturräumliche Gliederung NRW) Einzugsgebietsgröße (Digitale Gewässerstationierungskarte NRW 1:25.000) Gefälle (Digitales Geländemodell NRW) Boden (Digitale Bodenkarte NRW) Physiko-chemische Messwerte (für die Abgrenzung von silikatischen und karbonatischen Gewässertypen des Mittelgebirges) Biologische Daten (z. B. zur Ermittlung der Verbreitung von Gammarus fossarum (Bach flea crab) as an indicator taxon for the delimitation of low mountain ranges and lowlands) The task of river typology is to classify the natural diversity of rivers according to common morphological, physico-chemical, hydrological and biocenotic characteristics. There are two type cards in North Rhine-Westphalia: the NRW and LAWA type card. The "grosser" LAWA types apply in particular to rivers with a catchment area of more than 10 km2, the status of which must be regularly reported in the course of the implementation of the European Water Framework Directive. The objective of the NRW type map is the small-scale representation of the finely differentiated NRW types. They serve as a guide for the ecological improvement and natural development of the rivers. The first river type atlas was published in 2002 as LUA leaflet No. 36. The experience and findings gained with the application of the River Type Atlas have been incorporated into the revised River Type Atlas published in 2015 as LANUV Worksheet 25.